[PATCH v2 1/7] mfd: Add core driver for Nuvoton NCT6694

Ming Yu
2024-11-21T06:41:06Z

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 <tmyu0@nuvoton.com>
---
MAINTAINERS | 7 +
drivers/mfd/Kconfig | 10 +
drivers/mfd/Makefile | 2 +
drivers/mfd/nct6694.c | 382 ++++++++++++++++++++++++++++++++++++
include/linux/mfd/nct6694.h | 139 +++++++++++++
5 files changed, 540 insertions(+)
create mode 100644 drivers/mfd/nct6694.c
create mode 100644 include/linux/mfd/nct6694.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 67d2159406c2..9c9a94ff8f98 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16541,6 +16541,13 @@ 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 03c1e4e3eea4..07ccc32f9985 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -558,6 +558,16 @@ config MFD_MX25_TSADC
i.MX25 processors. They consist of a conversion queue for general
purpose ADC and a queue for Touchscreens.

+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 devcie driver and core APIs.
+ Additional drivers must be enabled in order to use the functionality
+ of the device.
+
config MFD_HI6421_PMIC
tristate "HiSilicon Hi6421 PMU/Codec IC"
depends on OF
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index e057d6d6faef..9d0365ba6a26 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -117,6 +117,8 @@ obj-$(CONFIG_TWL6040_CORE) += twl6040.o

