Re: [PATCH] hwmon: corsair-cpro: Change to hid driver

Guenter Roeck
2020-07-15T14:39:19Z

On Tue, Jul 14, 2020 at 12:52:30PM +0200, Marius Zachmann wrote:
> I found a project which uses hidraw to communicate with the device.
> Because I do not want to break any existing userspace code, I
> changed this to a hid driver, so hidraw can still be used.
> Do I need to include the hid maintainers for the undo in hid-quirks?

I think I'll squash this patch with the others.

>
> Signed-off-by: Marius Zachmann <mail@mariuszachmann.de>
> ---
> drivers/hid/hid-quirks.c | 2 -
> drivers/hwmon/Kconfig | 4 +-
> drivers/hwmon/corsair-cpro.c | 114 ++++++++++++++++++++++++++---------
> 3 files changed, 86 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/hid/hid-quirks.c b/drivers/hid/hid-quirks.c
> index 7b7bc7737c53..ca8b5c261c7c 100644
> --- a/drivers/hid/hid-quirks.c
> +++ b/drivers/hid/hid-quirks.c
> @@ -699,8 +699,6 @@ static const struct hid_device_id hid_ignore_list[] = {
> { HID_USB_DEVICE(USB_VENDOR_ID_AXENTIA, USB_DEVICE_ID_AXENTIA_FM_RADIO) },
> { HID_USB_DEVICE(USB_VENDOR_ID_BERKSHIRE, USB_DEVICE_ID_BERKSHIRE_PCWD) },
> { HID_USB_DEVICE(USB_VENDOR_ID_CIDC, 0x0103) },
> - { HID_USB_DEVICE(USB_VENDOR_ID_CORSAIR, 0x0c10) },
> - { HID_USB_DEVICE(USB_VENDOR_ID_CORSAIR, 0x1d00) },
> { HID_USB_DEVICE(USB_VENDOR_ID_CYGNAL, USB_DEVICE_ID_CYGNAL_RADIO_SI470X) },
> { HID_USB_DEVICE(USB_VENDOR_ID_CYGNAL, USB_DEVICE_ID_CYGNAL_RADIO_SI4713) },
> { HID_USB_DEVICE(USB_VENDOR_ID_CMEDIA, USB_DEVICE_ID_CM109) },
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 8b046a5dfa40..c603d8c8e3d2 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -441,7 +441,7 @@ config SENSORS_BT1_PVT_ALARMS
>
> config SENSORS_CORSAIR_CPRO
> tristate "Corsair Commander Pro controller"
> - depends on USB
> + depends on HID
> help
> If you say yes here you get support for the Corsair Commander Pro
> controller.
> @@ -1716,7 +1716,7 @@ config SENSORS_ADS7871
>
> config SENSORS_AMC6821
> tristate "Texas Instruments AMC6821"
> - depends on I2C
> + depends on I2C

Unrelated change; please drop.

> help
> If you say yes here you get support for the Texas Instruments
> AMC6821 hardware monitoring chips.
> diff --git a/drivers/hwmon/corsair-cpro.c b/drivers/hwmon/corsair-cpro.c
> index fe625190e3a1..4310ee5aca24 100644
> --- a/drivers/hwmon/corsair-cpro.c
> +++ b/drivers/hwmon/corsair-cpro.c
> @@ -5,13 +5,14 @@
> */
>
> #include <linux/bitops.h>
> +#include <linux/completion.h>
> +#include <linux/hid.h>
> #include <linux/hwmon.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> #include <linux/mutex.h>
> #include <linux/slab.h>
> #include <linux/types.h>
> -#include <linux/usb.h>
>
> #define USB_VENDOR_ID_CORSAIR 0x1b1c
> #define USB_PRODUCT_ID_CORSAIR_COMMANDERPRO 0x0c10
> @@ -62,7 +63,8 @@
> #define NUM_TEMP_SENSORS 4
>
> struct ccp_device {
> - struct usb_device *udev;
> + struct hid_device *hdev;
> + struct completion wait_input_report;
> struct mutex mutex; /* whenever buffer is used, lock before send_usb_cmd */
> u8 *buffer;
> int pwm[6];
> @@ -75,7 +77,7 @@ struct ccp_device {
> /* send command, check for error in response, response in ccp->buffer */
> static int send_usb_cmd(struct ccp_device *ccp, u8 command, u8 byte1, u8 byte2, u8 byte3)
> {
> - int actual_length;
> + unsigned long t;
> int ret;
>
> memset(ccp->buffer, 0x00, OUT_BUFFER_SIZE);
> @@ -84,26 +86,39 @@ static int send_usb_cmd(struct ccp_device *ccp, u8 command, u8 byte1, u8 byte2,
> ccp->buffer[2] = byte2;
> ccp->buffer[3] = byte3;
>
> - ret = usb_bulk_msg(ccp->udev, usb_sndintpipe(ccp->udev, 2), ccp->buffer, OUT_BUFFER_SIZE,
> - &actual_length, 1000);
> - if (ret)
> - return ret;
> + reinit_completion(&ccp->wait_input_report);
>
> - /* response needs to be received every time */
> - ret = usb_bulk_msg(ccp->udev, usb_rcvintpipe(ccp->udev, 1), ccp->buffer, IN_BUFFER_SIZE,
> - &actual_length, 1000);
> - if (ret)
> + ret = hid_hw_output_report(ccp->hdev, ccp->buffer, OUT_BUFFER_SIZE);
> + if (ret < 0)
> return ret;
>
> + t = wait_for_completion_timeout(&ccp->wait_input_report, msecs_to_jiffies(300));

Please use a define for the timeout.

