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

On Tue, 14 Jan 2025, Ming Yu wrote:

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.

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.

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]