[PATCH v5 0/7] Add Nuvoton NCT6694 MFD drivers

[PATCH v5 0/7] Add Nuvoton NCT6694 MFD drivers

[Ming Yu]

This patch series introduces support for Nuvoton NCT6694, a peripheral
expander based on USB interface. It models the chip as an MFD driver
(1/7), GPIO driver(2/7), I2C Adapter driver(3/7), CANfd driver(4/7),
WDT driver(5/7), HWMON driver(6/7), and RTC driver(7/7).

The MFD driver implements USB device functionality to issue
custom-define USB bulk pipe packets for NCT6694. Each child device can
use the USB functions nct6694_read_msg() and nct6694_write_msg() to issue
a command. They can also request interrupt that will be called when the
USB device receives its interrupt pipe.

The following introduces the custom-define USB transactions:
	nct6694_read_msg - Send bulk-out pipe to write request packet
			   Receive bulk-in pipe to read response packet
			   Receive bulk-in pipe to read data packet

	nct6694_write_msg - Send bulk-out pipe to write request packet
			    Send bulk-out pipe to write data packet
			    Receive bulk-in pipe to read response packet
			    Receive bulk-in pipe to read data packet

Changes since version 4:
- Modify arguments in read/write function to a pointer to cmd_header
- Modify all callers that call the read/write function
- Move the nct6694_canfd.c to drivers/net/can/usb/
- Fix the missing rx offload function in nct6694_canfd.c
- Fix warngings in nct6694-hwmon.c

Changes since version 3:
- Modify array buffer to structure for each drivers
- Fix defines and comments for each drivers
- Add header <linux/bits.h> and use BIT macro in nct6694.c and
  gpio-nct6694.c
- Modify mutex_init() to devm_mutex_init()
- Add rx-offload helper in nct6694_canfd.c
- Drop watchdog_init_timeout() in nct6694_wdt.c
- Modify the division method to DIV_ROUND_CLOSEST() in nct6694-hwmon.c
- Drop private mutex and use rtc core lock in rtc-nct6694.c
- Modify device_set_wakeup_capable() to device_init_wakeup() in
  rtc-nct6694.c

Changes since version 2:
- Add MODULE_ALIAS() for each child driver
- Modify gpio line names be a local variable in gpio-nct6694.c
- Drop unnecessary platform_get_drvdata() in gpio-nct6694.c
- Rename each command in nct6694_canfd.c
- Modify each function name consistently in nct6694_canfd.c
- Modify the pretimeout validation procedure in nct6694_wdt.c
- Fix warnings in nct6694-hwmon.c

Changes since version 1:
- Implement IRQ domain to handle IRQ demux in nct6694.c
- Modify USB_DEVICE to USB_DEVICE_AND_INTERFACE_INFO API in nct6694.c
- Add each driver's command structure
- Fix USB functions in nct6694.c
- Fix platform driver registration in each child driver
- Sort each driver's header files alphabetically
- Drop unnecessary header in gpio-nct6694.c
- Add gpio line names in gpio-nct6694.c
- Fix errors and warnings in nct6694_canfd.c
- Fix TX-flow control in nct6694_canfd.c
- Fix warnings in nct6694_wdt.c
- Drop unnecessary logs in nct6694_wdt.c
- Modify start() function to setup device in nct6694_wdt.c
- Add voltage sensors functionality in nct6694-hwmon.c
- Add temperature sensors functionality in nct6694-hwmon.c
- Fix overwrite error return values in nct6694-hwmon.c
- Add write value limitation for each write() function in nct6694-hwmon.c
- Drop unnecessary logs in rtc-nct6694.c
- Fix overwrite error return values in rtc-nct6694.c
- Modify to use dev_err_probe API in rtc-nct6694.c


Ming Yu (7):
  mfd: Add core driver for Nuvoton NCT6694
  gpio: Add Nuvoton NCT6694 GPIO support
  i2c: Add Nuvoton NCT6694 I2C support
  can: Add Nuvoton NCT6694 CAN support
  watchdog: Add Nuvoton NCT6694 WDT support
  hwmon: Add Nuvoton NCT6694 HWMON support
  rtc: Add Nuvoton NCT6694 RTC support

 MAINTAINERS                         |  13 +
 drivers/gpio/Kconfig                |  12 +
 drivers/gpio/Makefile               |   1 +
 drivers/gpio/gpio-nct6694.c         | 458 ++++++++++++++
 drivers/hwmon/Kconfig               |  10 +
 drivers/hwmon/Makefile              |   1 +
 drivers/hwmon/nct6694-hwmon.c       | 947 ++++++++++++++++++++++++++++
 drivers/i2c/busses/Kconfig          |  10 +
 drivers/i2c/busses/Makefile         |   1 +
 drivers/i2c/busses/i2c-nct6694.c    | 157 +++++
 drivers/mfd/Kconfig                 |  10 +
 drivers/mfd/Makefile                |   2 +
 drivers/mfd/nct6694.c               | 388 ++++++++++++
 drivers/net/can/usb/Kconfig         |  10 +
 drivers/net/can/usb/Makefile        |   1 +
 drivers/net/can/usb/nct6694_canfd.c | 856 +++++++++++++++++++++++++
 drivers/rtc/Kconfig                 |  10 +
 drivers/rtc/Makefile                |   1 +
 drivers/rtc/rtc-nct6694.c           | 286 +++++++++
 drivers/watchdog/Kconfig            |  11 +
 drivers/watchdog/Makefile           |   1 +
 drivers/watchdog/nct6694_wdt.c      | 295 +++++++++
 include/linux/mfd/nct6694.h         | 109 ++++
 23 files changed, 3590 insertions(+)
 create mode 100644 drivers/gpio/gpio-nct6694.c
 create mode 100644 drivers/hwmon/nct6694-hwmon.c
 create mode 100644 drivers/i2c/busses/i2c-nct6694.c
 create mode 100644 drivers/mfd/nct6694.c
 create mode 100644 drivers/net/can/usb/nct6694_canfd.c
 create mode 100644 drivers/rtc/rtc-nct6694.c
 create mode 100644 drivers/watchdog/nct6694_wdt.c
 create mode 100644 include/linux/mfd/nct6694.h

-- 
2.34.1

[PATCH v5 1/7] mfd: Add core driver for Nuvoton NCT6694

[Ming Yu]

The Nuvoton NCT6694 is a peripheral expander with 16 GPIO chips,
6 I2C controllers, 2 CANfd controllers, 2 Watchdog timers, ADC,
PWM, and RTC.

This driver implements USB device functionality and shares the
chip's peripherals as a child device.

Each child device can use the USB functions nct6694_read_msg()
and nct6694_write_msg() to issue a command. They can also request
interrupt that will be called when the USB device receives its
interrupt pipe.

Signed-off-by: Ming Yu <a0282524688@gmail.com>
---
 MAINTAINERS                 |   7 +
 drivers/mfd/Kconfig         |  10 +
 drivers/mfd/Makefile        |   2 +
 drivers/mfd/nct6694.c       | 388 ++++++++++++++++++++++++++++++++++++
 include/linux/mfd/nct6694.h | 109 ++++++++++
 5 files changed, 516 insertions(+)
 create mode 100644 drivers/mfd/nct6694.c
 create mode 100644 include/linux/mfd/nct6694.h

diff --git a/MAINTAINERS b/MAINTAINERS
index a87ddad78e26..79568f82b98a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16717,6 +16717,13 @@ F:	drivers/nubus/
 F:	include/linux/nubus.h
 F:	include/uapi/linux/nubus.h
 
+NUVOTON NCT6694 MFD DRIVER
+M:	Ming Yu <tmyu0@nuvoton.com>
+L:	linux-kernel@vger.kernel.org
+S:	Supported
+F:	drivers/mfd/nct6694.c
+F:	include/linux/mfd/nct6694.h
+
 NVIDIA (rivafb and nvidiafb) FRAMEBUFFER DRIVER
 M:	Antonino Daplas <adaplas@gmail.com>
 L:	linux-fbdev@vger.kernel.org
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index ae23b317a64e..3e641bfeeb38 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -1045,6 +1045,16 @@ config MFD_MENF21BMC
 	  This driver can also be built as a module. If so the module
 	  will be called menf21bmc.
 
+config MFD_NCT6694
+	tristate "Nuvoton NCT6694 support"
+	select MFD_CORE
+	depends on USB
+	help
+	  This adds support for Nuvoton USB device NCT6694 sharing peripherals
+	  This includes the USB device driver and core APIs.
+	  Additional drivers must be enabled in order to use the functionality
+	  of the device.
+
 config MFD_OCELOT
 	tristate "Microsemi Ocelot External Control Support"
 	depends on SPI_MASTER
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index e057d6d6faef..3c902d3704dc 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -121,6 +121,8 @@ obj-$(CONFIG_MFD_MC13XXX)	+= mc13xxx-core.o
 obj-$(CONFIG_MFD_MC13XXX_SPI)	+= mc13xxx-spi.o
 obj-$(CONFIG_MFD_MC13XXX_I2C)	+= mc13xxx-i2c.o
 
+obj-$(CONFIG_MFD_NCT6694)	+= nct6694.o
+
 obj-$(CONFIG_MFD_CORE)		+= mfd-core.o
 
 ocelot-soc-objs			:= ocelot-core.o ocelot-spi.o
diff --git a/drivers/mfd/nct6694.c b/drivers/mfd/nct6694.c
new file mode 100644
index 000000000000..294b6b7a902e
--- /dev/null
+++ b/drivers/mfd/nct6694.c
@@ -0,0 +1,388 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Nuvoton NCT6694 MFD driver based on USB interface.
+ *
+ * Copyright (C) 2024 Nuvoton Technology Corp.
+ */
+
+#include <linux/bits.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/nct6694.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+
+#define MFD_DEV_SIMPLE(_name)				\
+{							\
+	.name = NCT6694_DEV_##_name,			\
+}							\
+
+#define MFD_DEV_WITH_ID(_name, _id)			\
+{							\
+	.name = NCT6694_DEV_##_name,			\
+	.id = _id,					\
+}
+
+/* MFD device resources */
+static const struct mfd_cell nct6694_dev[] = {
+	MFD_DEV_WITH_ID(GPIO, 0x0),
+	MFD_DEV_WITH_ID(GPIO, 0x1),
+	MFD_DEV_WITH_ID(GPIO, 0x2),
+	MFD_DEV_WITH_ID(GPIO, 0x3),
+	MFD_DEV_WITH_ID(GPIO, 0x4),
+	MFD_DEV_WITH_ID(GPIO, 0x5),
+	MFD_DEV_WITH_ID(GPIO, 0x6),
+	MFD_DEV_WITH_ID(GPIO, 0x7),
+	MFD_DEV_WITH_ID(GPIO, 0x8),
+	MFD_DEV_WITH_ID(GPIO, 0x9),
+	MFD_DEV_WITH_ID(GPIO, 0xA),
+	MFD_DEV_WITH_ID(GPIO, 0xB),
+	MFD_DEV_WITH_ID(GPIO, 0xC),
+	MFD_DEV_WITH_ID(GPIO, 0xD),
+	MFD_DEV_WITH_ID(GPIO, 0xE),
+	MFD_DEV_WITH_ID(GPIO, 0xF),
+
+	MFD_DEV_WITH_ID(I2C, 0x0),
+	MFD_DEV_WITH_ID(I2C, 0x1),
+	MFD_DEV_WITH_ID(I2C, 0x2),
+	MFD_DEV_WITH_ID(I2C, 0x3),
+	MFD_DEV_WITH_ID(I2C, 0x4),
+	MFD_DEV_WITH_ID(I2C, 0x5),
+
+	MFD_DEV_WITH_ID(CAN, 0x0),
+	MFD_DEV_WITH_ID(CAN, 0x1),
+
+	MFD_DEV_WITH_ID(WDT, 0x0),
+	MFD_DEV_WITH_ID(WDT, 0x1),
+
+	MFD_DEV_SIMPLE(HWMON),
+	MFD_DEV_SIMPLE(RTC),
+};
+
+static int nct6694_response_err_handling(struct nct6694 *nct6694,
+					 unsigned char err_status)
+{
+	struct device *dev = &nct6694->udev->dev;
+
+	switch (err_status) {
+	case NCT6694_NO_ERROR:
+		return err_status;
+	case NCT6694_NOT_SUPPORT_ERROR:
+		dev_dbg(dev, "%s: Command is not supported!\n", __func__);
+		break;
+	case NCT6694_NO_RESPONSE_ERROR:
+		dev_dbg(dev, "%s: Command received no response!\n", __func__);
+		break;
+	case NCT6694_TIMEOUT_ERROR:
+		dev_dbg(dev, "%s: Command timed out!\n", __func__);
+		break;
+	case NCT6694_PENDING:
+		dev_dbg(dev, "%s: Command is pending!\n", __func__);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return -EIO;
+}
+
+int nct6694_read_msg(struct nct6694 *nct6694,
+		     struct nct6694_cmd_header *cmd_hd,
+		     void *buf)
+{
+	union nct6694_usb_msg *msg = nct6694->usb_msg;
+	int tx_len, rx_len, ret;
+
+	guard(mutex)(&nct6694->access_lock);
+
+	/* Send command packet to USB device */
+	memcpy(&msg->cmd_header, cmd_hd, sizeof(*cmd_hd));
+	msg->cmd_header.hctrl = NCT6694_HCTRL_GET;
+
+	ret = usb_bulk_msg(nct6694->udev,
+			   usb_sndbulkpipe(nct6694->udev, NCT6694_BULK_OUT_EP),
+			   &msg->cmd_header, sizeof(*msg), &tx_len,
+			   nct6694->timeout);
+	if (ret)
+		return ret;
+
+	/* Receive response packet from USB device */
+	ret = usb_bulk_msg(nct6694->udev,
+			   usb_rcvbulkpipe(nct6694->udev, NCT6694_BULK_IN_EP),
+			   &msg->response_header, sizeof(*msg), &rx_len,
+			   nct6694->timeout);
+	if (ret)
+		return ret;
+
+	/* Receive data packet from USB device */
+	ret = usb_bulk_msg(nct6694->udev,
+			   usb_rcvbulkpipe(nct6694->udev, NCT6694_BULK_IN_EP),
+			   buf, le16_to_cpu(cmd_hd->len), &rx_len,
+			   nct6694->timeout);
+	if (ret)
+		return ret;
+
+	if (rx_len != le16_to_cpu(cmd_hd->len)) {
+		dev_dbg(&nct6694->udev->dev, "%s: Received length is not match!\n",
+			__func__);
+		return -EIO;
+	}
+
+	return nct6694_response_err_handling(nct6694, msg->response_header.sts);
+}
+EXPORT_SYMBOL(nct6694_read_msg);
+
+int nct6694_write_msg(struct nct6694 *nct6694, struct nct6694_cmd_header *cmd_hd,
+		      void *buf)
+{
+	union nct6694_usb_msg *msg = nct6694->usb_msg;
+	int tx_len, rx_len, ret;
+
+	guard(mutex)(&nct6694->access_lock);
+
+	/* Send command packet to USB device */
+	memcpy(&msg->cmd_header, cmd_hd, sizeof(*cmd_hd));
+	msg->cmd_header.hctrl = NCT6694_HCTRL_SET;
+
+	ret = usb_bulk_msg(nct6694->udev,
+			   usb_sndbulkpipe(nct6694->udev, NCT6694_BULK_OUT_EP),
+			   &msg->cmd_header, sizeof(*msg), &tx_len,
+			   nct6694->timeout);
+	if (ret)
+		return ret;
+
+	/* Send data packet to USB device */
+	ret = usb_bulk_msg(nct6694->udev,
+			   usb_sndbulkpipe(nct6694->udev, NCT6694_BULK_OUT_EP),
+			   buf, le16_to_cpu(cmd_hd->len), &tx_len,
+			   nct6694->timeout);
+	if (ret)
+		return ret;
+
+	/* Receive response packet from USB device */
+	ret = usb_bulk_msg(nct6694->udev,
+			   usb_rcvbulkpipe(nct6694->udev, NCT6694_BULK_IN_EP),
+			   &msg->response_header, sizeof(*msg), &rx_len,
+			   nct6694->timeout);
+	if (ret)
+		return ret;
+
+	/* Receive data packet from USB device */
+	ret = usb_bulk_msg(nct6694->udev,
+			   usb_rcvbulkpipe(nct6694->udev, NCT6694_BULK_IN_EP),
+			   buf, le16_to_cpu(cmd_hd->len), &rx_len,
+			   nct6694->timeout);
+	if (ret)
+		return ret;
+
+	if (rx_len != le16_to_cpu(cmd_hd->len)) {
+		dev_dbg(&nct6694->udev->dev, "%s: Sent length is not match!\n",
+			__func__);
+		return -EIO;
+	}
+
+	return nct6694_response_err_handling(nct6694, msg->response_header.sts);
+}
+EXPORT_SYMBOL(nct6694_write_msg);
+
+static void usb_int_callback(struct urb *urb)
+{
+	struct nct6694 *nct6694 = urb->context;
+	struct device *dev = &nct6694->udev->dev;
+	unsigned int *int_status = urb->transfer_buffer;
+	int ret;
+
+	switch (urb->status) {
+	case 0:
+		break;
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+		return;
+	default:
+		goto resubmit;
+	}
+
+	while (*int_status) {
+		int irq = __ffs(*int_status);
+
+		generic_handle_irq_safe(irq_find_mapping(nct6694->domain, irq));
+		*int_status &= ~BIT(irq);
+	}
+
+resubmit:
+	ret = usb_submit_urb(urb, GFP_ATOMIC);
+	if (ret)
+		dev_dbg(dev, "%s: Failed to resubmit urb, status %pe",
+			__func__, ERR_PTR(ret));
+}
+
+static void nct6694_irq_lock(struct irq_data *data)
+{
+	struct nct6694 *nct6694 = irq_data_get_irq_chip_data(data);
+
+	mutex_lock(&nct6694->irq_lock);
+}
+
+static void nct6694_irq_sync_unlock(struct irq_data *data)
+{
+	struct nct6694 *nct6694 = irq_data_get_irq_chip_data(data);
+
+	mutex_unlock(&nct6694->irq_lock);
+}
+
+static void nct6694_irq_enable(struct irq_data *data)
+{
+	struct nct6694 *nct6694 = irq_data_get_irq_chip_data(data);
+	irq_hw_number_t hwirq = irqd_to_hwirq(data);
+
+	nct6694->irq_enable |= BIT(hwirq);
+}
+
+static void nct6694_irq_disable(struct irq_data *data)
+{
+	struct nct6694 *nct6694 = irq_data_get_irq_chip_data(data);
+	irq_hw_number_t hwirq = irqd_to_hwirq(data);
+
+	nct6694->irq_enable &= ~BIT(hwirq);
+}
+
+static struct irq_chip nct6694_irq_chip = {
+	.name = "nct6694-irq",
+	.flags = IRQCHIP_SKIP_SET_WAKE,
+	.irq_bus_lock = nct6694_irq_lock,
+	.irq_bus_sync_unlock = nct6694_irq_sync_unlock,
+	.irq_enable = nct6694_irq_enable,
+	.irq_disable = nct6694_irq_disable,
+};
+
+static int nct6694_irq_domain_map(struct irq_domain *d, unsigned int irq,
+				  irq_hw_number_t hw)
+{
+	struct nct6694 *nct6694 = d->host_data;
+
+	irq_set_chip_data(irq, nct6694);
+	irq_set_chip_and_handler(irq, &nct6694_irq_chip, handle_simple_irq);
+
+	return 0;
+}
+
+static void nct6694_irq_domain_unmap(struct irq_domain *d, unsigned int irq)
+{
+	irq_set_chip_and_handler(irq, NULL, NULL);
+	irq_set_chip_data(irq, NULL);
+}
+
+static const struct irq_domain_ops nct6694_irq_domain_ops = {
+	.map	= nct6694_irq_domain_map,
+	.unmap	= nct6694_irq_domain_unmap,
+};
+
+static int nct6694_usb_probe(struct usb_interface *iface,
+			     const struct usb_device_id *id)
+{
+	struct usb_device *udev = interface_to_usbdev(iface);
+	struct usb_endpoint_descriptor *int_endpoint;
+	struct usb_host_interface *interface;
+	struct device *dev = &udev->dev;
+	struct nct6694 *nct6694;
+	int pipe, maxp;
+	int ret;
+
+	interface = iface->cur_altsetting;
+
+	int_endpoint = &interface->endpoint[0].desc;
+	if (!usb_endpoint_is_int_in(int_endpoint))
+		return -ENODEV;
+
+	nct6694 = devm_kzalloc(dev, sizeof(*nct6694), GFP_KERNEL);
+	if (!nct6694)
+		return -ENOMEM;
+
+	pipe = usb_rcvintpipe(udev, NCT6694_INT_IN_EP);
+	maxp = usb_maxpacket(udev, pipe);
+
+	nct6694->usb_msg = devm_kzalloc(dev, sizeof(union nct6694_usb_msg),
+					GFP_KERNEL);
+	if (!nct6694->usb_msg)
+		return -ENOMEM;
+
+	nct6694->int_buffer = devm_kzalloc(dev, maxp, GFP_KERNEL);
+	if (!nct6694->int_buffer)
+		return -ENOMEM;
+
+	nct6694->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!nct6694->int_in_urb)
+		return -ENOMEM;
+
+	nct6694->domain = irq_domain_add_simple(NULL, NCT6694_NR_IRQS, 0,
+						&nct6694_irq_domain_ops,
+						nct6694);
+	if (!nct6694->domain) {
+		ret = -ENODEV;
+		goto err_urb;
+	}
+
+	nct6694->udev = udev;
+	nct6694->timeout = NCT6694_URB_TIMEOUT;	/* Wait until urb complete */
+
+	devm_mutex_init(dev, &nct6694->access_lock);
+	devm_mutex_init(dev, &nct6694->irq_lock);
+
+	usb_fill_int_urb(nct6694->int_in_urb, udev, pipe,
+			 nct6694->int_buffer, maxp, usb_int_callback,
+			 nct6694, int_endpoint->bInterval);
+	ret = usb_submit_urb(nct6694->int_in_urb, GFP_KERNEL);
+	if (ret)
+		goto err_urb;
+
+	dev_set_drvdata(dev, nct6694);
+	usb_set_intfdata(iface, nct6694);
+
+	ret = mfd_add_hotplug_devices(dev, nct6694_dev, ARRAY_SIZE(nct6694_dev));
+	if (ret)
+		goto err_mfd;
+
+	return 0;
+
+err_mfd:
+	usb_kill_urb(nct6694->int_in_urb);
+err_urb:
+	usb_free_urb(nct6694->int_in_urb);
+	return ret;
+}
+
+static void nct6694_usb_disconnect(struct usb_interface *iface)
+{
+	struct usb_device *udev = interface_to_usbdev(iface);
+	struct nct6694 *nct6694 = usb_get_intfdata(iface);
+
+	mfd_remove_devices(&udev->dev);
+	usb_kill_urb(nct6694->int_in_urb);
+	usb_free_urb(nct6694->int_in_urb);
+}
+
+static const struct usb_device_id nct6694_ids[] = {
+	{ USB_DEVICE_AND_INTERFACE_INFO(NCT6694_VENDOR_ID,
+					NCT6694_PRODUCT_ID,
+					0xFF, 0x00, 0x00)},
+	{}
+};
+MODULE_DEVICE_TABLE(usb, nct6694_ids);
+
+static struct usb_driver nct6694_usb_driver = {
+	.name	= "nct6694",
+	.id_table = nct6694_ids,
+	.probe = nct6694_usb_probe,
+	.disconnect = nct6694_usb_disconnect,
+};
+
+module_usb_driver(nct6694_usb_driver);
+
+MODULE_DESCRIPTION("USB-MFD driver for NCT6694");
+MODULE_AUTHOR("Ming Yu <tmyu0@nuvoton.com>");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/mfd/nct6694.h b/include/linux/mfd/nct6694.h
new file mode 100644
index 000000000000..67ca835589ad
--- /dev/null
+++ b/include/linux/mfd/nct6694.h
@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Nuvoton NCT6694 USB transaction and data structure.
+ *
+ * Copyright (C) 2024 Nuvoton Technology Corp.
+ */
+
+#ifndef __MFD_NCT6694_H
+#define __MFD_NCT6694_H
+
+#define NCT6694_DEV_GPIO	"nct6694-gpio"
+#define NCT6694_DEV_I2C		"nct6694-i2c"
+#define NCT6694_DEV_CAN		"nct6694-can"
+#define NCT6694_DEV_WDT		"nct6694-wdt"
+#define NCT6694_DEV_HWMON	"nct6694-hwmon"
+#define NCT6694_DEV_RTC		"nct6694-rtc"
+
+#define NCT6694_VENDOR_ID	0x0416
+#define NCT6694_PRODUCT_ID	0x200B
+#define NCT6694_INT_IN_EP	0x81
+#define NCT6694_BULK_IN_EP	0x02
+#define NCT6694_BULK_OUT_EP	0x03
+
+#define NCT6694_HCTRL_SET	0x40
+#define NCT6694_HCTRL_GET	0x80
+
+#define NCT6694_URB_TIMEOUT	1000
+
+enum nct6694_irq_id {
+	NCT6694_IRQ_GPIO0 = 0,
+	NCT6694_IRQ_GPIO1,
+	NCT6694_IRQ_GPIO2,
+	NCT6694_IRQ_GPIO3,
+	NCT6694_IRQ_GPIO4,
+	NCT6694_IRQ_GPIO5,
+	NCT6694_IRQ_GPIO6,
+	NCT6694_IRQ_GPIO7,
+	NCT6694_IRQ_GPIO8,
+	NCT6694_IRQ_GPIO9,
+	NCT6694_IRQ_GPIOA,
+	NCT6694_IRQ_GPIOB,
+	NCT6694_IRQ_GPIOC,
+	NCT6694_IRQ_GPIOD,
+	NCT6694_IRQ_GPIOE,
+	NCT6694_IRQ_GPIOF,
+	NCT6694_IRQ_CAN1,
+	NCT6694_IRQ_CAN2,
+	NCT6694_IRQ_RTC,
+	NCT6694_NR_IRQS,
+};
+
+enum nct6694_response_err_status {
+	NCT6694_NO_ERROR = 0,
+	NCT6694_FORMAT_ERROR,
+	NCT6694_RESERVED1,
+	NCT6694_RESERVED2,
+	NCT6694_NOT_SUPPORT_ERROR,
+	NCT6694_NO_RESPONSE_ERROR,
+	NCT6694_TIMEOUT_ERROR,
+	NCT6694_PENDING,
+};
+
+struct __packed nct6694_cmd_header {
+	u8 rsv1;
+	u8 mod;
+	union __packed {
+		__le16 offset;
+		struct __packed {
+			u8 cmd;
+			u8 sel;
+		};
+	};
+	u8 hctrl;
+	u8 rsv2;
+	__le16 len;
+};
+
+struct __packed nct6694_response_header {
+	u8 sequence_id;
+	u8 sts;
+	u8 reserved[4];
+	__le16 len;
+};
+
+union __packed nct6694_usb_msg {
+	struct nct6694_cmd_header cmd_header;
+	struct nct6694_response_header response_header;
+};
+
+struct nct6694 {
+	struct usb_device *udev;
+	struct urb *int_in_urb;
+	struct irq_domain *domain;
+	struct mutex access_lock;
+	struct mutex irq_lock;
+	union nct6694_usb_msg *usb_msg;
+	unsigned char *int_buffer;
+	unsigned int irq_enable;
+	/* time in msec to wait for the urb to the complete */
+	long timeout;
+};
+
+int nct6694_read_msg(struct nct6694 *nct6694, struct nct6694_cmd_header *cmd_hd,
+		     void *buf);
+
+int nct6694_write_msg(struct nct6694 *nct6694, struct nct6694_cmd_header *cmd_hd,
+		      void *buf);
+
+#endif
-- 
2.34.1

[PATCH v5 2/7] gpio: Add Nuvoton NCT6694 GPIO support

[Ming Yu]

This driver supports GPIO and IRQ functionality for NCT6694 MFD
device based on USB interface.

Signed-off-by: Ming Yu <a0282524688@gmail.com>
---
 MAINTAINERS                 |   1 +
 drivers/gpio/Kconfig        |  12 +
 drivers/gpio/Makefile       |   1 +
 drivers/gpio/gpio-nct6694.c | 458 ++++++++++++++++++++++++++++++++++++
 4 files changed, 472 insertions(+)
 create mode 100644 drivers/gpio/gpio-nct6694.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 79568f82b98a..f752051f4c3b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16721,6 +16721,7 @@ NUVOTON NCT6694 MFD DRIVER
 M:	Ming Yu <tmyu0@nuvoton.com>
 L:	linux-kernel@vger.kernel.org
 S:	Supported
+F:	drivers/gpio/gpio-nct6694.c
 F:	drivers/mfd/nct6694.c
 F:	include/linux/mfd/nct6694.h
 
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 93ee3aa092f8..808fbfdbff3b 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1461,6 +1461,18 @@ config GPIO_MAX77650
 	  GPIO driver for MAX77650/77651 PMIC from Maxim Semiconductor.
 	  These chips have a single pin that can be configured as GPIO.
 
