HID: uclogic: Add support for XP-PEN Deco L

The XP-PEN Deco L (UGEE) needs to be initialized by sending a buffer of
magic data, discovered by sniffing the Windows driver traffic.

In order to differentiate UGEE tablets that need this kind of
initialization from the previous ones, name them v2 internally and
create an entry point for them.

After initialization, the template report descriptors can be discovered
by parsing a string descriptor, similar to the one exposed by HUION v1
devices.

Add all the required elements to support the device.

Signed-off-by: José Expósito <[e-mail]>
Signed-off-by: Jiri Kosina <[e-mail]>

drivers/hid/hid-ids.h

···
 #define USB_DEVICE_ID_UGEE_XPPEN_TABLET_G540	0x0075
 #define USB_DEVICE_ID_UGEE_XPPEN_TABLET_G640	0x0094
 #define USB_DEVICE_ID_UGEE_XPPEN_TABLET_DECO01	0x0042
+#define USB_DEVICE_ID_UGEE_XPPEN_TABLET_DECO_L	0x0935
 #define USB_DEVICE_ID_UGEE_XPPEN_TABLET_STAR06	0x0078
 #define USB_DEVICE_ID_UGEE_TABLET_G5		0x0074
 #define USB_DEVICE_ID_UGEE_TABLET_EX07S		0x0071

drivers/hid/hid-uclogic-core.c

···
 	{ HID_USB_DEVICE(USB_VENDOR_ID_UGEE,
 				USB_DEVICE_ID_UGEE_XPPEN_TABLET_DECO01) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_UGEE,
+				USB_DEVICE_ID_UGEE_XPPEN_TABLET_DECO_L) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_UGEE,
 				USB_DEVICE_ID_UGEE_XPPEN_TABLET_STAR06) },
 	{ }
 };

