Hi Christophe

Thank you for your comments,
I will update the code in the next patch.

Best regards,
Ming

Christophe JAILLET [off-list ref] 於 2024年10月26日 週六 下午10:58寫道：

Le 24/10/2024 à 10:59, Ming Yu a écrit :

quoted

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 register
a handler function that will be called when the USB device receives
its interrupt pipe.

Signed-off-by: Ming Yu <redacted>
---

...

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;
+     int pipe, maxp, bulk_pipe;
+     int ret = EINVAL;

Nitpick: no need to init

quoted

+
+     interface = iface->cur_altsetting;
+     /* Binding interface class : 0xFF */
+     if (interface->desc.bInterfaceClass != USB_CLASS_VENDOR_SPEC ||
+         interface->desc.bInterfaceSubClass != 0x00 ||
+         interface->desc.bInterfaceProtocol != 0x00)
+             return -ENODEV;
+
+     int_endpoint = &interface->endpoint[0].desc;
+     if (!usb_endpoint_is_int_in(int_endpoint))
+             return -ENODEV;
+
+     nct6694 = devm_kzalloc(&udev->dev, sizeof(*nct6694), GFP_KERNEL);
+     if (!nct6694)
+             return -ENOMEM;
+
+     pipe = usb_rcvintpipe(udev, INT_IN_ENDPOINT);
+     maxp = usb_maxpacket(udev, pipe);
+
+     nct6694->cmd_buffer = devm_kcalloc(dev, CMD_PACKET_SZ,
+                                        sizeof(unsigned char), GFP_KERNEL);
+     if (!nct6694->cmd_buffer)
+             return -ENOMEM;
+     nct6694->rx_buffer = devm_kcalloc(dev, MAX_PACKET_SZ,
+                                       sizeof(unsigned char), GFP_KERNEL);
+     if (!nct6694->rx_buffer)
+             return -ENOMEM;
+     nct6694->tx_buffer = devm_kcalloc(dev, MAX_PACKET_SZ,
+                                       sizeof(unsigned char), GFP_KERNEL);
+     if (!nct6694->tx_buffer)
+             return -ENOMEM;
+     nct6694->int_buffer = devm_kcalloc(dev, 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) {
+             dev_err(&udev->dev, "Failed to allocate INT-in urb!\n");
+             return -ENOMEM;
+     }
+
+     /* Bulk pipe maximum packet for each transaction */
+     bulk_pipe = usb_sndbulkpipe(udev, BULK_OUT_ENDPOINT);
+     nct6694->maxp = usb_maxpacket(udev, bulk_pipe);
+
+     mutex_init(&nct6694->access_lock);
+     nct6694->udev = udev;
+     nct6694->timeout = URB_TIMEOUT; /* Wait until urb complete */
+
+     INIT_LIST_HEAD(&nct6694->handler_list);
+     spin_lock_init(&nct6694->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(&udev->dev, nct6694);
+     usb_set_intfdata(iface, nct6694);
+
+     ret = mfd_add_hotplug_devices(&udev->dev, nct6694_dev,
+                                   ARRAY_SIZE(nct6694_dev));
+     if (ret) {
+             dev_err(&udev->dev, "Failed to add mfd's child device\n");
+             goto err_mfd;
+     }
+
+     nct6694->async_workqueue = alloc_ordered_workqueue("asyn_workqueue", 0);

Missing error handling.

quoted

+
+     dev_info(&udev->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 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);
+     flush_workqueue(nct6694->async_workqueue);
+     destroy_workqueue(nct6694->async_workqueue);
+     usb_set_intfdata(iface, NULL);
+     usb_kill_urb(nct6694->int_in_urb);
+     usb_free_urb(nct6694->int_in_urb);
+}
+
+static const struct usb_device_id nct6694_ids[] = {
+     { USB_DEVICE(NCT6694_VENDOR_ID, NCT6694_PRODUCT_ID)},

Nitpick: space missing before the ending }

quoted

+     {},

Nitpick: usually, no comma is added after a {} terminator.

quoted

+};
+MODULE_DEVICE_TABLE(usb, nct6694_ids);

...

CJ