+config GPIO_NCT6694
+	tristate "Nuvoton NCT6694 GPIO controller support"
+	depends on MFD_NCT6694
+	select GENERIC_IRQ_CHIP
+	select GPIOLIB_IRQCHIP
+	help
+	  This driver supports 8 GPIO pins per bank that can all be interrupt
+	  sources.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called gpio-nct6694.
+
 config GPIO_PALMAS
 	bool "TI PALMAS series PMICs GPIO"
 	depends on MFD_PALMAS
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index af3ba4d81b58..def8487540ab 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -121,6 +121,7 @@ obj-$(CONFIG_GPIO_MT7621)		+= gpio-mt7621.o
 obj-$(CONFIG_GPIO_MVEBU)		+= gpio-mvebu.o
 obj-$(CONFIG_GPIO_MXC)			+= gpio-mxc.o
 obj-$(CONFIG_GPIO_MXS)			+= gpio-mxs.o
+obj-$(CONFIG_GPIO_NCT6694)		+= gpio-nct6694.o
 obj-$(CONFIG_GPIO_NOMADIK)		+= gpio-nomadik.o
 obj-$(CONFIG_GPIO_NPCM_SGPIO)		+= gpio-npcm-sgpio.o
 obj-$(CONFIG_GPIO_OCTEON)		+= gpio-octeon.o
diff --git a/drivers/gpio/gpio-nct6694.c b/drivers/gpio/gpio-nct6694.c
new file mode 100644
index 000000000000..a3fc97a90782
--- /dev/null
+++ b/drivers/gpio/gpio-nct6694.c
@@ -0,0 +1,458 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Nuvoton NCT6694 GPIO controller driver based on USB interface.
+ *
+ * Copyright (C) 2024 Nuvoton Technology Corp.
+ */
+
+#include <linux/bits.h>
+#include <linux/gpio/driver.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/nct6694.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+/*
+ * USB command module type for NCT6694 GPIO controller.
+ * This defines the module type used for communication with the NCT6694
+ * GPIO controller over the USB interface.
+ */
+#define NCT6694_GPIO_MOD	0xFF
+
+#define NCT6694_GPIO_VER	0x90
+#define NCT6694_GPIO_VALID	0x110
+#define NCT6694_GPI_DATA	0x120
+#define NCT6694_GPO_DIR		0x170
+#define NCT6694_GPO_TYPE	0x180
+#define NCT6694_GPO_DATA	0x190
+
+#define NCT6694_GPI_STS		0x130
+#define NCT6694_GPI_CLR		0x140
+#define NCT6694_GPI_FALLING	0x150
+#define NCT6694_GPI_RISING	0x160
+
+#define NCT6694_NR_GPIO		8
+
+struct nct6694_gpio_data {
+	struct nct6694 *nct6694;
+	struct gpio_chip gpio;
+	struct mutex lock;
+	/* Protect irq operation */
+	struct mutex irq_lock;
+
+	unsigned char reg_val;
+	unsigned char irq_trig_falling;
+	unsigned char irq_trig_rising;
+
+	/* Current gpio group */
+	unsigned char group;
+};
+
+static int nct6694_get_direction(struct gpio_chip *gpio, unsigned int offset)
+{
+	struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_GPIO_MOD,
+		.offset = cpu_to_le16(NCT6694_GPO_DIR + data->group),
+		.len = cpu_to_le16(sizeof(data->reg_val))
+	};
+	int ret;
+
+	guard(mutex)(&data->lock);
+
+	ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
+	if (ret < 0)
+		return ret;
+
+	return !(BIT(offset) & data->reg_val);
+}
+
+static int nct6694_direction_input(struct gpio_chip *gpio, unsigned int offset)
+{
+	struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_GPIO_MOD,
+		.offset = cpu_to_le16(NCT6694_GPO_DIR + data->group),
+		.len = cpu_to_le16(sizeof(data->reg_val))
+	};
+	int ret;
+
+	guard(mutex)(&data->lock);
+
+	ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
+	if (ret < 0)
+		return ret;
+
+	data->reg_val &= ~BIT(offset);
+
+	return nct6694_write_msg(data->nct6694, &cmd_hd, &data->reg_val);
+}
+
+static int nct6694_direction_output(struct gpio_chip *gpio,
+				    unsigned int offset, int val)
+{
+	struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_GPIO_MOD,
+		.offset = cpu_to_le16(NCT6694_GPO_DIR + data->group),
+		.len = cpu_to_le16(sizeof(data->reg_val))
+	};
+	int ret;
+
+	guard(mutex)(&data->lock);
+
+	/* Set direction to output */
+	ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
+	if (ret < 0)
+		return ret;
+
+	data->reg_val |= BIT(offset);
+	ret = nct6694_write_msg(data->nct6694, &cmd_hd, &data->reg_val);
+	if (ret < 0)
+		return ret;
+
+	/* Then set output level */
+	cmd_hd.offset = cpu_to_le16(NCT6694_GPO_DATA + data->group);
+	ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
+	if (ret < 0)
+		return ret;
+
+	if (val)
+		data->reg_val |= BIT(offset);
+	else
+		data->reg_val &= ~BIT(offset);
+
+	return nct6694_write_msg(data->nct6694, &cmd_hd, &data->reg_val);
+}
+
+static int nct6694_get_value(struct gpio_chip *gpio, unsigned int offset)
+{
+	struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_GPIO_MOD,
+		.offset = cpu_to_le16(NCT6694_GPO_DIR + data->group),
+		.len = cpu_to_le16(sizeof(data->reg_val))
+	};
+	int ret;
+
+	guard(mutex)(&data->lock);
+
+	ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
+	if (ret < 0)
+		return ret;
+
+	if (BIT(offset) & data->reg_val) {
+		cmd_hd.offset = cpu_to_le16(NCT6694_GPO_DATA + data->group);
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
+		if (ret < 0)
+			return ret;
+
+		return !!(BIT(offset) & data->reg_val);
+	}
+
+	cmd_hd.offset = cpu_to_le16(NCT6694_GPI_DATA + data->group);
+	ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
+	if (ret < 0)
+		return ret;
+
+	return !!(BIT(offset) & data->reg_val);
+}
+
+static void nct6694_set_value(struct gpio_chip *gpio, unsigned int offset,
+			      int val)
+{
+	struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_GPIO_MOD,
+		.offset = cpu_to_le16(NCT6694_GPO_DATA + data->group),
+		.len = cpu_to_le16(sizeof(data->reg_val))
+	};
+
+	guard(mutex)(&data->lock);
+
+	nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
+
+	if (val)
+		data->reg_val |= BIT(offset);
+	else
+		data->reg_val &= ~BIT(offset);
+
+	nct6694_write_msg(data->nct6694, &cmd_hd, &data->reg_val);
+}
+
+static int nct6694_set_config(struct gpio_chip *gpio, unsigned int offset,
+			      unsigned long config)
+{
+	struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_GPIO_MOD,
+		.offset = cpu_to_le16(NCT6694_GPO_TYPE + data->group),
+		.len = cpu_to_le16(sizeof(data->reg_val))
+	};
+	int ret;
+
+	guard(mutex)(&data->lock);
+
+	ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
+	if (ret < 0)
+		return ret;
+
+	switch (pinconf_to_config_param(config)) {
+	case PIN_CONFIG_DRIVE_OPEN_DRAIN:
+		data->reg_val |= BIT(offset);
+		break;
+	case PIN_CONFIG_DRIVE_PUSH_PULL:
+		data->reg_val &= ~BIT(offset);
+		break;
+	default:
+		return -ENOTSUPP;
+	}
+
+	return nct6694_write_msg(data->nct6694, &cmd_hd, &data->reg_val);
+}
+
+static int nct6694_init_valid_mask(struct gpio_chip *gpio,
+				   unsigned long *valid_mask,
+				   unsigned int ngpios)
+{
+	struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_GPIO_MOD,
+		.offset = cpu_to_le16(NCT6694_GPIO_VALID + data->group),
+		.len = cpu_to_le16(sizeof(data->reg_val))
+	};
+	int ret;
+
+	guard(mutex)(&data->lock);
+
+	ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
+	if (ret < 0)
+		return ret;
+
+	*valid_mask = data->reg_val;
+
+	return ret;
+}
+
+static irqreturn_t nct6694_irq_handler(int irq, void *priv)
+{
+	struct nct6694_gpio_data *data = priv;
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_GPIO_MOD,
+		.offset = cpu_to_le16(NCT6694_GPI_STS + data->group),
+		.len = cpu_to_le16(sizeof(data->reg_val))
+	};
+	unsigned char status;
+	int ret;
+
+	guard(mutex)(&data->lock);
+
+	ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->reg_val);
+	if (ret)
+		return IRQ_NONE;
+
+	status = data->reg_val;
+
+	while (status) {
+		int bit = __ffs(status);
+
+		data->reg_val = BIT(bit);
+		handle_nested_irq(irq_find_mapping(data->gpio.irq.domain, bit));
+		status &= ~BIT(bit);
+		cmd_hd.offset = cpu_to_le16(NCT6694_GPI_CLR + data->group);
+		nct6694_write_msg(data->nct6694, &cmd_hd, &data->reg_val);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int nct6694_get_irq_trig(struct nct6694_gpio_data *data)
+{
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_GPIO_MOD,
+		.offset = cpu_to_le16(NCT6694_GPI_FALLING + data->group),
+		.len = cpu_to_le16(sizeof(data->reg_val))
+	};
+	int ret;
+
+	guard(mutex)(&data->lock);
+
+	ret = nct6694_read_msg(data->nct6694, &cmd_hd, &data->irq_trig_falling);
+	if (ret)
+		return ret;
+
+	cmd_hd.offset = cpu_to_le16(NCT6694_GPI_RISING + data->group);
+	return nct6694_read_msg(data->nct6694, &cmd_hd, &data->irq_trig_rising);
+}
+
+static void nct6694_irq_mask(struct irq_data *d)
+{
+	struct gpio_chip *gpio = irq_data_get_irq_chip_data(d);
+	irq_hw_number_t hwirq = irqd_to_hwirq(d);
+
+	gpiochip_disable_irq(gpio, hwirq);
+}
+
+static void nct6694_irq_unmask(struct irq_data *d)
+{
+	struct gpio_chip *gpio = irq_data_get_irq_chip_data(d);
+	irq_hw_number_t hwirq = irqd_to_hwirq(d);
+
+	gpiochip_enable_irq(gpio, hwirq);
+}
+
+static int nct6694_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct gpio_chip *gpio = irq_data_get_irq_chip_data(d);
+	struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
+	irq_hw_number_t hwirq = irqd_to_hwirq(d);
+
+	guard(mutex)(&data->lock);
+
+	switch (type) {
+	case IRQ_TYPE_EDGE_RISING:
+		data->irq_trig_rising |= BIT(hwirq);
+		break;
+
+	case IRQ_TYPE_EDGE_FALLING:
+		data->irq_trig_falling |= BIT(hwirq);
+		break;
+
+	case IRQ_TYPE_EDGE_BOTH:
+		data->irq_trig_rising |= BIT(hwirq);
+		data->irq_trig_falling |= BIT(hwirq);
+		break;
+
+	default:
+		return -ENOTSUPP;
+	}
+
+	return 0;
+}
+
+static void nct6694_irq_bus_lock(struct irq_data *d)
+{
+	struct gpio_chip *gpio = irq_data_get_irq_chip_data(d);
+	struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
+
+	mutex_lock(&data->irq_lock);
+}
+
+static void nct6694_irq_bus_sync_unlock(struct irq_data *d)
+{
+	struct gpio_chip *gpio = irq_data_get_irq_chip_data(d);
+	struct nct6694_gpio_data *data = gpiochip_get_data(gpio);
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_GPIO_MOD,
+		.offset = cpu_to_le16(NCT6694_GPI_FALLING + data->group),
+		.len = cpu_to_le16(sizeof(data->reg_val))
+	};
+
+	scoped_guard(mutex, &data->lock) {
+		nct6694_write_msg(data->nct6694, &cmd_hd, &data->irq_trig_falling);
+
+		cmd_hd.offset = cpu_to_le16(NCT6694_GPI_RISING + data->group);
+		nct6694_write_msg(data->nct6694, &cmd_hd, &data->irq_trig_rising);
+	}
+
+	mutex_unlock(&data->irq_lock);
+}
+
+static const struct irq_chip nct6694_irq_chip = {
+	.name			= "nct6694-gpio",
+	.irq_mask		= nct6694_irq_mask,
+	.irq_unmask		= nct6694_irq_unmask,
+	.irq_set_type		= nct6694_irq_set_type,
+	.irq_bus_lock		= nct6694_irq_bus_lock,
+	.irq_bus_sync_unlock	= nct6694_irq_bus_sync_unlock,
+	.flags			= IRQCHIP_IMMUTABLE,
+	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
+static int nct6694_gpio_probe(struct platform_device *pdev)
+{
+	const struct mfd_cell *cell = mfd_get_cell(pdev);
+	struct device *dev = &pdev->dev;
+	struct nct6694 *nct6694 = dev_get_drvdata(pdev->dev.parent);
+	struct nct6694_gpio_data *data;
+	struct gpio_irq_chip *girq;
+	int ret, irq, i;
+	char **names;
+
+	irq = irq_create_mapping(nct6694->domain,
+				 NCT6694_IRQ_GPIO0 + cell->id);
+	if (!irq)
+		return -EINVAL;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	names = devm_kcalloc(dev, NCT6694_NR_GPIO, sizeof(char *),
+			     GFP_KERNEL);
+	if (!names)
+		return -ENOMEM;
+
+	for (i = 0; i < NCT6694_NR_GPIO; i++) {
+		names[i] = devm_kasprintf(dev, GFP_KERNEL, "GPIO%X%d",
+					  cell->id, i);
+		if (!names[i])
+			return -ENOMEM;
+	}
+
+	data->nct6694 = nct6694;
+	data->group = cell->id;
+
+	data->gpio.names		= (const char * const*)names;
+	data->gpio.label		= pdev->name;
+	data->gpio.direction_input	= nct6694_direction_input;
+	data->gpio.get			= nct6694_get_value;
+	data->gpio.direction_output	= nct6694_direction_output;
+	data->gpio.set			= nct6694_set_value;
+	data->gpio.get_direction	= nct6694_get_direction;
+	data->gpio.set_config		= nct6694_set_config;
+	data->gpio.init_valid_mask	= nct6694_init_valid_mask;
+	data->gpio.base			= -1;
+	data->gpio.can_sleep		= false;
+	data->gpio.owner		= THIS_MODULE;
+	data->gpio.ngpio		= NCT6694_NR_GPIO;
+
+	devm_mutex_init(dev, &data->lock);
+	devm_mutex_init(dev, &data->irq_lock);
+
+	ret = nct6694_get_irq_trig(data);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to get irq trigger type\n");
+
+	girq = &data->gpio.irq;
+	gpio_irq_chip_set_chip(girq, &nct6694_irq_chip);
+	girq->parent_handler = NULL;
+	girq->num_parents = 0;
+	girq->parents = NULL;
+	girq->default_type = IRQ_TYPE_NONE;
+	girq->handler = handle_level_irq;
+	girq->threaded = true;
+
+	ret = devm_request_threaded_irq(dev, irq, NULL, nct6694_irq_handler,
+					IRQF_ONESHOT | IRQF_SHARED,
+					"nct6694-gpio", data);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to request irq\n");
+
+	return devm_gpiochip_add_data(dev, &data->gpio, data);
+}
+
+static struct platform_driver nct6694_gpio_driver = {
+	.driver = {
+		.name	= "nct6694-gpio",
+	},
+	.probe		= nct6694_gpio_probe,
+};
+
+module_platform_driver(nct6694_gpio_driver);
+
+MODULE_DESCRIPTION("USB-GPIO controller driver for NCT6694");
+MODULE_AUTHOR("Ming Yu <tmyu0@nuvoton.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:nct6694-gpio");
-- 
2.34.1

[PATCH v5 3/7] i2c: Add Nuvoton NCT6694 I2C support

[Ming Yu]

This driver supports I2C adapter functionality for NCT6694 MFD
device based on USB interface, each I2C controller use default
baudrate(100K).

Signed-off-by: Ming Yu <a0282524688@gmail.com>
---
 MAINTAINERS                      |   1 +
 drivers/i2c/busses/Kconfig       |  10 ++
 drivers/i2c/busses/Makefile      |   1 +
 drivers/i2c/busses/i2c-nct6694.c | 157 +++++++++++++++++++++++++++++++
 4 files changed, 169 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-nct6694.c

diff --git a/MAINTAINERS b/MAINTAINERS
index f752051f4c3b..4e72f749cdf2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16722,6 +16722,7 @@ M:	Ming Yu <tmyu0@nuvoton.com>
 L:	linux-kernel@vger.kernel.org
 S:	Supported
 F:	drivers/gpio/gpio-nct6694.c
+F:	drivers/i2c/busses/i2c-nct6694.c
 F:	drivers/mfd/nct6694.c
 F:	include/linux/mfd/nct6694.h
 
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index ceb3ecdf884b..a3f60e6953bd 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -1328,6 +1328,16 @@ config I2C_LJCA
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-ljca.
 
+config I2C_NCT6694
+	tristate "Nuvoton NCT6694 I2C adapter support"
+	depends on MFD_NCT6694
+	help
+	  If you say yes to this option, support will be included for Nuvoton
+	  NCT6694, a USB to I2C interface.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called i2c-nct6694.
+
 config I2C_CP2615
 	tristate "Silicon Labs CP2615 USB sound card and I2C adapter"
 	depends on USB
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 1c2a4510abe4..c5a60116dd54 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -133,6 +133,7 @@ obj-$(CONFIG_I2C_GXP)		+= i2c-gxp.o
 obj-$(CONFIG_I2C_DIOLAN_U2C)	+= i2c-diolan-u2c.o
 obj-$(CONFIG_I2C_DLN2)		+= i2c-dln2.o
 obj-$(CONFIG_I2C_LJCA)		+= i2c-ljca.o
+obj-$(CONFIG_I2C_NCT6694)	+= i2c-nct6694.o
 obj-$(CONFIG_I2C_CP2615) += i2c-cp2615.o
 obj-$(CONFIG_I2C_PARPORT)	+= i2c-parport.o
 obj-$(CONFIG_I2C_PCI1XXXX)	+= i2c-mchp-pci1xxxx.o
diff --git a/drivers/i2c/busses/i2c-nct6694.c b/drivers/i2c/busses/i2c-nct6694.c
new file mode 100644
index 000000000000..49e8110662e2
--- /dev/null
+++ b/drivers/i2c/busses/i2c-nct6694.c
@@ -0,0 +1,157 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Nuvoton NCT6694 I2C adapter driver based on USB interface.
+ *
+ * Copyright (C) 2024 Nuvoton Technology Corp.
+ */
+
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/nct6694.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+/*
+ * USB command module type for NCT6694 I2C controller.
+ * This defines the module type used for communication with the NCT6694
+ * I2C controller over the USB interface.
+ */
+#define NCT6694_I2C_MOD		0x03
+
+/* Command 00h - I2C Deliver */
+#define NCT6694_I2C_DELIVER	0x00
+#define NCT6694_I2C_DELIVER_SEL	0x00
+
+enum i2c_baudrate {
+	I2C_BR_25K = 0,
+	I2C_BR_50K,
+	I2C_BR_100K,
+	I2C_BR_200K,
+	I2C_BR_400K,
+	I2C_BR_800K,
+	I2C_BR_1M
+};
+
+struct __packed nct6694_i2c_deliver {
+	u8 port;
+	u8 br;
+	u8 addr;
+	u8 w_cnt;
+	u8 r_cnt;
+	u8 rsv[11];
+	u8 write_data[0x40];
+	u8 read_data[0x40];
+};
+
+struct nct6694_i2c_data {
+	struct nct6694 *nct6694;
+	struct i2c_adapter adapter;
+	struct nct6694_i2c_deliver *deliver;
+	unsigned char port;
+	unsigned char br;
+};
+
+static int nct6694_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
+{
+	struct nct6694_i2c_data *data = adap->algo_data;
+	struct nct6694_i2c_deliver *deliver = data->deliver;
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_I2C_MOD,
+		.cmd = NCT6694_I2C_DELIVER,
+		.sel = NCT6694_I2C_DELIVER_SEL,
+		.len = cpu_to_le16(sizeof(*deliver))
+	};
+	int ret, i;
+
+	for (i = 0; i < num ; i++) {
+		struct i2c_msg *msg_temp = &msgs[i];
+
+		memset(deliver, 0, sizeof(*deliver));
+
+		if (msg_temp->len > 64)
+			return -EPROTO;
+
+		deliver->port = data->port;
+		deliver->br = data->br;
+		deliver->addr = i2c_8bit_addr_from_msg(msg_temp);
+		if (msg_temp->flags & I2C_M_RD) {
+			deliver->r_cnt = msg_temp->len;
+			ret = nct6694_write_msg(data->nct6694, &cmd_hd, deliver);
+			if (ret < 0)
+				return ret;
+
+			memcpy(msg_temp->buf, deliver->read_data, msg_temp->len);
+		} else {
+			deliver->w_cnt = msg_temp->len;
+			memcpy(deliver->write_data, msg_temp->buf, msg_temp->len);
+			ret = nct6694_write_msg(data->nct6694, &cmd_hd, deliver);
+			if (ret < 0)
+				return ret;
+		}
+	}
+
+	return num;
+}
+
+static u32 nct6694_func(struct i2c_adapter *adapter)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm algorithm = {
+	.master_xfer = nct6694_xfer,
+	.functionality = nct6694_func,
+};
+
+static int nct6694_i2c_probe(struct platform_device *pdev)
+{
+	const struct mfd_cell *cell = mfd_get_cell(pdev);
+	struct nct6694 *nct6694 = dev_get_drvdata(pdev->dev.parent);
+	struct nct6694_i2c_data *data;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->deliver = devm_kzalloc(&pdev->dev, sizeof(struct nct6694_i2c_deliver),
+				     GFP_KERNEL);
+	if (!data->deliver)
+		return -ENOMEM;
+
+	data->nct6694 = nct6694;
+	data->port = cell->id;
+	data->br = I2C_BR_100K;
+
+	sprintf(data->adapter.name, "NCT6694 I2C Adapter %d", cell->id);
+	data->adapter.owner = THIS_MODULE;
+	data->adapter.algo = &algorithm;
+	data->adapter.dev.parent = &pdev->dev;
+	data->adapter.algo_data = data;
+
+	platform_set_drvdata(pdev, data);
+
+	return i2c_add_adapter(&data->adapter);
+}
+
+static void nct6694_i2c_remove(struct platform_device *pdev)
+{
+	struct nct6694_i2c_data *data = platform_get_drvdata(pdev);
+
+	i2c_del_adapter(&data->adapter);
+}
+
+static struct platform_driver nct6694_i2c_driver = {
+	.driver = {
+		.name	= "nct6694-i2c",
+	},
+	.probe		= nct6694_i2c_probe,
+	.remove		= nct6694_i2c_remove,
+};
+
+module_platform_driver(nct6694_i2c_driver);
+
+MODULE_DESCRIPTION("USB-I2C adapter driver for NCT6694");
+MODULE_AUTHOR("Ming Yu <tmyu0@nuvoton.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:nct6694-i2c");
-- 
2.34.1

[PATCH v5 4/7] can: Add Nuvoton NCT6694 CAN support

[Ming Yu]

This driver supports Socket CANfd functionality for NCT6694 MFD
device based on USB interface.

Signed-off-by: Ming Yu <a0282524688@gmail.com>
---
 MAINTAINERS                         |   1 +
 drivers/net/can/usb/Kconfig         |  10 +
 drivers/net/can/usb/Makefile        |   1 +
 drivers/net/can/usb/nct6694_canfd.c | 856 ++++++++++++++++++++++++++++
 4 files changed, 868 insertions(+)
 create mode 100644 drivers/net/can/usb/nct6694_canfd.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 4e72f749cdf2..6e9b78202d6f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16724,6 +16724,7 @@ S:	Supported
 F:	drivers/gpio/gpio-nct6694.c
 F:	drivers/i2c/busses/i2c-nct6694.c
 F:	drivers/mfd/nct6694.c
+F:	drivers/net/can/usb/nct6694_canfd.c
 F:	include/linux/mfd/nct6694.h
 
 NVIDIA (rivafb and nvidiafb) FRAMEBUFFER DRIVER
diff --git a/drivers/net/can/usb/Kconfig b/drivers/net/can/usb/Kconfig
index 9dae0c71a2e1..53254012cdc4 100644
--- a/drivers/net/can/usb/Kconfig
+++ b/drivers/net/can/usb/Kconfig
@@ -133,6 +133,16 @@ config CAN_MCBA_USB
 	  This driver supports the CAN BUS Analyzer interface
 	  from Microchip (http://www.microchip.com/development-tools/).
 
+config CAN_NCT6694
+	tristate "Nuvoton NCT6694 Socket CANfd support"
+	depends on MFD_NCT6694
+	help
+	  If you say yes to this option, support will be included for Nuvoton
+	  NCT6694, a USB device to socket CANfd controller.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called nct6694_canfd.
+
 config CAN_PEAK_USB
 	tristate "PEAK PCAN-USB/USB Pro interfaces for CAN 2.0b/CAN-FD"
 	help
diff --git a/drivers/net/can/usb/Makefile b/drivers/net/can/usb/Makefile
index 8b11088e9a59..fcafb1ac262e 100644
--- a/drivers/net/can/usb/Makefile
+++ b/drivers/net/can/usb/Makefile
@@ -11,5 +11,6 @@ obj-$(CONFIG_CAN_F81604) += f81604.o
 obj-$(CONFIG_CAN_GS_USB) += gs_usb.o
 obj-$(CONFIG_CAN_KVASER_USB) += kvaser_usb/
 obj-$(CONFIG_CAN_MCBA_USB) += mcba_usb.o
+obj-$(CONFIG_CAN_NCT6694) += nct6694_canfd.o
 obj-$(CONFIG_CAN_PEAK_USB) += peak_usb/
 obj-$(CONFIG_CAN_UCAN) += ucan.o
diff --git a/drivers/net/can/usb/nct6694_canfd.c b/drivers/net/can/usb/nct6694_canfd.c
new file mode 100644
index 000000000000..7a15c39021ff
--- /dev/null
+++ b/drivers/net/can/usb/nct6694_canfd.c
@@ -0,0 +1,856 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Nuvoton NCT6694 Socket CANfd driver based on USB interface.
+ *
+ * Copyright (C) 2024 Nuvoton Technology Corp.
+ */
+
+#include <linux/can/dev.h>
+#include <linux/can/rx-offload.h>
+#include <linux/ethtool.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/nct6694.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/platform_device.h>
+
+#define DRVNAME "nct6694-can"
+
+/*
+ * USB command module type for NCT6694 CANfd controller.
+ * This defines the module type used for communication with the NCT6694
+ * CANfd controller over the USB interface.
+ */
+#define NCT6694_CAN_MOD			0x05
+
+/* Command 00h - CAN Setting and Initialization */
+#define NCT6694_CAN_SETTING		0x00
+#define NCT6694_CAN_SETTING_SEL(idx)	(idx ? 0x01 : 0x00)
+#define NCT6694_CAN_SETTING_CTRL1_MON	BIT(0)
+#define NCT6694_CAN_SETTING_CTRL1_NISO	BIT(1)
+#define NCT6694_CAN_SETTING_CTRL1_LBCK	BIT(2)
+
+/* Command 01h - CAN Information */
+#define NCT6694_CAN_INFORMATION		0x01
+#define NCT6694_CAN_INFORMATION_SEL	0x00
+
+/* Command 02h - CAN Event */
+#define NCT6694_CAN_EVENT		0x02
+#define NCT6694_CAN_EVENT_SEL(idx, mask)	\
+	((idx ? 0x80 : 0x00) | ((mask) & 0xFF))
+#define NCT6694_CAN_EVENT_ERR		BIT(0)
+#define NCT6694_CAN_EVENT_STATUS	BIT(1)
+#define NCT6694_CAN_EVENT_TX_EVT	BIT(2)
+#define NCT6694_CAN_EVENT_RX_EVT	BIT(3)
+#define NCT6694_CAN_EVENT_REC		BIT(4)
+#define NCT6694_CAN_EVENT_TEC		BIT(5)
+#define NCT6694_CAN_EVENT_MASK		GENMASK(3, 0)
+#define NCT6694_CAN_EVT_TX_FIFO_EMPTY	BIT(7)	/* Read-clear */
+#define NCT6694_CAN_EVT_RX_DATA_LOST	BIT(5)	/* Read-clear */
+#define NCT6694_CAN_EVT_RX_HALF_FULL	BIT(6)	/* Read-clear */
+#define NCT6694_CAN_EVT_RX_DATA_IN	BIT(7)	/* Read-clear*/
+
+/* Command 10h - CAN Deliver */
+#define NCT6694_CAN_DELIVER		0x10
+#define NCT6694_CAN_DELIVER_SEL(buf_cnt)	\
+	((buf_cnt) & 0xFF)
+
+/* Command 11h - CAN Receive */
+#define NCT6694_CAN_RECEIVE		0x11
+#define NCT6694_CAN_RECEIVE_SEL(idx, buf_cnt)	\
+	((idx ? 0x80 : 0x00) | ((buf_cnt) & 0xFF))
+
+#define NCT6694_CAN_FRAME_TAG_CAN0	0xC0
+#define NCT6694_CAN_FRAME_TAG_CAN1	0xC1
+#define NCT6694_CAN_FRAME_FLAG_EFF	BIT(0)
+#define NCT6694_CAN_FRAME_FLAG_RTR	BIT(1)
+#define NCT6694_CAN_FRAME_FLAG_FD	BIT(2)
+#define NCT6694_CAN_FRAME_FLAG_BRS	BIT(3)
+#define NCT6694_CAN_FRAME_FLAG_ERR	BIT(4)
+
+#define NCT6694_NAPI_WEIGHT		32
+
+enum nct6694_event_err {
+	NCT6694_CAN_EVT_ERR_NO_ERROR = 0,
+	NCT6694_CAN_EVT_ERR_CRC_ERROR,
+	NCT6694_CAN_EVT_ERR_STUFF_ERROR,
+	NCT6694_CAN_EVT_ERR_ACK_ERROR,
+	NCT6694_CAN_EVT_ERR_FORM_ERROR,
+	NCT6694_CAN_EVT_ERR_BIT_ERROR,
+	NCT6694_CAN_EVT_ERR_TIMEOUT_ERROR,
+	NCT6694_CAN_EVT_ERR_UNKNOWN_ERROR,
+};
+
+enum nct6694_event_status {
+	NCT6694_CAN_EVT_STS_ERROR_ACTIVE = 0,
+	NCT6694_CAN_EVT_STS_ERROR_PASSIVE,
+	NCT6694_CAN_EVT_STS_BUS_OFF,
+	NCT6694_CAN_EVT_STS_WARNING,
+};
+
+struct __packed nct6694_can_setting {
+	__le32 nbr;
+	__le32 dbr;
+	u8 active;
+	u8 reserved[3];
+	__le16 ctrl1;
+	__le16 ctrl2;
+	__le32 nbtp;
+	__le32 dbtp;
+};
+
+struct __packed nct6694_can_information {
+	u8 tx_fifo_cnt;
+	u8 rx_fifo_cnt;
+	u8 reserved[2];
+	__le32 can_clk;
+};
+
+struct __packed nct6694_can_event {
+	u8 err;
+	u8 status;
+	u8 tx_evt;
+	u8 rx_evt;
+	u8 rec;
+	u8 tec;
+	u8 reserved[2];
+};
+
+struct __packed nct6694_can_frame {
+	u8 tag;
+	u8 flag;
+	u8 reserved;
+	u8 length;
+	__le32 id;
+	u8 data[64];
+};
+
+union __packed nct6694_can_tx {
+	struct nct6694_can_frame frame;
+	struct nct6694_can_setting setting;
+};
+
+union __packed nct6694_can_rx {
+	struct nct6694_can_event event[2];
+	struct nct6694_can_frame frame;
+	struct nct6694_can_information info;
+};
+
+struct nct6694_can_priv {
+	struct can_priv can;	/* must be the first member */
+	struct can_rx_offload offload;
+	struct net_device *ndev;
+	struct nct6694 *nct6694;
+	struct mutex lock;
+	struct sk_buff *tx_skb;
+	struct workqueue_struct *wq;
+	struct work_struct tx_work;
+	union nct6694_can_tx *tx;
+	union nct6694_can_rx *rx;
+	unsigned char can_idx;
+};
+
+static inline struct nct6694_can_priv *rx_offload_to_priv(struct can_rx_offload *offload)
+{
+	return container_of(offload, struct nct6694_can_priv, offload);
+}
+
+static const struct can_bittiming_const nct6694_can_bittiming_nominal_const = {
+	.name = DRVNAME,
+	.tseg1_min = 2,
+	.tseg1_max = 256,
+	.tseg2_min = 2,
+	.tseg2_max = 128,
+	.sjw_max = 128,
+	.brp_min = 1,
+	.brp_max = 511,
+	.brp_inc = 1,
+};
+
+static const struct can_bittiming_const nct6694_can_bittiming_data_const = {
+	.name = DRVNAME,
+	.tseg1_min = 1,
+	.tseg1_max = 32,
+	.tseg2_min = 1,
+	.tseg2_max = 16,
+	.sjw_max = 16,
+	.brp_min = 1,
+	.brp_max = 31,
+	.brp_inc = 1,
+};
+
+static void nct6694_can_rx_offload(struct can_rx_offload *offload,
+				   struct sk_buff *skb)
+{
+	struct nct6694_can_priv *priv = rx_offload_to_priv(offload);
+	int ret;
+
+	ret = can_rx_offload_queue_tail(offload, skb);
+	if (ret)
+		priv->ndev->stats.rx_fifo_errors++;
+}
+
+static void nct6694_can_handle_lost_msg(struct net_device *ndev)
+{
+	struct nct6694_can_priv *priv = netdev_priv(ndev);
+	struct net_device_stats *stats = &ndev->stats;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+
+	netdev_err(ndev, "RX FIFO overflow, message(s) lost.\n");
+
+	stats->rx_errors++;
+	stats->rx_over_errors++;
+
+	skb = alloc_can_err_skb(ndev, &cf);
+	if (!skb)
+		return;
+
+	cf->can_id |= CAN_ERR_CRTL;
+	cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+
+	nct6694_can_rx_offload(&priv->offload, skb);
+}
+
+static void nct6694_can_rx(struct net_device *ndev, u8 rx_evt)
+{
+	struct nct6694_can_priv *priv = netdev_priv(ndev);
+	struct nct6694_can_frame *frame = &priv->rx->frame;
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_CAN_MOD,
+		.cmd = NCT6694_CAN_RECEIVE,
+		.sel = NCT6694_CAN_RECEIVE_SEL(priv->can_idx, 1),
+		.len = cpu_to_le16(sizeof(*frame))
+	};
+	struct canfd_frame *cfd;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+	int ret;
+
+	ret = nct6694_read_msg(priv->nct6694, &cmd_hd, frame);
+	if (ret)
+		return;
+
+	if (frame->flag & NCT6694_CAN_FRAME_FLAG_FD) {
+		skb = alloc_canfd_skb(priv->ndev, &cfd);
+		if (!skb)
+			return;
+
+		cfd->can_id = le32_to_cpu(frame->id);
+		cfd->len = frame->length;
+		if (frame->flag & NCT6694_CAN_FRAME_FLAG_EFF)
+			cfd->can_id |= CAN_EFF_FLAG;
+		if (frame->flag & NCT6694_CAN_FRAME_FLAG_BRS)
+			cfd->flags |= CANFD_BRS;
+		if (frame->flag & NCT6694_CAN_FRAME_FLAG_ERR)
+			cfd->flags |= CANFD_ESI;
+
+		memcpy(cfd->data, frame->data, cfd->len);
+	} else {
+		skb = alloc_can_skb(priv->ndev, &cf);
+		if (!skb)
+			return;
+
+		cf->can_id = le32_to_cpu(frame->id);
+		cf->len = frame->length;
+		if (frame->flag & NCT6694_CAN_FRAME_FLAG_EFF)
+			cf->can_id |= CAN_EFF_FLAG;
+		if (frame->flag & NCT6694_CAN_FRAME_FLAG_RTR)
+			cf->can_id |= CAN_RTR_FLAG;
+
+		memcpy(cf->data, frame->data, cf->len);
+	}
+
+	nct6694_can_rx_offload(&priv->offload, skb);
+}
+
+static void nct6694_can_clean(struct net_device *ndev)
+{
+	struct nct6694_can_priv *priv = netdev_priv(ndev);
+
+	if (priv->tx_skb || netif_queue_stopped(ndev))
+		ndev->stats.tx_errors++;
+	dev_kfree_skb(priv->tx_skb);
+	priv->tx_skb = NULL;
+}
+
+static int nct6694_can_get_berr_counter(const struct net_device *ndev,
+					struct can_berr_counter *bec)
+{
+	struct nct6694_can_priv *priv = netdev_priv(ndev);
+	struct nct6694_can_event *evt = priv->rx->event;
+	struct nct6694_cmd_header cmd_hd;
+	u8 mask = NCT6694_CAN_EVENT_REC | NCT6694_CAN_EVENT_TEC;
+	int ret;
+
+	guard(mutex)(&priv->lock);
+
+	cmd_hd = (struct nct6694_cmd_header) {
+		.mod = NCT6694_CAN_MOD,
+		.cmd = NCT6694_CAN_EVENT,
+		.sel = NCT6694_CAN_EVENT_SEL(priv->can_idx, mask),
+		.len = cpu_to_le16(sizeof(priv->rx->event))
+	};
+
+	ret = nct6694_read_msg(priv->nct6694, &cmd_hd, evt);
+	if (ret < 0)
+		return ret;
+
+	bec->rxerr = evt[priv->can_idx].rec;
+	bec->txerr = evt[priv->can_idx].tec;
+
+	return 0;
+}
+
+static void nct6694_can_handle_state_change(struct net_device *ndev,
+					    u8 status)
+{
+	struct nct6694_can_priv *priv = netdev_priv(ndev);
+	enum can_state new_state = priv->can.state;
+	enum can_state rx_state, tx_state;
+	struct can_berr_counter bec;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+
+	nct6694_can_get_berr_counter(ndev, &bec);
+	can_state_get_by_berr_counter(ndev, &bec, &tx_state, &rx_state);
+
+	switch (status) {
+	case NCT6694_CAN_EVT_STS_ERROR_ACTIVE:
+		new_state = CAN_STATE_ERROR_ACTIVE;
+		break;
+	case NCT6694_CAN_EVT_STS_ERROR_PASSIVE:
+		new_state = CAN_STATE_ERROR_PASSIVE;
+		break;
+	case NCT6694_CAN_EVT_STS_BUS_OFF:
+		new_state = CAN_STATE_BUS_OFF;
+		break;
+	case NCT6694_CAN_EVT_STS_WARNING:
+		new_state = CAN_STATE_ERROR_WARNING;
+		break;
+	default:
+		netdev_err(ndev, "Receive unknown CAN status event.\n");
+		return;
+	}
+
+	/* state hasn't changed */
+	if (new_state == priv->can.state)
+		return;
+
+	skb = alloc_can_err_skb(ndev, &cf);
+
+	tx_state = bec.txerr >= bec.rxerr ? new_state : 0;
+	rx_state = bec.txerr <= bec.rxerr ? new_state : 0;
+	can_change_state(ndev, cf, tx_state, rx_state);
+
+	if (new_state == CAN_STATE_BUS_OFF) {
+		can_bus_off(ndev);
+	} else if (skb) {
+		cf->can_id |= CAN_ERR_CNT;
+		cf->data[6] = bec.txerr;
+		cf->data[7] = bec.rxerr;
+	}
+
+	nct6694_can_rx_offload(&priv->offload, skb);
+}
+
+static void nct6694_handle_bus_err(struct net_device *ndev, u8 bus_err)
+{
+	struct nct6694_can_priv *priv = netdev_priv(ndev);
+	struct can_frame *cf;
+	struct sk_buff *skb;
+
+	if (bus_err == NCT6694_CAN_EVT_ERR_NO_ERROR)
+		return;
+
+	priv->can.can_stats.bus_error++;
+
+	skb = alloc_can_err_skb(ndev, &cf);
+	if (skb)
+		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+
+	switch (bus_err) {
+	case NCT6694_CAN_EVT_ERR_CRC_ERROR:
+		netdev_dbg(ndev, "CRC error\n");
+		ndev->stats.rx_errors++;
+		if (skb)
+			cf->data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ;
+		break;
+
+	case NCT6694_CAN_EVT_ERR_STUFF_ERROR:
+		netdev_dbg(ndev, "Stuff error\n");
+		ndev->stats.rx_errors++;
+		if (skb)
+			cf->data[2] |= CAN_ERR_PROT_STUFF;
+		break;
+
+	case NCT6694_CAN_EVT_ERR_ACK_ERROR:
+		netdev_dbg(ndev, "Ack error\n");
+		ndev->stats.tx_errors++;
+		if (skb) {
+			cf->can_id |= CAN_ERR_ACK;
+			cf->data[2] |= CAN_ERR_PROT_TX;
+		}
+		break;
+
+	case NCT6694_CAN_EVT_ERR_FORM_ERROR:
+		netdev_dbg(ndev, "Form error\n");
+		ndev->stats.rx_errors++;
+		if (skb)
+			cf->data[2] |= CAN_ERR_PROT_FORM;
+		break;
+
+	case NCT6694_CAN_EVT_ERR_BIT_ERROR:
+		netdev_dbg(ndev, "Bit error\n");
+		ndev->stats.tx_errors++;
+		if (skb)
+			cf->data[2] |= CAN_ERR_PROT_TX | CAN_ERR_PROT_BIT;
+		break;
+
+	default:
+		break;
+	}
+
+	nct6694_can_rx_offload(&priv->offload, skb);
+}
+
+static void nct6694_can_tx_irq(struct net_device *ndev)
+{
+	struct nct6694_can_priv *priv = netdev_priv(ndev);
+	struct net_device_stats *stats = &ndev->stats;
+
+	guard(mutex)(&priv->lock);
+	stats->tx_bytes += can_get_echo_skb(ndev, 0, NULL);
+	stats->tx_packets++;
+	netif_wake_queue(ndev);
+}
+
+static irqreturn_t nct6694_can_irq(int irq, void *data)
+{
+	struct net_device *ndev = data;
+	struct nct6694_can_priv *priv = netdev_priv(ndev);
+	struct nct6694_can_event *evt = priv->rx->event;
+	struct nct6694_cmd_header cmd_hd;
+	u8 tx_evt, rx_evt, bus_err, can_status;
+	u8 mask_sts = NCT6694_CAN_EVENT_MASK;
+	irqreturn_t handled = IRQ_NONE;
+	int can_idx = priv->can_idx;
+	int ret;
+
+	scoped_guard(mutex, &priv->lock) {
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_CAN_MOD,
+			.cmd = NCT6694_CAN_EVENT,
+			.sel = NCT6694_CAN_EVENT_SEL(priv->can_idx, mask_sts),
+			.len = cpu_to_le16(sizeof(priv->rx->event))
+		};
+
+		ret = nct6694_read_msg(priv->nct6694, &cmd_hd, evt);
+		if (ret < 0)
+			return handled;
+
+		tx_evt = evt[can_idx].tx_evt;
+		rx_evt = evt[can_idx].rx_evt;
+		bus_err = evt[can_idx].err;
+		can_status = evt[can_idx].status;
+	}
+
+	if (rx_evt & NCT6694_CAN_EVT_RX_DATA_IN) {
+		nct6694_can_rx(ndev, rx_evt);
+		handled = IRQ_HANDLED;
+	}
+
+	if (rx_evt & NCT6694_CAN_EVT_RX_DATA_LOST) {
+		nct6694_can_handle_lost_msg(ndev);
+		handled = IRQ_HANDLED;
+	}
+
+	if (can_status) {
+		nct6694_can_handle_state_change(ndev, can_status);
+		handled = IRQ_HANDLED;
+	}
+
+	if (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) {
+		nct6694_handle_bus_err(ndev, bus_err);
+		handled = IRQ_HANDLED;
+	}
+
+	if (handled)
+		can_rx_offload_threaded_irq_finish(&priv->offload);
+
+	if (tx_evt & NCT6694_CAN_EVT_TX_FIFO_EMPTY)
+		nct6694_can_tx_irq(ndev);
+
+	return handled;
+}
+
+static void nct6694_can_tx(struct net_device *ndev)
+{
+	struct nct6694_can_priv *priv = netdev_priv(ndev);
+	struct nct6694_can_frame *frame = &priv->tx->frame;
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_CAN_MOD,
+		.cmd = NCT6694_CAN_DELIVER,
+		.sel = NCT6694_CAN_DELIVER_SEL(1),
+		.len = cpu_to_le16(sizeof(*frame))
+	};
+	struct net_device_stats *stats = &ndev->stats;
+	struct sk_buff *skb = priv->tx_skb;
+	struct canfd_frame *cfd;
+	struct can_frame *cf;
+	u32 txid;
+	int err;
+
+	memset(frame, 0, sizeof(*frame));
+
+	if (priv->can_idx == 0)
+		frame->tag = NCT6694_CAN_FRAME_TAG_CAN0;
+	else
+		frame->tag = NCT6694_CAN_FRAME_TAG_CAN1;
+
+	if (can_is_canfd_skb(skb)) {
+		cfd = (struct canfd_frame *)priv->tx_skb->data;
+
+		if (cfd->flags & CANFD_BRS)
+			frame->flag |= NCT6694_CAN_FRAME_FLAG_BRS;
+
+		if (cfd->can_id & CAN_EFF_FLAG) {
+			txid = cfd->can_id & CAN_EFF_MASK;
+			frame->flag |= NCT6694_CAN_FRAME_FLAG_EFF;
+		} else {
+			txid = cfd->can_id & CAN_SFF_MASK;
+		}
+		frame->flag |= NCT6694_CAN_FRAME_FLAG_FD;
+		frame->id = cpu_to_le32(txid);
+		frame->length = cfd->len;
+
+		memcpy(frame->data, cfd->data, cfd->len);
+	} else {
+		cf = (struct can_frame *)priv->tx_skb->data;
+
+		if (cf->can_id & CAN_RTR_FLAG)
+			frame->flag |= NCT6694_CAN_FRAME_FLAG_RTR;
+
+		if (cf->can_id & CAN_EFF_FLAG) {
+			txid = cf->can_id & CAN_EFF_MASK;
+			frame->flag |= NCT6694_CAN_FRAME_FLAG_EFF;
+		} else {
+			txid = cf->can_id & CAN_SFF_MASK;
+		}
+		frame->id = cpu_to_le32(txid);
+		frame->length = cf->len;
+
+		memcpy(frame->data, cf->data, cf->len);
+	}
+
+	err = nct6694_write_msg(priv->nct6694, &cmd_hd, frame);
+	if (err) {
+		netdev_err(ndev, "%s: Tx FIFO full!\n", __func__);
+		can_free_echo_skb(ndev, 0, NULL);
+		stats->tx_dropped++;
+		stats->tx_errors++;
+		netif_wake_queue(ndev);
+	}
+}
+
+static void nct6694_can_tx_work(struct work_struct *work)
+{
+	struct nct6694_can_priv *priv = container_of(work,
+						     struct nct6694_can_priv,
+						     tx_work);
+	struct net_device *ndev = priv->ndev;
+
+	guard(mutex)(&priv->lock);
+
+	if (priv->tx_skb) {
+		if (priv->can.state == CAN_STATE_BUS_OFF) {
+			nct6694_can_clean(ndev);
+		} else {
+			nct6694_can_tx(ndev);
+			can_put_echo_skb(priv->tx_skb, ndev, 0, 0);
+			priv->tx_skb = NULL;
+		}
+	}
+}
+
+static netdev_tx_t nct6694_can_start_xmit(struct sk_buff *skb,
+					  struct net_device *ndev)
+{
+	struct nct6694_can_priv *priv = netdev_priv(ndev);
+
+	if (can_dev_dropped_skb(ndev, skb))
+		return NETDEV_TX_OK;
+
+	if (priv->tx_skb) {
+		netdev_err(ndev, "hard_xmit called while tx busy\n");
+		return NETDEV_TX_BUSY;
+	}
+
+	netif_stop_queue(ndev);
+	priv->tx_skb = skb;
+	queue_work(priv->wq, &priv->tx_work);
+
+	return NETDEV_TX_OK;
+}
+
+static int nct6694_can_start(struct net_device *ndev)
+{
+	struct nct6694_can_priv *priv = netdev_priv(ndev);
+	struct nct6694_can_setting *setting = &priv->tx->setting;
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_CAN_MOD,
+		.cmd = NCT6694_CAN_SETTING,
+		.sel = NCT6694_CAN_SETTING_SEL(priv->can_idx),
+		.len = cpu_to_le16(sizeof(*setting))
+	};
+	const struct can_bittiming *n_bt = &priv->can.bittiming;
+	const struct can_bittiming *d_bt = &priv->can.data_bittiming;
+	int ret;
+
+	guard(mutex)(&priv->lock);
+
+	memset(setting, 0, sizeof(*setting));
+	setting->nbr = cpu_to_le32(n_bt->bitrate);
+	setting->dbr = cpu_to_le32(d_bt->bitrate);
+
+	if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
+		setting->ctrl1 |= cpu_to_le16(NCT6694_CAN_SETTING_CTRL1_MON);
+
+	if ((priv->can.ctrlmode & CAN_CTRLMODE_FD) &&
+	    priv->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO)
+		setting->ctrl1 |= cpu_to_le16(NCT6694_CAN_SETTING_CTRL1_NISO);
+
+	if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
+		setting->ctrl1 |= cpu_to_le16(NCT6694_CAN_SETTING_CTRL1_LBCK);
+
+	ret = nct6694_write_msg(priv->nct6694, &cmd_hd, setting);
+	if (ret)
+		return ret;
+
+	priv->can.state = CAN_STATE_ERROR_ACTIVE;
+
+	return ret;
+}
+
+static int nct6694_can_stop(struct net_device *ndev)
+{
+	struct nct6694_can_priv *priv = netdev_priv(ndev);
+
+	netif_stop_queue(ndev);
+	free_irq(ndev->irq, ndev);
+	destroy_workqueue(priv->wq);
+	priv->wq = NULL;
+	nct6694_can_clean(ndev);
+	priv->can.state = CAN_STATE_STOPPED;
+	can_rx_offload_disable(&priv->offload);
+	close_candev(ndev);
+
+	return 0;
+}
+
+static int nct6694_can_set_mode(struct net_device *ndev, enum can_mode mode)
+{
+	switch (mode) {
+	case CAN_MODE_START:
+		nct6694_can_clean(ndev);
+		nct6694_can_start(ndev);
+		netif_wake_queue(ndev);
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int nct6694_can_open(struct net_device *ndev)
+{
+	struct nct6694_can_priv *priv = netdev_priv(ndev);
+	int ret;
+
+	ret = open_candev(ndev);
+	if (ret)
+		return ret;
+
+	can_rx_offload_enable(&priv->offload);
+
+	ret = request_threaded_irq(ndev->irq, NULL,
+				   nct6694_can_irq, IRQF_ONESHOT,
+				   "nct6694_can", ndev);
+	if (ret) {
+		netdev_err(ndev, "Failed to request IRQ\n");
+		goto close_candev;
+	}
+
+	priv->wq = alloc_ordered_workqueue("%s-nct6694_wq",
+					   WQ_FREEZABLE | WQ_MEM_RECLAIM,
+					   ndev->name);
+	if (!priv->wq) {
+		ret = -ENOMEM;
+		goto free_irq;
+	}
+
+	priv->tx_skb = NULL;
+
+	ret = nct6694_can_start(ndev);
+	if (ret)
+		goto destroy_wq;
+
+	netif_start_queue(ndev);
+
+	return 0;
+
+destroy_wq:
+	destroy_workqueue(priv->wq);
+free_irq:
+	free_irq(ndev->irq, ndev);
+close_candev:
+	can_rx_offload_disable(&priv->offload);
+	close_candev(ndev);
+	return ret;
+}
+
+static const struct net_device_ops nct6694_can_netdev_ops = {
+	.ndo_open = nct6694_can_open,
+	.ndo_stop = nct6694_can_stop,
+	.ndo_start_xmit = nct6694_can_start_xmit,
+	.ndo_change_mtu = can_change_mtu,
+};
+
+static const struct ethtool_ops nct6694_can_ethtool_ops = {
+	.get_ts_info = ethtool_op_get_ts_info,
+};
+
+static int nct6694_can_get_clock(struct nct6694_can_priv *priv)
+{
+	struct nct6694_can_information *info = &priv->rx->info;
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_CAN_MOD,
+		.cmd = NCT6694_CAN_INFORMATION,
+		.sel = NCT6694_CAN_INFORMATION_SEL,
+		.len = cpu_to_le16(sizeof(*info))
+	};
+	int ret;
+
+	ret = nct6694_read_msg(priv->nct6694, &cmd_hd, info);
+	if (ret)
+		return ret;
+
+	return le32_to_cpu(info->can_clk);
+}
+
+static int nct6694_can_probe(struct platform_device *pdev)
+{
+	const struct mfd_cell *cell = mfd_get_cell(pdev);
+	struct nct6694 *nct6694 = dev_get_drvdata(pdev->dev.parent);
+	struct nct6694_can_priv *priv;
+	struct net_device *ndev;
+	int ret, irq, can_clk;
+
+	irq = irq_create_mapping(nct6694->domain,
+				 NCT6694_IRQ_CAN1 + cell->id);
+	if (!irq)
+		return irq;
+
+	ndev = alloc_candev(sizeof(struct nct6694_can_priv), 1);
+	if (!ndev)
+		return -ENOMEM;
+
+	ndev->irq = irq;
+	ndev->flags |= IFF_ECHO;
+	ndev->netdev_ops = &nct6694_can_netdev_ops;
+	ndev->ethtool_ops = &nct6694_can_ethtool_ops;
+
+	priv = netdev_priv(ndev);
+	priv->nct6694 = nct6694;
+	priv->ndev = ndev;
+
+	priv->tx = devm_kzalloc(&pdev->dev, sizeof(union nct6694_can_tx),
+				GFP_KERNEL);
+	if (!priv->tx) {
+		ret = -ENOMEM;
+		goto free_candev;
+	}
+
+	priv->rx = devm_kzalloc(&pdev->dev, sizeof(union nct6694_can_rx),
+				GFP_KERNEL);
+	if (!priv->rx) {
+		ret = -ENOMEM;
+		goto free_candev;
+	}
+
+	can_clk = nct6694_can_get_clock(priv);
+	if (can_clk < 0) {
+		ret = dev_err_probe(&pdev->dev, can_clk,
+				    "Failed to get clock\n");
+		goto free_candev;
+	}
+
+	devm_mutex_init(&pdev->dev, &priv->lock);
+	INIT_WORK(&priv->tx_work, nct6694_can_tx_work);
+
+	priv->can_idx = cell->id;
+	priv->can.state = CAN_STATE_STOPPED;
+	priv->can.clock.freq = can_clk;
+	priv->can.bittiming_const = &nct6694_can_bittiming_nominal_const;
+	priv->can.data_bittiming_const = &nct6694_can_bittiming_data_const;
+	priv->can.do_set_mode = nct6694_can_set_mode;
+	priv->can.do_get_berr_counter = nct6694_can_get_berr_counter;
+
+	priv->can.ctrlmode = CAN_CTRLMODE_FD;
+
+	priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK		|
+				       CAN_CTRLMODE_LISTENONLY		|
+				       CAN_CTRLMODE_FD			|
+				       CAN_CTRLMODE_FD_NON_ISO		|
+				       CAN_CTRLMODE_BERR_REPORTING;
+
+	ret = can_rx_offload_add_manual(ndev, &priv->offload,
+					NCT6694_NAPI_WEIGHT);
+	if (ret) {
+		dev_err_probe(&pdev->dev, ret, "Failed to add rx_offload\n");
+		goto free_candev;
+	}
+
+	platform_set_drvdata(pdev, priv);
+	SET_NETDEV_DEV(priv->ndev, &pdev->dev);
+
+	ret = register_candev(priv->ndev);
+	if (ret)
+		goto del_rx_offload;
+
+	return 0;
+
+del_rx_offload:
+	can_rx_offload_del(&priv->offload);
+free_candev:
+	free_candev(ndev);
+	return ret;
+}
+
+static void nct6694_can_remove(struct platform_device *pdev)
+{
+	struct nct6694_can_priv *priv = platform_get_drvdata(pdev);
+
+	cancel_work_sync(&priv->tx_work);
+	unregister_candev(priv->ndev);
+	can_rx_offload_del(&priv->offload);
+	free_candev(priv->ndev);
+}
+
+static struct platform_driver nct6694_can_driver = {
+	.driver = {
+		.name	= DRVNAME,
+	},
+	.probe		= nct6694_can_probe,
+	.remove		= nct6694_can_remove,
+};
+
+module_platform_driver(nct6694_can_driver);
+
+MODULE_DESCRIPTION("USB-CAN FD driver for NCT6694");
+MODULE_AUTHOR("Ming Yu <tmyu0@nuvoton.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:nct6694-can");
-- 
2.34.1