drivers/hid/hid-uclogic-params.c

···
 }
 
 /**
+ * uclogic_probe_interface() - some tablets, like the Parblo A610 PLUS V2 or
+ * the XP-PEN Deco Mini 7, need to be initialized by sending them magic data.
+ *
+ * @hdev:	The HID device of the tablet interface to initialize and get
+ *		parameters from. Cannot be NULL.
+ * @magic_arr:	The magic data that should be sent to probe the interface.
+ *		Cannot be NULL.
+ * @magic_size:	Size of the magic data.
+ * @endpoint:	Endpoint where the magic data should be sent.
+ *
+ * Returns:
+ *	Zero, if successful. A negative errno code on error.
+ */
+static int uclogic_probe_interface(struct hid_device *hdev, u8 *magic_arr,
+				   int magic_size, int endpoint)
+{
+	struct usb_device *udev;
+	unsigned int pipe = 0;
+	int sent;
+	u8 *buf = NULL;
+	int rc = 0;
+
+	if (!hdev || !magic_arr) {
+		rc = -EINVAL;
+		goto cleanup;
+	}
+
+	buf = kmemdup(magic_arr, magic_size, GFP_KERNEL);
+	if (!buf) {
+		rc = -ENOMEM;
+		goto cleanup;
+	}
+
+	udev = hid_to_usb_dev(hdev);
+	pipe = usb_sndintpipe(udev, endpoint);
+
+	rc = usb_interrupt_msg(udev, pipe, buf, magic_size, &sent, 1000);
+	if (rc || sent != magic_size) {
+		hid_err(hdev, "Interface probing failed: %d\n", rc);
+		rc = -1;
+		goto cleanup;
+	}
+
+	rc = 0;
+cleanup:
+	kfree(buf);
+	return rc;
+}
+
+/**
+ * uclogic_params_ugee_v2_init() - initialize a UGEE graphics tablets by
+ * discovering their parameters.
+ *
+ * These tables, internally designed as v2 to differentiate them from older
+ * models, expect a payload of magic data in orther to be switched to the fully
+ * functional mode and expose their parameters in a similar way to the
+ * information present in uclogic_params_pen_init_v1() but with some
+ * differences.
+ *
+ * @params:	Parameters to fill in (to be cleaned with
+ *		uclogic_params_cleanup()). Not modified in case of error.
+ *		Cannot be NULL.
+ * @hdev:	The HID device of the tablet interface to initialize and get
+ *		parameters from. Cannot be NULL.
+ *
+ * Returns:
+ *	Zero, if successful. A negative errno code on error.
+ */
+static int uclogic_params_ugee_v2_init(struct uclogic_params *params,
+				       struct hid_device *hdev)
+{
+	int rc = 0;
+	struct usb_interface *iface;
+	__u8 bInterfaceNumber;
+	const int str_desc_len = 12;
+	__u8 *str_desc = NULL;
+	__u8 *rdesc_pen = NULL;
+	__u8 *rdesc_frame = NULL;
+	s32 desc_params[UCLOGIC_RDESC_PH_ID_NUM];
+	s32 resolution;
+	__u8 magic_arr[] = {
+		0x02, 0xb0, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+	};
+	/* The resulting parameters (noop) */
+	struct uclogic_params p = {0, };
+
+	if (!params || !hdev) {
+		rc = -EINVAL;
+		goto cleanup;
+	}
+
+	iface = to_usb_interface(hdev->dev.parent);
+	bInterfaceNumber = iface->cur_altsetting->desc.bInterfaceNumber;
+	if (bInterfaceNumber != 2) {
+		uclogic_params_init_invalid(&p);
+		goto output;
+	}
+
+	/*
+	 * Initialize the interface by sending magic data.
+	 * The specific data was discovered by sniffing the Windows driver
+	 * traffic.
+	 */
+	rc = uclogic_probe_interface(hdev, magic_arr, sizeof(magic_arr), 0x03);
+	if (rc) {
+		uclogic_params_init_invalid(&p);
+		goto output;
+	}
+
+	/*
+	 * Read the string descriptor containing pen and frame parameters.
+	 * The specific string descriptor and data were discovered by sniffing
+	 * the Windows driver traffic.
+	 */
+	rc = uclogic_params_get_str_desc(&str_desc, hdev, 100, str_desc_len);
+	if (rc != str_desc_len) {
+		hid_err(hdev, "failed retrieving pen and frame parameters: %d\n", rc);
+		uclogic_params_init_invalid(&p);
+		goto output;
+	}
+
+	desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_LM] =
+		get_unaligned_le16(str_desc + 2);
+	desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_LM] =
+		get_unaligned_le16(str_desc + 4);
+	desc_params[UCLOGIC_RDESC_FRAME_PH_ID_UM] = str_desc[6];
+	desc_params[UCLOGIC_RDESC_PEN_PH_ID_PRESSURE_LM] =
+		get_unaligned_le16(str_desc + 8);
+	resolution = get_unaligned_le16(str_desc + 10);
+	if (resolution == 0) {
+		desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_PM] = 0;
+		desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_PM] = 0;
+	} else {
+		desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_PM] =
+			desc_params[UCLOGIC_RDESC_PEN_PH_ID_X_LM] * 1000 /
+			resolution;
+		desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_PM] =
+			desc_params[UCLOGIC_RDESC_PEN_PH_ID_Y_LM] * 1000 /
+			resolution;
+	}
+	kfree(str_desc);
+	str_desc = NULL;
+
+	/* Initialize the pen interface */
+	rdesc_pen = uclogic_rdesc_template_apply(
+				uclogic_rdesc_ugee_v2_pen_template_arr,
+				uclogic_rdesc_ugee_v2_pen_template_size,
+				desc_params, ARRAY_SIZE(desc_params));
+	if (!rdesc_pen) {
+		rc = -ENOMEM;
+		goto cleanup;
+	}
+
+	p.pen.desc_ptr = rdesc_pen;
+	p.pen.desc_size = uclogic_rdesc_ugee_v2_pen_template_size;
+	p.pen.id = 0x02;
+	p.pen.subreport_list[0].value = 0xf0;
+	p.pen.subreport_list[0].id = UCLOGIC_RDESC_V1_FRAME_ID;
+
+	/* Initialize the frame interface */
+	rdesc_frame = uclogic_rdesc_template_apply(
+				uclogic_rdesc_ugee_v2_frame_btn_template_arr,
+				uclogic_rdesc_ugee_v2_frame_btn_template_size,
+				desc_params, ARRAY_SIZE(desc_params));
+	if (!rdesc_frame) {
+		rc = -ENOMEM;
+		goto cleanup;
+	}
+
+	rc = uclogic_params_frame_init_with_desc(&p.frame_list[0],
+						 rdesc_frame,
+						 uclogic_rdesc_ugee_v2_frame_btn_template_size,
+						 UCLOGIC_RDESC_V1_FRAME_ID);
+	kfree(rdesc_frame);
+	if (rc) {
+		uclogic_params_init_invalid(&p);
+		goto output;
+	}
+
+output:
+	/* Output parameters */
+	memcpy(params, &p, sizeof(*params));
+	memset(&p, 0, sizeof(p));
+	rc = 0;
+cleanup:
+	kfree(str_desc);
+	uclogic_params_cleanup(&p);
+	return rc;
+}
+
+/**
  * uclogic_params_init() - initialize a tablet interface and discover its
  * parameters.
  *
···
 		} else {
 			uclogic_params_init_invalid(&p);
 		}
+		break;
+	case VID_PID(USB_VENDOR_ID_UGEE,
+		     USB_DEVICE_ID_UGEE_XPPEN_TABLET_DECO_L):
+		rc = uclogic_params_ugee_v2_init(&p, hdev);
+		if (rc != 0)
+			goto cleanup;
 		break;
 	case VID_PID(USB_VENDOR_ID_TRUST,
 		     USB_DEVICE_ID_TRUST_PANORA_TABLET):

drivers/hid/hid-uclogic-rdesc.c

···
 const size_t uclogic_rdesc_v2_frame_dial_size =
 			sizeof(uclogic_rdesc_v2_frame_dial_arr);
 