obj-$(CONFIG_MFD_MX25_TSADC) += fsl-imx25-tsadc.o

+obj-$(CONFIG_MFD_NCT6694) += nct6694.o
+
obj-$(CONFIG_MFD_MC13XXX) += mc13xxx-core.o
obj-$(CONFIG_MFD_MC13XXX_SPI) += mc13xxx-spi.o
obj-$(CONFIG_MFD_MC13XXX_I2C) += mc13xxx-i2c.o
diff --git a/drivers/mfd/nct6694.c b/drivers/mfd/nct6694.c
new file mode 100644
index 000000000000..071333d13eae
--- /dev/null
+++ b/drivers/mfd/nct6694.c
@@ -0,0 +1,382 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Nuvoton NCT6694 MFD driver based on USB interface.
+ *
+ * Copyright (C) 2024 Nuvoton Technology Corp.
+ */
+
+#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 support!\n", __func__);
+ break;
+ case NCT6694_NO_RESPONSE_ERROR:
+ dev_dbg(dev, "%s: Command is no response!\n", __func__);
+ break;
+ case NCT6694_TIMEOUT_ERROR:
+ dev_dbg(dev, "%s: Command is timeout!\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, u8 mod, u16 offset,
+ u16 length, void *buf)
+{
+ struct nct6694_cmd_header *cmd_header = nct6694->cmd_header;
+ struct nct6694_response_header *response_header = nct6694->response_header;
+ struct usb_device *udev = nct6694->udev;
+ int tx_len, rx_len, ret;
+
+ guard(mutex)(&nct6694->access_lock);
+
+ /* Send command packet to USB device */
+ cmd_header->mod = mod;
+ cmd_header->cmd = offset & 0xFF;
+ cmd_header->sel = (offset >> 8) & 0xFF;
+ cmd_header->hctrl = NCT6694_HCTRL_GET;
+ cmd_header->len = length;
+
+ ret = usb_bulk_msg(udev, usb_sndbulkpipe(udev, NCT6694_BULK_OUT_EP),
+ cmd_header, NCT6694_CMD_PACKET_SZ, &tx_len,
+ nct6694->timeout);
+ if (ret)
+ return ret;
+
+ /* Receive response packet from USB device */
+ ret = usb_bulk_msg(udev, usb_rcvbulkpipe(udev, NCT6694_BULK_IN_EP),
+ response_header, NCT6694_CMD_PACKET_SZ, &rx_len,
+ nct6694->timeout);
+ if (ret)
+ return ret;
+
+ ret = usb_bulk_msg(udev, usb_rcvbulkpipe(udev, NCT6694_BULK_IN_EP),
+ buf, NCT6694_MAX_PACKET_SZ, &rx_len, nct6694->timeout);
+ if (ret)
+ return ret;
+
+ return nct6694_response_err_handling(nct6694, response_header->sts);
+}
+EXPORT_SYMBOL(nct6694_read_msg);
+
+int nct6694_write_msg(struct nct6694 *nct6694, u8 mod, u16 offset,
+ u16 length, void *buf)
+{
+ struct nct6694_cmd_header *cmd_header = nct6694->cmd_header;
+ struct nct6694_response_header *response_header = nct6694->response_header;
+ struct usb_device *udev = nct6694->udev;
+ int tx_len, rx_len, ret;
+
+ guard(mutex)(&nct6694->access_lock);
+
+ /* Send command packet to USB device */
+ cmd_header->mod = mod;
+ cmd_header->cmd = offset & 0xFF;
+ cmd_header->sel = (offset >> 8) & 0xFF;
+ cmd_header->hctrl = NCT6694_HCTRL_SET;
+ cmd_header->len = length;
+
+ ret = usb_bulk_msg(udev, usb_sndbulkpipe(udev, NCT6694_BULK_OUT_EP),
+ cmd_header, NCT6694_CMD_PACKET_SZ, &tx_len,
+ nct6694->timeout);
+ if (ret)
+ return ret;
+
+ ret = usb_bulk_msg(udev, usb_sndbulkpipe(udev, NCT6694_BULK_OUT_EP),
+ buf, length, &tx_len, nct6694->timeout);
+ if (ret)
+ return ret;
+
+ /* Receive response packet from USB device */
+ ret = usb_bulk_msg(udev, usb_rcvbulkpipe(udev, NCT6694_BULK_IN_EP),
+ response_header, NCT6694_CMD_PACKET_SZ, &rx_len,
+ nct6694->timeout);
+ if (ret)
+ return ret;
+
+ ret = usb_bulk_msg(udev, usb_rcvbulkpipe(udev, NCT6694_BULK_IN_EP),
+ buf, NCT6694_MAX_PACKET_SZ, &rx_len, nct6694->timeout);
+ if (ret)
+ return ret;
+
+ return nct6694_response_err_handling(nct6694, 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);
+
+ if (*int_status & (1 << irq))
+ generic_handle_irq_safe(irq_find_mapping(nct6694->domain, irq));
+
+ *int_status &= ~(1 << irq);
+ }
+
+resubmit:
+ ret = usb_submit_urb(urb, GFP_ATOMIC);
+ if (ret)
+ dev_dbg(dev, "%s: Failed to resubmit urb, status %d",
+ __func__, 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);
+ unsigned int irq = data->hwirq;
+
+ nct6694->irq_enable |= (1 << irq);
+}
+
+static void nct6694_irq_disable(struct irq_data *data)
+{
+ struct nct6694 *nct6694 = irq_data_get_irq_chip_data(data);
+ unsigned int irq = data->hwirq;
+
+ nct6694->irq_enable &= ~(1 << irq);
+}
+
+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 device *dev = &udev->dev;
+ struct usb_host_interface *interface;
+ struct usb_endpoint_descriptor *int_endpoint;
+ struct nct6694 *nct6694;
+ struct nct6694_cmd_header *cmd_header;
+ struct nct6694_response_header *response_header;
+ 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);
+
+ cmd_header = devm_kzalloc(dev, sizeof(*cmd_header),
+ GFP_KERNEL);
+ if (!cmd_header)
+ return -ENOMEM;
+
+ response_header = devm_kzalloc(dev, sizeof(*response_header),
+ GFP_KERNEL);
+ if (!response_header)
+ return -ENOMEM;
+
+ nct6694->int_buffer = devm_kcalloc(dev, NCT6694_MAX_PACKET_SZ,
+ sizeof(unsigned char), 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)
+ return -ENODEV;
+
+ nct6694->udev = udev;
+ nct6694->timeout = NCT6694_URB_TIMEOUT; /* Wait until urb complete */
+ nct6694->cmd_header = cmd_header;
+ nct6694->response_header = response_header;
+
+ mutex_init(&nct6694->access_lock);
+ mutex_init(&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;
+
+ dev_info(dev, "Probed device: (%04X:%04X)\n", id->idVendor, id->idProduct);
+ return 0;
+
+err_mfd:
+ usb_kill_urb(nct6694->int_in_urb);
+err_urb:
+ usb_free_urb(nct6694->int_in_urb);
+ return dev_err_probe(dev, ret, "Probe failed\n");
+}
+
+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..9733d47f5a01
--- /dev/null
+++ b/include/linux/mfd/nct6694.h
@@ -0,0 +1,139 @@
+/* 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_MAX_PACKET_SZ 0x200
+
+#define NCT6694_CMD_PACKET_SZ 0x8
+#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 nct6694 {
+ struct usb_device *udev;
+ struct urb *int_in_urb;
+ struct irq_domain *domain;
+ struct nct6694_cmd_header *cmd_header;
+ struct nct6694_response_header *response_header;
+ struct mutex access_lock;
+ struct mutex irq_lock;
+ unsigned char *int_buffer;
+ unsigned int irq_enable;
+ /* time in msec to wait for the urb to the complete */
+ long timeout;
+};
+
+struct nct6694_cmd_header {
+ unsigned char rsv1;
+ unsigned char mod;
+ unsigned char cmd;
+ unsigned char sel;
+ unsigned char hctrl;
+ unsigned char rsv2;
+ unsigned short len;
+} __packed;
+
+struct nct6694_response_header {
+ unsigned char sequence_id;
+ unsigned char sts;
+ unsigned int rsv;
+ unsigned short len;
+} __packed;
+
+/*
+ * nct6694_read_msg - Receive data from NCT6694 USB device
+ *
+ * @nct6694 - Nuvoton NCT6694 structure
+ * @mod - Module byte
+ * @offset - Offset byte or (Select byte | Command byte)
+ * @length - Length byte
+ * @buf - Read data from rx buffer
+ *
+ * USB Transaction format:
+ *
+ * OUT |RSV|MOD|CMD|SEL|HCTL|RSV|LEN_L|LEN_H|
+ * OUT |SEQ|STS|RSV|RSV|RSV|RSV||LEN_L|LEN_H|
+ * IN |-------D------A------D------A-------|
+ * IN ......
+ * IN |-------D------A------D------A-------|
+ */
+int nct6694_read_msg(struct nct6694 *nct6694, u8 mod, u16 offset,
+ u16 length, void *buf);
+
+/*
+ * nct6694_read_msg - Transmit data to NCT6694 USB device
+ *
+ * @nct6694 - Nuvoton NCT6694 structure
+ * @mod - Module byte
+ * @offset - Offset byte or (Select byte | Command byte)
+ * @length - Length byte
+ * @buf - Write data to tx buffer
+ *
+ * USB Transaction format:
+ *
+ * OUT |RSV|MOD|CMD|SEL|HCTL|RSV|LEN_L|LEN_H|
+ * OUT |-------D------A------D------A-------|
+ * OUT ......
+ * OUT |-------D------A------D------A-------|
+ * IN |SEQ|STS|RSV|RSV|RSV|RSV||LEN_L|LEN_H|
+ * IN |-------D------A------D------A-------|
+ * IN ......
+ * IN |-------D------A------D------A-------|
+ */
+int nct6694_write_msg(struct nct6694 *nct6694, u8 mod, u16 offset,
+ u16 length, void *buf);
+
+#endif
--
2.34.1