[PATCH v5 5/7] watchdog: Add Nuvoton NCT6694 WDT support

[Ming Yu]

This driver supports Watchdog timer functionality for NCT6694 MFD
device based on USB interface.

Signed-off-by: Ming Yu <a0282524688@gmail.com>
---
 MAINTAINERS                    |   1 +
 drivers/watchdog/Kconfig       |  11 ++
 drivers/watchdog/Makefile      |   1 +
 drivers/watchdog/nct6694_wdt.c | 295 +++++++++++++++++++++++++++++++++
 4 files changed, 308 insertions(+)
 create mode 100644 drivers/watchdog/nct6694_wdt.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 6e9b78202d6f..a772747d493f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16725,6 +16725,7 @@ F:	drivers/gpio/gpio-nct6694.c
 F:	drivers/i2c/busses/i2c-nct6694.c
 F:	drivers/mfd/nct6694.c
 F:	drivers/net/can/usb/nct6694_canfd.c
+F:	drivers/watchdog/nct6694_wdt.c
 F:	include/linux/mfd/nct6694.h
 
 NVIDIA (rivafb and nvidiafb) FRAMEBUFFER DRIVER
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index f81705f8539a..4c4f826368c4 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -748,6 +748,17 @@ config MAX77620_WATCHDOG
 	  MAX77620 chips. To compile this driver as a module,
 	  choose M here: the module will be called max77620_wdt.
 
+config NCT6694_WATCHDOG
+	tristate "Nuvoton NCT6694 watchdog support"
+	depends on MFD_NCT6694
+	select WATCHDOG_CORE
+	help
+	  Say Y here to support Nuvoton NCT6694 watchdog timer
+	  functionality.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called nct6694_wdt.
+
 config IMX2_WDT
 	tristate "IMX2+ Watchdog"
 	depends on ARCH_MXC || ARCH_LAYERSCAPE || COMPILE_TEST
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 8411626fa162..de2a04ff8a92 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -232,6 +232,7 @@ obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o
 obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o
 obj-$(CONFIG_MAX63XX_WATCHDOG) += max63xx_wdt.o
 obj-$(CONFIG_MAX77620_WATCHDOG) += max77620_wdt.o
+obj-$(CONFIG_NCT6694_WATCHDOG) += nct6694_wdt.o
 obj-$(CONFIG_ZIIRAVE_WATCHDOG) += ziirave_wdt.o
 obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
 obj-$(CONFIG_MENF21BMC_WATCHDOG) += menf21bmc_wdt.o
diff --git a/drivers/watchdog/nct6694_wdt.c b/drivers/watchdog/nct6694_wdt.c
new file mode 100644
index 000000000000..351867c2fd1d
--- /dev/null
+++ b/drivers/watchdog/nct6694_wdt.c
@@ -0,0 +1,295 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Nuvoton NCT6694 WDT driver based on USB interface.
+ *
+ * Copyright (C) 2024 Nuvoton Technology Corp.
+ */
+
+#include <linux/kernel.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/nct6694.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/watchdog.h>
+
+#define DRVNAME "nct6694-wdt"
+
+#define NCT6694_DEFAULT_TIMEOUT		10
+#define NCT6694_DEFAULT_PRETIMEOUT	0
+
+/*
+ * USB command module type for NCT6694 WDT controller.
+ * This defines the module type used for communication with the NCT6694
+ * WDT controller over the USB interface.
+ */
+#define NCT6694_WDT_MOD			0x07
+
+/* Command 00h - WDT Setup */
+#define NCT6694_WDT_SETUP		0x00
+#define NCT6694_WDT_SETUP_SEL(idx)	(idx ? 0x01 : 0x00)
+
+/* Command 01h - WDT Command */
+#define NCT6694_WDT_COMMAND		0x01
+#define NCT6694_WDT_COMMAND_SEL(idx)	(idx ? 0x01 : 0x00)
+
+static unsigned int timeout = NCT6694_DEFAULT_TIMEOUT;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
+
+static unsigned int pretimeout = NCT6694_DEFAULT_PRETIMEOUT;
+module_param(pretimeout, int, 0);
+MODULE_PARM_DESC(pretimeout, "Watchdog pre-timeout in seconds");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+			   __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+enum {
+	NCT6694_ACTION_NONE = 0,
+	NCT6694_ACTION_SIRQ,
+	NCT6694_ACTION_GPO,
+};
+
+struct __packed nct6694_wdt_setup {
+	__le32 pretimeout;
+	__le32 timeout;
+	u8 owner;
+	u8 scratch;
+	u8 control;
+	u8 status;
+	__le32 countdown;
+};
+
+struct __packed nct6694_wdt_cmd {
+	__le32 wdt_cmd;
+	__le32 reserved;
+};
+
+union __packed nct6694_wdt_msg {
+	struct nct6694_wdt_setup setup;
+	struct nct6694_wdt_cmd cmd;
+};
+
+struct nct6694_wdt_data {
+	struct watchdog_device wdev;
+	struct device *dev;
+	struct nct6694 *nct6694;
+	struct mutex lock;
+	union nct6694_wdt_msg *msg;
+	unsigned int wdev_idx;
+};
+
+static int nct6694_wdt_setting(struct watchdog_device *wdev,
+			       u32 timeout_val, u8 timeout_act,
+			       u32 pretimeout_val, u8 pretimeout_act)
+{
+	struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
+	struct nct6694_wdt_setup *setup = &data->msg->setup;
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_WDT_MOD,
+		.cmd = NCT6694_WDT_SETUP,
+		.sel = NCT6694_WDT_SETUP_SEL(data->wdev_idx),
+		.len = cpu_to_le16(sizeof(*setup))
+	};
+	unsigned int timeout_fmt, pretimeout_fmt;
+
+	guard(mutex)(&data->lock);
+
+	if (pretimeout_val == 0)
+		pretimeout_act = NCT6694_ACTION_NONE;
+
+	timeout_fmt = (timeout_val * 1000) | (timeout_act << 24);
+	pretimeout_fmt = (pretimeout_val * 1000) | (pretimeout_act << 24);
+
+	memset(setup, 0, sizeof(*setup));
+	setup->timeout = cpu_to_le32(timeout_fmt);
+	setup->pretimeout = cpu_to_le32(pretimeout_fmt);
+
+	return nct6694_write_msg(data->nct6694, &cmd_hd, setup);
+}
+
+static int nct6694_wdt_start(struct watchdog_device *wdev)
+{
+	struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
+	int ret;
+
+	ret = nct6694_wdt_setting(wdev, wdev->timeout, NCT6694_ACTION_GPO,
+				  wdev->pretimeout, NCT6694_ACTION_GPO);
+	if (ret)
+		return ret;
+
+	dev_dbg(data->dev, "Setting WDT(%d): timeout = %d, pretimeout = %d\n",
+		data->wdev_idx, wdev->timeout, wdev->pretimeout);
+
+	return ret;
+}
+
+static int nct6694_wdt_stop(struct watchdog_device *wdev)
+{
+	struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
+	struct nct6694_wdt_cmd *cmd = &data->msg->cmd;
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_WDT_MOD,
+		.cmd = NCT6694_WDT_COMMAND,
+		.sel = NCT6694_WDT_COMMAND_SEL(data->wdev_idx),
+		.len = cpu_to_le16(sizeof(*cmd))
+	};
+
+	guard(mutex)(&data->lock);
+
+	memcpy(&cmd->wdt_cmd, "WDTC", 4);
+	cmd->reserved = 0;
+
+	return nct6694_write_msg(data->nct6694, &cmd_hd, cmd);
+}
+
+static int nct6694_wdt_ping(struct watchdog_device *wdev)
+{
+	struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
+	struct nct6694_wdt_cmd *cmd = &data->msg->cmd;
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_WDT_MOD,
+		.cmd = NCT6694_WDT_COMMAND,
+		.sel = NCT6694_WDT_COMMAND_SEL(data->wdev_idx),
+		.len = cpu_to_le16(sizeof(*cmd))
+	};
+
+	guard(mutex)(&data->lock);
+	memcpy(&cmd->wdt_cmd, "WDTS", 4);
+	cmd->reserved = 0;
+
+	return nct6694_write_msg(data->nct6694, &cmd_hd, cmd);
+}
+
+static int nct6694_wdt_set_timeout(struct watchdog_device *wdev,
+				   unsigned int timeout)
+{
+	int ret;
+
+	ret = nct6694_wdt_setting(wdev, timeout, NCT6694_ACTION_GPO,
+				  wdev->pretimeout, NCT6694_ACTION_GPO);
+	if (ret)
+		return ret;
+
+	wdev->timeout = timeout;
+
+	return 0;
+}
+
+static int nct6694_wdt_set_pretimeout(struct watchdog_device *wdev,
+				      unsigned int pretimeout)
+{
+	int ret;
+
+	ret = nct6694_wdt_setting(wdev, wdev->timeout, NCT6694_ACTION_GPO,
+				  pretimeout, NCT6694_ACTION_GPO);
+	if (ret)
+		return ret;
+
+	wdev->pretimeout = pretimeout;
+
+	return 0;
+}
+
+static unsigned int nct6694_wdt_get_time(struct watchdog_device *wdev)
+{
+	struct nct6694_wdt_data *data = watchdog_get_drvdata(wdev);
+	struct nct6694_wdt_setup *setup = &data->msg->setup;
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_WDT_MOD,
+		.cmd = NCT6694_WDT_SETUP,
+		.sel = NCT6694_WDT_SETUP_SEL(data->wdev_idx),
+		.len = cpu_to_le16(sizeof(*setup))
+	};
+	unsigned int timeleft_ms;
+	int ret;
+
+	guard(mutex)(&data->lock);
+
+	ret = nct6694_read_msg(data->nct6694, &cmd_hd, setup);
+	if (ret)
+		return 0;
+
+	timeleft_ms = le32_to_cpu(setup->countdown);
+
+	return timeleft_ms / 1000;
+}
+
+static const struct watchdog_info nct6694_wdt_info = {
+	.options = WDIOF_SETTIMEOUT	|
+		   WDIOF_KEEPALIVEPING	|
+		   WDIOF_MAGICCLOSE	|
+		   WDIOF_PRETIMEOUT,
+	.identity = DRVNAME,
+};
+
+static const struct watchdog_ops nct6694_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = nct6694_wdt_start,
+	.stop = nct6694_wdt_stop,
+	.set_timeout = nct6694_wdt_set_timeout,
+	.set_pretimeout = nct6694_wdt_set_pretimeout,
+	.get_timeleft = nct6694_wdt_get_time,
+	.ping = nct6694_wdt_ping,
+};
+
+static int nct6694_wdt_probe(struct platform_device *pdev)
+{
+	const struct mfd_cell *cell = mfd_get_cell(pdev);
+	struct device *dev = &pdev->dev;
+	struct nct6694 *nct6694 = dev_get_drvdata(pdev->dev.parent);
+	struct nct6694_wdt_data *data;
+	struct watchdog_device *wdev;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->msg = devm_kzalloc(dev, sizeof(union nct6694_wdt_msg),
+				 GFP_KERNEL);
+	if (!data->msg)
+		return -ENOMEM;
+
+	data->dev = dev;
+	data->nct6694 = nct6694;
+	data->wdev_idx = cell->id;
+
+	wdev = &data->wdev;
+	wdev->info = &nct6694_wdt_info;
+	wdev->ops = &nct6694_wdt_ops;
+	wdev->timeout = timeout;
+	wdev->pretimeout = pretimeout;
+	if (timeout < pretimeout) {
+		dev_warn(data->dev, "pretimeout < timeout. Setting to zero\n");
+		wdev->pretimeout = 0;
+	}
+
+	wdev->min_timeout = 1;
+	wdev->max_timeout = 255;
+
+	devm_mutex_init(dev, &data->lock);
+
+	platform_set_drvdata(pdev, data);
+
+	watchdog_set_drvdata(&data->wdev, data);
+	watchdog_set_nowayout(&data->wdev, nowayout);
+	watchdog_stop_on_reboot(&data->wdev);
+
+	return devm_watchdog_register_device(dev, &data->wdev);
+}
+
+static struct platform_driver nct6694_wdt_driver = {
+	.driver = {
+		.name	= DRVNAME,
+	},
+	.probe		= nct6694_wdt_probe,
+};
+
+module_platform_driver(nct6694_wdt_driver);
+
+MODULE_DESCRIPTION("USB-WDT driver for NCT6694");
+MODULE_AUTHOR("Ming Yu <tmyu0@nuvoton.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:nct6694-wdt");
-- 
2.34.1

[PATCH v5 6/7] hwmon: Add Nuvoton NCT6694 HWMON support

[Ming Yu]

This driver supports Hardware monitor functionality for NCT6694 MFD
device based on USB interface.

Signed-off-by: Ming Yu <a0282524688@gmail.com>
---
 MAINTAINERS                   |   1 +
 drivers/hwmon/Kconfig         |  10 +
 drivers/hwmon/Makefile        |   1 +
 drivers/hwmon/nct6694-hwmon.c | 947 ++++++++++++++++++++++++++++++++++
 4 files changed, 959 insertions(+)
 create mode 100644 drivers/hwmon/nct6694-hwmon.c

diff --git a/MAINTAINERS b/MAINTAINERS
index a772747d493f..a14a2d65b8a6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16722,6 +16722,7 @@ M:	Ming Yu <tmyu0@nuvoton.com>
 L:	linux-kernel@vger.kernel.org
 S:	Supported
 F:	drivers/gpio/gpio-nct6694.c
+F:	drivers/hwmon/nct6694-hwmon.c
 F:	drivers/i2c/busses/i2c-nct6694.c
 F:	drivers/mfd/nct6694.c
 F:	drivers/net/can/usb/nct6694_canfd.c
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index dd376602f3f1..df40986424bd 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1636,6 +1636,16 @@ config SENSORS_NCT6683
 	  This driver can also be built as a module. If so, the module
 	  will be called nct6683.
 
