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

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Message-ID: <5d1c39c3-b686-40ce-b8af-72dfddeb68da@wanadoo.fr>
Date: Sat, 26 Oct 2024 16:58:47 +0200
From: Christophe JAILLET <christophe.jaillet@...adoo.fr>
To: Ming Yu <a0282524688@...il.com>
Cc: tmyu0@...oton.com, lee@...nel.org, linus.walleij@...aro.org,
 brgl@...ev.pl, andi.shyti@...nel.org, mkl@...gutronix.de,
 mailhol.vincent@...adoo.fr, andrew+netdev@...n.ch, davem@...emloft.net,
 edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com,
 wim@...ux-watchdog.org, linux@...ck-us.net, jdelvare@...e.com,
 jic23@...nel.org, lars@...afoo.de, ukleinek@...nel.org,
 alexandre.belloni@...tlin.com, linux-kernel@...r.kernel.org,
 linux-gpio@...r.kernel.org, linux-i2c@...r.kernel.org,
 linux-can@...r.kernel.org, netdev@...r.kernel.org,
 linux-watchdog@...r.kernel.org, linux-hwmon@...r.kernel.org,
 linux-iio@...r.kernel.org, linux-pwm@...r.kernel.org,
 linux-rtc@...r.kernel.org
Subject: Re: [PATCH v1 1/9] mfd: Add core driver for Nuvoton NCT6694

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@...lic.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