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

Ming Yu
2025-01-14T03:30:29Z

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