Re: [PATCH 3/6] HID: asus: add support for T3304 detachable keyboard

[Denis Benato <denis.benato@linux.dev>]

On 5/3/26 09:26, James Ye wrote:
> ASUSTek Computer, Inc. T3304 Soft Keyboard [0b05:1aad] is the detachable
> keyboard of the ASUS Vivobook 13 Slate OLED (T3304). It presents as a
> USB device with two interfaces: a keyboard and a pointing device
> (touchpad).
>
> Basic keyboard and full touchpad functionality work out-of-the-box with
> hid-generic and hid-multitouch, but function key combos e.g. volume,
> brightness control, home/end/pgup/pgdown require initialization.
>
> Bind the keyboard interface to hid-asus for initialization. The
> OEM-specific report descriptors required for this are present only on
> the touchpad interface, not the keyboard, so a quirk is used to add the
> required feature descriptor.
Reviewed-By: Denis Benato <denis.benato@linux.dev>
> Signed-off-by: James Ye <jye836@gmail.com>
> ---
>  drivers/hid/hid-asus.c | 58 +++++++++++++++++++++++++++++++++++++++---
>  drivers/hid/hid-ids.h  |  1 +
>  2 files changed, 56 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/hid/hid-asus.c b/drivers/hid/hid-asus.c
> index ef9d5eba4dc9..e4c97fddfaf1 100644
> --- a/drivers/hid/hid-asus.c
> +++ b/drivers/hid/hid-asus.c
> @@ -99,6 +99,7 @@ MODULE_DESCRIPTION("Asus HID Keyboard and TouchPad");
>  #define QUIRK_ROG_CLAYMORE_II_KEYBOARD	BIT(12)
>  #define QUIRK_ROG_ALLY_XPAD		BIT(13)
>  #define QUIRK_HID_FN_LOCK		BIT(14)
> +#define QUIRK_T3304_KEYBOARD		BIT(15)
>
>  #define I2C_KEYBOARD_QUIRKS			(QUIRK_FIX_NOTEBOOK_REPORT | \
>  						 QUIRK_NO_INIT_REPORTS | \
> @@ -494,6 +495,14 @@ static int asus_kbd_init(struct hid_device *hdev, u8 report_id)
>  		return ret;
>  	}
>
> +	struct asus_drvdata *drvdata = hid_get_drvdata(hdev);
> +
> +	/* T3304 keyboard always replies with 16 0xff bytes. Don't check for
> +	 * acknowledgment.
> +	 */
> +	if (drvdata->quirks & QUIRK_T3304_KEYBOARD)
> +		return 0;
> +
>  	u8 *readbuf __free(kfree) = kzalloc(FEATURE_KBD_REPORT_SIZE, GFP_KERNEL);
>  	if (!readbuf)
>  		return -ENOMEM;
> @@ -1312,10 +1321,12 @@ static int asus_probe(struct hid_device *hdev, const struct hid_device_id *id)
>  		hid_warn(hdev, "Failed to initialize backlight.\n");
>
>  	/*
> -	 * For ROG keyboards, skip rename for consistency and ->input check as
> -	 * some devices do not have inputs.
> +	 * For ROG and T3304 keyboards, skip rename for consistency.
> +	 * For ROG keyboards, skip ->input check as some devices do not have
> +	 * inputs.
