Dear Christophe,

Thank you for your comments,

Christophe JAILLET [off-list ref] 於 2024年12月12日 週四 上午12:44寫道：

quoted

+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);

Nitpick: This could be moved a few lines below, should it still comply
with your coding style.

I think the lock should be placed here to prevent the cmd_header from
being overwritten by another caller.
Could you share your perspective on this?

quoted

+
+     /* 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);

Nitpick: This could be moved a few lines below, should it still comply
with your coding style.

I think the lock should be placed here to prevent the cmd_header from
being overwritten by another caller.
Could you share your perspective on this?

quoted

+
+     /* Send command packet to USB device  */

Nitpick: double space before */

Fix it in v4.

quoted

+     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;

...

quoted

+static struct irq_chip nct6694_irq_chip = {

const?

Fix it in v4.

quoted

+     .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,
+};

...

quoted

+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);

Why for cmd_header and response_header we use a temp variable, while
here we update directly nct6694->int_buffer?

It would save a few LoC do remove this temp var.

Fix it in v4.

quoted

+     if (!nct6694->int_buffer)
+             return -ENOMEM;
+
+     nct6694->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+     if (!nct6694->int_in_urb)
+             return -ENOMEM;

...

Best regards,
Ming