> + if (!t)
> + return -ETIMEDOUT;

> +
> /* first byte of response is error code */
> if (ccp->buffer[0] != 0x00) {
> - dev_dbg(&ccp->udev->dev, "device response error: %d", ccp->buffer[0]);
> + hid_dbg(ccp->hdev, "device response error: %d", ccp->buffer[0]);
> return -EIO;
> }
>
> return 0;
> }
>
> +static int ccp_raw_event(struct hid_device *hdev, struct hid_report *report, u8 *data, int size)
> +{
> + struct ccp_device *ccp = hid_get_drvdata(hdev);
> +
> + /* only copy buffer when requested */
> + if (completion_done(&ccp->wait_input_report))
> + return 0;
> +
> + memcpy(ccp->buffer, data, min(IN_BUFFER_SIZE, size));
> + complete(&ccp->wait_input_report);
> +
> + return 0;
> +}
> +
> /* requests and returns single data values depending on channel */
> static int get_data(struct ccp_device *ccp, int command, int channel)
> {
> @@ -437,57 +452,96 @@ static int get_temp_cnct(struct ccp_device *ccp)
> return 0;
> }
>
> -static int ccp_probe(struct usb_interface *intf, const struct usb_device_id *id)
> +static int ccp_probe(struct hid_device *hdev, const struct hid_device_id *id)
> {
> struct device *hwmon_dev;
> struct ccp_device *ccp;
> int ret;
>
> - ccp = devm_kzalloc(&intf->dev, sizeof(*ccp), GFP_KERNEL);
> + ccp = devm_kzalloc(&hdev->dev, sizeof(*ccp), GFP_KERNEL);
> if (!ccp)
> return -ENOMEM;
>
> - ccp->buffer = devm_kmalloc(&intf->dev, OUT_BUFFER_SIZE, GFP_KERNEL);
> + ccp->buffer = devm_kmalloc(&hdev->dev, OUT_BUFFER_SIZE, GFP_KERNEL);
> if (!ccp->buffer)
> return -ENOMEM;
>
> + ret = hid_parse(hdev);
> + if (ret)
> + return ret;
> +
> + ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
> + if (ret)
> + return ret;
> +
> + ret = hid_hw_open(hdev);
> + if (ret)
> + goto out_hw_stop;
> +
> + ccp->hdev = hdev;
> + hid_set_drvdata(hdev, ccp);
> mutex_init(&ccp->mutex);
> + init_completion(&ccp->wait_input_report);
>
> - ccp->udev = interface_to_usbdev(intf);
> + hid_device_io_start(hdev);
>
> /* temp and fan connection status only updates when device is powered on */
> ret = get_temp_cnct(ccp);
> if (ret)
> - return ret;
> + goto out_hw_close;
>
> ret = get_fan_cnct(ccp);
> if (ret)
> - return ret;
> -
> - hwmon_dev = devm_hwmon_device_register_with_info(&intf->dev, "corsaircpro", ccp,
> + goto out_hw_close;
> + hwmon_dev = devm_hwmon_device_register_with_info(&hdev->dev, "corsaircpro", ccp,
> &ccp_chip_info, 0);

You'll have to use hwmon_device_register_with_info() and call the remove
function explicitly in ccp_remove() to avoid race conditions.
Alternatively, you could use devm_add_action_or_reset() to handle
hid_hw_close() and hid_hw_stop(), but that would probably not be worth
the added complexity.

> + if (IS_ERR(hwmon_dev)) {
> + ret = PTR_ERR(hwmon_dev);
> + goto out_hw_close;
> + }
> +
> + return 0;
>
> - return PTR_ERR_OR_ZERO(hwmon_dev);
> +out_hw_close:
> + hid_hw_close(hdev);
> +out_hw_stop:
> + hid_hw_stop(hdev);
> + return ret;
> }
>
> -static void ccp_disconnect(struct usb_interface *intf)
> +static void ccp_remove(struct hid_device *hdev)
> {
> + hid_hw_close(hdev);
> + hid_hw_stop(hdev);
> }
>
> -static const struct usb_device_id ccp_devices[] = {
> - { USB_DEVICE(USB_VENDOR_ID_CORSAIR, USB_PRODUCT_ID_CORSAIR_COMMANDERPRO) },
> - { USB_DEVICE(USB_VENDOR_ID_CORSAIR, USB_PRODUCT_ID_CORSAIR_1000D) },
> +static const struct hid_device_id ccp_devices[] = {
> + { HID_USB_DEVICE(USB_VENDOR_ID_CORSAIR, USB_PRODUCT_ID_CORSAIR_COMMANDERPRO) },
> + { HID_USB_DEVICE(USB_VENDOR_ID_CORSAIR, USB_PRODUCT_ID_CORSAIR_1000D) },
> { }
> };
>
> -static struct usb_driver ccp_driver = {
> +static struct hid_driver ccp_driver = {
> .name = "corsair-cpro",
> + .id_table = ccp_devices,
> .probe = ccp_probe,
> - .disconnect = ccp_disconnect,
> - .id_table = ccp_devices
> + .remove = ccp_remove,
> + .raw_event = ccp_raw_event,
> };
>
> -MODULE_DEVICE_TABLE(usb, ccp_devices);
> +MODULE_DEVICE_TABLE(hid, ccp_devices);
> MODULE_LICENSE("GPL");
>
> -module_usb_driver(ccp_driver);
> +static int __init ccp_init(void)
> +{
> + return hid_register_driver(&ccp_driver);
> +}
> +
> +static void __exit ccp_exit(void)
> +{
> + hid_unregister_driver(&ccp_driver);
> +}
> +
> +/* make sure, it is loaded after hid */
> +late_initcall(ccp_init);
> +module_exit(ccp_exit);
> --
> 2.27.0