Re: [PATCH v1 1/9] mfd: Add core driver for Nuvoton NCT6694

Christophe JAILLET
2024-10-26T15:00:15Z

Le 24/10/2024 à 10:59, Ming Yu a écrit :
> 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 <tmyu0-KrzQf0k3Iz9BDgjK7y7TUQ@public.gmane.org>
> ---

...

> +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

> +
> + 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.

> +
> + 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 }

> + {},

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

> +};
> +MODULE_DEVICE_TABLE(usb, nct6694_ids);

...

CJ