+config SENSORS_NCT6694
+	tristate "Nuvoton NCT6694 Hardware Monitor support"
+	depends on MFD_NCT6694
+	help
+	  Say Y here to support Nuvoton NCT6694 hardware monitoring
+	  functionality.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called nct6694-hwmon.
+
 config SENSORS_NCT6775_CORE
 	tristate
 	select REGMAP
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index b827b92f2a78..27a43e67cdb7 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -168,6 +168,7 @@ obj-$(CONFIG_SENSORS_MLXREG_FAN) += mlxreg-fan.o
 obj-$(CONFIG_SENSORS_MENF21BMC_HWMON) += menf21bmc_hwmon.o
 obj-$(CONFIG_SENSORS_MR75203)	+= mr75203.o
 obj-$(CONFIG_SENSORS_NCT6683)	+= nct6683.o
+obj-$(CONFIG_SENSORS_NCT6694)	+= nct6694-hwmon.o
 obj-$(CONFIG_SENSORS_NCT6775_CORE) += nct6775-core.o
 nct6775-objs			:= nct6775-platform.o
 obj-$(CONFIG_SENSORS_NCT6775)	+= nct6775.o
diff --git a/drivers/hwmon/nct6694-hwmon.c b/drivers/hwmon/nct6694-hwmon.c
new file mode 100644
index 000000000000..b2f115b5d8eb
--- /dev/null
+++ b/drivers/hwmon/nct6694-hwmon.c
@@ -0,0 +1,947 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Nuvoton NCT6694 HWMON driver based on USB interface.
+ *
+ * Copyright (C) 2024 Nuvoton Technology Corp.
+ */
+
+#include <linux/bits.h>
+#include <linux/bitfield.h>
+#include <linux/hwmon.h>
+#include <linux/kernel.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/nct6694.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+/*
+ * USB command module type for NCT6694 report channel
+ * This defines the module type used for communication with the NCT6694
+ * report channel over the USB interface.
+ */
+#define NCT6694_RPT_MOD			0xFF
+
+/* Report channel */
+/*
+ * The report channel is used to report the status of the hardware monitor
+ * devices, such as voltage, temperature, fan speed, and PWM.
+ */
+#define NCT6694_VIN_IDX(x)		(0x00 + (x))
+#define NCT6694_TIN_IDX(x)			\
+	({ typeof(x) (_x) = (x);		\
+	 ((_x) < 10) ? (0x10 + ((_x) * 2)) :	\
+	 (0x30 + (((_x) - 10) * 2)); })
+#define NCT6694_FIN_IDX(x)		(0x50 + ((x) * 2))
+#define NCT6694_PWM_IDX(x)		(0x70 + (x))
+#define NCT6694_VIN_STS(x)		(0x68 + (x))
+#define NCT6694_TIN_STS(x)		(0x6A + (x))
+#define NCT6694_FIN_STS(x)		(0x6E + (x))
+
+/*
+ * USB command module type for NCT6694 HWMON controller.
+ * This defines the module type used for communication with the NCT6694
+ * HWMON controller over the USB interface.
+ */
+#define NCT6694_HWMON_MOD		0x00
+
+/* Command 00h - Hardware Monitor Control */
+#define NCT6694_HWMON_CONTROL		0x00
+#define NCT6694_HWMON_CONTROL_SEL	0x00
+
+/* Command 02h - Alarm Control */
+#define NCT6694_HWMON_ALARM		0x02
+#define NCT6694_HWMON_ALARM_SEL		0x00
+
+/*
+ * USB command module type for NCT6694 PWM controller.
+ * This defines the module type used for communication with the NCT6694
+ * PWM controller over the USB interface.
+ */
+#define NCT6694_PWM_MOD			0x01
+
+/* PWM Command - Manual Control */
+#define NCT6694_PWM_CONTROL		0x01
+#define NCT6694_PWM_CONTROL_SEL		0x00
+
+#define NCT6694_FREQ_FROM_REG(reg)	((reg) * 25000 / 255)
+#define NCT6694_FREQ_TO_REG(val)	\
+	(DIV_ROUND_CLOSEST(clamp_val((val), 100, 25000) * 255, 25000))
+
+#define NCT6694_LSB_REG_MASK		GENMASK(7, 5)
+#define NCT6694_TIN_HYST_MASK		GENMASK(7, 5)
+
+enum nct6694_hwmon_temp_mode {
+	NCT6694_HWMON_TWOTIME_IRQ = 0,
+	NCT6694_HWMON_ONETIME_IRQ,
+	NCT6694_HWMON_REALTIME_IRQ,
+	NCT6694_HWMON_COMPARE_IRQ,
+};
+
+struct __packed nct6694_hwmon_control {
+	u8 vin_en[2];
+	u8 tin_en[2];
+	u8 fin_en[2];
+	u8 pwm_en[2];
+	u8 reserved1[40];
+	u8 pwm_freq[10];
+	u8 reserved2[6];
+};
+
+struct __packed nct6694_hwmon_alarm {
+	u8 smi_ctrl;
+	u8 reserved1[15];
+	struct {
+		u8 hl;
+		u8 ll;
+	} vin_limit[16];
+	struct {
+		u8 hyst;
+		s8 hl;
+	} tin_cfg[32];
+	__be16 fin_ll[10];
+	u8 reserved2[4];
+};
+
+struct __packed nct6694_pwm_control {
+	u8 mal_en[2];
+	u8 mal_val[10];
+	u8 reserved[12];
+};
+
+union __packed nct6694_hwmon_rpt {
+	u8 vin;
+	struct {
+		u8 msb;
+		u8 lsb;
+	} tin;
+	__be16 fin;
+	u8 pwm;
+	u8 status;
+};
+
+union __packed nct6694_hwmon_msg {
+	struct nct6694_hwmon_alarm hwmon_alarm;
+	struct nct6694_pwm_control pwm_ctrl;
+};
+
+struct nct6694_hwmon_data {
+	struct nct6694 *nct6694;
+	struct mutex lock;
+	struct nct6694_hwmon_control hwmon_en;
+	union nct6694_hwmon_rpt *rpt;
+	union nct6694_hwmon_msg *msg;
+};
+
+static inline long in_from_reg(u8 reg)
+{
+	return reg * 16;
+}
+
+static inline u8 in_to_reg(long val)
+{
+	return DIV_ROUND_CLOSEST(val, 16);
+}
+
+static inline long temp_from_reg(s8 reg)
+{
+	return reg * 1000;
+}
+
+static inline s8 temp_to_reg(long val)
+{
+	return DIV_ROUND_CLOSEST(val, 1000);
+}
+
+#define NCT6694_HWMON_IN_CONFIG (HWMON_I_INPUT | HWMON_I_ENABLE |	\
+				 HWMON_I_MAX | HWMON_I_MIN |		\
+				 HWMON_I_ALARM)
+#define NCT6694_HWMON_TEMP_CONFIG (HWMON_T_INPUT | HWMON_T_ENABLE |	\
+				   HWMON_T_MAX | HWMON_T_MAX_HYST |	\
+				   HWMON_T_MAX_ALARM)
+#define NCT6694_HWMON_FAN_CONFIG (HWMON_F_INPUT | HWMON_F_ENABLE |	\
+				  HWMON_F_MIN | HWMON_F_MIN_ALARM)
+#define NCT6694_HWMON_PWM_CONFIG (HWMON_PWM_INPUT | HWMON_PWM_ENABLE |	\
+				  HWMON_PWM_FREQ)
+static const struct hwmon_channel_info *nct6694_info[] = {
+	HWMON_CHANNEL_INFO(in,
+			   NCT6694_HWMON_IN_CONFIG,	/* VIN0 */
+			   NCT6694_HWMON_IN_CONFIG,	/* VIN1 */
+			   NCT6694_HWMON_IN_CONFIG,	/* VIN2 */
+			   NCT6694_HWMON_IN_CONFIG,	/* VIN3 */
+			   NCT6694_HWMON_IN_CONFIG,	/* VIN5 */
+			   NCT6694_HWMON_IN_CONFIG,	/* VIN6 */
+			   NCT6694_HWMON_IN_CONFIG,	/* VIN7 */
+			   NCT6694_HWMON_IN_CONFIG,	/* VIN14 */
+			   NCT6694_HWMON_IN_CONFIG,	/* VIN15 */
+			   NCT6694_HWMON_IN_CONFIG,	/* VIN16 */
+			   NCT6694_HWMON_IN_CONFIG,	/* VBAT */
+			   NCT6694_HWMON_IN_CONFIG,	/* VSB */
+			   NCT6694_HWMON_IN_CONFIG,	/* AVSB */
+			   NCT6694_HWMON_IN_CONFIG,	/* VCC */
+			   NCT6694_HWMON_IN_CONFIG,	/* VHIF */
+			   NCT6694_HWMON_IN_CONFIG),	/* VTT */
+
+	HWMON_CHANNEL_INFO(temp,
+			   NCT6694_HWMON_TEMP_CONFIG,	/* THR1 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* THR2 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* THR14 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* THR15 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* THR16 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* TDP0 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* TDP1 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* TDP2 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* TDP3 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* TDP4 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* DTIN0 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* DTIN1 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* DTIN2 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* DTIN3 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* DTIN4 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* DTIN5 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* DTIN6 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* DTIN7 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* DTIN8 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* DTIN9 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* DTIN10 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* DTIN11 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* DTIN12 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* DTIN13 */
+			   NCT6694_HWMON_TEMP_CONFIG,	/* DTIN14 */
+			   NCT6694_HWMON_TEMP_CONFIG),	/* DTIN15 */
+
+	HWMON_CHANNEL_INFO(fan,
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN0 */
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN1 */
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN2 */
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN3 */
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN4 */
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN5 */
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN6 */
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN7 */
+			   NCT6694_HWMON_FAN_CONFIG,	/* FIN8 */
+			   NCT6694_HWMON_FAN_CONFIG),	/* FIN9 */
+
+	HWMON_CHANNEL_INFO(pwm,
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM0 */
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM1 */
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM2 */
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM3 */
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM4 */
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM5 */
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM6 */
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM7 */
+			   NCT6694_HWMON_PWM_CONFIG,	/* PWM8 */
+			   NCT6694_HWMON_PWM_CONFIG),	/* PWM9 */
+	NULL
+};
+
+static int nct6694_in_read(struct device *dev, u32 attr, int channel,
+			   long *val)
+{
+	struct nct6694_hwmon_data *data = dev_get_drvdata(dev);
+	struct nct6694_cmd_header cmd_hd;
+	unsigned char vin_en;
+	int ret;
+
+	guard(mutex)(&data->lock);
+
+	switch (attr) {
+	case hwmon_in_enable:
+		vin_en = data->hwmon_en.vin_en[(channel / 8)];
+		*val = !!(vin_en & BIT(channel % 8));
+
+		return 0;
+	case hwmon_in_input:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_RPT_MOD,
+			.offset = cpu_to_le16(NCT6694_VIN_IDX(channel)),
+			.len = cpu_to_le16(sizeof(data->rpt->vin))
+		};
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->rpt->vin);
+		if (ret)
+			return ret;
+
+		*val = in_from_reg(data->rpt->vin);
+
+		return 0;
+	case hwmon_in_max:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_HWMON_MOD,
+			.cmd = NCT6694_HWMON_ALARM,
+			.sel = NCT6694_HWMON_ALARM_SEL,
+			.len = cpu_to_le16(sizeof(data->msg->hwmon_alarm))
+		};
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->msg->hwmon_alarm);
+		if (ret)
+			return ret;
+
+		*val = in_from_reg(data->msg->hwmon_alarm.vin_limit[channel].hl);
+
+		return 0;
+	case hwmon_in_min:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_HWMON_MOD,
+			.cmd = NCT6694_HWMON_ALARM,
+			.sel = NCT6694_HWMON_ALARM_SEL,
+			.len = cpu_to_le16(sizeof(data->msg->hwmon_alarm))
+		};
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->msg->hwmon_alarm);
+		if (ret)
+			return ret;
+
+		*val = in_from_reg(data->msg->hwmon_alarm.vin_limit[channel].ll);
+
+		return 0;
+	case hwmon_in_alarm:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_RPT_MOD,
+			.offset = cpu_to_le16(NCT6694_VIN_STS(channel / 8)),
+			.len = cpu_to_le16(sizeof(data->rpt->status))
+		};
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->rpt->status);
+		if (ret)
+			return ret;
+
+		*val = !!(data->rpt->status & BIT(channel % 8));
+
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int nct6694_temp_read(struct device *dev, u32 attr, int channel,
+			     long *val)
+{
+	struct nct6694_hwmon_data *data = dev_get_drvdata(dev);
+	struct nct6694_cmd_header cmd_hd;
+	unsigned char temp_en, temp_hyst;
+	signed char temp_max;
+	int ret, temp_raw;
+
+	guard(mutex)(&data->lock);
+
+	switch (attr) {
+	case hwmon_temp_enable:
+		temp_en = data->hwmon_en.tin_en[channel / 8];
+		*val = !!(temp_en & BIT(channel % 8));
+
+		return 0;
+	case hwmon_temp_input:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_RPT_MOD,
+			.offset = cpu_to_le16(NCT6694_TIN_IDX(channel)),
+			.len = cpu_to_le16(sizeof(data->rpt->tin))
+		};
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->rpt->tin);
+		if (ret)
+			return ret;
+
+		temp_raw = data->rpt->tin.msb << 3;
+		temp_raw |= FIELD_GET(NCT6694_LSB_REG_MASK, data->rpt->tin.lsb);
+
+		/* Real temperature(milli degrees Celsius) = temp_raw * 1000 * 0.125 */
+		*val = sign_extend32(temp_raw, 10) * 125;
+
+		return 0;
+	case hwmon_temp_max:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_HWMON_MOD,
+			.cmd = NCT6694_HWMON_ALARM,
+			.sel = NCT6694_HWMON_ALARM_SEL,
+			.len = cpu_to_le16(sizeof(data->msg->hwmon_alarm))
+		};
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->msg->hwmon_alarm);
+		if (ret)
+			return ret;
+
+		*val = temp_from_reg(data->msg->hwmon_alarm.tin_cfg[channel].hl);
+
+		return 0;
+	case hwmon_temp_max_hyst:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_HWMON_MOD,
+			.cmd = NCT6694_HWMON_ALARM,
+			.sel = NCT6694_HWMON_ALARM_SEL,
+			.len = cpu_to_le16(sizeof(data->msg->hwmon_alarm))
+		};
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->msg->hwmon_alarm);
+		if (ret)
+			return ret;
+
+		temp_max = data->msg->hwmon_alarm.tin_cfg[channel].hl;
+		temp_hyst = FIELD_GET(NCT6694_TIN_HYST_MASK,
+				      data->msg->hwmon_alarm.tin_cfg[channel].hyst);
+		*val = temp_from_reg(temp_max - temp_hyst);
+
+		return 0;
+	case hwmon_temp_max_alarm:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_RPT_MOD,
+			.offset = cpu_to_le16(NCT6694_TIN_STS(channel / 8)),
+			.len = cpu_to_le16(sizeof(data->rpt->status))
+		};
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->rpt->status);
+		if (ret)
+			return ret;
+
+		*val = !!(data->rpt->status & BIT(channel % 8));
+
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int nct6694_fan_read(struct device *dev, u32 attr, int channel,
+			    long *val)
+{
+	struct nct6694_hwmon_data *data = dev_get_drvdata(dev);
+	struct nct6694_cmd_header cmd_hd;
+	unsigned char fanin_en;
+	int ret;
+
+	guard(mutex)(&data->lock);
+
+	switch (attr) {
+	case hwmon_fan_enable:
+		fanin_en = data->hwmon_en.fin_en[channel / 8];
+		*val = !!(fanin_en & BIT(channel % 8));
+
+		return 0;
+	case hwmon_fan_input:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_RPT_MOD,
+			.offset = cpu_to_le16(NCT6694_FIN_IDX(channel)),
+			.len = cpu_to_le16(sizeof(data->rpt->fin))
+		};
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->rpt->fin);
+		if (ret)
+			return ret;
+
+		*val = be16_to_cpu(data->rpt->fin);
+
+		return 0;
+	case hwmon_fan_min:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_HWMON_MOD,
+			.cmd = NCT6694_HWMON_ALARM,
+			.sel = NCT6694_HWMON_ALARM_SEL,
+			.len = cpu_to_le16(sizeof(data->msg->hwmon_alarm))
+		};
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->msg->hwmon_alarm);
+		if (ret)
+			return ret;
+
+		*val = be16_to_cpu(data->msg->hwmon_alarm.fin_ll[channel]);
+
+		return 0;
+	case hwmon_fan_min_alarm:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_RPT_MOD,
+			.offset = cpu_to_le16(NCT6694_FIN_STS(channel / 8)),
+			.len = cpu_to_le16(sizeof(data->rpt->status))
+		};
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->rpt->status);
+		if (ret)
+			return ret;
+
+		*val = !!(data->rpt->status & BIT(channel % 8));
+
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int nct6694_pwm_read(struct device *dev, u32 attr, int channel,
+			    long *val)
+{
+	struct nct6694_hwmon_data *data = dev_get_drvdata(dev);
+	struct nct6694_cmd_header cmd_hd;
+	unsigned char pwm_en;
+	int ret;
+
+	guard(mutex)(&data->lock);
+
+	switch (attr) {
+	case hwmon_pwm_enable:
+		pwm_en = data->hwmon_en.pwm_en[channel / 8];
+		*val = !!(pwm_en & BIT(channel % 8));
+
+		return 0;
+	case hwmon_pwm_input:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_RPT_MOD,
+			.offset = cpu_to_le16(NCT6694_PWM_IDX(channel)),
+			.len = cpu_to_le16(sizeof(data->rpt->pwm))
+		};
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->rpt->pwm);
+		if (ret)
+			return ret;
+
+		*val = data->rpt->pwm;
+
+		return 0;
+	case hwmon_pwm_freq:
+		*val = NCT6694_FREQ_FROM_REG(data->hwmon_en.pwm_freq[channel]);
+
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int nct6694_in_write(struct device *dev, u32 attr, int channel,
+			    long val)
+{
+	struct nct6694_hwmon_data *data = dev_get_drvdata(dev);
+	struct nct6694_cmd_header cmd_hd;
+	int ret;
+
+	guard(mutex)(&data->lock);
+
+	switch (attr) {
+	case hwmon_in_enable:
+		if (val == 0)
+			data->hwmon_en.vin_en[channel / 8] &= ~BIT(channel % 8);
+		else if (val == 1)
+			data->hwmon_en.vin_en[channel / 8] |= BIT(channel % 8);
+		else
+			return -EINVAL;
+
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_HWMON_MOD,
+			.cmd = NCT6694_HWMON_CONTROL,
+			.sel = NCT6694_HWMON_CONTROL_SEL,
+			.len = cpu_to_le16(sizeof(data->hwmon_en))
+		};
+
+		return nct6694_write_msg(data->nct6694, &cmd_hd,
+					 &data->hwmon_en);
+	case hwmon_in_max:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_HWMON_MOD,
+			.cmd = NCT6694_HWMON_ALARM,
+			.sel = NCT6694_HWMON_ALARM_SEL,
+			.len = cpu_to_le16(sizeof(data->msg->hwmon_alarm))
+		};
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->msg->hwmon_alarm);
+		if (ret)
+			return ret;
+
+		val = clamp_val(val, 0, 2032);
+		data->msg->hwmon_alarm.vin_limit[channel].hl = in_to_reg(val);
+
+		return nct6694_write_msg(data->nct6694, &cmd_hd,
+					 &data->msg->hwmon_alarm);
+	case hwmon_in_min:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_HWMON_MOD,
+			.cmd = NCT6694_HWMON_ALARM,
+			.sel = NCT6694_HWMON_ALARM_SEL,
+			.len = cpu_to_le16(sizeof(data->msg->hwmon_alarm))
+		};
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->msg->hwmon_alarm);
+		if (ret)
+			return ret;
+
+		val = clamp_val(val, 0, 2032);
+		data->msg->hwmon_alarm.vin_limit[channel].ll = in_to_reg(val);
+
+		return nct6694_write_msg(data->nct6694, &cmd_hd,
+					 &data->msg->hwmon_alarm);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int nct6694_temp_write(struct device *dev, u32 attr, int channel,
+			      long val)
+{
+	struct nct6694_hwmon_data *data = dev_get_drvdata(dev);
+	struct nct6694_cmd_header cmd_hd;
+	unsigned char temp_hyst;
+	signed char temp_max;
+	int ret;
+
+	guard(mutex)(&data->lock);
+
+	switch (attr) {
+	case hwmon_temp_enable:
+		if (val == 0)
+			data->hwmon_en.tin_en[channel / 8] &= ~BIT(channel % 8);
+		else if (val == 1)
+			data->hwmon_en.tin_en[channel / 8] |= BIT(channel % 8);
+		else
+			return -EINVAL;
+
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_HWMON_MOD,
+			.cmd = NCT6694_HWMON_CONTROL,
+			.sel = NCT6694_HWMON_CONTROL_SEL,
+			.len = cpu_to_le16(sizeof(data->hwmon_en))
+		};
+
+		return nct6694_write_msg(data->nct6694, &cmd_hd,
+					 &data->hwmon_en);
+	case hwmon_temp_max:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_HWMON_MOD,
+			.cmd = NCT6694_HWMON_ALARM,
+			.sel = NCT6694_HWMON_ALARM_SEL,
+			.len = cpu_to_le16(sizeof(data->msg->hwmon_alarm))
+		};
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->msg->hwmon_alarm);
+		if (ret)
+			return ret;
+
+		val = clamp_val(val, -127000, 127000);
+		data->msg->hwmon_alarm.tin_cfg[channel].hl = temp_to_reg(val);
+
+		return nct6694_write_msg(data->nct6694, &cmd_hd,
+					 &data->msg->hwmon_alarm);
+	case hwmon_temp_max_hyst:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_HWMON_MOD,
+			.cmd = NCT6694_HWMON_ALARM,
+			.sel = NCT6694_HWMON_ALARM_SEL,
+			.len = cpu_to_le16(sizeof(data->msg->hwmon_alarm))
+		};
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->msg->hwmon_alarm);
+
+		val = clamp_val(val, -127000, 127000);
+		temp_max = data->msg->hwmon_alarm.tin_cfg[channel].hl;
+		temp_hyst = temp_max - temp_to_reg(val);
+		temp_hyst = clamp_val(temp_hyst, 0, 7);
+		data->msg->hwmon_alarm.tin_cfg[channel].hyst =
+			(data->msg->hwmon_alarm.tin_cfg[channel].hyst & ~NCT6694_TIN_HYST_MASK) |
+			FIELD_PREP(NCT6694_TIN_HYST_MASK, temp_hyst);
+
+		return nct6694_write_msg(data->nct6694, &cmd_hd,
+					 &data->msg->hwmon_alarm);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int nct6694_fan_write(struct device *dev, u32 attr, int channel,
+			     long val)
+{
+	struct nct6694_hwmon_data *data = dev_get_drvdata(dev);
+	struct nct6694_cmd_header cmd_hd;
+	int ret;
+
+	guard(mutex)(&data->lock);
+
+	switch (attr) {
+	case hwmon_fan_enable:
+		if (val == 0)
+			data->hwmon_en.fin_en[channel / 8] &= ~BIT(channel % 8);
+		else if (val == 1)
+			data->hwmon_en.fin_en[channel / 8] |= BIT(channel % 8);
+		else
+			return -EINVAL;
+
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_HWMON_MOD,
+			.cmd = NCT6694_HWMON_CONTROL,
+			.sel = NCT6694_HWMON_CONTROL_SEL,
+			.len = cpu_to_le16(sizeof(data->hwmon_en))
+		};
+
+		return nct6694_write_msg(data->nct6694, &cmd_hd,
+					 &data->hwmon_en);
+	case hwmon_fan_min:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_HWMON_MOD,
+			.cmd = NCT6694_HWMON_ALARM,
+			.sel = NCT6694_HWMON_ALARM_SEL,
+			.len = cpu_to_le16(sizeof(data->msg->hwmon_alarm))
+		};
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->msg->hwmon_alarm);
+		if (ret)
+			return ret;
+
+		val = clamp_val(val, 1, 65535);
+		data->msg->hwmon_alarm.fin_ll[channel] = cpu_to_be16(val);
+
+		return nct6694_write_msg(data->nct6694, &cmd_hd,
+					 &data->msg->hwmon_alarm);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int nct6694_pwm_write(struct device *dev, u32 attr, int channel,
+			     long val)
+{
+	struct nct6694_hwmon_data *data = dev_get_drvdata(dev);
+	struct nct6694_cmd_header cmd_hd;
+	int ret;
+
+	guard(mutex)(&data->lock);
+
+	switch (attr) {
+	case hwmon_pwm_enable:
+		if (val == 0)
+			data->hwmon_en.pwm_en[channel / 8] &= ~BIT(channel % 8);
+		else if (val == 1)
+			data->hwmon_en.pwm_en[channel / 8] |= BIT(channel % 8);
+		else
+			return -EINVAL;
+
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_HWMON_MOD,
+			.cmd = NCT6694_HWMON_CONTROL,
+			.sel = NCT6694_HWMON_CONTROL_SEL,
+			.len = cpu_to_le16(sizeof(data->hwmon_en))
+		};
+
+		return nct6694_write_msg(data->nct6694, &cmd_hd,
+					 &data->hwmon_en);
+	case hwmon_pwm_input:
+		if (val < 0 || val > 255)
+			return -EINVAL;
+
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_PWM_MOD,
+			.cmd = NCT6694_PWM_CONTROL,
+			.sel = NCT6694_PWM_CONTROL_SEL,
+			.len = cpu_to_le16(sizeof(data->msg->pwm_ctrl))
+		};
+
+		ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+				       &data->msg->pwm_ctrl);
+		if (ret)
+			return ret;
+
+		data->msg->pwm_ctrl.mal_val[channel] = val;
+
+		return nct6694_write_msg(data->nct6694, &cmd_hd,
+					 &data->msg->pwm_ctrl);
+	case hwmon_pwm_freq:
+		cmd_hd = (struct nct6694_cmd_header) {
+			.mod = NCT6694_HWMON_MOD,
+			.cmd = NCT6694_HWMON_CONTROL,
+			.sel = NCT6694_HWMON_CONTROL_SEL,
+			.len = cpu_to_le16(sizeof(data->hwmon_en))
+		};
+
+		data->hwmon_en.pwm_freq[channel] = NCT6694_FREQ_TO_REG(val);
+
+		return nct6694_write_msg(data->nct6694, &cmd_hd,
+					 &data->hwmon_en);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int nct6694_read(struct device *dev, enum hwmon_sensor_types type,
+			u32 attr, int channel, long *val)
+{
+	switch (type) {
+	case hwmon_in:
+		/* in mV */
+		return nct6694_in_read(dev, attr, channel, val);
+	case hwmon_temp:
+		/* in mC */
+		return nct6694_temp_read(dev, attr, channel, val);
+	case hwmon_fan:
+		/* in RPM */
+		return nct6694_fan_read(dev, attr, channel, val);
+	case hwmon_pwm:
+		/* in value 0~255 */
+		return nct6694_pwm_read(dev, attr, channel, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int nct6694_write(struct device *dev, enum hwmon_sensor_types type,
+			 u32 attr, int channel, long val)
+{
+	switch (type) {
+	case hwmon_in:
+		return nct6694_in_write(dev, attr, channel, val);
+	case hwmon_temp:
+		return nct6694_temp_write(dev, attr, channel, val);
+	case hwmon_fan:
+		return nct6694_fan_write(dev, attr, channel, val);
+	case hwmon_pwm:
+		return nct6694_pwm_write(dev, attr, channel, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static umode_t nct6694_is_visible(const void *data,
+				  enum hwmon_sensor_types type,
+				  u32 attr, int channel)
+{
+	switch (type) {
+	case hwmon_in:
+		switch (attr) {
+		case hwmon_in_enable:
+		case hwmon_in_max:
+		case hwmon_in_min:
+			return 0644;
+		case hwmon_in_alarm:
+		case hwmon_in_input:
+			return 0444;
+		default:
+			return 0;
+		}
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_enable:
+		case hwmon_temp_max:
+		case hwmon_temp_max_hyst:
+			return 0644;
+		case hwmon_temp_input:
+		case hwmon_temp_max_alarm:
+			return 0444;
+		default:
+			return 0;
+		}
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_enable:
+		case hwmon_fan_min:
+			return 0644;
+		case hwmon_fan_input:
+		case hwmon_fan_min_alarm:
+			return 0444;
+		default:
+			return 0;
+		}
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_enable:
+		case hwmon_pwm_freq:
+		case hwmon_pwm_input:
+			return 0644;
+		default:
+			return 0;
+		}
+	default:
+		return 0;
+	}
+}
+
+static const struct hwmon_ops nct6694_hwmon_ops = {
+	.is_visible = nct6694_is_visible,
+	.read = nct6694_read,
+	.write = nct6694_write,
+};
+
+static const struct hwmon_chip_info nct6694_chip_info = {
+	.ops = &nct6694_hwmon_ops,
+	.info = nct6694_info,
+};
+
+static int nct6694_hwmon_init(struct nct6694_hwmon_data *data)
+{
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_HWMON_MOD,
+		.cmd = NCT6694_HWMON_CONTROL,
+		.sel = NCT6694_HWMON_CONTROL_SEL,
+		.len = cpu_to_le16(sizeof(data->hwmon_en))
+	};
+	int ret;
+
+	/*
+	 * Record each Hardware Monitor Channel enable status
+	 * and PWM frequency register
+	 */
+	ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+			       &data->hwmon_en);
+	if (ret)
+		return ret;
+
+	cmd_hd = (struct nct6694_cmd_header) {
+		.mod = NCT6694_HWMON_MOD,
+		.cmd = NCT6694_HWMON_ALARM,
+		.sel = NCT6694_HWMON_ALARM_SEL,
+		.len = cpu_to_le16(sizeof(data->msg->hwmon_alarm))
+	};
+
+	/* Select hwmon device alarm mode */
+	ret = nct6694_read_msg(data->nct6694, &cmd_hd,
+			       &data->msg->hwmon_alarm);
+	if (ret)
+		return ret;
+
+	data->msg->hwmon_alarm.smi_ctrl = NCT6694_HWMON_REALTIME_IRQ;
+
+	return nct6694_write_msg(data->nct6694, &cmd_hd,
+				 &data->msg->hwmon_alarm);
+}
+
+static int nct6694_hwmon_probe(struct platform_device *pdev)
+{
+	struct nct6694_hwmon_data *data;
+	struct nct6694 *nct6694 = dev_get_drvdata(pdev->dev.parent);
+	struct device *hwmon_dev;
+	int ret;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->rpt = devm_kzalloc(&pdev->dev, sizeof(union nct6694_hwmon_rpt),
+				 GFP_KERNEL);
+	if (!data->rpt)
+		return -ENOMEM;
+
+	data->msg = devm_kzalloc(&pdev->dev, sizeof(union nct6694_hwmon_msg),
+				 GFP_KERNEL);
+	if (!data->msg)
+		return -ENOMEM;
+
+	data->nct6694 = nct6694;
+	devm_mutex_init(&pdev->dev, &data->lock);
+
+	ret = nct6694_hwmon_init(data);
+	if (ret)
+		return ret;
+
+	/* Register hwmon device to HWMON framework */
+	hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
+							 "nct6694", data,
+							 &nct6694_chip_info,
+							 NULL);
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static struct platform_driver nct6694_hwmon_driver = {
+	.driver = {
+		.name	= "nct6694-hwmon",
+	},
+	.probe		= nct6694_hwmon_probe,
+};
+
+module_platform_driver(nct6694_hwmon_driver);
+
+MODULE_DESCRIPTION("USB-HWMON driver for NCT6694");
+MODULE_AUTHOR("Ming Yu <tmyu0@nuvoton.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:nct6694-hwmon");
-- 
2.34.1

[PATCH v5 7/7] rtc: Add Nuvoton NCT6694 RTC support

[Ming Yu]

This driver supports RTC functionality for NCT6694 MFD device
based on USB interface.

Signed-off-by: Ming Yu <a0282524688@gmail.com>
---
 MAINTAINERS               |   1 +
 drivers/rtc/Kconfig       |  10 ++
 drivers/rtc/Makefile      |   1 +
 drivers/rtc/rtc-nct6694.c | 286 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 298 insertions(+)
 create mode 100644 drivers/rtc/rtc-nct6694.c

diff --git a/MAINTAINERS b/MAINTAINERS
index a14a2d65b8a6..5275ff7a793c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16726,6 +16726,7 @@ F:	drivers/hwmon/nct6694-hwmon.c
 F:	drivers/i2c/busses/i2c-nct6694.c
 F:	drivers/mfd/nct6694.c
 F:	drivers/net/can/usb/nct6694_canfd.c
+F:	drivers/rtc/rtc-nct6694.c
 F:	drivers/watchdog/nct6694_wdt.c
 F:	include/linux/mfd/nct6694.h
 
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index a60bcc791a48..aeab67acbc84 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -416,6 +416,16 @@ config RTC_DRV_NCT3018Y
 	   This driver can also be built as a module, if so, the module will be
 	   called "rtc-nct3018y".
 
+config RTC_DRV_NCT6694
+	tristate "Nuvoton NCT6694 RTC support"
+	depends on MFD_NCT6694
+	help
+	  If you say yes to this option, support will be included for Nuvoton
+	  NCT6694, a USB device to RTC.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called rtc-nct6694.
+
 config RTC_DRV_RK808
 	tristate "Rockchip RK805/RK808/RK809/RK817/RK818 RTC"
 	depends on MFD_RK8XX
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 489b4ab07068..d0d6f4a4972e 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -118,6 +118,7 @@ obj-$(CONFIG_RTC_DRV_MXC)	+= rtc-mxc.o
 obj-$(CONFIG_RTC_DRV_MXC_V2)	+= rtc-mxc_v2.o
 obj-$(CONFIG_RTC_DRV_GAMECUBE)	+= rtc-gamecube.o
 obj-$(CONFIG_RTC_DRV_NCT3018Y)	+= rtc-nct3018y.o
+obj-$(CONFIG_RTC_DRV_NCT6694)	+= rtc-nct6694.o
 obj-$(CONFIG_RTC_DRV_NTXEC)	+= rtc-ntxec.o
 obj-$(CONFIG_RTC_DRV_OMAP)	+= rtc-omap.o
 obj-$(CONFIG_RTC_DRV_OPAL)	+= rtc-opal.o
diff --git a/drivers/rtc/rtc-nct6694.c b/drivers/rtc/rtc-nct6694.c
new file mode 100644
index 000000000000..dbb5ccae2796
--- /dev/null
+++ b/drivers/rtc/rtc-nct6694.c
@@ -0,0 +1,286 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Nuvoton NCT6694 RTC driver based on USB interface.
+ *
+ * Copyright (C) 2024 Nuvoton Technology Corp.
+ */
+
+#include <linux/bcd.h>
+#include <linux/irqdomain.h>
+#include <linux/kernel.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/nct6694.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/slab.h>
+
+/*
+ * USB command module type for NCT6694 RTC controller.
+ * This defines the module type used for communication with the NCT6694
+ * RTC controller over the USB interface.
+ */
+#define NCT6694_RTC_MOD		0x08
+
+/* Command 00h - RTC Time */
+#define NCT6694_RTC_TIME	0x0000
+#define NCT6694_RTC_TIME_SEL	0x00
+
+/* Command 01h - RTC Alarm */
+#define NCT6694_RTC_ALARM	0x01
+#define NCT6694_RTC_ALARM_SEL	0x00
+
+/* Command 02h - RTC Status */
+#define NCT6694_RTC_STATUS	0x02
+#define NCT6694_RTC_STATUS_SEL	0x00
+
+#define NCT6694_RTC_IRQ_INT_EN	BIT(0)	/* Transmit a USB INT-in when RTC alarm */
+#define NCT6694_RTC_IRQ_GPO_EN	BIT(5)	/* Trigger a GPO Low Pulse when RTC alarm */
+
+#define NCT6694_RTC_IRQ_EN	(NCT6694_RTC_IRQ_INT_EN | NCT6694_RTC_IRQ_GPO_EN)
+#define NCT6694_RTC_IRQ_STS	BIT(0)	/* Write 1 clear IRQ status */
+
+struct __packed nct6694_rtc_time {
+	u8 sec;
+	u8 min;
+	u8 hour;
+	u8 week;
+	u8 day;
+	u8 month;
+	u8 year;
+};
+
+struct __packed nct6694_rtc_alarm {
+	u8 sec;
+	u8 min;
+	u8 hour;
+	u8 alarm_en;
+	u8 alarm_pend;
+};
+
+struct __packed nct6694_rtc_status {
+	u8 irq_en;
+	u8 irq_pend;
+};
+
+union __packed nct6694_rtc_msg {
+	struct nct6694_rtc_time time;
+	struct nct6694_rtc_alarm alarm;
+	struct nct6694_rtc_status sts;
+};
+
+struct nct6694_rtc_data {
+	struct nct6694 *nct6694;
+	struct rtc_device *rtc;
+	union nct6694_rtc_msg *msg;
+};
+
+static int nct6694_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct nct6694_rtc_data *data = dev_get_drvdata(dev);
+	struct nct6694_rtc_time *time = &data->msg->time;
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_RTC_MOD,
+		.cmd = NCT6694_RTC_TIME,
+		.sel = NCT6694_RTC_TIME_SEL,
+		.len = cpu_to_le16(sizeof(*time))
+	};
+	int ret;
+
+	ret = nct6694_read_msg(data->nct6694, &cmd_hd, time);
+	if (ret)
+		return ret;
+
+	tm->tm_sec = bcd2bin(time->sec);		/* tm_sec expect 0 ~ 59 */
+	tm->tm_min = bcd2bin(time->min);		/* tm_min expect 0 ~ 59 */
+	tm->tm_hour = bcd2bin(time->hour);		/* tm_hour expect 0 ~ 23 */
+	tm->tm_wday = bcd2bin(time->week) - 1;		/* tm_wday expect 0 ~ 6 */
+	tm->tm_mday = bcd2bin(time->day);		/* tm_mday expect 1 ~ 31 */
+	tm->tm_mon = bcd2bin(time->month) - 1;		/* tm_month expect 0 ~ 11 */
+	tm->tm_year = bcd2bin(time->year) + 100;	/* tm_year expect since 1900 */
+
+	return ret;
+}
+
+static int nct6694_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct nct6694_rtc_data *data = dev_get_drvdata(dev);
+	struct nct6694_rtc_time *time = &data->msg->time;
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_RTC_MOD,
+		.cmd = NCT6694_RTC_TIME,
+		.sel = NCT6694_RTC_TIME_SEL,
+		.len = cpu_to_le16(sizeof(*time))
+	};
+
+	time->sec = bin2bcd(tm->tm_sec);
+	time->min = bin2bcd(tm->tm_min);
+	time->hour = bin2bcd(tm->tm_hour);
+	time->week = bin2bcd(tm->tm_wday + 1);
+	time->day = bin2bcd(tm->tm_mday);
+	time->month = bin2bcd(tm->tm_mon + 1);
+	time->year = bin2bcd(tm->tm_year - 100);
+
+	return nct6694_write_msg(data->nct6694, &cmd_hd, time);
+}
+
+static int nct6694_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct nct6694_rtc_data *data = dev_get_drvdata(dev);
+	struct nct6694_rtc_alarm *alarm = &data->msg->alarm;
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_RTC_MOD,
+		.cmd = NCT6694_RTC_ALARM,
+		.sel = NCT6694_RTC_ALARM_SEL,
+		.len = cpu_to_le16(sizeof(*alarm))
+	};
+	int ret;
+
+	ret = nct6694_read_msg(data->nct6694, &cmd_hd, alarm);
+	if (ret)
+		return ret;
+
+	alrm->time.tm_sec = bcd2bin(alarm->sec);
+	alrm->time.tm_min = bcd2bin(alarm->min);
+	alrm->time.tm_hour = bcd2bin(alarm->hour);
+	alrm->enabled = alarm->alarm_en;
+	alrm->pending = alarm->alarm_pend;
+
+	return ret;
+}
+
+static int nct6694_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct nct6694_rtc_data *data = dev_get_drvdata(dev);
+	struct nct6694_rtc_alarm *alarm = &data->msg->alarm;
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_RTC_MOD,
+		.cmd = NCT6694_RTC_ALARM,
+		.sel = NCT6694_RTC_ALARM_SEL,
+		.len = cpu_to_le16(sizeof(*alarm))
+	};
+
+	alarm->sec = bin2bcd(alrm->time.tm_sec);
+	alarm->min = bin2bcd(alrm->time.tm_min);
+	alarm->hour = bin2bcd(alrm->time.tm_hour);
+	alarm->alarm_en = alrm->enabled ? NCT6694_RTC_IRQ_EN : 0;
+	alarm->alarm_pend = 0;
+
+	return nct6694_write_msg(data->nct6694, &cmd_hd, alarm);
+}
+
+static int nct6694_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct nct6694_rtc_data *data = dev_get_drvdata(dev);
+	struct nct6694_rtc_status *sts = &data->msg->sts;
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_RTC_MOD,
+		.cmd = NCT6694_RTC_STATUS,
+		.sel = NCT6694_RTC_STATUS_SEL,
+		.len = cpu_to_le16(sizeof(*sts))
+	};
+
+	if (enabled)
+		sts->irq_en |= NCT6694_RTC_IRQ_EN;
+	else
+		sts->irq_en &= ~NCT6694_RTC_IRQ_EN;
+
+	sts->irq_pend = 0;
+
+	return nct6694_write_msg(data->nct6694, &cmd_hd, sts);
+}
+
+static const struct rtc_class_ops nct6694_rtc_ops = {
+	.read_time = nct6694_rtc_read_time,
+	.set_time = nct6694_rtc_set_time,
+	.read_alarm = nct6694_rtc_read_alarm,
+	.set_alarm = nct6694_rtc_set_alarm,
+	.alarm_irq_enable = nct6694_rtc_alarm_irq_enable,
+};
+
+static irqreturn_t nct6694_irq(int irq, void *dev_id)
+{
+	struct nct6694_rtc_data *data = dev_id;
+	struct nct6694_rtc_status *sts = &data->msg->sts;
+	struct nct6694_cmd_header cmd_hd = {
+		.mod = NCT6694_RTC_MOD,
+		.cmd = NCT6694_RTC_STATUS,
+		.sel = NCT6694_RTC_STATUS_SEL,
+		.len = cpu_to_le16(sizeof(*sts))
+	};
+	int ret;
+
+	rtc_lock(data->rtc);
+
+	sts->irq_en = NCT6694_RTC_IRQ_EN;
+	sts->irq_pend = NCT6694_RTC_IRQ_STS;
+	ret = nct6694_write_msg(data->nct6694, &cmd_hd, sts);
+	if (ret) {
+		rtc_unlock(data->rtc);
+		return IRQ_NONE;
+	}
+
+	rtc_update_irq(data->rtc, 1, RTC_IRQF | RTC_AF);
+
+	rtc_unlock(data->rtc);
+
+	return IRQ_HANDLED;
+}
+
+static int nct6694_rtc_probe(struct platform_device *pdev)
+{
+	struct nct6694_rtc_data *data;
+	struct nct6694 *nct6694 = dev_get_drvdata(pdev->dev.parent);
+	int ret, irq;
+
+	irq = irq_create_mapping(nct6694->domain, NCT6694_IRQ_RTC);
+	if (!irq)
+		return -EINVAL;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->msg = devm_kzalloc(&pdev->dev, sizeof(union nct6694_rtc_msg),
+				 GFP_KERNEL);
+	if (!data->msg)
+		return -ENOMEM;
+
+	data->rtc = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(data->rtc))
+		return PTR_ERR(data->rtc);
+
+	data->nct6694 = nct6694;
+	data->rtc->ops = &nct6694_rtc_ops;
+	data->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
+	data->rtc->range_max = RTC_TIMESTAMP_END_2099;
+
+	platform_set_drvdata(pdev, data);
+
+	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+					nct6694_irq, IRQF_ONESHOT,
+					"nct6694-rtc", data);
+	if (ret < 0)
+		return dev_err_probe(&pdev->dev, ret, "Failed to request irq\n");
+
+	ret = devm_rtc_register_device(data->rtc);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret, "Failed to register rtc\n");
+
+	device_init_wakeup(&pdev->dev, true);
+	return 0;
+}
+
+static struct platform_driver nct6694_rtc_driver = {
+	.driver = {
+		.name	= "nct6694-rtc",
+	},
+	.probe		= nct6694_rtc_probe,
+};
+
+module_platform_driver(nct6694_rtc_driver);
+
+MODULE_DESCRIPTION("USB-RTC driver for NCT6694");
+MODULE_AUTHOR("Ming Yu <tmyu0@nuvoton.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:nct6694-rtc");
-- 
2.34.1

Re: [PATCH v5 4/7] can: Add Nuvoton NCT6694 CAN support

[Vincent Mailhol]

Hi Ming,

Now the structure finally looks good! I did a deeper review than before.