>  	 */
> -	if (drvdata->quirks & QUIRK_ROG_NKEY_KEYBOARD)
> +	if (drvdata->quirks & QUIRK_ROG_NKEY_KEYBOARD ||
> +	    drvdata->quirks & QUIRK_T3304_KEYBOARD)
>  		return 0;
>
>  	/*
> @@ -1369,6 +1380,22 @@ static const __u8 asus_g752_fixed_rdesc[] = {
>          0x2A, 0xFF, 0x00,		/*   Usage Maximum (0xFF)       */
>  };
>
> +static const __u8 asus_t3304_fixed_rdesc[] = {
> +	0x06, 0x31, 0xff,              // Usage Page (Vendor Usage Page 0xff31)
> +	0x09, 0x76,                    // Usage (Vendor Usage 0x76)
> +	0xa1, 0x01,                    // Collection (Application)
> +	0x05, 0xff,                    //  Usage Page (Vendor Usage Page 0xff)
> +	0x85, 0x5a,                    //  Report ID (90)
> +	0x19, 0x00,                    //  Usage Minimum (0)
> +	0x2a, 0xff, 0x00,              //  Usage Maximum (255)
> +	0x15, 0x00,                    //  Logical Minimum (0)
> +	0x26, 0xff, 0x00,              //  Logical Maximum (255)
> +	0x75, 0x08,                    //  Report Size (8)
> +	0x95, 0x0f,                    //  Report Count (15)
> +	0xb1, 0x02,                    //  Feature (Data,Var,Abs)
> +	0xc0,                          // End Collection
> +};
> +
>  static const __u8 *asus_report_fixup(struct hid_device *hdev, __u8 *rdesc,
>  		unsigned int *rsize)
>  {
> @@ -1473,6 +1500,28 @@ static const __u8 *asus_report_fixup(struct hid_device *hdev, __u8 *rdesc,
>  		}
>  	}
>
> +	/* T3304 keyboard's vendor descriptors are on the touchpad interface,
> +	 * not the keyboard. But we need hid-multitouch to handle the touchpad,
> +	 * Add a descriptor with only the config report so that this driver can
> +	 * perform initialization.
> +	 */
> +	if (drvdata->quirks & QUIRK_T3304_KEYBOARD) {
> +		__u8 *new_rdesc;
> +		size_t new_size = *rsize + sizeof(asus_t3304_fixed_rdesc);
> +
> +		new_rdesc = devm_kzalloc(&hdev->dev, new_size, GFP_KERNEL);
> +		if (new_rdesc == NULL)
> +			return rdesc;
> +
> +		hid_info(hdev, "Fixing up Asus T3304 keyboard report descriptor\n");
> +		memcpy(new_rdesc, rdesc, *rsize);
> +		memcpy(new_rdesc + *rsize, asus_t3304_fixed_rdesc,
> +		       sizeof(asus_t3304_fixed_rdesc));
> +
> +		*rsize = new_size;
> +		rdesc = new_rdesc;
> +	}
> +
>  	return rdesc;
>  }
>
> @@ -1536,6 +1585,9 @@ static const struct hid_device_id asus_devices[] = {
>  	  QUIRK_USE_KBD_BACKLIGHT | QUIRK_ROG_NKEY_KEYBOARD },
>  	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
>  		USB_VENDOR_ID_ASUSTEK, USB_DEVICE_ID_ASUSTEK_T101HA_KEYBOARD) },
> +	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
> +		USB_VENDOR_ID_ASUSTEK, USB_DEVICE_ID_ASUSTEK_T3304_KEYBOARD),
> +	  QUIRK_T3304_KEYBOARD },
>  	{ }
>  };
>  MODULE_DEVICE_TABLE(hid, asus_devices);
> diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
> index 0cf63742315b..ecf30e36a99d 100644
> --- a/drivers/hid/hid-ids.h
> +++ b/drivers/hid/hid-ids.h
> @@ -219,6 +219,7 @@
>  #define USB_DEVICE_ID_ASUSTEK_T100CHI_KEYBOARD	0x8502
>  #define USB_DEVICE_ID_ASUSTEK_T101HA_KEYBOARD	0x183d
>  #define USB_DEVICE_ID_ASUSTEK_T304_KEYBOARD	0x184a
> +#define USB_DEVICE_ID_ASUSTEK_T3304_KEYBOARD	0x1aad
>  #define USB_DEVICE_ID_ASUSTEK_I2C_KEYBOARD	0x8585
>  #define USB_DEVICE_ID_ASUSTEK_I2C_TOUCHPAD	0x0101
>  #define USB_DEVICE_ID_ASUSTEK_ROG_KEYBOARD1 0x1854
> --
> 2.54.0