HID: asus: Add support for multi-touch touchpad on Medion Akoya E1239T

The multi-touch touchpad found on the Medion Akoya E1239T's keyboard-dock,
uses the same custom multi-touch protocol as the Asus keyboard-docks
(same chipset vendor, Integrated Technology Express / ITE).

Add support for this using the existing multi-touch touchpad support in
the hid-asus driver.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-asus.c b/drivers/hid/hid-asus.c
index 6d97dbb..317d739 100644
--- a/drivers/hid/hid-asus.c
+++ b/drivers/hid/hid-asus.c
@@ -40,6 +40,7 @@ MODULE_AUTHOR("Frederik Wenigwieser <frederik.wenigwieser@gmail.com>");
 MODULE_DESCRIPTION("Asus HID Keyboard and TouchPad");
 
 #define T100_TPAD_INTF 2
+#define MEDION_E1239T_TPAD_INTF 1
 
 #define T100CHI_MOUSE_REPORT_ID 0x06
 #define FEATURE_REPORT_ID 0x0d
@@ -77,6 +78,7 @@ MODULE_DESCRIPTION("Asus HID Keyboard and TouchPad");
 #define QUIRK_G752_KEYBOARD		BIT(8)
 #define QUIRK_T101HA_DOCK		BIT(9)
 #define QUIRK_T90CHI			BIT(10)
+#define QUIRK_MEDION_E1239T		BIT(11)
 
 #define I2C_KEYBOARD_QUIRKS			(QUIRK_FIX_NOTEBOOK_REPORT | \
 						 QUIRK_NO_INIT_REPORTS | \
@@ -170,6 +172,16 @@ static const struct asus_touchpad_info asus_t100chi_tp = {
 	.report_size = 15 /* 2 byte header + 3 * 4 + 1 byte footer */,
 };
 
+static const struct asus_touchpad_info medion_e1239t_tp = {
+	.max_x = 2640,
+	.max_y = 1380,
+	.res_x = 29, /* units/mm */
+	.res_y = 28, /* units/mm */
+	.contact_size = 5,
+	.max_contacts = 5,
+	.report_size = 32 /* 2 byte header + 5 * 5 + 5 byte footer */,
+};
+
 static void asus_report_contact_down(struct asus_drvdata *drvdat,
 		int toolType, u8 *data)
 {
@@ -877,6 +889,17 @@ static int asus_probe(struct hid_device *hdev, const struct hid_device_id *id)
 		drvdata->tp = &asus_t100chi_tp;
 	}
 
+	if ((drvdata->quirks & QUIRK_MEDION_E1239T) &&
+	    hid_is_using_ll_driver(hdev, &usb_hid_driver)) {
+		struct usb_host_interface *alt =
+			to_usb_interface(hdev->dev.parent)->altsetting;
+
+		if (alt->desc.bInterfaceNumber == MEDION_E1239T_TPAD_INTF) {
+			drvdata->quirks |= QUIRK_SKIP_INPUT_MAPPING;
+			drvdata->tp = &medion_e1239t_tp;
+		}
+	}
+
 	if (drvdata->quirks & QUIRK_NO_INIT_REPORTS)
 		hdev->quirks |= HID_QUIRK_NO_INIT_REPORTS;
 
@@ -1056,7 +1079,8 @@ static const struct hid_device_id asus_devices[] = {
 	{ 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 },
-
+	{ HID_USB_DEVICE(USB_VENDOR_ID_ITE, USB_DEVICE_ID_ITE_MEDION_E1239T),
+		QUIRK_MEDION_E1239T },
 	{ }
 };
 MODULE_DEVICE_TABLE(hid, asus_devices);
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index 1c71a1a..09eb3d8b7 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -640,6 +640,7 @@
 #define I2C_DEVICE_ID_ITE_LENOVO_LEGION_Y720	0x837a
 #define USB_DEVICE_ID_ITE_LENOVO_YOGA900	0x8396
 #define USB_DEVICE_ID_ITE8595		0x8595
+#define USB_DEVICE_ID_ITE_MEDION_E1239T	0xce50
 
 #define USB_VENDOR_ID_JABRA		0x0b0e
 #define USB_DEVICE_ID_JABRA_SPEAK_410	0x0412