Right now, I am mostly concerned of the double use of mutexes:

  - nct6694_can_priv->lock in this can driver
  - nct6694->access_lock in the core driver

checkpatch.pl actually suggests you to add comments to those mutexes:

  CHECK: struct mutex definition without comment
  #146: FILE: drivers/net/can/usb/nct6694_canfd.c:146:
  +      struct mutex lock;

On Tue. 14 Jan 2025 at 12:32, Ming Yu <a0282524688@gmail.com> wrote:
> This driver supports Socket CANfd functionality for NCT6694 MFD
> device based on USB interface.
>
> Signed-off-by: Ming Yu <a0282524688@gmail.com>
> ---
>  MAINTAINERS                         |   1 +
>  drivers/net/can/usb/Kconfig         |  10 +
>  drivers/net/can/usb/Makefile        |   1 +
>  drivers/net/can/usb/nct6694_canfd.c | 856 ++++++++++++++++++++++++++++
>  4 files changed, 868 insertions(+)
>  create mode 100644 drivers/net/can/usb/nct6694_canfd.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 4e72f749cdf2..6e9b78202d6f 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -16724,6 +16724,7 @@ S:      Supported
>  F:     drivers/gpio/gpio-nct6694.c
>  F:     drivers/i2c/busses/i2c-nct6694.c
>  F:     drivers/mfd/nct6694.c
> +F:     drivers/net/can/usb/nct6694_canfd.c
>  F:     include/linux/mfd/nct6694.h
>
>  NVIDIA (rivafb and nvidiafb) FRAMEBUFFER DRIVER
> diff --git a/drivers/net/can/usb/Kconfig b/drivers/net/can/usb/Kconfig
> index 9dae0c71a2e1..53254012cdc4 100644
> --- a/drivers/net/can/usb/Kconfig
> +++ b/drivers/net/can/usb/Kconfig
> @@ -133,6 +133,16 @@ config CAN_MCBA_USB
>           This driver supports the CAN BUS Analyzer interface
>           from Microchip (http://www.microchip.com/development-tools/).
>
> +config CAN_NCT6694
> +       tristate "Nuvoton NCT6694 Socket CANfd support"
> +       depends on MFD_NCT6694

Your driver uses the CAN rx offload. You need to select it here.

          select CAN_RX_OFFLOAD

> +       help
> +         If you say yes to this option, support will be included for Nuvoton
> +         NCT6694, a USB device to socket CANfd controller.
> +
> +         This driver can also be built as a module. If so, the module will
> +         be called nct6694_canfd.

Here, the name is nct6694_canfd...

>  config CAN_PEAK_USB
>         tristate "PEAK PCAN-USB/USB Pro interfaces for CAN 2.0b/CAN-FD"
>         help
> diff --git a/drivers/net/can/usb/Makefile b/drivers/net/can/usb/Makefile
> index 8b11088e9a59..fcafb1ac262e 100644
> --- a/drivers/net/can/usb/Makefile
> +++ b/drivers/net/can/usb/Makefile
> @@ -11,5 +11,6 @@ obj-$(CONFIG_CAN_F81604) += f81604.o
>  obj-$(CONFIG_CAN_GS_USB) += gs_usb.o
>  obj-$(CONFIG_CAN_KVASER_USB) += kvaser_usb/
>  obj-$(CONFIG_CAN_MCBA_USB) += mcba_usb.o
> +obj-$(CONFIG_CAN_NCT6694) += nct6694_canfd.o
>  obj-$(CONFIG_CAN_PEAK_USB) += peak_usb/
>  obj-$(CONFIG_CAN_UCAN) += ucan.o
> diff --git a/drivers/net/can/usb/nct6694_canfd.c b/drivers/net/can/usb/nct6694_canfd.c
> new file mode 100644
> index 000000000000..7a15c39021ff
> --- /dev/null
> +++ b/drivers/net/can/usb/nct6694_canfd.c
> @@ -0,0 +1,856 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Nuvoton NCT6694 Socket CANfd driver based on USB interface.
> + *
> + * Copyright (C) 2024 Nuvoton Technology Corp.
> + */
> +
> +#include <linux/can/dev.h>
> +#include <linux/can/rx-offload.h>
> +#include <linux/ethtool.h>
> +#include <linux/irqdomain.h>
> +#include <linux/kernel.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mfd/nct6694.h>
> +#include <linux/module.h>
> +#include <linux/netdevice.h>
> +#include <linux/platform_device.h>
> +
> +#define DRVNAME "nct6694-can"

... but here, it is nct6694-can.

Use a consistent name between the module name and the driver name.

> +/*
> + * USB command module type for NCT6694 CANfd controller.
> + * This defines the module type used for communication with the NCT6694
> + * CANfd controller over the USB interface.
> + */
> +#define NCT6694_CAN_MOD                        0x05
> +
> +/* Command 00h - CAN Setting and Initialization */
> +#define NCT6694_CAN_SETTING            0x00
> +#define NCT6694_CAN_SETTING_SEL(idx)   (idx ? 0x01 : 0x00)

What are the possible values for idx? Isn't it only 0 or 1? If so, no
need for this NCT6694_CAN_SETTING_SEL() macro. Directly assign the
channel index to the selector field.

> +#define NCT6694_CAN_SETTING_CTRL1_MON  BIT(0)
> +#define NCT6694_CAN_SETTING_CTRL1_NISO BIT(1)
> +#define NCT6694_CAN_SETTING_CTRL1_LBCK BIT(2)
> +
> +/* Command 01h - CAN Information */
> +#define NCT6694_CAN_INFORMATION                0x01
> +#define NCT6694_CAN_INFORMATION_SEL    0x00
> +
> +/* Command 02h - CAN Event */
> +#define NCT6694_CAN_EVENT              0x02
> +#define NCT6694_CAN_EVENT_SEL(idx, mask)       \
> +       ((idx ? 0x80 : 0x00) | ((mask) & 0xFF))

Can idx and mask really overlap? Shouldn't this be:

  #define NCT6694_CAN_EVENT_SEL(idx, mask)  \
          ((idx ? 0x80 : 0x00) | ((mask) & 0x7F))

> +#define NCT6694_CAN_EVENT_ERR          BIT(0)
> +#define NCT6694_CAN_EVENT_STATUS       BIT(1)
> +#define NCT6694_CAN_EVENT_TX_EVT       BIT(2)
> +#define NCT6694_CAN_EVENT_RX_EVT       BIT(3)
> +#define NCT6694_CAN_EVENT_REC          BIT(4)
> +#define NCT6694_CAN_EVENT_TEC          BIT(5)
> +#define NCT6694_CAN_EVENT_MASK         GENMASK(3, 0)
> +#define NCT6694_CAN_EVT_TX_FIFO_EMPTY  BIT(7)  /* Read-clear */
> +#define NCT6694_CAN_EVT_RX_DATA_LOST   BIT(5)  /* Read-clear */
> +#define NCT6694_CAN_EVT_RX_HALF_FULL   BIT(6)  /* Read-clear */
> +#define NCT6694_CAN_EVT_RX_DATA_IN     BIT(7)  /* Read-clear*/

Some of those macro are not used:

  drivers/net/can/usb/nct6694_canfd.c:52: warning: macro
"NCT6694_CAN_EVT_RX_HALF_FULL" is not used [-Wunused-macros]
     52 | #define NCT6694_CAN_EVT_RX_HALF_FULL BIT(6) /* Read-clear */
        |
  drivers/net/can/usb/nct6694_canfd.c:43: warning: macro
"NCT6694_CAN_EVENT_ERR" is not used [-Wunused-macros]
     43 | #define NCT6694_CAN_EVENT_ERR  BIT(0)
        |
  drivers/net/can/usb/nct6694_canfd.c:44: warning: macro
"NCT6694_CAN_EVENT_STATUS" is not used [-Wunused-macros]
     44 | #define NCT6694_CAN_EVENT_STATUS BIT(1)
        |
  drivers/net/can/usb/nct6694_canfd.c:46: warning: macro
"NCT6694_CAN_EVENT_RX_EVT" is not used [-Wunused-macros]
     46 | #define NCT6694_CAN_EVENT_RX_EVT BIT(3)
        |
  drivers/net/can/usb/nct6694_canfd.c:45: warning: macro
"NCT6694_CAN_EVENT_TX_EVT" is not used [-Wunused-macros]
     45 | #define NCT6694_CAN_EVENT_TX_EVT BIT(2)
        |

Is this OK?

> +/* Command 10h - CAN Deliver */
> +#define NCT6694_CAN_DELIVER            0x10
> +#define NCT6694_CAN_DELIVER_SEL(buf_cnt)       \
> +       ((buf_cnt) & 0xFF)
> +
> +/* Command 11h - CAN Receive */
> +#define NCT6694_CAN_RECEIVE            0x11
> +#define NCT6694_CAN_RECEIVE_SEL(idx, buf_cnt)  \
> +       ((idx ? 0x80 : 0x00) | ((buf_cnt) & 0xFF))

Can idx and buf_cnt really overlap? Shouldn't this be:

  #define NCT6694_CAN_RECEIVE_SEL(idx, buf_cnt)  \
          ((idx ? 0x80 : 0x00) | ((buf_cnt) & 0x7F))

> +#define NCT6694_CAN_FRAME_TAG_CAN0     0xC0
> +#define NCT6694_CAN_FRAME_TAG_CAN1     0xC1
> +#define NCT6694_CAN_FRAME_FLAG_EFF     BIT(0)
> +#define NCT6694_CAN_FRAME_FLAG_RTR     BIT(1)
> +#define NCT6694_CAN_FRAME_FLAG_FD      BIT(2)
> +#define NCT6694_CAN_FRAME_FLAG_BRS     BIT(3)
> +#define NCT6694_CAN_FRAME_FLAG_ERR     BIT(4)
> +
> +#define NCT6694_NAPI_WEIGHT            32
> +
> +enum nct6694_event_err {
> +       NCT6694_CAN_EVT_ERR_NO_ERROR = 0,
> +       NCT6694_CAN_EVT_ERR_CRC_ERROR,
> +       NCT6694_CAN_EVT_ERR_STUFF_ERROR,
> +       NCT6694_CAN_EVT_ERR_ACK_ERROR,
> +       NCT6694_CAN_EVT_ERR_FORM_ERROR,
> +       NCT6694_CAN_EVT_ERR_BIT_ERROR,
> +       NCT6694_CAN_EVT_ERR_TIMEOUT_ERROR,
> +       NCT6694_CAN_EVT_ERR_UNKNOWN_ERROR,
> +};
> +
> +enum nct6694_event_status {
> +       NCT6694_CAN_EVT_STS_ERROR_ACTIVE = 0,
> +       NCT6694_CAN_EVT_STS_ERROR_PASSIVE,
> +       NCT6694_CAN_EVT_STS_BUS_OFF,
> +       NCT6694_CAN_EVT_STS_WARNING,
> +};
> +
> +struct __packed nct6694_can_setting {
> +       __le32 nbr;
> +       __le32 dbr;
> +       u8 active;
> +       u8 reserved[3];
> +       __le16 ctrl1;
> +       __le16 ctrl2;
> +       __le32 nbtp;
> +       __le32 dbtp;
> +};
> +
> +struct __packed nct6694_can_information {
> +       u8 tx_fifo_cnt;
> +       u8 rx_fifo_cnt;
> +       u8 reserved[2];
> +       __le32 can_clk;
> +};
> +
> +struct __packed nct6694_can_event {
> +       u8 err;
> +       u8 status;
> +       u8 tx_evt;
> +       u8 rx_evt;
> +       u8 rec;
> +       u8 tec;
> +       u8 reserved[2];
> +};
> +
> +struct __packed nct6694_can_frame {
> +       u8 tag;
> +       u8 flag;
> +       u8 reserved;
> +       u8 length;
> +       __le32 id;
> +       u8 data[64];

Nitpick, use CANFD_MAX_DLEN here:

          u8 data[CANFD_MAX_DLEN];

> +};
> +
> +union __packed nct6694_can_tx {
> +       struct nct6694_can_frame frame;
> +       struct nct6694_can_setting setting;
> +};
> +
> +union __packed nct6694_can_rx {
> +       struct nct6694_can_event event[2];
> +       struct nct6694_can_frame frame;
> +       struct nct6694_can_information info;
> +};
> +
> +struct nct6694_can_priv {
> +       struct can_priv can;    /* must be the first member */
> +       struct can_rx_offload offload;
> +       struct net_device *ndev;
> +       struct nct6694 *nct6694;
> +       struct mutex lock;
> +       struct sk_buff *tx_skb;
> +       struct workqueue_struct *wq;
> +       struct work_struct tx_work;
> +       union nct6694_can_tx *tx;
> +       union nct6694_can_rx *rx;
> +       unsigned char can_idx;
> +};
> +
> +static inline struct nct6694_can_priv *rx_offload_to_priv(struct can_rx_offload *offload)
> +{
> +       return container_of(offload, struct nct6694_can_priv, offload);
> +}
> +
> +static const struct can_bittiming_const nct6694_can_bittiming_nominal_const = {
> +       .name = DRVNAME,
> +       .tseg1_min = 2,
> +       .tseg1_max = 256,
> +       .tseg2_min = 2,
> +       .tseg2_max = 128,
> +       .sjw_max = 128,
> +       .brp_min = 1,
> +       .brp_max = 511,
> +       .brp_inc = 1,
> +};
> +
> +static const struct can_bittiming_const nct6694_can_bittiming_data_const = {
> +       .name = DRVNAME,
> +       .tseg1_min = 1,
> +       .tseg1_max = 32,
> +       .tseg2_min = 1,
> +       .tseg2_max = 16,
> +       .sjw_max = 16,
> +       .brp_min = 1,
> +       .brp_max = 31,
> +       .brp_inc = 1,
> +};
> +
> +static void nct6694_can_rx_offload(struct can_rx_offload *offload,
> +                                  struct sk_buff *skb)
> +{
> +       struct nct6694_can_priv *priv = rx_offload_to_priv(offload);
> +       int ret;
> +
> +       ret = can_rx_offload_queue_tail(offload, skb);
> +       if (ret)
> +               priv->ndev->stats.rx_fifo_errors++;
> +}
> +
> +static void nct6694_can_handle_lost_msg(struct net_device *ndev)
> +{
> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> +       struct net_device_stats *stats = &ndev->stats;
> +       struct can_frame *cf;
> +       struct sk_buff *skb;
> +
> +       netdev_err(ndev, "RX FIFO overflow, message(s) lost.\n");
> +
> +       stats->rx_errors++;
> +       stats->rx_over_errors++;
> +
> +       skb = alloc_can_err_skb(ndev, &cf);
> +       if (!skb)
> +               return;
> +
> +       cf->can_id |= CAN_ERR_CRTL;
> +       cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
> +
> +       nct6694_can_rx_offload(&priv->offload, skb);
> +}
> +
> +static void nct6694_can_rx(struct net_device *ndev, u8 rx_evt)
> +{
> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> +       struct nct6694_can_frame *frame = &priv->rx->frame;
> +       struct nct6694_cmd_header cmd_hd = {
> +               .mod = NCT6694_CAN_MOD,
> +               .cmd = NCT6694_CAN_RECEIVE,
> +               .sel = NCT6694_CAN_RECEIVE_SEL(priv->can_idx, 1),
> +               .len = cpu_to_le16(sizeof(*frame))
> +       };
> +       struct canfd_frame *cfd;
> +       struct can_frame *cf;
> +       struct sk_buff *skb;
> +       int ret;
> +
> +       ret = nct6694_read_msg(priv->nct6694, &cmd_hd, frame);
> +       if (ret)
> +               return;
> +
> +       if (frame->flag & NCT6694_CAN_FRAME_FLAG_FD) {

Reduce scope of variable when possible: move declaration of cfd here:

                struct canfd_frame *cfd;

> +               skb = alloc_canfd_skb(priv->ndev, &cfd);
> +               if (!skb)
> +                       return;
> +
> +               cfd->can_id = le32_to_cpu(frame->id);
> +               cfd->len = frame->length;

No. I asked you to sanitize the length in this message:

  https://lore.kernel.org/linux-can/8d66cf66-5564-4272-8c3e-51b715c3d785@wanadoo.fr/

Never use the length as is.

> +               if (frame->flag & NCT6694_CAN_FRAME_FLAG_EFF)
> +                       cfd->can_id |= CAN_EFF_FLAG;
> +               if (frame->flag & NCT6694_CAN_FRAME_FLAG_BRS)
> +                       cfd->flags |= CANFD_BRS;
> +               if (frame->flag & NCT6694_CAN_FRAME_FLAG_ERR)
> +                       cfd->flags |= CANFD_ESI;
> +
> +               memcpy(cfd->data, frame->data, cfd->len);
> +       } else {

Reduce scope of variable when possible: move declaration of cf here:

                struct canfd_frame *cf;

> +               skb = alloc_can_skb(priv->ndev, &cf);
> +               if (!skb)
> +                       return;
> +
> +               cf->can_id = le32_to_cpu(frame->id);
> +               cf->len = frame->length;

Ditto, sanitize the length.

> +               if (frame->flag & NCT6694_CAN_FRAME_FLAG_EFF)
> +                       cf->can_id |= CAN_EFF_FLAG;
> +               if (frame->flag & NCT6694_CAN_FRAME_FLAG_RTR)
> +                       cf->can_id |= CAN_RTR_FLAG;
> +
> +               memcpy(cf->data, frame->data, cf->len);

Only copy can data if the frame is not an RTR frame.

                  if (frame->flag & NCT6694_CAN_FRAME_FLAG_RTR)
                          cf->can_id |= CAN_RTR_FLAG;
                  else
                          memcpy(cf->data, frame->data, cf->len);

I already asked you to do this in below comment:

  https://lore.kernel.org/linux-can/a25ea362-142f-4e27-8194-787d9829f607@wanadoo.fr/

> +       }
> +
> +       nct6694_can_rx_offload(&priv->offload, skb);
> +}
> +
> +static void nct6694_can_clean(struct net_device *ndev)
> +{
> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> +
> +       if (priv->tx_skb || netif_queue_stopped(ndev))
> +               ndev->stats.tx_errors++;
> +       dev_kfree_skb(priv->tx_skb);
> +       priv->tx_skb = NULL;
> +}
> +
> +static int nct6694_can_get_berr_counter(const struct net_device *ndev,
> +                                       struct can_berr_counter *bec)
> +{
> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> +       struct nct6694_can_event *evt = priv->rx->event;
> +       struct nct6694_cmd_header cmd_hd;
> +       u8 mask = NCT6694_CAN_EVENT_REC | NCT6694_CAN_EVENT_TEC;
> +       int ret;
> +
> +       guard(mutex)(&priv->lock);
> +
> +       cmd_hd = (struct nct6694_cmd_header) {
> +               .mod = NCT6694_CAN_MOD,
> +               .cmd = NCT6694_CAN_EVENT,
> +               .sel = NCT6694_CAN_EVENT_SEL(priv->can_idx, mask),
> +               .len = cpu_to_le16(sizeof(priv->rx->event))
> +       };
> +
> +       ret = nct6694_read_msg(priv->nct6694, &cmd_hd, evt);
> +       if (ret < 0)
> +               return ret;

You are holding the priv->lock mutex before calling
nct6694_read_msg(). But nct6694_read_msg() then holds the
nct6694->access_lock mutex. Why do you need a double mutex here? What
kind of race scenario are you trying to prevent here?

> +       bec->rxerr = evt[priv->can_idx].rec;
> +       bec->txerr = evt[priv->can_idx].tec;
> +
> +       return 0;
> +}
> +
> +static void nct6694_can_handle_state_change(struct net_device *ndev,
> +                                           u8 status)
> +{
> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> +       enum can_state new_state = priv->can.state;
> +       enum can_state rx_state, tx_state;
> +       struct can_berr_counter bec;
> +       struct can_frame *cf;
> +       struct sk_buff *skb;
> +
> +       nct6694_can_get_berr_counter(ndev, &bec);
> +       can_state_get_by_berr_counter(ndev, &bec, &tx_state, &rx_state);

Here, you set up tx_state and rx_state...

> +       switch (status) {
> +       case NCT6694_CAN_EVT_STS_ERROR_ACTIVE:
> +               new_state = CAN_STATE_ERROR_ACTIVE;
> +               break;
> +       case NCT6694_CAN_EVT_STS_ERROR_PASSIVE:
> +               new_state = CAN_STATE_ERROR_PASSIVE;
> +               break;
> +       case NCT6694_CAN_EVT_STS_BUS_OFF:
> +               new_state = CAN_STATE_BUS_OFF;
> +               break;
> +       case NCT6694_CAN_EVT_STS_WARNING:
> +               new_state = CAN_STATE_ERROR_WARNING;
> +               break;
> +       default:
> +               netdev_err(ndev, "Receive unknown CAN status event.\n");
> +               return;
> +       }
> +
> +       /* state hasn't changed */
> +       if (new_state == priv->can.state)
> +               return;
> +
> +       skb = alloc_can_err_skb(ndev, &cf);
> +
> +       tx_state = bec.txerr >= bec.rxerr ? new_state : 0;
> +       rx_state = bec.txerr <= bec.rxerr ? new_state : 0;

... but you never used the values returned by
can_state_get_by_berr_counter() and just overwrote the tx and rx
state.

What is the logic here? Why do you need to manually adjust those two
values? Isn't the logic in can_change_state() sufficient?

> +       can_change_state(ndev, cf, tx_state, rx_state);
> +
> +       if (new_state == CAN_STATE_BUS_OFF) {

Same for the new_state. The function can_change_state() calculate the
new state from tx_state and rx_state and save it under
can_priv->state. But here, you do your own calculation.

Only keep one of the two. If your device already tells you the state,
then fine! Just use the information from your device and do not use
can_change_state(). Here, you are doing double work resulting in a
weird mix.

> +               can_bus_off(ndev);
> +       } else if (skb) {
> +               cf->can_id |= CAN_ERR_CNT;
> +               cf->data[6] = bec.txerr;
> +               cf->data[7] = bec.rxerr;
> +       }
> +
> +       nct6694_can_rx_offload(&priv->offload, skb);
> +}
> +
> +static void nct6694_handle_bus_err(struct net_device *ndev, u8 bus_err)
> +{
> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> +       struct can_frame *cf;
> +       struct sk_buff *skb;
> +
> +       if (bus_err == NCT6694_CAN_EVT_ERR_NO_ERROR)
> +               return;
> +
> +       priv->can.can_stats.bus_error++;
> +
> +       skb = alloc_can_err_skb(ndev, &cf);
> +       if (skb)
> +               cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
> +
> +       switch (bus_err) {
> +       case NCT6694_CAN_EVT_ERR_CRC_ERROR:
> +               netdev_dbg(ndev, "CRC error\n");
> +               ndev->stats.rx_errors++;
> +               if (skb)
> +                       cf->data[3] |= CAN_ERR_PROT_LOC_CRC_SEQ;
> +               break;
> +
> +       case NCT6694_CAN_EVT_ERR_STUFF_ERROR:
> +               netdev_dbg(ndev, "Stuff error\n");
> +               ndev->stats.rx_errors++;
> +               if (skb)
> +                       cf->data[2] |= CAN_ERR_PROT_STUFF;
> +               break;
> +
> +       case NCT6694_CAN_EVT_ERR_ACK_ERROR:
> +               netdev_dbg(ndev, "Ack error\n");
> +               ndev->stats.tx_errors++;
> +               if (skb) {
> +                       cf->can_id |= CAN_ERR_ACK;
> +                       cf->data[2] |= CAN_ERR_PROT_TX;
> +               }
> +               break;
> +
> +       case NCT6694_CAN_EVT_ERR_FORM_ERROR:
> +               netdev_dbg(ndev, "Form error\n");
> +               ndev->stats.rx_errors++;
> +               if (skb)
> +                       cf->data[2] |= CAN_ERR_PROT_FORM;
> +               break;
> +
> +       case NCT6694_CAN_EVT_ERR_BIT_ERROR:
> +               netdev_dbg(ndev, "Bit error\n");
> +               ndev->stats.tx_errors++;
> +               if (skb)
> +                       cf->data[2] |= CAN_ERR_PROT_TX | CAN_ERR_PROT_BIT;
> +               break;
> +
> +       default:
> +               break;
> +       }
> +
> +       nct6694_can_rx_offload(&priv->offload, skb);
> +}
> +
> +static void nct6694_can_tx_irq(struct net_device *ndev)
> +{
> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> +       struct net_device_stats *stats = &ndev->stats;
> +
> +       guard(mutex)(&priv->lock);
> +       stats->tx_bytes += can_get_echo_skb(ndev, 0, NULL);
> +       stats->tx_packets++;
> +       netif_wake_queue(ndev);
> +}
> +
> +static irqreturn_t nct6694_can_irq(int irq, void *data)
> +{
> +       struct net_device *ndev = data;
> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> +       struct nct6694_can_event *evt = priv->rx->event;
> +       struct nct6694_cmd_header cmd_hd;
> +       u8 tx_evt, rx_evt, bus_err, can_status;
> +       u8 mask_sts = NCT6694_CAN_EVENT_MASK;

No need for the mask_sts variable. Directly use NCT6694_CAN_EVENT_MASK.

> +       irqreturn_t handled = IRQ_NONE;
> +       int can_idx = priv->can_idx;
> +       int ret;
> +
> +       scoped_guard(mutex, &priv->lock) {

Reduce scope of variable when possible: move the declarations of
cmd_hd and ret here.

> +               cmd_hd = (struct nct6694_cmd_header) {
> +                       .mod = NCT6694_CAN_MOD,
> +                       .cmd = NCT6694_CAN_EVENT,
> +                       .sel = NCT6694_CAN_EVENT_SEL(priv->can_idx, mask_sts),
> +                       .len = cpu_to_le16(sizeof(priv->rx->event))
> +               };
> +
> +               ret = nct6694_read_msg(priv->nct6694, &cmd_hd, evt);
> +               if (ret < 0)
> +                       return handled;
> +
> +               tx_evt = evt[can_idx].tx_evt;
> +               rx_evt = evt[can_idx].rx_evt;
> +               bus_err = evt[can_idx].err;
> +               can_status = evt[can_idx].status;
> +       }
> +
> +       if (rx_evt & NCT6694_CAN_EVT_RX_DATA_IN) {
> +               nct6694_can_rx(ndev, rx_evt);
> +               handled = IRQ_HANDLED;
> +       }
> +
> +       if (rx_evt & NCT6694_CAN_EVT_RX_DATA_LOST) {
> +               nct6694_can_handle_lost_msg(ndev);
> +               handled = IRQ_HANDLED;
> +       }
> +
> +       if (can_status) {
> +               nct6694_can_handle_state_change(ndev, can_status);
> +               handled = IRQ_HANDLED;
> +       }
> +
> +       if (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) {
> +               nct6694_handle_bus_err(ndev, bus_err);
> +               handled = IRQ_HANDLED;
> +       }
> +
> +       if (handled)
> +               can_rx_offload_threaded_irq_finish(&priv->offload);
> +
> +       if (tx_evt & NCT6694_CAN_EVT_TX_FIFO_EMPTY)
> +               nct6694_can_tx_irq(ndev);
> +
> +       return handled;
> +}
> +
> +static void nct6694_can_tx(struct net_device *ndev)
> +{
> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> +       struct nct6694_can_frame *frame = &priv->tx->frame;
> +       struct nct6694_cmd_header cmd_hd = {
> +               .mod = NCT6694_CAN_MOD,
> +               .cmd = NCT6694_CAN_DELIVER,
> +               .sel = NCT6694_CAN_DELIVER_SEL(1),
> +               .len = cpu_to_le16(sizeof(*frame))
> +       };
> +       struct net_device_stats *stats = &ndev->stats;
> +       struct sk_buff *skb = priv->tx_skb;
> +       struct canfd_frame *cfd;
> +       struct can_frame *cf;
> +       u32 txid;
> +       int err;
> +
> +       memset(frame, 0, sizeof(*frame));
> +
> +       if (priv->can_idx == 0)
> +               frame->tag = NCT6694_CAN_FRAME_TAG_CAN0;
> +       else
> +               frame->tag = NCT6694_CAN_FRAME_TAG_CAN1;
> +
> +       if (can_is_canfd_skb(skb)) {

Reduce scope of variable when possible: move declaration of cfd here:

                struct canfd_frame *cfd;

> +               cfd = (struct canfd_frame *)priv->tx_skb->data;
> +
> +               if (cfd->flags & CANFD_BRS)
> +                       frame->flag |= NCT6694_CAN_FRAME_FLAG_BRS;
> +
> +               if (cfd->can_id & CAN_EFF_FLAG) {
> +                       txid = cfd->can_id & CAN_EFF_MASK;
> +                       frame->flag |= NCT6694_CAN_FRAME_FLAG_EFF;
> +               } else {
> +                       txid = cfd->can_id & CAN_SFF_MASK;
> +               }
> +               frame->flag |= NCT6694_CAN_FRAME_FLAG_FD;
> +               frame->id = cpu_to_le32(txid);
> +               frame->length = cfd->len;
> +
> +               memcpy(frame->data, cfd->data, cfd->len);
> +       } else {

Reduce scope of variable when possible: move declaration of cf here:

                struct canfd_frame *cf;

> +               cf = (struct can_frame *)priv->tx_skb->data;
> +
> +               if (cf->can_id & CAN_RTR_FLAG)
> +                       frame->flag |= NCT6694_CAN_FRAME_FLAG_RTR;
> +
> +               if (cf->can_id & CAN_EFF_FLAG) {
> +                       txid = cf->can_id & CAN_EFF_MASK;
> +                       frame->flag |= NCT6694_CAN_FRAME_FLAG_EFF;
> +               } else {
> +                       txid = cf->can_id & CAN_SFF_MASK;
> +               }
> +               frame->id = cpu_to_le32(txid);
> +               frame->length = cf->len;
> +
> +               memcpy(frame->data, cf->data, cf->len);

Don't copy cf->data if the can frame is a RTR frame.

> +       }
> +
> +       err = nct6694_write_msg(priv->nct6694, &cmd_hd, frame);
> +       if (err) {
> +               netdev_err(ndev, "%s: Tx FIFO full!\n", __func__);
> +               can_free_echo_skb(ndev, 0, NULL);
> +               stats->tx_dropped++;
> +               stats->tx_errors++;
> +               netif_wake_queue(ndev);
> +       }
> +}
> +
> +static void nct6694_can_tx_work(struct work_struct *work)
> +{
> +       struct nct6694_can_priv *priv = container_of(work,
> +                                                    struct nct6694_can_priv,
> +                                                    tx_work);
> +       struct net_device *ndev = priv->ndev;
> +
> +       guard(mutex)(&priv->lock);
> +
> +       if (priv->tx_skb) {
> +               if (priv->can.state == CAN_STATE_BUS_OFF) {
> +                       nct6694_can_clean(ndev);
> +               } else {
> +                       nct6694_can_tx(ndev);
> +                       can_put_echo_skb(priv->tx_skb, ndev, 0, 0);
> +                       priv->tx_skb = NULL;
> +               }
> +       }
> +}
> +
> +static netdev_tx_t nct6694_can_start_xmit(struct sk_buff *skb,
> +                                         struct net_device *ndev)
> +{
> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> +
> +       if (can_dev_dropped_skb(ndev, skb))
> +               return NETDEV_TX_OK;
> +
> +       if (priv->tx_skb) {
> +               netdev_err(ndev, "hard_xmit called while tx busy\n");
> +               return NETDEV_TX_BUSY;
> +       }
> +
> +       netif_stop_queue(ndev);
> +       priv->tx_skb = skb;
> +       queue_work(priv->wq, &priv->tx_work);
> +
> +       return NETDEV_TX_OK;
> +}
> +
> +static int nct6694_can_start(struct net_device *ndev)
> +{
> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> +       struct nct6694_can_setting *setting = &priv->tx->setting;
> +       struct nct6694_cmd_header cmd_hd = {
> +               .mod = NCT6694_CAN_MOD,
> +               .cmd = NCT6694_CAN_SETTING,
> +               .sel = NCT6694_CAN_SETTING_SEL(priv->can_idx),
> +               .len = cpu_to_le16(sizeof(*setting))
> +       };
> +       const struct can_bittiming *n_bt = &priv->can.bittiming;
> +       const struct can_bittiming *d_bt = &priv->can.data_bittiming;
> +       int ret;
> +
> +       guard(mutex)(&priv->lock);
> +
> +       memset(setting, 0, sizeof(*setting));
> +       setting->nbr = cpu_to_le32(n_bt->bitrate);
> +       setting->dbr = cpu_to_le32(d_bt->bitrate);
> +
> +       if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
> +               setting->ctrl1 |= cpu_to_le16(NCT6694_CAN_SETTING_CTRL1_MON);
> +
> +       if ((priv->can.ctrlmode & CAN_CTRLMODE_FD) &&
> +           priv->can.ctrlmode & CAN_CTRLMODE_FD_NON_ISO)
> +               setting->ctrl1 |= cpu_to_le16(NCT6694_CAN_SETTING_CTRL1_NISO);
> +
> +       if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
> +               setting->ctrl1 |= cpu_to_le16(NCT6694_CAN_SETTING_CTRL1_LBCK);
> +
> +       ret = nct6694_write_msg(priv->nct6694, &cmd_hd, setting);
> +       if (ret)
> +               return ret;
> +
> +       priv->can.state = CAN_STATE_ERROR_ACTIVE;
> +
> +       return ret;
> +}
> +
> +static int nct6694_can_stop(struct net_device *ndev)
> +{
> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> +
> +       netif_stop_queue(ndev);
> +       free_irq(ndev->irq, ndev);
> +       destroy_workqueue(priv->wq);
> +       priv->wq = NULL;
> +       nct6694_can_clean(ndev);
> +       priv->can.state = CAN_STATE_STOPPED;
> +       can_rx_offload_disable(&priv->offload);
> +       close_candev(ndev);
> +
> +       return 0;
> +}
> +
> +static int nct6694_can_set_mode(struct net_device *ndev, enum can_mode mode)
> +{
> +       switch (mode) {
> +       case CAN_MODE_START:
> +               nct6694_can_clean(ndev);
> +               nct6694_can_start(ndev);
> +               netif_wake_queue(ndev);
> +               break;
> +       default:
> +               return -EOPNOTSUPP;
> +       }
> +
> +       return 0;
> +}
> +
> +static int nct6694_can_open(struct net_device *ndev)
> +{
> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> +       int ret;
> +
> +       ret = open_candev(ndev);
> +       if (ret)
> +               return ret;
> +
> +       can_rx_offload_enable(&priv->offload);
> +
> +       ret = request_threaded_irq(ndev->irq, NULL,
> +                                  nct6694_can_irq, IRQF_ONESHOT,
> +                                  "nct6694_can", ndev);
> +       if (ret) {
> +               netdev_err(ndev, "Failed to request IRQ\n");
> +               goto close_candev;
> +       }
> +
> +       priv->wq = alloc_ordered_workqueue("%s-nct6694_wq",
> +                                          WQ_FREEZABLE | WQ_MEM_RECLAIM,
> +                                          ndev->name);
> +       if (!priv->wq) {
> +               ret = -ENOMEM;
> +               goto free_irq;
> +       }
> +
> +       priv->tx_skb = NULL;
> +
> +       ret = nct6694_can_start(ndev);
> +       if (ret)
> +               goto destroy_wq;
> +
> +       netif_start_queue(ndev);
> +
> +       return 0;
> +
> +destroy_wq:
> +       destroy_workqueue(priv->wq);
> +free_irq:
> +       free_irq(ndev->irq, ndev);
> +close_candev:
> +       can_rx_offload_disable(&priv->offload);
> +       close_candev(ndev);
> +       return ret;
> +}
> +
> +static const struct net_device_ops nct6694_can_netdev_ops = {
> +       .ndo_open = nct6694_can_open,
> +       .ndo_stop = nct6694_can_stop,
> +       .ndo_start_xmit = nct6694_can_start_xmit,
> +       .ndo_change_mtu = can_change_mtu,
> +};
> +
> +static const struct ethtool_ops nct6694_can_ethtool_ops = {
> +       .get_ts_info = ethtool_op_get_ts_info,
> +};
> +
> +static int nct6694_can_get_clock(struct nct6694_can_priv *priv)
> +{
> +       struct nct6694_can_information *info = &priv->rx->info;
> +       struct nct6694_cmd_header cmd_hd = {
> +               .mod = NCT6694_CAN_MOD,
> +               .cmd = NCT6694_CAN_INFORMATION,
> +               .sel = NCT6694_CAN_INFORMATION_SEL,
> +               .len = cpu_to_le16(sizeof(*info))
> +       };
> +       int ret;
> +
> +       ret = nct6694_read_msg(priv->nct6694, &cmd_hd, info);
> +       if (ret)
> +               return ret;
> +
> +       return le32_to_cpu(info->can_clk);
> +}
> +
> +static int nct6694_can_probe(struct platform_device *pdev)
> +{
> +       const struct mfd_cell *cell = mfd_get_cell(pdev);
> +       struct nct6694 *nct6694 = dev_get_drvdata(pdev->dev.parent);
> +       struct nct6694_can_priv *priv;
> +       struct net_device *ndev;
> +       int ret, irq, can_clk;
> +
> +       irq = irq_create_mapping(nct6694->domain,
> +                                NCT6694_IRQ_CAN1 + cell->id);
> +       if (!irq)
> +               return irq;
> +
> +       ndev = alloc_candev(sizeof(struct nct6694_can_priv), 1);
> +       if (!ndev)
> +               return -ENOMEM;
> +
> +       ndev->irq = irq;
> +       ndev->flags |= IFF_ECHO;
> +       ndev->netdev_ops = &nct6694_can_netdev_ops;
> +       ndev->ethtool_ops = &nct6694_can_ethtool_ops;

Your device has two CAN interfaces, right? Do not forget to populate
netdev->dev_port.

          netdev->dev_port = cell->id;

> +       priv = netdev_priv(ndev);
> +       priv->nct6694 = nct6694;
> +       priv->ndev = ndev;
> +
> +       priv->tx = devm_kzalloc(&pdev->dev, sizeof(union nct6694_can_tx),
> +                               GFP_KERNEL);
> +       if (!priv->tx) {
> +               ret = -ENOMEM;
> +               goto free_candev;
> +       }
> +
> +       priv->rx = devm_kzalloc(&pdev->dev, sizeof(union nct6694_can_rx),
> +                               GFP_KERNEL);
> +       if (!priv->rx) {
> +               ret = -ENOMEM;
> +               goto free_candev;
> +       }
> +
> +       can_clk = nct6694_can_get_clock(priv);
> +       if (can_clk < 0) {
> +               ret = dev_err_probe(&pdev->dev, can_clk,
> +                                   "Failed to get clock\n");
> +               goto free_candev;
> +       }
> +
> +       devm_mutex_init(&pdev->dev, &priv->lock);
> +       INIT_WORK(&priv->tx_work, nct6694_can_tx_work);
> +
> +       priv->can_idx = cell->id;
> +       priv->can.state = CAN_STATE_STOPPED;
> +       priv->can.clock.freq = can_clk;
> +       priv->can.bittiming_const = &nct6694_can_bittiming_nominal_const;
> +       priv->can.data_bittiming_const = &nct6694_can_bittiming_data_const;
> +       priv->can.do_set_mode = nct6694_can_set_mode;
> +       priv->can.do_get_berr_counter = nct6694_can_get_berr_counter;
> +
> +       priv->can.ctrlmode = CAN_CTRLMODE_FD;
> +
> +       priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK            |
> +                                      CAN_CTRLMODE_LISTENONLY          |
> +                                      CAN_CTRLMODE_FD                  |
> +                                      CAN_CTRLMODE_FD_NON_ISO          |
> +                                      CAN_CTRLMODE_BERR_REPORTING;
> +
> +       ret = can_rx_offload_add_manual(ndev, &priv->offload,
> +                                       NCT6694_NAPI_WEIGHT);
> +       if (ret) {
> +               dev_err_probe(&pdev->dev, ret, "Failed to add rx_offload\n");
> +               goto free_candev;
> +       }
> +
> +       platform_set_drvdata(pdev, priv);
> +       SET_NETDEV_DEV(priv->ndev, &pdev->dev);
> +
> +       ret = register_candev(priv->ndev);
> +       if (ret)
> +               goto del_rx_offload;
> +
> +       return 0;
> +
> +del_rx_offload:
> +       can_rx_offload_del(&priv->offload);
> +free_candev:
> +       free_candev(ndev);
> +       return ret;
> +}
> +
> +static void nct6694_can_remove(struct platform_device *pdev)
> +{
> +       struct nct6694_can_priv *priv = platform_get_drvdata(pdev);
> +
> +       cancel_work_sync(&priv->tx_work);
> +       unregister_candev(priv->ndev);
> +       can_rx_offload_del(&priv->offload);
> +       free_candev(priv->ndev);
> +}
> +
> +static struct platform_driver nct6694_can_driver = {
> +       .driver = {
> +               .name   = DRVNAME,
> +       },
> +       .probe          = nct6694_can_probe,
> +       .remove         = nct6694_can_remove,
> +};
> +
> +module_platform_driver(nct6694_can_driver);
> +
> +MODULE_DESCRIPTION("USB-CAN FD driver for NCT6694");
> +MODULE_AUTHOR("Ming Yu <tmyu0@nuvoton.com>");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:nct6694-can");


Yours sincerely,
Vincent Mailhol

Re: [PATCH v5 4/7] can: Add Nuvoton NCT6694 CAN support

[Ming Yu]

Dear Vincent,

Thank you for your reply,
I'll add comments to describe these locks in the next patch,

Vincent Mailhol <mailhol.vincent@wanadoo.fr> 於 2025年1月14日 週二 下午4:06寫道：
>
...
> > +config CAN_NCT6694
> > +       tristate "Nuvoton NCT6694 Socket CANfd support"
> > +       depends on MFD_NCT6694
>
> Your driver uses the CAN rx offload. You need to select it here.
>
>           select CAN_RX_OFFLOAD
>

Understood! I'll add it in v6.

