HID: asus: Add T100CHI bluetooth keyboard dock special keys mapping

The Asus Transformer T100CHI comes with a Bluetooth keyboard dock which
uses the same 0xff31 Asus vendor HUT page as other Asus keyboards.

This commit adds its device-id to hid-asus and fixes an issue in the
descriptor of the 0xff31 Usage, which together fixes the special keys
on this keyboard not working.

Signed-off-by: Hans de Goede <[e-mail]>
Signed-off-by: Jiri Kosina <[e-mail]>

drivers/hid/hid-asus.c

···
 #define QUIRK_NO_CONSUMER_USAGES	BIT(4)
 #define QUIRK_USE_KBD_BACKLIGHT		BIT(5)
 #define QUIRK_T100_KEYBOARD		BIT(6)
+#define QUIRK_T100CHI			BIT(7)
 
 #define I2C_KEYBOARD_QUIRKS			(QUIRK_FIX_NOTEBOOK_REPORT | \
 						 QUIRK_NO_INIT_REPORTS | \
···
 		hid_info(hdev, "Fixing up Asus notebook report descriptor\n");
 		rdesc[55] = 0xdd;
 	}
+	/* For the T100TA keyboard dock */
 	if (drvdata->quirks & QUIRK_T100_KEYBOARD &&
 		 *rsize == 76 && rdesc[73] == 0x81 && rdesc[74] == 0x01) {
 		hid_info(hdev, "Fixing up Asus T100 keyb report descriptor\n");
 		rdesc[74] &= ~HID_MAIN_ITEM_CONSTANT;
+	}
+	/* For the T100CHI keyboard dock */
+	if (drvdata->quirks & QUIRK_T100CHI &&
+		 *rsize == 403 && rdesc[388] == 0x09 && rdesc[389] == 0x76) {
+		/*
+		 * Change Usage (76h) to Usage Minimum (00h), Usage Maximum
+		 * (FFh) and clear the flags in the Input() byte.
+		 * Note the descriptor has a bogus 0 byte at the end so we
+		 * only need 1 extra byte.
+		 */
+		*rsize = 404;
+		rdesc = kmemdup(rdesc, *rsize, GFP_KERNEL);
+		if (!rdesc)
+			return NULL;
+
+		hid_info(hdev, "Fixing up T100CHI keyb report descriptor\n");
+		memmove(rdesc + 392, rdesc + 390, 12);
+		rdesc[388] = 0x19;
+		rdesc[389] = 0x00;
+		rdesc[390] = 0x29;
+		rdesc[391] = 0xff;
+		rdesc[402] = 0x00;
 	}
 
 	return rdesc;
···
 	{ HID_USB_DEVICE(USB_VENDOR_ID_CHICONY, USB_DEVICE_ID_ASUS_AK1D) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_TURBOX, USB_DEVICE_ID_ASUS_MD_5110) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_JESS, USB_DEVICE_ID_ASUS_MD_5112) },
+	{ HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_ASUSTEK,
+		USB_DEVICE_ID_ASUSTEK_T100CHI_KEYBOARD), QUIRK_T100CHI },
+
 	{ }
 };
 MODULE_DEVICE_TABLE(hid, asus_devices);

drivers/hid/hid-core.c

···
 	{ HID_USB_DEVICE(USB_VENDOR_ID_ASUSTEK, USB_DEVICE_ID_ASUSTEK_T100_KEYBOARD) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_JESS, USB_DEVICE_ID_ASUS_MD_5112) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_TURBOX, USB_DEVICE_ID_ASUS_MD_5110) },
+	{ HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_ASUSTEK, USB_DEVICE_ID_ASUSTEK_T100CHI_KEYBOARD) },
 #endif
 #if IS_ENABLED(CONFIG_HID_AUREAL)
 	{ HID_USB_DEVICE(USB_VENDOR_ID_AUREAL, USB_DEVICE_ID_AUREAL_W01RN) },

drivers/hid/hid-ids.h

···
 #define USB_DEVICE_ID_ASUSTEK_LCM	0x1726
 #define USB_DEVICE_ID_ASUSTEK_LCM2	0x175b
 #define USB_DEVICE_ID_ASUSTEK_T100_KEYBOARD	0x17e0
+#define USB_DEVICE_ID_ASUSTEK_T100CHI_KEYBOARD	0x8502
 #define USB_DEVICE_ID_ASUSTEK_I2C_KEYBOARD	0x8585
 #define USB_DEVICE_ID_ASUSTEK_I2C_TOUCHPAD	0x0101
 #define USB_DEVICE_ID_ASUSTEK_ROG_KEYBOARD1 0x1854