> > +       help
> > +         If you say yes to this option, support will be included for Nuvoton
> > +         NCT6694, a USB device to socket CANfd controller.
> > +
> > +         This driver can also be built as a module. If so, the module will
> > +         be called nct6694_canfd.
>
> Here, the name is nct6694_canfd...
>
> >  config CAN_PEAK_USB
> >         tristate "PEAK PCAN-USB/USB Pro interfaces for CAN 2.0b/CAN-FD"
> >         help
> > diff --git a/drivers/net/can/usb/Makefile b/drivers/net/can/usb/Makefile
> > index 8b11088e9a59..fcafb1ac262e 100644
> > --- a/drivers/net/can/usb/Makefile
> > +++ b/drivers/net/can/usb/Makefile
> > @@ -11,5 +11,6 @@ obj-$(CONFIG_CAN_F81604) += f81604.o
> >  obj-$(CONFIG_CAN_GS_USB) += gs_usb.o
> >  obj-$(CONFIG_CAN_KVASER_USB) += kvaser_usb/
> >  obj-$(CONFIG_CAN_MCBA_USB) += mcba_usb.o
> > +obj-$(CONFIG_CAN_NCT6694) += nct6694_canfd.o
> >  obj-$(CONFIG_CAN_PEAK_USB) += peak_usb/
> >  obj-$(CONFIG_CAN_UCAN) += ucan.o
> > diff --git a/drivers/net/can/usb/nct6694_canfd.c b/drivers/net/can/usb/nct6694_canfd.c
> > new file mode 100644
> > index 000000000000..7a15c39021ff
> > --- /dev/null
> > +++ b/drivers/net/can/usb/nct6694_canfd.c
> > @@ -0,0 +1,856 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Nuvoton NCT6694 Socket CANfd driver based on USB interface.
> > + *
> > + * Copyright (C) 2024 Nuvoton Technology Corp.
> > + */
> > +
> > +#include <linux/can/dev.h>
> > +#include <linux/can/rx-offload.h>
> > +#include <linux/ethtool.h>
> > +#include <linux/irqdomain.h>
> > +#include <linux/kernel.h>
> > +#include <linux/mfd/core.h>
> > +#include <linux/mfd/nct6694.h>
> > +#include <linux/module.h>
> > +#include <linux/netdevice.h>
> > +#include <linux/platform_device.h>
> > +
> > +#define DRVNAME "nct6694-can"
>
> ... but here, it is nct6694-can.
>
> Use a consistent name between the module name and the driver name.
>

Okay, Fix it in v6.

> > +/*
> > + * USB command module type for NCT6694 CANfd controller.
> > + * This defines the module type used for communication with the NCT6694
> > + * CANfd controller over the USB interface.
> > + */
> > +#define NCT6694_CAN_MOD                        0x05
> > +
> > +/* Command 00h - CAN Setting and Initialization */
> > +#define NCT6694_CAN_SETTING            0x00
> > +#define NCT6694_CAN_SETTING_SEL(idx)   (idx ? 0x01 : 0x00)
>
> What are the possible values for idx? Isn't it only 0 or 1? If so, no
> need for this NCT6694_CAN_SETTING_SEL() macro. Directly assign the
> channel index to the selector field.
>

Okay, Fix it in v6.

> > +#define NCT6694_CAN_SETTING_CTRL1_MON  BIT(0)
> > +#define NCT6694_CAN_SETTING_CTRL1_NISO BIT(1)
> > +#define NCT6694_CAN_SETTING_CTRL1_LBCK BIT(2)
> > +
> > +/* Command 01h - CAN Information */
> > +#define NCT6694_CAN_INFORMATION                0x01
> > +#define NCT6694_CAN_INFORMATION_SEL    0x00
> > +
> > +/* Command 02h - CAN Event */
> > +#define NCT6694_CAN_EVENT              0x02
> > +#define NCT6694_CAN_EVENT_SEL(idx, mask)       \
> > +       ((idx ? 0x80 : 0x00) | ((mask) & 0xFF))
>
> Can idx and mask really overlap? Shouldn't this be:
>
>   #define NCT6694_CAN_EVENT_SEL(idx, mask)  \
>           ((idx ? 0x80 : 0x00) | ((mask) & 0x7F))
>

Sorry, you're right, I'll fix it in v6.

> > +#define NCT6694_CAN_EVENT_ERR          BIT(0)
> > +#define NCT6694_CAN_EVENT_STATUS       BIT(1)
> > +#define NCT6694_CAN_EVENT_TX_EVT       BIT(2)
> > +#define NCT6694_CAN_EVENT_RX_EVT       BIT(3)
> > +#define NCT6694_CAN_EVENT_REC          BIT(4)
> > +#define NCT6694_CAN_EVENT_TEC          BIT(5)
> > +#define NCT6694_CAN_EVENT_MASK         GENMASK(3, 0)
> > +#define NCT6694_CAN_EVT_TX_FIFO_EMPTY  BIT(7)  /* Read-clear */
> > +#define NCT6694_CAN_EVT_RX_DATA_LOST   BIT(5)  /* Read-clear */
> > +#define NCT6694_CAN_EVT_RX_HALF_FULL   BIT(6)  /* Read-clear */
> > +#define NCT6694_CAN_EVT_RX_DATA_IN     BIT(7)  /* Read-clear*/
>
> Some of those macro are not used:
>
>   drivers/net/can/usb/nct6694_canfd.c:52: warning: macro
> "NCT6694_CAN_EVT_RX_HALF_FULL" is not used [-Wunused-macros]
>      52 | #define NCT6694_CAN_EVT_RX_HALF_FULL BIT(6) /* Read-clear */
>         |
>   drivers/net/can/usb/nct6694_canfd.c:43: warning: macro
> "NCT6694_CAN_EVENT_ERR" is not used [-Wunused-macros]
>      43 | #define NCT6694_CAN_EVENT_ERR  BIT(0)
>         |
>   drivers/net/can/usb/nct6694_canfd.c:44: warning: macro
> "NCT6694_CAN_EVENT_STATUS" is not used [-Wunused-macros]
>      44 | #define NCT6694_CAN_EVENT_STATUS BIT(1)
>         |
>   drivers/net/can/usb/nct6694_canfd.c:46: warning: macro
> "NCT6694_CAN_EVENT_RX_EVT" is not used [-Wunused-macros]
>      46 | #define NCT6694_CAN_EVENT_RX_EVT BIT(3)
>         |
>   drivers/net/can/usb/nct6694_canfd.c:45: warning: macro
> "NCT6694_CAN_EVENT_TX_EVT" is not used [-Wunused-macros]
>      45 | #define NCT6694_CAN_EVENT_TX_EVT BIT(2)
>         |
>
> Is this OK?
>

Yes, these macros are replaced by  NCT6694_CAN_EVENT_MASK, I'll drop
them in the next patch.

> > +/* Command 10h - CAN Deliver */
> > +#define NCT6694_CAN_DELIVER            0x10
> > +#define NCT6694_CAN_DELIVER_SEL(buf_cnt)       \
> > +       ((buf_cnt) & 0xFF)
> > +
> > +/* Command 11h - CAN Receive */
> > +#define NCT6694_CAN_RECEIVE            0x11
> > +#define NCT6694_CAN_RECEIVE_SEL(idx, buf_cnt)  \
> > +       ((idx ? 0x80 : 0x00) | ((buf_cnt) & 0xFF))
>
> Can idx and buf_cnt really overlap? Shouldn't this be:
>
>   #define NCT6694_CAN_RECEIVE_SEL(idx, buf_cnt)  \
>           ((idx ? 0x80 : 0x00) | ((buf_cnt) & 0x7F))
>

Fix it in v6.

> > +#define NCT6694_CAN_FRAME_TAG_CAN0     0xC0
> > +#define NCT6694_CAN_FRAME_TAG_CAN1     0xC1
> > +#define NCT6694_CAN_FRAME_FLAG_EFF     BIT(0)
> > +#define NCT6694_CAN_FRAME_FLAG_RTR     BIT(1)
> > +#define NCT6694_CAN_FRAME_FLAG_FD      BIT(2)
> > +#define NCT6694_CAN_FRAME_FLAG_BRS     BIT(3)
> > +#define NCT6694_CAN_FRAME_FLAG_ERR     BIT(4)
> > +
> > +#define NCT6694_NAPI_WEIGHT            32
> > +
> > +enum nct6694_event_err {
> > +       NCT6694_CAN_EVT_ERR_NO_ERROR = 0,
> > +       NCT6694_CAN_EVT_ERR_CRC_ERROR,
> > +       NCT6694_CAN_EVT_ERR_STUFF_ERROR,
> > +       NCT6694_CAN_EVT_ERR_ACK_ERROR,
> > +       NCT6694_CAN_EVT_ERR_FORM_ERROR,
> > +       NCT6694_CAN_EVT_ERR_BIT_ERROR,
> > +       NCT6694_CAN_EVT_ERR_TIMEOUT_ERROR,
> > +       NCT6694_CAN_EVT_ERR_UNKNOWN_ERROR,
> > +};
> > +
> > +enum nct6694_event_status {
> > +       NCT6694_CAN_EVT_STS_ERROR_ACTIVE = 0,
> > +       NCT6694_CAN_EVT_STS_ERROR_PASSIVE,
> > +       NCT6694_CAN_EVT_STS_BUS_OFF,
> > +       NCT6694_CAN_EVT_STS_WARNING,
> > +};
> > +
> > +struct __packed nct6694_can_setting {
> > +       __le32 nbr;
> > +       __le32 dbr;
> > +       u8 active;
> > +       u8 reserved[3];
> > +       __le16 ctrl1;
> > +       __le16 ctrl2;
> > +       __le32 nbtp;
> > +       __le32 dbtp;
> > +};
> > +
> > +struct __packed nct6694_can_information {
> > +       u8 tx_fifo_cnt;
> > +       u8 rx_fifo_cnt;
> > +       u8 reserved[2];
> > +       __le32 can_clk;
> > +};
> > +
> > +struct __packed nct6694_can_event {
> > +       u8 err;
> > +       u8 status;
> > +       u8 tx_evt;
> > +       u8 rx_evt;
> > +       u8 rec;
> > +       u8 tec;
> > +       u8 reserved[2];
> > +};
> > +
> > +struct __packed nct6694_can_frame {
> > +       u8 tag;
> > +       u8 flag;
> > +       u8 reserved;
> > +       u8 length;
> > +       __le32 id;
> > +       u8 data[64];
>
> Nitpick, use CANFD_MAX_DLEN here:
>
>           u8 data[CANFD_MAX_DLEN];
>

Fix it in v6.

> > +};
> > +
...
> > +static void nct6694_can_rx(struct net_device *ndev, u8 rx_evt)
> > +{
> > +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> > +       struct nct6694_can_frame *frame = &priv->rx->frame;
> > +       struct nct6694_cmd_header cmd_hd = {
> > +               .mod = NCT6694_CAN_MOD,
> > +               .cmd = NCT6694_CAN_RECEIVE,
> > +               .sel = NCT6694_CAN_RECEIVE_SEL(priv->can_idx, 1),
> > +               .len = cpu_to_le16(sizeof(*frame))
> > +       };
> > +       struct canfd_frame *cfd;
> > +       struct can_frame *cf;
> > +       struct sk_buff *skb;
> > +       int ret;
> > +
> > +       ret = nct6694_read_msg(priv->nct6694, &cmd_hd, frame);
> > +       if (ret)
> > +               return;
> > +
> > +       if (frame->flag & NCT6694_CAN_FRAME_FLAG_FD) {
>
> Reduce scope of variable when possible: move declaration of cfd here:
>
>                 struct canfd_frame *cfd;
>

Okay! Fix it in v6.

> > +               skb = alloc_canfd_skb(priv->ndev, &cfd);
> > +               if (!skb)
> > +                       return;
> > +
> > +               cfd->can_id = le32_to_cpu(frame->id);
> > +               cfd->len = frame->length;
>
> No. I asked you to sanitize the length in this message:
>
>   https://lore.kernel.org/linux-can/8d66cf66-5564-4272-8c3e-51b715c3d785@wanadoo.fr/
>
> Never use the length as is.
>

Sorry! I misunderstood your meaning.
I'll Fix it to cfd->len = canfd_sanitize_len(frame->length).

> > +               if (frame->flag & NCT6694_CAN_FRAME_FLAG_EFF)
> > +                       cfd->can_id |= CAN_EFF_FLAG;
> > +               if (frame->flag & NCT6694_CAN_FRAME_FLAG_BRS)
> > +                       cfd->flags |= CANFD_BRS;
> > +               if (frame->flag & NCT6694_CAN_FRAME_FLAG_ERR)
> > +                       cfd->flags |= CANFD_ESI;
> > +
> > +               memcpy(cfd->data, frame->data, cfd->len);
> > +       } else {
>
> Reduce scope of variable when possible: move declaration of cf here:
>
>                 struct canfd_frame *cf;
>

Fix it in v6.

> > +               skb = alloc_can_skb(priv->ndev, &cf);
> > +               if (!skb)
> > +                       return;
> > +
> > +               cf->can_id = le32_to_cpu(frame->id);
> > +               cf->len = frame->length;
>
> Ditto, sanitize the length.
>

Fix it in v6.

> > +               if (frame->flag & NCT6694_CAN_FRAME_FLAG_EFF)
> > +                       cf->can_id |= CAN_EFF_FLAG;
> > +               if (frame->flag & NCT6694_CAN_FRAME_FLAG_RTR)
> > +                       cf->can_id |= CAN_RTR_FLAG;
> > +
> > +               memcpy(cf->data, frame->data, cf->len);
>
> Only copy can data if the frame is not an RTR frame.
>
>                   if (frame->flag & NCT6694_CAN_FRAME_FLAG_RTR)
>                           cf->can_id |= CAN_RTR_FLAG;
>                   else
>                           memcpy(cf->data, frame->data, cf->len);
>
> I already asked you to do this in below comment:
>
>   https://lore.kernel.org/linux-can/a25ea362-142f-4e27-8194-787d9829f607@wanadoo.fr/
>

Sorry for forgetting the part, I'll fix it in the next patch.

> > +       }
> > +
> > +       nct6694_can_rx_offload(&priv->offload, skb);
> > +}
> > +
> > +static void nct6694_can_clean(struct net_device *ndev)
> > +{
> > +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> > +
> > +       if (priv->tx_skb || netif_queue_stopped(ndev))
> > +               ndev->stats.tx_errors++;
> > +       dev_kfree_skb(priv->tx_skb);
> > +       priv->tx_skb = NULL;
> > +}
> > +
> > +static int nct6694_can_get_berr_counter(const struct net_device *ndev,
> > +                                       struct can_berr_counter *bec)
> > +{
> > +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> > +       struct nct6694_can_event *evt = priv->rx->event;
> > +       struct nct6694_cmd_header cmd_hd;
> > +       u8 mask = NCT6694_CAN_EVENT_REC | NCT6694_CAN_EVENT_TEC;
> > +       int ret;
> > +
> > +       guard(mutex)(&priv->lock);
> > +
> > +       cmd_hd = (struct nct6694_cmd_header) {
> > +               .mod = NCT6694_CAN_MOD,
> > +               .cmd = NCT6694_CAN_EVENT,
> > +               .sel = NCT6694_CAN_EVENT_SEL(priv->can_idx, mask),
> > +               .len = cpu_to_le16(sizeof(priv->rx->event))
> > +       };
> > +
> > +       ret = nct6694_read_msg(priv->nct6694, &cmd_hd, evt);
> > +       if (ret < 0)
> > +               return ret;
>
> You are holding the priv->lock mutex before calling
> nct6694_read_msg(). But nct6694_read_msg() then holds the
> nct6694->access_lock mutex. Why do you need a double mutex here? What
> kind of race scenario are you trying to prevent here?
>

I think priv->lock need to be placed here to prevent priv->rx from
being assigned by other functions, and nct6694->access_lock ensures
that the nct6694_read_msg() transaction is completed.
But in this case, cmd_hd does not need to be in priv->lock's scope.

> > +       bec->rxerr = evt[priv->can_idx].rec;
> > +       bec->txerr = evt[priv->can_idx].tec;
> > +
> > +       return 0;
> > +}
> > +
> > +static void nct6694_can_handle_state_change(struct net_device *ndev,
> > +                                           u8 status)
> > +{
> > +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> > +       enum can_state new_state = priv->can.state;
> > +       enum can_state rx_state, tx_state;
> > +       struct can_berr_counter bec;
> > +       struct can_frame *cf;
> > +       struct sk_buff *skb;
> > +
> > +       nct6694_can_get_berr_counter(ndev, &bec);
> > +       can_state_get_by_berr_counter(ndev, &bec, &tx_state, &rx_state);
>
> Here, you set up tx_state and rx_state...
>
> > +       switch (status) {
> > +       case NCT6694_CAN_EVT_STS_ERROR_ACTIVE:
> > +               new_state = CAN_STATE_ERROR_ACTIVE;
> > +               break;
> > +       case NCT6694_CAN_EVT_STS_ERROR_PASSIVE:
> > +               new_state = CAN_STATE_ERROR_PASSIVE;
> > +               break;
> > +       case NCT6694_CAN_EVT_STS_BUS_OFF:
> > +               new_state = CAN_STATE_BUS_OFF;
> > +               break;
> > +       case NCT6694_CAN_EVT_STS_WARNING:
> > +               new_state = CAN_STATE_ERROR_WARNING;
> > +               break;
> > +       default:
> > +               netdev_err(ndev, "Receive unknown CAN status event.\n");
> > +               return;
> > +       }
> > +
> > +       /* state hasn't changed */
> > +       if (new_state == priv->can.state)
> > +               return;
> > +
> > +       skb = alloc_can_err_skb(ndev, &cf);
> > +
> > +       tx_state = bec.txerr >= bec.rxerr ? new_state : 0;
> > +       rx_state = bec.txerr <= bec.rxerr ? new_state : 0;
>
> ... but you never used the values returned by
> can_state_get_by_berr_counter() and just overwrote the tx and rx
> state.
>
> What is the logic here? Why do you need to manually adjust those two
> values? Isn't the logic in can_change_state() sufficient?
>
> > +       can_change_state(ndev, cf, tx_state, rx_state);
> > +
> > +       if (new_state == CAN_STATE_BUS_OFF) {
>
> Same for the new_state. The function can_change_state() calculate the
> new state from tx_state and rx_state and save it under
> can_priv->state. But here, you do your own calculation.
>
> Only keep one of the two. If your device already tells you the state,
> then fine! Just use the information from your device and do not use
> can_change_state(). Here, you are doing double work resulting in a
> weird mix.
>

Okay! I will revert nct6694_can_handle_state_change() back to the v3 version.

> > +               can_bus_off(ndev);
> > +       } else if (skb) {
> > +               cf->can_id |= CAN_ERR_CNT;
> > +               cf->data[6] = bec.txerr;
> > +               cf->data[7] = bec.rxerr;
> > +       }
> > +
> > +       nct6694_can_rx_offload(&priv->offload, skb);
> > +}
> > +
...
> > +static irqreturn_t nct6694_can_irq(int irq, void *data)
> > +{
> > +       struct net_device *ndev = data;
> > +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> > +       struct nct6694_can_event *evt = priv->rx->event;
> > +       struct nct6694_cmd_header cmd_hd;
> > +       u8 tx_evt, rx_evt, bus_err, can_status;
> > +       u8 mask_sts = NCT6694_CAN_EVENT_MASK;
>
> No need for the mask_sts variable. Directly use NCT6694_CAN_EVENT_MASK.
>

Okay! Fix it in v6.

> > +       irqreturn_t handled = IRQ_NONE;
> > +       int can_idx = priv->can_idx;
> > +       int ret;
> > +
> > +       scoped_guard(mutex, &priv->lock) {
>
> Reduce scope of variable when possible: move the declarations of
> cmd_hd and ret here.
>

Okay! Fix it in v6.

> > +               cmd_hd = (struct nct6694_cmd_header) {
> > +                       .mod = NCT6694_CAN_MOD,
> > +                       .cmd = NCT6694_CAN_EVENT,
> > +                       .sel = NCT6694_CAN_EVENT_SEL(priv->can_idx, mask_sts),
> > +                       .len = cpu_to_le16(sizeof(priv->rx->event))
> > +               };
> > +
...
> > +static void nct6694_can_tx(struct net_device *ndev)
> > +{
> > +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> > +       struct nct6694_can_frame *frame = &priv->tx->frame;
> > +       struct nct6694_cmd_header cmd_hd = {
> > +               .mod = NCT6694_CAN_MOD,
> > +               .cmd = NCT6694_CAN_DELIVER,
> > +               .sel = NCT6694_CAN_DELIVER_SEL(1),
> > +               .len = cpu_to_le16(sizeof(*frame))
> > +       };
> > +       struct net_device_stats *stats = &ndev->stats;
> > +       struct sk_buff *skb = priv->tx_skb;
> > +       struct canfd_frame *cfd;
> > +       struct can_frame *cf;
> > +       u32 txid;
> > +       int err;
> > +
> > +       memset(frame, 0, sizeof(*frame));
> > +
> > +       if (priv->can_idx == 0)
> > +               frame->tag = NCT6694_CAN_FRAME_TAG_CAN0;
> > +       else
> > +               frame->tag = NCT6694_CAN_FRAME_TAG_CAN1;
> > +
> > +       if (can_is_canfd_skb(skb)) {
>
> Reduce scope of variable when possible: move declaration of cfd here:
>
>                 struct canfd_frame *cfd;
>

Okay! Fix it in v6.

> > +               cfd = (struct canfd_frame *)priv->tx_skb->data;
> > +
> > +               if (cfd->flags & CANFD_BRS)
> > +                       frame->flag |= NCT6694_CAN_FRAME_FLAG_BRS;
> > +
> > +               if (cfd->can_id & CAN_EFF_FLAG) {
> > +                       txid = cfd->can_id & CAN_EFF_MASK;
> > +                       frame->flag |= NCT6694_CAN_FRAME_FLAG_EFF;
> > +               } else {
> > +                       txid = cfd->can_id & CAN_SFF_MASK;
> > +               }
> > +               frame->flag |= NCT6694_CAN_FRAME_FLAG_FD;
> > +               frame->id = cpu_to_le32(txid);
> > +               frame->length = cfd->len;
> > +
> > +               memcpy(frame->data, cfd->data, cfd->len);
> > +       } else {
>
> Reduce scope of variable when possible: move declaration of cf here:
>
>                 struct canfd_frame *cf;
>

Okay! Fix it in v6.

> > +               cf = (struct can_frame *)priv->tx_skb->data;
> > +
> > +               if (cf->can_id & CAN_RTR_FLAG)
> > +                       frame->flag |= NCT6694_CAN_FRAME_FLAG_RTR;
> > +
> > +               if (cf->can_id & CAN_EFF_FLAG) {
> > +                       txid = cf->can_id & CAN_EFF_MASK;
> > +                       frame->flag |= NCT6694_CAN_FRAME_FLAG_EFF;
> > +               } else {
> > +                       txid = cf->can_id & CAN_SFF_MASK;
> > +               }
> > +               frame->id = cpu_to_le32(txid);
> > +               frame->length = cf->len;
> > +
> > +               memcpy(frame->data, cf->data, cf->len);
>
> Don't copy cf->data if the can frame is a RTR frame.
>

Okay! Fix it in v6.

> > +       }
> > +
> > +       err = nct6694_write_msg(priv->nct6694, &cmd_hd, frame);
> > +       if (err) {
> > +               netdev_err(ndev, "%s: Tx FIFO full!\n", __func__);
> > +               can_free_echo_skb(ndev, 0, NULL);
> > +               stats->tx_dropped++;
> > +               stats->tx_errors++;
> > +               netif_wake_queue(ndev);
> > +       }
> > +}
> > +
...
> > +static int nct6694_can_probe(struct platform_device *pdev)
> > +{
> > +       const struct mfd_cell *cell = mfd_get_cell(pdev);
> > +       struct nct6694 *nct6694 = dev_get_drvdata(pdev->dev.parent);
> > +       struct nct6694_can_priv *priv;
> > +       struct net_device *ndev;
> > +       int ret, irq, can_clk;
> > +
> > +       irq = irq_create_mapping(nct6694->domain,
> > +                                NCT6694_IRQ_CAN1 + cell->id);
> > +       if (!irq)
> > +               return irq;
> > +
> > +       ndev = alloc_candev(sizeof(struct nct6694_can_priv), 1);
> > +       if (!ndev)
> > +               return -ENOMEM;
> > +
> > +       ndev->irq = irq;
> > +       ndev->flags |= IFF_ECHO;
> > +       ndev->netdev_ops = &nct6694_can_netdev_ops;
> > +       ndev->ethtool_ops = &nct6694_can_ethtool_ops;
>
> Your device has two CAN interfaces, right? Do not forget to populate
> netdev->dev_port.
>
>           netdev->dev_port = cell->id;
>

Okay! I'll add it in v6.

> > +       priv = netdev_priv(ndev);
> > +       priv->nct6694 = nct6694;
> > +       priv->ndev = ndev;
> > +

Best regards,
Ming

Re: [PATCH v5 2/7] gpio: Add Nuvoton NCT6694 GPIO support

[Bartosz Golaszewski]

On Tue, Jan 14, 2025 at 4:30 AM Ming Yu <a0282524688@gmail.com> wrote:
>
> This driver supports GPIO and IRQ functionality for NCT6694 MFD
> device based on USB interface.
>
> Signed-off-by: Ming Yu <a0282524688@gmail.com>
> ---

Please pick up review tags when resending.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Re: [PATCH v5 4/7] can: Add Nuvoton NCT6694 CAN support

[Vincent Mailhol]

On 14/01/2025 at 19:46, Ming Yu wrote:
> Dear Vincent,
> 
> Thank you for your reply,
> I'll add comments to describe these locks in the next patch,
> 
> Vincent Mailhol <mailhol.vincent@wanadoo.fr> 於 2025年1月14日 週二 下午4:06寫道：

(...)

>>> +static int nct6694_can_get_berr_counter(const struct net_device *ndev,
>>> +                                       struct can_berr_counter *bec)
>>> +{
>>> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
>>> +       struct nct6694_can_event *evt = priv->rx->event;
>>> +       struct nct6694_cmd_header cmd_hd;
>>> +       u8 mask = NCT6694_CAN_EVENT_REC | NCT6694_CAN_EVENT_TEC;
>>> +       int ret;
>>> +
>>> +       guard(mutex)(&priv->lock);
>>> +
>>> +       cmd_hd = (struct nct6694_cmd_header) {
>>> +               .mod = NCT6694_CAN_MOD,
>>> +               .cmd = NCT6694_CAN_EVENT,
>>> +               .sel = NCT6694_CAN_EVENT_SEL(priv->can_idx, mask),
>>> +               .len = cpu_to_le16(sizeof(priv->rx->event))
>>> +       };
>>> +
>>> +       ret = nct6694_read_msg(priv->nct6694, &cmd_hd, evt);
>>> +       if (ret < 0)
>>> +               return ret;
>>
>> You are holding the priv->lock mutex before calling
>> nct6694_read_msg(). But nct6694_read_msg() then holds the
>> nct6694->access_lock mutex. Why do you need a double mutex here? What
>> kind of race scenario are you trying to prevent here?
>>
> 
> I think priv->lock need to be placed here to prevent priv->rx from
> being assigned by other functions, and nct6694->access_lock ensures
> that the nct6694_read_msg() transaction is completed.
> But in this case, cmd_hd does not need to be in priv->lock's scope.

So, the only reason for holding priv->lock is because priv->rx is shared
between functions.

struct nct6694_can_event is only 8 bytes. And you only need it for the
life time of the function so it can simply be declared on the stack:

  	struct nct6694_can_event evt;

and with this, no more need to hold the lock. And the same thing also
applies to the other functions.

Here, by trying to optimize the memory for only a few bytes, you are
getting a huge penalty on the performance by putting locks on all the
functions. This is not a good tradeoff.

>>> +       bec->rxerr = evt[priv->can_idx].rec;
>>> +       bec->txerr = evt[priv->can_idx].tec;
>>> +
>>> +       return 0;
>>> +}


Yours sincerely,
Vincent Mailhol

Re: [PATCH v5 4/7] can: Add Nuvoton NCT6694 CAN support

[Ming Yu]

Vincent Mailhol <mailhol.vincent@wanadoo.fr> 於 2025年1月14日 週二 下午11:12寫道：
>
...
> >>> +static int nct6694_can_get_berr_counter(const struct net_device *ndev,
> >>> +                                       struct can_berr_counter *bec)
> >>> +{
> >>> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> >>> +       struct nct6694_can_event *evt = priv->rx->event;
> >>> +       struct nct6694_cmd_header cmd_hd;
> >>> +       u8 mask = NCT6694_CAN_EVENT_REC | NCT6694_CAN_EVENT_TEC;
> >>> +       int ret;
> >>> +
> >>> +       guard(mutex)(&priv->lock);
> >>> +
> >>> +       cmd_hd = (struct nct6694_cmd_header) {
> >>> +               .mod = NCT6694_CAN_MOD,
> >>> +               .cmd = NCT6694_CAN_EVENT,
> >>> +               .sel = NCT6694_CAN_EVENT_SEL(priv->can_idx, mask),
> >>> +               .len = cpu_to_le16(sizeof(priv->rx->event))
> >>> +       };
> >>> +
> >>> +       ret = nct6694_read_msg(priv->nct6694, &cmd_hd, evt);
> >>> +       if (ret < 0)
> >>> +               return ret;
> >>
> >> You are holding the priv->lock mutex before calling
> >> nct6694_read_msg(). But nct6694_read_msg() then holds the
> >> nct6694->access_lock mutex. Why do you need a double mutex here? What
> >> kind of race scenario are you trying to prevent here?
> >>
> >
> > I think priv->lock need to be placed here to prevent priv->rx from
> > being assigned by other functions, and nct6694->access_lock ensures
> > that the nct6694_read_msg() transaction is completed.
> > But in this case, cmd_hd does not need to be in priv->lock's scope.
>
> So, the only reason for holding priv->lock is because priv->rx is shared
> between functions.
>
> struct nct6694_can_event is only 8 bytes. And you only need it for the
> life time of the function so it can simply be declared on the stack:
>
>         struct nct6694_can_event evt;
>
> and with this, no more need to hold the lock. And the same thing also
> applies to the other functions.
>
> Here, by trying to optimize the memory for only a few bytes, you are
> getting a huge penalty on the performance by putting locks on all the
> functions. This is not a good tradeoff.
>

Since nct6694_read_msg()/nct6694_write_msg() process URBs via
usb_bulk_msg(), the transferred data must not be located on the stack.
For more details about allocating buffers for transmitting data,
please refer to the link:
https://lore.kernel.org/linux-can/20241028-observant-gentle-doberman-0a2baa-mkl@pengutronix.de/

Thanks,
Ming

Re: [PATCH v5 4/7] can: Add Nuvoton NCT6694 CAN support

[Vincent Mailhol]

On 15/01/2025 at 11:11, Ming Yu wrote:
> Vincent Mailhol <mailhol.vincent@wanadoo.fr> 於 2025年1月14日 週二 下午11:12寫道：
>>
> ...
>>>>> +static int nct6694_can_get_berr_counter(const struct net_device *ndev,
>>>>> +                                       struct can_berr_counter *bec)
>>>>> +{
>>>>> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
>>>>> +       struct nct6694_can_event *evt = priv->rx->event;
>>>>> +       struct nct6694_cmd_header cmd_hd;
>>>>> +       u8 mask = NCT6694_CAN_EVENT_REC | NCT6694_CAN_EVENT_TEC;
>>>>> +       int ret;
>>>>> +
>>>>> +       guard(mutex)(&priv->lock);
>>>>> +
>>>>> +       cmd_hd = (struct nct6694_cmd_header) {
>>>>> +               .mod = NCT6694_CAN_MOD,
>>>>> +               .cmd = NCT6694_CAN_EVENT,
>>>>> +               .sel = NCT6694_CAN_EVENT_SEL(priv->can_idx, mask),
>>>>> +               .len = cpu_to_le16(sizeof(priv->rx->event))
>>>>> +       };
>>>>> +
>>>>> +       ret = nct6694_read_msg(priv->nct6694, &cmd_hd, evt);
>>>>> +       if (ret < 0)
>>>>> +               return ret;
>>>>
>>>> You are holding the priv->lock mutex before calling
>>>> nct6694_read_msg(). But nct6694_read_msg() then holds the
>>>> nct6694->access_lock mutex. Why do you need a double mutex here? What
>>>> kind of race scenario are you trying to prevent here?
>>>>
>>>
>>> I think priv->lock need to be placed here to prevent priv->rx from
>>> being assigned by other functions, and nct6694->access_lock ensures
>>> that the nct6694_read_msg() transaction is completed.
>>> But in this case, cmd_hd does not need to be in priv->lock's scope.
>>
>> So, the only reason for holding priv->lock is because priv->rx is shared
>> between functions.
>>
>> struct nct6694_can_event is only 8 bytes. And you only need it for the
>> life time of the function so it can simply be declared on the stack:
>>
>>         struct nct6694_can_event evt;
>>
>> and with this, no more need to hold the lock. And the same thing also
>> applies to the other functions.
>>
>> Here, by trying to optimize the memory for only a few bytes, you are
>> getting a huge penalty on the performance by putting locks on all the
>> functions. This is not a good tradeoff.
>>
> 
> Since nct6694_read_msg()/nct6694_write_msg() process URBs via
> usb_bulk_msg(), the transferred data must not be located on the stack.
> For more details about allocating buffers for transmitting data,
> please refer to the link:
> https://lore.kernel.org/linux-can/20241028-observant-gentle-doberman-0a2baa-mkl@pengutronix.de/

Ack, I forgot that you can not use stack memory in usb_bulk_msg().

Then, instead, you can either:

  - do a dynamic memory allocation directly in the function (good for
    when you are outside of the hot path, for example struct
    nct6694_can_setting)

  - and for the other structures which are part of the hot path
    (typically struct nct6694_can_frame) continue to use a dynamically
    allocated buffer stored in your priv but change the type of
    nct6694_can_tx and nct6694_can_rx from union to structures.

And no more overlaps, thus no more need for the mutex.


Yours sincerely,
Vincent Mailhol

Re: [PATCH v5 4/7] can: Add Nuvoton NCT6694 CAN support

[Ming Yu]

Vincent Mailhol <mailhol.vincent@wanadoo.fr> 於 2025年1月15日 週三 上午11:36寫道：
> >>>>> +static int nct6694_can_get_berr_counter(const struct net_device *ndev,
> >>>>> +                                       struct can_berr_counter *bec)
> >>>>> +{
> >>>>> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> >>>>> +       struct nct6694_can_event *evt = priv->rx->event;
> >>>>> +       struct nct6694_cmd_header cmd_hd;
> >>>>> +       u8 mask = NCT6694_CAN_EVENT_REC | NCT6694_CAN_EVENT_TEC;
> >>>>> +       int ret;
> >>>>> +
> >>>>> +       guard(mutex)(&priv->lock);
> >>>>> +
> >>>>> +       cmd_hd = (struct nct6694_cmd_header) {
> >>>>> +               .mod = NCT6694_CAN_MOD,
> >>>>> +               .cmd = NCT6694_CAN_EVENT,
> >>>>> +               .sel = NCT6694_CAN_EVENT_SEL(priv->can_idx, mask),
> >>>>> +               .len = cpu_to_le16(sizeof(priv->rx->event))
> >>>>> +       };
> >>>>> +
> >>>>> +       ret = nct6694_read_msg(priv->nct6694, &cmd_hd, evt);
> >>>>> +       if (ret < 0)
> >>>>> +               return ret;
> >>>>
> >>>> You are holding the priv->lock mutex before calling
> >>>> nct6694_read_msg(). But nct6694_read_msg() then holds the
> >>>> nct6694->access_lock mutex. Why do you need a double mutex here? What
> >>>> kind of race scenario are you trying to prevent here?
> >>>>
> >>>
> >>> I think priv->lock need to be placed here to prevent priv->rx from
> >>> being assigned by other functions, and nct6694->access_lock ensures
> >>> that the nct6694_read_msg() transaction is completed.
> >>> But in this case, cmd_hd does not need to be in priv->lock's scope.
> >>
> >> So, the only reason for holding priv->lock is because priv->rx is shared
> >> between functions.
> >>
> >> struct nct6694_can_event is only 8 bytes. And you only need it for the
> >> life time of the function so it can simply be declared on the stack:
> >>
> >>         struct nct6694_can_event evt;
> >>
> >> and with this, no more need to hold the lock. And the same thing also
> >> applies to the other functions.
> >>
> >> Here, by trying to optimize the memory for only a few bytes, you are
> >> getting a huge penalty on the performance by putting locks on all the
> >> functions. This is not a good tradeoff.
> >>
> >
> > Since nct6694_read_msg()/nct6694_write_msg() process URBs via
> > usb_bulk_msg(), the transferred data must not be located on the stack.
> > For more details about allocating buffers for transmitting data,
> > please refer to the link:
> > https://lore.kernel.org/linux-can/20241028-observant-gentle-doberman-0a2baa-mkl@pengutronix.de/
>
> Ack, I forgot that you can not use stack memory in usb_bulk_msg().
>
> Then, instead, you can either:
>
>   - do a dynamic memory allocation directly in the function (good for
>     when you are outside of the hot path, for example struct
>     nct6694_can_setting)
>
>   - and for the other structures which are part of the hot path
>     (typically struct nct6694_can_frame) continue to use a dynamically
>     allocated buffer stored in your priv but change the type of
>     nct6694_can_tx and nct6694_can_rx from union to structures.
>
> And no more overlaps, thus no more need for the mutex.
>

Understood, I will remove the unions and add members to private
structure in the next patch.
e.g.
struct nct6694_can_priv {
    struct can_priv can;
    ...
    struct nct6694_can_frame tx;
    struct nct6694_can_frame rx;
};
And do dynamic memory allocation for struct nct6694_can_setting and
struct nct6694_can_information.

In addition, I would like to know your thoughts on how struct
nct6694_can_event[2] should be handled?
It is utilized in both nct6694_can_get_berr_counter() and
nct6694_can_irq(), with the latter being called more frequently during
runtime.

Thanks,
Ming

Re: [PATCH v5 4/7] can: Add Nuvoton NCT6694 CAN support

[Vincent Mailhol]

On Wed. 15 Jan 2025 at 14:35, Ming Yu <a0282524688@gmail.com> wrote:
> Vincent Mailhol <mailhol.vincent@wanadoo.fr> 於 2025年1月15日 週三 上午11:36寫道：
> > >>>>> +static int nct6694_can_get_berr_counter(const struct net_device *ndev,
> > >>>>> +                                       struct can_berr_counter *bec)
> > >>>>> +{
> > >>>>> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> > >>>>> +       struct nct6694_can_event *evt = priv->rx->event;
> > >>>>> +       struct nct6694_cmd_header cmd_hd;
> > >>>>> +       u8 mask = NCT6694_CAN_EVENT_REC | NCT6694_CAN_EVENT_TEC;
> > >>>>> +       int ret;
> > >>>>> +
> > >>>>> +       guard(mutex)(&priv->lock);
> > >>>>> +
> > >>>>> +       cmd_hd = (struct nct6694_cmd_header) {
> > >>>>> +               .mod = NCT6694_CAN_MOD,
> > >>>>> +               .cmd = NCT6694_CAN_EVENT,
> > >>>>> +               .sel = NCT6694_CAN_EVENT_SEL(priv->can_idx, mask),
> > >>>>> +               .len = cpu_to_le16(sizeof(priv->rx->event))
> > >>>>> +       };
> > >>>>> +
> > >>>>> +       ret = nct6694_read_msg(priv->nct6694, &cmd_hd, evt);
> > >>>>> +       if (ret < 0)
> > >>>>> +               return ret;
> > >>>>
> > >>>> You are holding the priv->lock mutex before calling
> > >>>> nct6694_read_msg(). But nct6694_read_msg() then holds the
> > >>>> nct6694->access_lock mutex. Why do you need a double mutex here? What
> > >>>> kind of race scenario are you trying to prevent here?
> > >>>>
> > >>>
> > >>> I think priv->lock need to be placed here to prevent priv->rx from
> > >>> being assigned by other functions, and nct6694->access_lock ensures
> > >>> that the nct6694_read_msg() transaction is completed.
> > >>> But in this case, cmd_hd does not need to be in priv->lock's scope.
> > >>
> > >> So, the only reason for holding priv->lock is because priv->rx is shared
> > >> between functions.
> > >>
> > >> struct nct6694_can_event is only 8 bytes. And you only need it for the
> > >> life time of the function so it can simply be declared on the stack:
> > >>
> > >>         struct nct6694_can_event evt;
> > >>
> > >> and with this, no more need to hold the lock. And the same thing also
> > >> applies to the other functions.
> > >>
> > >> Here, by trying to optimize the memory for only a few bytes, you are
> > >> getting a huge penalty on the performance by putting locks on all the
> > >> functions. This is not a good tradeoff.
> > >>
> > >
> > > Since nct6694_read_msg()/nct6694_write_msg() process URBs via
> > > usb_bulk_msg(), the transferred data must not be located on the stack.
> > > For more details about allocating buffers for transmitting data,
> > > please refer to the link:
> > > https://lore.kernel.org/linux-can/20241028-observant-gentle-doberman-0a2baa-mkl@pengutronix.de/
> >
> > Ack, I forgot that you can not use stack memory in usb_bulk_msg().
> >
> > Then, instead, you can either:
> >
> >   - do a dynamic memory allocation directly in the function (good for
> >     when you are outside of the hot path, for example struct
> >     nct6694_can_setting)
> >
> >   - and for the other structures which are part of the hot path
> >     (typically struct nct6694_can_frame) continue to use a dynamically
> >     allocated buffer stored in your priv but change the type of
> >     nct6694_can_tx and nct6694_can_rx from union to structures.
> >
> > And no more overlaps, thus no more need for the mutex.
> >
>
> Understood, I will remove the unions and add members to private
> structure in the next patch.
> e.g.
> struct nct6694_can_priv {
>     struct can_priv can;
>     ...
>     struct nct6694_can_frame tx;
>     struct nct6694_can_frame rx;
> };
> And do dynamic memory allocation for struct nct6694_can_setting and
> struct nct6694_can_information.
>
> In addition, I would like to know your thoughts on how struct
> nct6694_can_event[2] should be handled?
> It is utilized in both nct6694_can_get_berr_counter() and
> nct6694_can_irq(), with the latter being called more frequently during
> runtime.

For the nct6694_can_event in nct6694_can_irq(), I would say it is part
of the hot path and thus you can have it in your struct
nct6694_can_priv.

For the nct6694_can_get_berr_counter(), the easiest is actually to
just add the error counter structure to your nct6694_can_priv:

          struct can_berr_counter berr_cnt;

Each time you receive an event, you update this local error counter
copy, and this way, in your nct6694_can_get_berr_counter(), no more
need to query your device, you just return the berr_cnt which is saved
locally.


Yours sincerely,
Vincent Mailhol

Re: [PATCH v5 4/7] can: Add Nuvoton NCT6694 CAN support

[Ming Yu]

Vincent Mailhol <mailhol.vincent@wanadoo.fr> 於 2025年1月15日 週三 下午2:44寫道：
>
> On Wed. 15 Jan 2025 at 14:35, Ming Yu <a0282524688@gmail.com> wrote:
> > Vincent Mailhol <mailhol.vincent@wanadoo.fr> 於 2025年1月15日 週三 上午11:36寫道：
> > > >>>>> +static int nct6694_can_get_berr_counter(const struct net_device *ndev,
> > > >>>>> +                                       struct can_berr_counter *bec)
> > > >>>>> +{
> > > >>>>> +       struct nct6694_can_priv *priv = netdev_priv(ndev);
> > > >>>>> +       struct nct6694_can_event *evt = priv->rx->event;
> > > >>>>> +       struct nct6694_cmd_header cmd_hd;
> > > >>>>> +       u8 mask = NCT6694_CAN_EVENT_REC | NCT6694_CAN_EVENT_TEC;
> > > >>>>> +       int ret;
> > > >>>>> +
> > > >>>>> +       guard(mutex)(&priv->lock);
> > > >>>>> +
> > > >>>>> +       cmd_hd = (struct nct6694_cmd_header) {
> > > >>>>> +               .mod = NCT6694_CAN_MOD,
> > > >>>>> +               .cmd = NCT6694_CAN_EVENT,
> > > >>>>> +               .sel = NCT6694_CAN_EVENT_SEL(priv->can_idx, mask),
> > > >>>>> +               .len = cpu_to_le16(sizeof(priv->rx->event))
> > > >>>>> +       };
> > > >>>>> +
> > > >>>>> +       ret = nct6694_read_msg(priv->nct6694, &cmd_hd, evt);
> > > >>>>> +       if (ret < 0)
> > > >>>>> +               return ret;
> > > >>>>
> > > >>>> You are holding the priv->lock mutex before calling
> > > >>>> nct6694_read_msg(). But nct6694_read_msg() then holds the
> > > >>>> nct6694->access_lock mutex. Why do you need a double mutex here? What
> > > >>>> kind of race scenario are you trying to prevent here?
> > > >>>>
> > > >>>
> > > >>> I think priv->lock need to be placed here to prevent priv->rx from
> > > >>> being assigned by other functions, and nct6694->access_lock ensures
> > > >>> that the nct6694_read_msg() transaction is completed.
> > > >>> But in this case, cmd_hd does not need to be in priv->lock's scope.
> > > >>
> > > >> So, the only reason for holding priv->lock is because priv->rx is shared
> > > >> between functions.
> > > >>
> > > >> struct nct6694_can_event is only 8 bytes. And you only need it for the
> > > >> life time of the function so it can simply be declared on the stack:
> > > >>
> > > >>         struct nct6694_can_event evt;
> > > >>
> > > >> and with this, no more need to hold the lock. And the same thing also
> > > >> applies to the other functions.
> > > >>
> > > >> Here, by trying to optimize the memory for only a few bytes, you are
> > > >> getting a huge penalty on the performance by putting locks on all the
> > > >> functions. This is not a good tradeoff.
> > > >>
> > > >
> > > > Since nct6694_read_msg()/nct6694_write_msg() process URBs via
> > > > usb_bulk_msg(), the transferred data must not be located on the stack.
> > > > For more details about allocating buffers for transmitting data,
> > > > please refer to the link:
> > > > https://lore.kernel.org/linux-can/20241028-observant-gentle-doberman-0a2baa-mkl@pengutronix.de/
> > >
> > > Ack, I forgot that you can not use stack memory in usb_bulk_msg().
> > >
> > > Then, instead, you can either:
> > >
> > >   - do a dynamic memory allocation directly in the function (good for
> > >     when you are outside of the hot path, for example struct
> > >     nct6694_can_setting)
> > >
> > >   - and for the other structures which are part of the hot path
> > >     (typically struct nct6694_can_frame) continue to use a dynamically
> > >     allocated buffer stored in your priv but change the type of
> > >     nct6694_can_tx and nct6694_can_rx from union to structures.
> > >
> > > And no more overlaps, thus no more need for the mutex.
> > >
> >
> > Understood, I will remove the unions and add members to private
> > structure in the next patch.
> > e.g.
> > struct nct6694_can_priv {
> >     struct can_priv can;
> >     ...
> >     struct nct6694_can_frame tx;
> >     struct nct6694_can_frame rx;
> > };
> > And do dynamic memory allocation for struct nct6694_can_setting and
> > struct nct6694_can_information.
> >
> > In addition, I would like to know your thoughts on how struct
> > nct6694_can_event[2] should be handled?
> > It is utilized in both nct6694_can_get_berr_counter() and
> > nct6694_can_irq(), with the latter being called more frequently during
> > runtime.
>
> For the nct6694_can_event in nct6694_can_irq(), I would say it is part
> of the hot path and thus you can have it in your struct
> nct6694_can_priv.
>
> For the nct6694_can_get_berr_counter(), the easiest is actually to
> just add the error counter structure to your nct6694_can_priv:
>
>           struct can_berr_counter berr_cnt;
>
> Each time you receive an event, you update this local error counter
> copy, and this way, in your nct6694_can_get_berr_counter(), no more
> need to query your device, you just return the berr_cnt which is saved
> locally.
>

Understood! I will make these modifications in the next patch.

Best regards,
Ming

Re: [PATCH v5 2/7] gpio: Add Nuvoton NCT6694 GPIO support

[Ming Yu]

Dear Bartosz,

Understood!


Thanks,
Ming

Bartosz Golaszewski <brgl@bgdev.pl> 於 2025年1月14日 週二 下午8:12寫道：
>
> On Tue, Jan 14, 2025 at 4:30 AM Ming Yu <a0282524688@gmail.com> wrote:
> >
> > This driver supports GPIO and IRQ functionality for NCT6694 MFD
> > device based on USB interface.
> >
> > Signed-off-by: Ming Yu <a0282524688@gmail.com>
> > ---
>
> Please pick up review tags when resending.
>
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
> Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Re: [PATCH v5 1/7] mfd: Add core driver for Nuvoton NCT6694

[Lee Jones]

On Tue, 14 Jan 2025, Ming Yu wrote:

> The Nuvoton NCT6694 is a peripheral expander with 16 GPIO chips,
> 6 I2C controllers, 2 CANfd controllers, 2 Watchdog timers, ADC,
> PWM, and RTC.
> 
> This driver implements USB device functionality and shares the
> chip's peripherals as a child device.
> 
> Each child device can use the USB functions nct6694_read_msg()
> and nct6694_write_msg() to issue a command. They can also request
> interrupt that will be called when the USB device receives its
> interrupt pipe.
> 
> Signed-off-by: Ming Yu <a0282524688@gmail.com>
> ---
>  MAINTAINERS                 |   7 +
>  drivers/mfd/Kconfig         |  10 +
>  drivers/mfd/Makefile        |   2 +
>  drivers/mfd/nct6694.c       | 388 ++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/nct6694.h | 109 ++++++++++
>  5 files changed, 516 insertions(+)
>  create mode 100644 drivers/mfd/nct6694.c
>  create mode 100644 include/linux/mfd/nct6694.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index a87ddad78e26..79568f82b98a 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -16717,6 +16717,13 @@ F:	drivers/nubus/
>  F:	include/linux/nubus.h
>  F:	include/uapi/linux/nubus.h
>  
> +NUVOTON NCT6694 MFD DRIVER
> +M:	Ming Yu <tmyu0@nuvoton.com>
> +L:	linux-kernel@vger.kernel.org
> +S:	Supported
> +F:	drivers/mfd/nct6694.c
> +F:	include/linux/mfd/nct6694.h
> +
>  NVIDIA (rivafb and nvidiafb) FRAMEBUFFER DRIVER
>  M:	Antonino Daplas <adaplas@gmail.com>
>  L:	linux-fbdev@vger.kernel.org
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index ae23b317a64e..3e641bfeeb38 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -1045,6 +1045,16 @@ config MFD_MENF21BMC
>  	  This driver can also be built as a module. If so the module
>  	  will be called menf21bmc.
>  
> +config MFD_NCT6694
> +	tristate "Nuvoton NCT6694 support"
> +	select MFD_CORE
> +	depends on USB
> +	help
> +	  This adds support for Nuvoton USB device NCT6694 sharing peripherals

Missing full stop.

> +	  This includes the USB device driver and core APIs.
> +	  Additional drivers must be enabled in order to use the functionality

New sentences do not have to be on new lines.

> +	  of the device.

Please explain what this functionality is.

> +
>  config MFD_OCELOT
>  	tristate "Microsemi Ocelot External Control Support"
>  	depends on SPI_MASTER
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index e057d6d6faef..3c902d3704dc 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -121,6 +121,8 @@ obj-$(CONFIG_MFD_MC13XXX)	+= mc13xxx-core.o
>  obj-$(CONFIG_MFD_MC13XXX_SPI)	+= mc13xxx-spi.o
>  obj-$(CONFIG_MFD_MC13XXX_I2C)	+= mc13xxx-i2c.o
>  
> +obj-$(CONFIG_MFD_NCT6694)	+= nct6694.o
> +
>  obj-$(CONFIG_MFD_CORE)		+= mfd-core.o
>  
>  ocelot-soc-objs			:= ocelot-core.o ocelot-spi.o
> diff --git a/drivers/mfd/nct6694.c b/drivers/mfd/nct6694.c
> new file mode 100644
> index 000000000000..294b6b7a902e
> --- /dev/null
> +++ b/drivers/mfd/nct6694.c
> @@ -0,0 +1,388 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Nuvoton NCT6694 MFD driver based on USB interface.

No such thing as an MFD driver.  What is this device?

> + *
> + * Copyright (C) 2024 Nuvoton Technology Corp.
> + */
> +
> +#include <linux/bits.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/irqdomain.h>
> +#include <linux/kernel.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mfd/nct6694.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/usb.h>
> +
> +#define MFD_DEV_SIMPLE(_name)				\
> +{							\
> +	.name = NCT6694_DEV_##_name,			\

Device names are usually lower case.

> +}							\

MFD_CELL_NAME()

> +#define MFD_DEV_WITH_ID(_name, _id)			\
> +{							\
> +	.name = NCT6694_DEV_##_name,			\
> +	.id = _id,					\
> +}

MFD_CELL_BASIC()

Or add a new one to include/linux/mfd/core.h.

> +/* MFD device resources */

This comment is superfluous.

> +static const struct mfd_cell nct6694_dev[] = {
> +	MFD_DEV_WITH_ID(GPIO, 0x0),

Why doesn't PLATFORM_DEVID_AUTO work for you?

> +	MFD_DEV_WITH_ID(GPIO, 0x1),
> +	MFD_DEV_WITH_ID(GPIO, 0x2),
> +	MFD_DEV_WITH_ID(GPIO, 0x3),
> +	MFD_DEV_WITH_ID(GPIO, 0x4),
> +	MFD_DEV_WITH_ID(GPIO, 0x5),
> +	MFD_DEV_WITH_ID(GPIO, 0x6),
> +	MFD_DEV_WITH_ID(GPIO, 0x7),
> +	MFD_DEV_WITH_ID(GPIO, 0x8),
> +	MFD_DEV_WITH_ID(GPIO, 0x9),
> +	MFD_DEV_WITH_ID(GPIO, 0xA),
> +	MFD_DEV_WITH_ID(GPIO, 0xB),
> +	MFD_DEV_WITH_ID(GPIO, 0xC),
> +	MFD_DEV_WITH_ID(GPIO, 0xD),
> +	MFD_DEV_WITH_ID(GPIO, 0xE),
> +	MFD_DEV_WITH_ID(GPIO, 0xF),
> +
> +	MFD_DEV_WITH_ID(I2C, 0x0),
> +	MFD_DEV_WITH_ID(I2C, 0x1),
> +	MFD_DEV_WITH_ID(I2C, 0x2),
> +	MFD_DEV_WITH_ID(I2C, 0x3),
> +	MFD_DEV_WITH_ID(I2C, 0x4),
> +	MFD_DEV_WITH_ID(I2C, 0x5),
> +
> +	MFD_DEV_WITH_ID(CAN, 0x0),
> +	MFD_DEV_WITH_ID(CAN, 0x1),
> +
> +	MFD_DEV_WITH_ID(WDT, 0x0),
> +	MFD_DEV_WITH_ID(WDT, 0x1),
> +
> +	MFD_DEV_SIMPLE(HWMON),
> +	MFD_DEV_SIMPLE(RTC),
> +};
> +
> +static int nct6694_response_err_handling(struct nct6694 *nct6694,
> +					 unsigned char err_status)
> +{
> +	struct device *dev = &nct6694->udev->dev;
> +
> +	switch (err_status) {
> +	case NCT6694_NO_ERROR:
> +		return err_status;
> +	case NCT6694_NOT_SUPPORT_ERROR:
> +		dev_dbg(dev, "%s: Command is not supported!\n", __func__);

These should be dev_warns().

__func__ shouldn't be used in production code.

Users don't care about functions.

> +		break;
> +	case NCT6694_NO_RESPONSE_ERROR:
> +		dev_dbg(dev, "%s: Command received no response!\n", __func__);
> +		break;
> +	case NCT6694_TIMEOUT_ERROR:
> +		dev_dbg(dev, "%s: Command timed out!\n", __func__);
> +		break;
> +	case NCT6694_PENDING:
> +		dev_dbg(dev, "%s: Command is pending!\n", __func__);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return -EIO;
> +}
> +
> +int nct6694_read_msg(struct nct6694 *nct6694,
> +		     struct nct6694_cmd_header *cmd_hd,
> +		     void *buf)
> +{
> +	union nct6694_usb_msg *msg = nct6694->usb_msg;
> +	int tx_len, rx_len, ret;
> +
> +	guard(mutex)(&nct6694->access_lock);
> +
> +	/* Send command packet to USB device */
> +	memcpy(&msg->cmd_header, cmd_hd, sizeof(*cmd_hd));
> +	msg->cmd_header.hctrl = NCT6694_HCTRL_GET;
> +
> +	ret = usb_bulk_msg(nct6694->udev,
> +			   usb_sndbulkpipe(nct6694->udev, NCT6694_BULK_OUT_EP),
> +			   &msg->cmd_header, sizeof(*msg), &tx_len,
> +			   nct6694->timeout);
> +	if (ret)
> +		return ret;
> +
> +	/* Receive response packet from USB device */
> +	ret = usb_bulk_msg(nct6694->udev,
> +			   usb_rcvbulkpipe(nct6694->udev, NCT6694_BULK_IN_EP),
> +			   &msg->response_header, sizeof(*msg), &rx_len,
> +			   nct6694->timeout);
> +	if (ret)
> +		return ret;
> +
> +	/* Receive data packet from USB device */
> +	ret = usb_bulk_msg(nct6694->udev,
> +			   usb_rcvbulkpipe(nct6694->udev, NCT6694_BULK_IN_EP),
> +			   buf, le16_to_cpu(cmd_hd->len), &rx_len,
> +			   nct6694->timeout);
> +	if (ret)
> +		return ret;
> +
> +	if (rx_len != le16_to_cpu(cmd_hd->len)) {
> +		dev_dbg(&nct6694->udev->dev, "%s: Received length is not match!\n",

"does not match <something>"

> +			__func__);

This should be dev_err().

> +		return -EIO;
> +	}
> +
> +	return nct6694_response_err_handling(nct6694, msg->response_header.sts);
> +}
> +EXPORT_SYMBOL(nct6694_read_msg);
> +
> +int nct6694_write_msg(struct nct6694 *nct6694, struct nct6694_cmd_header *cmd_hd,
> +		      void *buf)
> +{
> +	union nct6694_usb_msg *msg = nct6694->usb_msg;
> +	int tx_len, rx_len, ret;
> +
> +	guard(mutex)(&nct6694->access_lock);
> +
> +	/* Send command packet to USB device */
> +	memcpy(&msg->cmd_header, cmd_hd, sizeof(*cmd_hd));
> +	msg->cmd_header.hctrl = NCT6694_HCTRL_SET;
> +
> +	ret = usb_bulk_msg(nct6694->udev,
> +			   usb_sndbulkpipe(nct6694->udev, NCT6694_BULK_OUT_EP),
> +			   &msg->cmd_header, sizeof(*msg), &tx_len,
> +			   nct6694->timeout);
> +	if (ret)
> +		return ret;
> +
> +	/* Send data packet to USB device */
> +	ret = usb_bulk_msg(nct6694->udev,
> +			   usb_sndbulkpipe(nct6694->udev, NCT6694_BULK_OUT_EP),
> +			   buf, le16_to_cpu(cmd_hd->len), &tx_len,
> +			   nct6694->timeout);
> +	if (ret)
> +		return ret;
> +
> +	/* Receive response packet from USB device */
> +	ret = usb_bulk_msg(nct6694->udev,
> +			   usb_rcvbulkpipe(nct6694->udev, NCT6694_BULK_IN_EP),
> +			   &msg->response_header, sizeof(*msg), &rx_len,
> +			   nct6694->timeout);
> +	if (ret)
> +		return ret;
> +
> +	/* Receive data packet from USB device */
> +	ret = usb_bulk_msg(nct6694->udev,
> +			   usb_rcvbulkpipe(nct6694->udev, NCT6694_BULK_IN_EP),
> +			   buf, le16_to_cpu(cmd_hd->len), &rx_len,
> +			   nct6694->timeout);
> +	if (ret)
> +		return ret;
> +
> +	if (rx_len != le16_to_cpu(cmd_hd->len)) {
> +		dev_dbg(&nct6694->udev->dev, "%s: Sent length is not match!\n",
> +			__func__);

This should be dev_err().

> +		return -EIO;
> +	}
> +
> +	return nct6694_response_err_handling(nct6694, msg->response_header.sts);
> +}
> +EXPORT_SYMBOL(nct6694_write_msg);
> +
> +static void usb_int_callback(struct urb *urb)
> +{
> +	struct nct6694 *nct6694 = urb->context;
> +	struct device *dev = &nct6694->udev->dev;
> +	unsigned int *int_status = urb->transfer_buffer;
> +	int ret;
> +
> +	switch (urb->status) {
> +	case 0:
> +		break;
> +	case -ECONNRESET:
> +	case -ENOENT:
> +	case -ESHUTDOWN:
> +		return;
> +	default:
> +		goto resubmit;
> +	}
> +
> +	while (*int_status) {
> +		int irq = __ffs(*int_status);
> +
> +		generic_handle_irq_safe(irq_find_mapping(nct6694->domain, irq));
> +		*int_status &= ~BIT(irq);
> +	}
> +
> +resubmit:
> +	ret = usb_submit_urb(urb, GFP_ATOMIC);
> +	if (ret)
> +		dev_dbg(dev, "%s: Failed to resubmit urb, status %pe",
> +			__func__, ERR_PTR(ret));
> +}
> +
> +static void nct6694_irq_lock(struct irq_data *data)
> +{
> +	struct nct6694 *nct6694 = irq_data_get_irq_chip_data(data);
> +
> +	mutex_lock(&nct6694->irq_lock);
> +}
> +
> +static void nct6694_irq_sync_unlock(struct irq_data *data)
> +{
> +	struct nct6694 *nct6694 = irq_data_get_irq_chip_data(data);
> +
> +	mutex_unlock(&nct6694->irq_lock);
> +}
> +
> +static void nct6694_irq_enable(struct irq_data *data)
> +{
> +	struct nct6694 *nct6694 = irq_data_get_irq_chip_data(data);
> +	irq_hw_number_t hwirq = irqd_to_hwirq(data);
> +
> +	nct6694->irq_enable |= BIT(hwirq);

Changing a bit mask doesn't actually {en,dis}able an IRQ, right?

> +}
> +
> +static void nct6694_irq_disable(struct irq_data *data)
> +{
> +	struct nct6694 *nct6694 = irq_data_get_irq_chip_data(data);
> +	irq_hw_number_t hwirq = irqd_to_hwirq(data);
> +
> +	nct6694->irq_enable &= ~BIT(hwirq);
> +}
> +
> +static struct irq_chip nct6694_irq_chip = {
> +	.name = "nct6694-irq",
> +	.flags = IRQCHIP_SKIP_SET_WAKE,
> +	.irq_bus_lock = nct6694_irq_lock,
> +	.irq_bus_sync_unlock = nct6694_irq_sync_unlock,
> +	.irq_enable = nct6694_irq_enable,
> +	.irq_disable = nct6694_irq_disable,
> +};
> +
> +static int nct6694_irq_domain_map(struct irq_domain *d, unsigned int irq,
> +				  irq_hw_number_t hw)
> +{
> +	struct nct6694 *nct6694 = d->host_data;
> +
> +	irq_set_chip_data(irq, nct6694);
> +	irq_set_chip_and_handler(irq, &nct6694_irq_chip, handle_simple_irq);
> +
> +	return 0;
> +}
> +
> +static void nct6694_irq_domain_unmap(struct irq_domain *d, unsigned int irq)
> +{
> +	irq_set_chip_and_handler(irq, NULL, NULL);
> +	irq_set_chip_data(irq, NULL);
> +}
> +
> +static const struct irq_domain_ops nct6694_irq_domain_ops = {
> +	.map	= nct6694_irq_domain_map,
> +	.unmap	= nct6694_irq_domain_unmap,
> +};
> +
> +static int nct6694_usb_probe(struct usb_interface *iface,
> +			     const struct usb_device_id *id)
> +{
> +	struct usb_device *udev = interface_to_usbdev(iface);
> +	struct usb_endpoint_descriptor *int_endpoint;
> +	struct usb_host_interface *interface;
> +	struct device *dev = &udev->dev;
> +	struct nct6694 *nct6694;
> +	int pipe, maxp;
> +	int ret;
> +
> +	interface = iface->cur_altsetting;

Initialise this during allocation.

> +	int_endpoint = &interface->endpoint[0].desc;
> +	if (!usb_endpoint_is_int_in(int_endpoint))
> +		return -ENODEV;
> +
> +	nct6694 = devm_kzalloc(dev, sizeof(*nct6694), GFP_KERNEL);
> +	if (!nct6694)
> +		return -ENOMEM;
> +
> +	pipe = usb_rcvintpipe(udev, NCT6694_INT_IN_EP);
> +	maxp = usb_maxpacket(udev, pipe);
> +
> +	nct6694->usb_msg = devm_kzalloc(dev, sizeof(union nct6694_usb_msg),
> +					GFP_KERNEL);

Unwrap this - you can use up to 100-chars.

> +	if (!nct6694->usb_msg)
> +		return -ENOMEM;
> +
> +	nct6694->int_buffer = devm_kzalloc(dev, maxp, GFP_KERNEL);
> +	if (!nct6694->int_buffer)
> +		return -ENOMEM;
> +
> +	nct6694->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);
> +	if (!nct6694->int_in_urb)
> +		return -ENOMEM;
> +
> +	nct6694->domain = irq_domain_add_simple(NULL, NCT6694_NR_IRQS, 0,
> +						&nct6694_irq_domain_ops,
> +						nct6694);
> +	if (!nct6694->domain) {
> +		ret = -ENODEV;
> +		goto err_urb;
> +	}
> +
> +	nct6694->udev = udev;
> +	nct6694->timeout = NCT6694_URB_TIMEOUT;	/* Wait until urb complete */

"URB completes"?

> +
> +	devm_mutex_init(dev, &nct6694->access_lock);
> +	devm_mutex_init(dev, &nct6694->irq_lock);
> +
> +	usb_fill_int_urb(nct6694->int_in_urb, udev, pipe,
> +			 nct6694->int_buffer, maxp, usb_int_callback,
> +			 nct6694, int_endpoint->bInterval);
> +	ret = usb_submit_urb(nct6694->int_in_urb, GFP_KERNEL);
> +	if (ret)
> +		goto err_urb;
> +
> +	dev_set_drvdata(dev, nct6694);
> +	usb_set_intfdata(iface, nct6694);

These two do the same thing.  You don't need both.

> +	ret = mfd_add_hotplug_devices(dev, nct6694_dev, ARRAY_SIZE(nct6694_dev));
> +	if (ret)
> +		goto err_mfd;
> +
> +	return 0;
> +
> +err_mfd:
> +	usb_kill_urb(nct6694->int_in_urb);
> +err_urb:
> +	usb_free_urb(nct6694->int_in_urb);
> +	return ret;
> +}
> +
> +static void nct6694_usb_disconnect(struct usb_interface *iface)
> +{
> +	struct usb_device *udev = interface_to_usbdev(iface);
> +	struct nct6694 *nct6694 = usb_get_intfdata(iface);
> +
> +	mfd_remove_devices(&udev->dev);

Does devm_* work here?

> +	usb_kill_urb(nct6694->int_in_urb);
> +	usb_free_urb(nct6694->int_in_urb);
> +}
> +
> +static const struct usb_device_id nct6694_ids[] = {
> +	{ USB_DEVICE_AND_INTERFACE_INFO(NCT6694_VENDOR_ID,
> +					NCT6694_PRODUCT_ID,
> +					0xFF, 0x00, 0x00)},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(usb, nct6694_ids);
> +
> +static struct usb_driver nct6694_usb_driver = {
> +	.name	= "nct6694",
> +	.id_table = nct6694_ids,
> +	.probe = nct6694_usb_probe,
> +	.disconnect = nct6694_usb_disconnect,
> +};
> +
> +module_usb_driver(nct6694_usb_driver);
> +
> +MODULE_DESCRIPTION("USB-MFD driver for NCT6694");

Remove all references to MFD.

> +MODULE_AUTHOR("Ming Yu <tmyu0@nuvoton.com>");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/mfd/nct6694.h b/include/linux/mfd/nct6694.h
> new file mode 100644
> index 000000000000..67ca835589ad
> --- /dev/null
> +++ b/include/linux/mfd/nct6694.h
> @@ -0,0 +1,109 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Nuvoton NCT6694 USB transaction and data structure.
> + *
> + * Copyright (C) 2024 Nuvoton Technology Corp.
> + */
> +
> +#ifndef __MFD_NCT6694_H
> +#define __MFD_NCT6694_H
> +
> +#define NCT6694_DEV_GPIO	"nct6694-gpio"
> +#define NCT6694_DEV_I2C		"nct6694-i2c"
> +#define NCT6694_DEV_CAN		"nct6694-can"
> +#define NCT6694_DEV_WDT		"nct6694-wdt"
> +#define NCT6694_DEV_HWMON	"nct6694-hwmon"
> +#define NCT6694_DEV_RTC		"nct6694-rtc"

Use raw strings in place please.

> +#define NCT6694_VENDOR_ID	0x0416
> +#define NCT6694_PRODUCT_ID	0x200B
> +#define NCT6694_INT_IN_EP	0x81
> +#define NCT6694_BULK_IN_EP	0x02
> +#define NCT6694_BULK_OUT_EP	0x03
> +
> +#define NCT6694_HCTRL_SET	0x40
> +#define NCT6694_HCTRL_GET	0x80
> +
> +#define NCT6694_URB_TIMEOUT	1000
> +
> +enum nct6694_irq_id {

These are never used.

> +	NCT6694_IRQ_GPIO0 = 0,
> +	NCT6694_IRQ_GPIO1,
> +	NCT6694_IRQ_GPIO2,
> +	NCT6694_IRQ_GPIO3,
> +	NCT6694_IRQ_GPIO4,
> +	NCT6694_IRQ_GPIO5,
> +	NCT6694_IRQ_GPIO6,
> +	NCT6694_IRQ_GPIO7,
> +	NCT6694_IRQ_GPIO8,
> +	NCT6694_IRQ_GPIO9,
> +	NCT6694_IRQ_GPIOA,
> +	NCT6694_IRQ_GPIOB,
> +	NCT6694_IRQ_GPIOC,
> +	NCT6694_IRQ_GPIOD,
> +	NCT6694_IRQ_GPIOE,
> +	NCT6694_IRQ_GPIOF,
> +	NCT6694_IRQ_CAN1,
> +	NCT6694_IRQ_CAN2,
> +	NCT6694_IRQ_RTC,
> +	NCT6694_NR_IRQS,
> +};
> +
> +enum nct6694_response_err_status {
> +	NCT6694_NO_ERROR = 0,
> +	NCT6694_FORMAT_ERROR,
> +	NCT6694_RESERVED1,
> +	NCT6694_RESERVED2,
> +	NCT6694_NOT_SUPPORT_ERROR,
> +	NCT6694_NO_RESPONSE_ERROR,
> +	NCT6694_TIMEOUT_ERROR,
> +	NCT6694_PENDING,
> +};
> +
> +struct __packed nct6694_cmd_header {
> +	u8 rsv1;
> +	u8 mod;
> +	union __packed {
> +		__le16 offset;
> +		struct __packed {
> +			u8 cmd;
> +			u8 sel;
> +		};
> +	};
> +	u8 hctrl;
> +	u8 rsv2;
> +	__le16 len;
> +};
> +
> +struct __packed nct6694_response_header {
> +	u8 sequence_id;
> +	u8 sts;
> +	u8 reserved[4];
> +	__le16 len;
> +};
> +
> +union __packed nct6694_usb_msg {
> +	struct nct6694_cmd_header cmd_header;
> +	struct nct6694_response_header response_header;
> +};
> +
> +struct nct6694 {

Do all of these values need to be stored?

> +	struct usb_device *udev;
> +	struct urb *int_in_urb;
> +	struct irq_domain *domain;
> +	struct mutex access_lock;
> +	struct mutex irq_lock;
> +	union nct6694_usb_msg *usb_msg;
> +	unsigned char *int_buffer;
> +	unsigned int irq_enable;
> +	/* time in msec to wait for the urb to the complete */

"Time"  "URB"
> +	long timeout;
> +};
> +
> +int nct6694_read_msg(struct nct6694 *nct6694, struct nct6694_cmd_header *cmd_hd,
> +		     void *buf);
> +
> +int nct6694_write_msg(struct nct6694 *nct6694, struct nct6694_cmd_header *cmd_hd,
> +		      void *buf);
> +
> +#endif
> -- 
> 2.34.1
> 

-- 
Lee Jones [李琼斯]

Re: [PATCH v5 4/7] can: Add Nuvoton NCT6694 CAN support

[Vincent Mailhol]

On 14/01/2025 at 12:30, Ming Yu wrote:

(...)

> +static void nct6694_can_clean(struct net_device *ndev)
> +{
> +	struct nct6694_can_priv *priv = netdev_priv(ndev);
> +
> +	if (priv->tx_skb || netif_queue_stopped(ndev))
> +		ndev->stats.tx_errors++;
> +	dev_kfree_skb(priv->tx_skb);

Use:

  	can_flush_echo_skb(ndev);

(related to the following comments).

> +	priv->tx_skb = NULL;
> +}

(...)

> +static void nct6694_can_tx_work(struct work_struct *work)
> +{
> +	struct nct6694_can_priv *priv = container_of(work,
> +						     struct nct6694_can_priv,
> +						     tx_work);
> +	struct net_device *ndev = priv->ndev;
> +
> +	guard(mutex)(&priv->lock);
> +
> +	if (priv->tx_skb) {
> +		if (priv->can.state == CAN_STATE_BUS_OFF) {

Just stop the queue when the can bus is off so that you do not have do
check the bus status each time a frame is sent.

> +			nct6694_can_clean(ndev);
> +		} else {
> +			nct6694_can_tx(ndev);
> +			can_put_echo_skb(priv->tx_skb, ndev, 0, 0);
> +			priv->tx_skb = NULL;
> +		}
> +	}
> +}
> +
> +static netdev_tx_t nct6694_can_start_xmit(struct sk_buff *skb,
> +					  struct net_device *ndev)
> +{
> +	struct nct6694_can_priv *priv = netdev_priv(ndev);
> +
> +	if (can_dev_dropped_skb(ndev, skb))
> +		return NETDEV_TX_OK;
> +
> +	if (priv->tx_skb) {
> +		netdev_err(ndev, "hard_xmit called while tx busy\n");
> +		return NETDEV_TX_BUSY;
> +	}
> +
> +	netif_stop_queue(ndev);
> +	priv->tx_skb = skb;

Here, you can directly do:

  	can_put_echo_skb(skb, ndev, 0, 0);

The skb remains accessible under priv->can.echo_skb[0]. With this, you
can remove the priv->tx_skb field.

> +	queue_work(priv->wq, &priv->tx_work);
> +
> +	return NETDEV_TX_OK;
> +}


Yours sincerely,
Vincent Mailhol

Re: [PATCH v5 1/7] mfd: Add core driver for Nuvoton NCT6694

[Ming Yu]

Dear Lee,

Thank you for your comments,

Lee Jones <lee@kernel.org> 於 2025年1月16日 週四 上午12:04寫道：
...
> > +config MFD_NCT6694
> > +     tristate "Nuvoton NCT6694 support"
> > +     select MFD_CORE
> > +     depends on USB
> > +     help
> > +       This adds support for Nuvoton USB device NCT6694 sharing peripherals
>
> Missing full stop.
>
> > +       This includes the USB device driver and core APIs.
> > +       Additional drivers must be enabled in order to use the functionality
>
> New sentences do not have to be on new lines.
>
> > +       of the device.
>
> Please explain what this functionality is.
>

Okay! I will fix these in the next patch.

> > +
> >  config MFD_OCELOT
> >       tristate "Microsemi Ocelot External Control Support"
> >       depends on SPI_MASTER
> > diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> > index e057d6d6faef..3c902d3704dc 100644
> > --- a/drivers/mfd/Makefile
> > +++ b/drivers/mfd/Makefile
> > @@ -121,6 +121,8 @@ obj-$(CONFIG_MFD_MC13XXX) += mc13xxx-core.o
> >  obj-$(CONFIG_MFD_MC13XXX_SPI)        += mc13xxx-spi.o
> >  obj-$(CONFIG_MFD_MC13XXX_I2C)        += mc13xxx-i2c.o
> >
> > +obj-$(CONFIG_MFD_NCT6694)    += nct6694.o
> > +
> >  obj-$(CONFIG_MFD_CORE)               += mfd-core.o
> >
> >  ocelot-soc-objs                      := ocelot-core.o ocelot-spi.o
> > diff --git a/drivers/mfd/nct6694.c b/drivers/mfd/nct6694.c
> > new file mode 100644
> > index 000000000000..294b6b7a902e
> > --- /dev/null
> > +++ b/drivers/mfd/nct6694.c
> > @@ -0,0 +1,388 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Nuvoton NCT6694 MFD driver based on USB interface.
>
> No such thing as an MFD driver.  What is this device?
>

Fix it in the v6.

> > + *
> > + * Copyright (C) 2024 Nuvoton Technology Corp.
> > + */
> > +
> > +#include <linux/bits.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/irq.h>
> > +#include <linux/irqdomain.h>
> > +#include <linux/kernel.h>
> > +#include <linux/mfd/core.h>
> > +#include <linux/mfd/nct6694.h>
> > +#include <linux/module.h>
> > +#include <linux/slab.h>
> > +#include <linux/usb.h>
> > +
> > +#define MFD_DEV_SIMPLE(_name)                                \
> > +{                                                    \
> > +     .name = NCT6694_DEV_##_name,                    \
>
> Device names are usually lower case.
>
> > +}                                                    \
>
> MFD_CELL_NAME()
>

Fix it in the v6.

> > +#define MFD_DEV_WITH_ID(_name, _id)                  \
> > +{                                                    \
> > +     .name = NCT6694_DEV_##_name,                    \
> > +     .id = _id,                                      \
> > +}
>
> MFD_CELL_BASIC()
>
> Or add a new one to include/linux/mfd/core.h.
>

Fix it in the v6.

> > +/* MFD device resources */
>
> This comment is superfluous.
>

Drop it in the v6.

> > +static const struct mfd_cell nct6694_dev[] = {
> > +     MFD_DEV_WITH_ID(GPIO, 0x0),
>
> Why doesn't PLATFORM_DEVID_AUTO work for you?
>

I need to manage these IDs to ensure that child devices can be
properly utilized within their respective modules.

> > +     MFD_DEV_WITH_ID(GPIO, 0x1),
> > +     MFD_DEV_WITH_ID(GPIO, 0x2),
> > +     MFD_DEV_WITH_ID(GPIO, 0x3),
> > +     MFD_DEV_WITH_ID(GPIO, 0x4),
> > +     MFD_DEV_WITH_ID(GPIO, 0x5),
> > +     MFD_DEV_WITH_ID(GPIO, 0x6),
> > +     MFD_DEV_WITH_ID(GPIO, 0x7),
> > +     MFD_DEV_WITH_ID(GPIO, 0x8),
> > +     MFD_DEV_WITH_ID(GPIO, 0x9),
> > +     MFD_DEV_WITH_ID(GPIO, 0xA),
> > +     MFD_DEV_WITH_ID(GPIO, 0xB),
> > +     MFD_DEV_WITH_ID(GPIO, 0xC),
> > +     MFD_DEV_WITH_ID(GPIO, 0xD),
> > +     MFD_DEV_WITH_ID(GPIO, 0xE),
> > +     MFD_DEV_WITH_ID(GPIO, 0xF),
> > +
> > +     MFD_DEV_WITH_ID(I2C, 0x0),
> > +     MFD_DEV_WITH_ID(I2C, 0x1),
> > +     MFD_DEV_WITH_ID(I2C, 0x2),
> > +     MFD_DEV_WITH_ID(I2C, 0x3),
> > +     MFD_DEV_WITH_ID(I2C, 0x4),
> > +     MFD_DEV_WITH_ID(I2C, 0x5),
> > +
> > +     MFD_DEV_WITH_ID(CAN, 0x0),
> > +     MFD_DEV_WITH_ID(CAN, 0x1),
> > +
> > +     MFD_DEV_WITH_ID(WDT, 0x0),
> > +     MFD_DEV_WITH_ID(WDT, 0x1),
> > +
> > +     MFD_DEV_SIMPLE(HWMON),
> > +     MFD_DEV_SIMPLE(RTC),
> > +};
> > +
> > +static int nct6694_response_err_handling(struct nct6694 *nct6694,
> > +                                      unsigned char err_status)
> > +{
> > +     struct device *dev = &nct6694->udev->dev;
> > +
> > +     switch (err_status) {
> > +     case NCT6694_NO_ERROR:
> > +             return err_status;
> > +     case NCT6694_NOT_SUPPORT_ERROR:
> > +             dev_dbg(dev, "%s: Command is not supported!\n", __func__);
>
> These should be dev_warns().
>
> __func__ shouldn't be used in production code.
>
> Users don't care about functions.
>

Fix it in the v6.

> > +             break;
> > +     case NCT6694_NO_RESPONSE_ERROR:
> > +             dev_dbg(dev, "%s: Command received no response!\n", __func__);
> > +             break;
> > +     case NCT6694_TIMEOUT_ERROR:
> > +             dev_dbg(dev, "%s: Command timed out!\n", __func__);
> > +             break;
> > +     case NCT6694_PENDING:
> > +             dev_dbg(dev, "%s: Command is pending!\n", __func__);
> > +             break;
> > +     default:
> > +             return -EINVAL;
> > +     }
> > +
> > +     return -EIO;
> > +}
> > +
> > +int nct6694_read_msg(struct nct6694 *nct6694,
> > +                  struct nct6694_cmd_header *cmd_hd,
> > +                  void *buf)
> > +{
> > +     union nct6694_usb_msg *msg = nct6694->usb_msg;
> > +     int tx_len, rx_len, ret;
> > +
> > +     guard(mutex)(&nct6694->access_lock);
> > +
> > +     /* Send command packet to USB device */
> > +     memcpy(&msg->cmd_header, cmd_hd, sizeof(*cmd_hd));
> > +     msg->cmd_header.hctrl = NCT6694_HCTRL_GET;
> > +
> > +     ret = usb_bulk_msg(nct6694->udev,
> > +                        usb_sndbulkpipe(nct6694->udev, NCT6694_BULK_OUT_EP),
> > +                        &msg->cmd_header, sizeof(*msg), &tx_len,
> > +                        nct6694->timeout);
> > +     if (ret)
> > +             return ret;
> > +
> > +     /* Receive response packet from USB device */
> > +     ret = usb_bulk_msg(nct6694->udev,
> > +                        usb_rcvbulkpipe(nct6694->udev, NCT6694_BULK_IN_EP),
> > +                        &msg->response_header, sizeof(*msg), &rx_len,
> > +                        nct6694->timeout);
> > +     if (ret)
> > +             return ret;
> > +
> > +     /* Receive data packet from USB device */
> > +     ret = usb_bulk_msg(nct6694->udev,
> > +                        usb_rcvbulkpipe(nct6694->udev, NCT6694_BULK_IN_EP),
> > +                        buf, le16_to_cpu(cmd_hd->len), &rx_len,
> > +                        nct6694->timeout);
> > +     if (ret)
> > +             return ret;
> > +
> > +     if (rx_len != le16_to_cpu(cmd_hd->len)) {
> > +             dev_dbg(&nct6694->udev->dev, "%s: Received length is not match!\n",
>
> "does not match <something>"
>

Fix it in the v6.

> > +                     __func__);
>
> This should be dev_err().
>

Fix it in the v6.

> > +             return -EIO;
> > +     }
> > +
> > +     return nct6694_response_err_handling(nct6694, msg->response_header.sts);
> > +}
> > +EXPORT_SYMBOL(nct6694_read_msg);
> > +
> > +int nct6694_write_msg(struct nct6694 *nct6694, struct nct6694_cmd_header *cmd_hd,
> > +                   void *buf)
> > +{
> > +     union nct6694_usb_msg *msg = nct6694->usb_msg;
> > +     int tx_len, rx_len, ret;
> > +
> > +     guard(mutex)(&nct6694->access_lock);
> > +
> > +     /* Send command packet to USB device */
> > +     memcpy(&msg->cmd_header, cmd_hd, sizeof(*cmd_hd));
> > +     msg->cmd_header.hctrl = NCT6694_HCTRL_SET;
> > +
> > +     ret = usb_bulk_msg(nct6694->udev,
> > +                        usb_sndbulkpipe(nct6694->udev, NCT6694_BULK_OUT_EP),
> > +                        &msg->cmd_header, sizeof(*msg), &tx_len,
> > +                        nct6694->timeout);
> > +     if (ret)
> > +             return ret;
> > +
> > +     /* Send data packet to USB device */
> > +     ret = usb_bulk_msg(nct6694->udev,
> > +                        usb_sndbulkpipe(nct6694->udev, NCT6694_BULK_OUT_EP),
> > +                        buf, le16_to_cpu(cmd_hd->len), &tx_len,
> > +                        nct6694->timeout);
> > +     if (ret)
> > +             return ret;
> > +
> > +     /* Receive response packet from USB device */
> > +     ret = usb_bulk_msg(nct6694->udev,
> > +                        usb_rcvbulkpipe(nct6694->udev, NCT6694_BULK_IN_EP),
> > +                        &msg->response_header, sizeof(*msg), &rx_len,
> > +                        nct6694->timeout);
> > +     if (ret)
> > +             return ret;
> > +
> > +     /* Receive data packet from USB device */
> > +     ret = usb_bulk_msg(nct6694->udev,
> > +                        usb_rcvbulkpipe(nct6694->udev, NCT6694_BULK_IN_EP),
> > +                        buf, le16_to_cpu(cmd_hd->len), &rx_len,
> > +                        nct6694->timeout);
> > +     if (ret)
> > +             return ret;
> > +
> > +     if (rx_len != le16_to_cpu(cmd_hd->len)) {
> > +             dev_dbg(&nct6694->udev->dev, "%s: Sent length is not match!\n",
> > +                     __func__);
>
> This should be dev_err().
>

Fix it in the v6.

> > +             return -EIO;
> > +     }
> > +
> > +     return nct6694_response_err_handling(nct6694, msg->response_header.sts);
> > +}
> > +EXPORT_SYMBOL(nct6694_write_msg);
> > +
> > +static void usb_int_callback(struct urb *urb)
> > +{
> > +     struct nct6694 *nct6694 = urb->context;
> > +     struct device *dev = &nct6694->udev->dev;
> > +     unsigned int *int_status = urb->transfer_buffer;
> > +     int ret;
> > +
> > +     switch (urb->status) {
> > +     case 0:
> > +             break;
> > +     case -ECONNRESET:
> > +     case -ENOENT:
> > +     case -ESHUTDOWN:
> > +             return;
> > +     default:
> > +             goto resubmit;
> > +     }
> > +
> > +     while (*int_status) {
> > +             int irq = __ffs(*int_status);
> > +
> > +             generic_handle_irq_safe(irq_find_mapping(nct6694->domain, irq));
> > +             *int_status &= ~BIT(irq);
> > +     }
> > +
> > +resubmit:
> > +     ret = usb_submit_urb(urb, GFP_ATOMIC);
> > +     if (ret)
> > +             dev_dbg(dev, "%s: Failed to resubmit urb, status %pe",
> > +                     __func__, ERR_PTR(ret));
> > +}
> > +
> > +static void nct6694_irq_lock(struct irq_data *data)
> > +{
> > +     struct nct6694 *nct6694 = irq_data_get_irq_chip_data(data);
> > +
> > +     mutex_lock(&nct6694->irq_lock);
> > +}
> > +
> > +static void nct6694_irq_sync_unlock(struct irq_data *data)
> > +{
> > +     struct nct6694 *nct6694 = irq_data_get_irq_chip_data(data);
> > +
> > +     mutex_unlock(&nct6694->irq_lock);
> > +}
> > +
> > +static void nct6694_irq_enable(struct irq_data *data)
> > +{
> > +     struct nct6694 *nct6694 = irq_data_get_irq_chip_data(data);
> > +     irq_hw_number_t hwirq = irqd_to_hwirq(data);
> > +
> > +     nct6694->irq_enable |= BIT(hwirq);
>
> Changing a bit mask doesn't actually {en,dis}able an IRQ, right?
>

Yes, it's only used to record irq.

> > +}
> > +
> > +static void nct6694_irq_disable(struct irq_data *data)
> > +{
> > +     struct nct6694 *nct6694 = irq_data_get_irq_chip_data(data);
> > +     irq_hw_number_t hwirq = irqd_to_hwirq(data);
> > +
> > +     nct6694->irq_enable &= ~BIT(hwirq);
> > +}
> > +
> > +static struct irq_chip nct6694_irq_chip = {
> > +     .name = "nct6694-irq",
> > +     .flags = IRQCHIP_SKIP_SET_WAKE,
> > +     .irq_bus_lock = nct6694_irq_lock,
> > +     .irq_bus_sync_unlock = nct6694_irq_sync_unlock,
> > +     .irq_enable = nct6694_irq_enable,
> > +     .irq_disable = nct6694_irq_disable,
> > +};
> > +
> > +static int nct6694_irq_domain_map(struct irq_domain *d, unsigned int irq,
> > +                               irq_hw_number_t hw)
> > +{
> > +     struct nct6694 *nct6694 = d->host_data;
> > +
> > +     irq_set_chip_data(irq, nct6694);
> > +     irq_set_chip_and_handler(irq, &nct6694_irq_chip, handle_simple_irq);
> > +
> > +     return 0;
> > +}
> > +
> > +static void nct6694_irq_domain_unmap(struct irq_domain *d, unsigned int irq)
> > +{
> > +     irq_set_chip_and_handler(irq, NULL, NULL);
> > +     irq_set_chip_data(irq, NULL);
> > +}
> > +
> > +static const struct irq_domain_ops nct6694_irq_domain_ops = {
> > +     .map    = nct6694_irq_domain_map,
> > +     .unmap  = nct6694_irq_domain_unmap,
> > +};
> > +
> > +static int nct6694_usb_probe(struct usb_interface *iface,
> > +                          const struct usb_device_id *id)
> > +{
> > +     struct usb_device *udev = interface_to_usbdev(iface);
> > +     struct usb_endpoint_descriptor *int_endpoint;
> > +     struct usb_host_interface *interface;
> > +     struct device *dev = &udev->dev;
> > +     struct nct6694 *nct6694;
> > +     int pipe, maxp;
> > +     int ret;
> > +
> > +     interface = iface->cur_altsetting;
>
> Initialise this during allocation.
>

Should these be moved before usb_fill_int_urb()?

> > +     int_endpoint = &interface->endpoint[0].desc;
> > +     if (!usb_endpoint_is_int_in(int_endpoint))
> > +             return -ENODEV;
> > +
> > +     nct6694 = devm_kzalloc(dev, sizeof(*nct6694), GFP_KERNEL);
> > +     if (!nct6694)
> > +             return -ENOMEM;
> > +
> > +     pipe = usb_rcvintpipe(udev, NCT6694_INT_IN_EP);
> > +     maxp = usb_maxpacket(udev, pipe);
> > +
> > +     nct6694->usb_msg = devm_kzalloc(dev, sizeof(union nct6694_usb_msg),
> > +                                     GFP_KERNEL);
>
> Unwrap this - you can use up to 100-chars.
>

Fix it in the v6.

> > +     if (!nct6694->usb_msg)
> > +             return -ENOMEM;
> > +
> > +     nct6694->int_buffer = devm_kzalloc(dev, maxp, GFP_KERNEL);
> > +     if (!nct6694->int_buffer)
> > +             return -ENOMEM;
> > +
> > +     nct6694->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);
> > +     if (!nct6694->int_in_urb)
> > +             return -ENOMEM;
> > +
> > +     nct6694->domain = irq_domain_add_simple(NULL, NCT6694_NR_IRQS, 0,
> > +                                             &nct6694_irq_domain_ops,
> > +                                             nct6694);
> > +     if (!nct6694->domain) {
> > +             ret = -ENODEV;
> > +             goto err_urb;
> > +     }
> > +
> > +     nct6694->udev = udev;
> > +     nct6694->timeout = NCT6694_URB_TIMEOUT; /* Wait until urb complete */
>
> "URB completes"?
>

Fix it in the v6.

> > +
> > +     devm_mutex_init(dev, &nct6694->access_lock);
> > +     devm_mutex_init(dev, &nct6694->irq_lock);
> > +
> > +     usb_fill_int_urb(nct6694->int_in_urb, udev, pipe,
> > +                      nct6694->int_buffer, maxp, usb_int_callback,
> > +                      nct6694, int_endpoint->bInterval);
> > +     ret = usb_submit_urb(nct6694->int_in_urb, GFP_KERNEL);
> > +     if (ret)
> > +             goto err_urb;
> > +
> > +     dev_set_drvdata(dev, nct6694);
> > +     usb_set_intfdata(iface, nct6694);
>
> These two do the same thing.  You don't need both.
>

Fix it in the v6.

> > +     ret = mfd_add_hotplug_devices(dev, nct6694_dev, ARRAY_SIZE(nct6694_dev));
> > +     if (ret)
> > +             goto err_mfd;
> > +
> > +     return 0;
> > +
> > +err_mfd:
> > +     usb_kill_urb(nct6694->int_in_urb);
> > +err_urb:
> > +     usb_free_urb(nct6694->int_in_urb);
> > +     return ret;
> > +}
> > +
> > +static void nct6694_usb_disconnect(struct usb_interface *iface)
> > +{
> > +     struct usb_device *udev = interface_to_usbdev(iface);
> > +     struct nct6694 *nct6694 = usb_get_intfdata(iface);
> > +
> > +     mfd_remove_devices(&udev->dev);
>
> Does devm_* work here?
>

No, or do you think mfd_add_hotplug_devices() should be replaced with
devm_mfd_add_devices()?

> > +     usb_kill_urb(nct6694->int_in_urb);
> > +     usb_free_urb(nct6694->int_in_urb);
> > +}
> > +
> > +static const struct usb_device_id nct6694_ids[] = {
> > +     { USB_DEVICE_AND_INTERFACE_INFO(NCT6694_VENDOR_ID,
> > +                                     NCT6694_PRODUCT_ID,
> > +                                     0xFF, 0x00, 0x00)},
> > +     {}
> > +};
> > +MODULE_DEVICE_TABLE(usb, nct6694_ids);
> > +
> > +static struct usb_driver nct6694_usb_driver = {
> > +     .name   = "nct6694",
> > +     .id_table = nct6694_ids,
> > +     .probe = nct6694_usb_probe,
> > +     .disconnect = nct6694_usb_disconnect,
> > +};
> > +
> > +module_usb_driver(nct6694_usb_driver);
> > +
> > +MODULE_DESCRIPTION("USB-MFD driver for NCT6694");
>
> Remove all references to MFD.
>

Fix it in the v6.

> > +MODULE_AUTHOR("Ming Yu <tmyu0@nuvoton.com>");
> > +MODULE_LICENSE("GPL");
> > diff --git a/include/linux/mfd/nct6694.h b/include/linux/mfd/nct6694.h
> > new file mode 100644
> > index 000000000000..67ca835589ad
> > --- /dev/null
> > +++ b/include/linux/mfd/nct6694.h
> > @@ -0,0 +1,109 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Nuvoton NCT6694 USB transaction and data structure.
> > + *
> > + * Copyright (C) 2024 Nuvoton Technology Corp.
> > + */
> > +
> > +#ifndef __MFD_NCT6694_H
> > +#define __MFD_NCT6694_H
> > +
> > +#define NCT6694_DEV_GPIO     "nct6694-gpio"
> > +#define NCT6694_DEV_I2C              "nct6694-i2c"
> > +#define NCT6694_DEV_CAN              "nct6694-can"
> > +#define NCT6694_DEV_WDT              "nct6694-wdt"
> > +#define NCT6694_DEV_HWMON    "nct6694-hwmon"
> > +#define NCT6694_DEV_RTC              "nct6694-rtc"
>
> Use raw strings in place please.
>

Fix it in the v6.

> > +#define NCT6694_VENDOR_ID    0x0416
> > +#define NCT6694_PRODUCT_ID   0x200B
> > +#define NCT6694_INT_IN_EP    0x81
> > +#define NCT6694_BULK_IN_EP   0x02
> > +#define NCT6694_BULK_OUT_EP  0x03
> > +
> > +#define NCT6694_HCTRL_SET    0x40
> > +#define NCT6694_HCTRL_GET    0x80
> > +
> > +#define NCT6694_URB_TIMEOUT  1000
> > +
> > +enum nct6694_irq_id {
>
> These are never used.
>

Some of these numbers ared used by child devices to map the irq_domain.
(e.g. NCT6694_IRQ_CAN1, NCT6694_IRQ_RTC)

> > +     NCT6694_IRQ_GPIO0 = 0,
> > +     NCT6694_IRQ_GPIO1,
> > +     NCT6694_IRQ_GPIO2,
> > +     NCT6694_IRQ_GPIO3,
> > +     NCT6694_IRQ_GPIO4,
> > +     NCT6694_IRQ_GPIO5,
> > +     NCT6694_IRQ_GPIO6,
> > +     NCT6694_IRQ_GPIO7,
> > +     NCT6694_IRQ_GPIO8,
> > +     NCT6694_IRQ_GPIO9,
> > +     NCT6694_IRQ_GPIOA,
> > +     NCT6694_IRQ_GPIOB,
> > +     NCT6694_IRQ_GPIOC,
> > +     NCT6694_IRQ_GPIOD,
> > +     NCT6694_IRQ_GPIOE,
> > +     NCT6694_IRQ_GPIOF,
> > +     NCT6694_IRQ_CAN1,
> > +     NCT6694_IRQ_CAN2,
> > +     NCT6694_IRQ_RTC,
> > +     NCT6694_NR_IRQS,
> > +};
> > +
> > +enum nct6694_response_err_status {
> > +     NCT6694_NO_ERROR = 0,
> > +     NCT6694_FORMAT_ERROR,
> > +     NCT6694_RESERVED1,
> > +     NCT6694_RESERVED2,
> > +     NCT6694_NOT_SUPPORT_ERROR,
> > +     NCT6694_NO_RESPONSE_ERROR,
> > +     NCT6694_TIMEOUT_ERROR,
> > +     NCT6694_PENDING,
> > +};
> > +
> > +struct __packed nct6694_cmd_header {
> > +     u8 rsv1;
> > +     u8 mod;
> > +     union __packed {
> > +             __le16 offset;
> > +             struct __packed {
> > +                     u8 cmd;
> > +                     u8 sel;
> > +             };
> > +     };
> > +     u8 hctrl;
> > +     u8 rsv2;
> > +     __le16 len;
> > +};
> > +
> > +struct __packed nct6694_response_header {
> > +     u8 sequence_id;
> > +     u8 sts;
> > +     u8 reserved[4];
> > +     __le16 len;
> > +};
> > +
> > +union __packed nct6694_usb_msg {
> > +     struct nct6694_cmd_header cmd_header;
> > +     struct nct6694_response_header response_header;
> > +};
> > +
> > +struct nct6694 {
>
> Do all of these values need to be stored?
>

I think that's right.

> > +     struct usb_device *udev;
> > +     struct urb *int_in_urb;
> > +     struct irq_domain *domain;
> > +     struct mutex access_lock;
> > +     struct mutex irq_lock;
> > +     union nct6694_usb_msg *usb_msg;
> > +     unsigned char *int_buffer;
> > +     unsigned int irq_enable;
> > +     /* time in msec to wait for the urb to the complete */
>
> "Time"  "URB"

Fix it in the v6.

> > +     long timeout;
> > +};
> > +
> > +int nct6694_read_msg(struct nct6694 *nct6694, struct nct6694_cmd_header *cmd_hd,
> > +                  void *buf);
> > +
> > +int nct6694_write_msg(struct nct6694 *nct6694, struct nct6694_cmd_header *cmd_hd,
> > +                   void *buf);
> > +
> > +#endif
> > --
> > 2.34.1
> >
>

Best regards,
Ming

Re: [PATCH v5 4/7] can: Add Nuvoton NCT6694 CAN support

[Ming Yu]

Hi Vincent,

I will remove priv->tx_skb in the next patch, but it seems that
can_flush_echo_skb() has not been EXPORT_SYMBOL_GPL().

I would like to know if nct6694_can_clean() requires modification.

Vincent Mailhol <mailhol.vincent@wanadoo.fr> 於 2025年1月16日 週四 上午12:45寫道：
> > +static void nct6694_can_clean(struct net_device *ndev)
> > +{
> > +     struct nct6694_can_priv *priv = netdev_priv(ndev);
> > +
> > +     if (priv->tx_skb || netif_queue_stopped(ndev))
> > +             ndev->stats.tx_errors++;
> > +     dev_kfree_skb(priv->tx_skb);
>
> Use:
>
>         can_flush_echo_skb(ndev);
>
> (related to the following comments).
>
> > +     priv->tx_skb = NULL;
> > +}
>
> (...)
>
> > +static void nct6694_can_tx_work(struct work_struct *work)
> > +{
> > +     struct nct6694_can_priv *priv = container_of(work,
> > +                                                  struct nct6694_can_priv,
> > +                                                  tx_work);
> > +     struct net_device *ndev = priv->ndev;
> > +
> > +     guard(mutex)(&priv->lock);
> > +
> > +     if (priv->tx_skb) {
> > +             if (priv->can.state == CAN_STATE_BUS_OFF) {
>
> Just stop the queue when the can bus is off so that you do not have do
> check the bus status each time a frame is sent.
>
> > +                     nct6694_can_clean(ndev);
> > +             } else {
> > +                     nct6694_can_tx(ndev);
> > +                     can_put_echo_skb(priv->tx_skb, ndev, 0, 0);
> > +                     priv->tx_skb = NULL;
> > +             }
> > +     }
> > +}
> > +
> > +static netdev_tx_t nct6694_can_start_xmit(struct sk_buff *skb,
> > +                                       struct net_device *ndev)
> > +{
> > +     struct nct6694_can_priv *priv = netdev_priv(ndev);
> > +
> > +     if (can_dev_dropped_skb(ndev, skb))
> > +             return NETDEV_TX_OK;
> > +
> > +     if (priv->tx_skb) {
> > +             netdev_err(ndev, "hard_xmit called while tx busy\n");
> > +             return NETDEV_TX_BUSY;
> > +     }
> > +
> > +     netif_stop_queue(ndev);
> > +     priv->tx_skb = skb;
>
> Here, you can directly do:
>
>         can_put_echo_skb(skb, ndev, 0, 0);
>
> The skb remains accessible under priv->can.echo_skb[0]. With this, you
> can remove the priv->tx_skb field.
>
> > +     queue_work(priv->wq, &priv->tx_work);
> > +
> > +     return NETDEV_TX_OK;
> > +}
>

Thanks,
Ming

Re: [PATCH v5 4/7] can: Add Nuvoton NCT6694 CAN support

[Vincent Mailhol]

On 16/01/2025 at 15:34, Ming Yu wrote:
> Hi Vincent,
> 
> I will remove priv->tx_skb in the next patch, but it seems that
> can_flush_echo_skb() has not been EXPORT_SYMBOL_GPL().
> 
> I would like to know if nct6694_can_clean() requires modification.

Indeed, you can can_free_echo_skb(ndev, 0, NULL) instead of
can_flush_echo_skb(ndev). That one is exported.


Yours sincerely,
Vincent Mailhol