+/* Fixed report descriptor template for UGEE v2 pen reports */
+const __u8 uclogic_rdesc_ugee_v2_pen_template_arr[] = {
+	0x05, 0x0d,         /*  Usage Page (Digitizers),                */
+	0x09, 0x01,         /*  Usage (Digitizer),                      */
+	0xa1, 0x01,         /*  Collection (Application),               */
+	0x85, 0x02,         /*      Report ID (2),                      */
+	0x09, 0x20,         /*      Usage (Stylus),                     */
+	0xa1, 0x00,         /*      Collection (Physical),              */
+	0x09, 0x42,         /*          Usage (Tip Switch),             */
+	0x09, 0x44,         /*          Usage (Barrel Switch),          */
+	0x09, 0x46,         /*          Usage (Tablet Pick),            */
+	0x75, 0x01,         /*          Report Size (1),                */
+	0x95, 0x03,         /*          Report Count (3),               */
+	0x14,               /*          Logical Minimum (0),            */
+	0x25, 0x01,         /*          Logical Maximum (1),            */
+	0x81, 0x02,         /*          Input (Variable),               */
+	0x95, 0x02,         /*          Report Count (2),               */
+	0x81, 0x03,         /*          Input (Constant, Variable),     */
+	0x09, 0x32,         /*          Usage (In Range),               */
+	0x95, 0x01,         /*          Report Count (1),               */
+	0x81, 0x02,         /*          Input (Variable),               */
+	0x95, 0x02,         /*          Report Count (2),               */
+	0x81, 0x03,         /*          Input (Constant, Variable),     */
+	0x75, 0x10,         /*          Report Size (16),               */
+	0x95, 0x01,         /*          Report Count (1),               */
+	0x35, 0x00,         /*          Physical Minimum (0),           */
+	0xa4,               /*          Push,                           */
+	0x05, 0x01,         /*          Usage Page (Desktop),           */
+	0x09, 0x30,         /*          Usage (X),                      */
+	0x65, 0x13,         /*          Unit (Inch),                    */
+	0x55, 0x0d,         /*          Unit Exponent (-3),             */
+	0x27, UCLOGIC_RDESC_PEN_PH(X_LM),
+			    /*          Logical Maximum (PLACEHOLDER),  */
+	0x47, UCLOGIC_RDESC_PEN_PH(X_PM),
+			    /*          Physical Maximum (PLACEHOLDER), */
+	0x81, 0x02,         /*          Input (Variable),               */
+	0x09, 0x31,         /*          Usage (Y),                      */
+	0x27, UCLOGIC_RDESC_PEN_PH(Y_LM),
+			    /*          Logical Maximum (PLACEHOLDER),  */
+	0x47, UCLOGIC_RDESC_PEN_PH(Y_PM),
+			    /*          Physical Maximum (PLACEHOLDER), */
+	0x81, 0x02,         /*          Input (Variable),               */
+	0xb4,               /*          Pop,                            */
+	0x09, 0x30,         /*          Usage (Tip Pressure),           */
+	0x45, 0x00,         /*          Physical Maximum (0),           */
+	0x27, UCLOGIC_RDESC_PEN_PH(PRESSURE_LM),
+			    /*          Logical Maximum (PLACEHOLDER),  */
+	0x75, 0x0D,         /*          Report Size (13),               */
+	0x95, 0x01,         /*          Report Count (1),               */
+	0x81, 0x02,         /*          Input (Variable),               */
+	0x75, 0x01,         /*          Report Size (1),                */
+	0x95, 0x03,         /*          Report Count (3),               */
+	0x81, 0x01,         /*          Input (Constant),               */
+	0x09, 0x3d,         /*          Usage (X Tilt),                 */
+	0x35, 0xC3,         /*          Physical Minimum (-61),         */
+	0x45, 0x3C,         /*          Physical Maximum (60),          */
+	0x15, 0xC3,         /*          Logical Minimum (-61),          */
+	0x25, 0x3C,         /*          Logical Maximum (60),           */
+	0x75, 0x08,         /*          Report Size (8),                */
+	0x95, 0x01,         /*          Report Count (1),               */
+	0x81, 0x02,         /*          Input (Variable),               */
+	0x09, 0x3e,         /*          Usage (Y Tilt),                 */
+	0x35, 0xC3,         /*          Physical Minimum (-61),         */
+	0x45, 0x3C,         /*          Physical Maximum (60),          */
+	0x15, 0xC3,         /*          Logical Minimum (-61),          */
+	0x25, 0x3C,         /*          Logical Maximum (60),           */
+	0x81, 0x02,         /*          Input (Variable),               */
+	0xc0,               /*      End Collection,                     */
+	0xc0,               /*  End Collection                          */
+};
+const size_t uclogic_rdesc_ugee_v2_pen_template_size =
+			sizeof(uclogic_rdesc_ugee_v2_pen_template_arr);
+
+/* Fixed report descriptor template for UGEE v2 frame reports (buttons only) */
+const __u8 uclogic_rdesc_ugee_v2_frame_btn_template_arr[] = {
+	0x05, 0x01,         /*  Usage Page (Desktop),                   */
+	0x09, 0x07,         /*  Usage (Keypad),                         */
+	0xA1, 0x01,         /*  Collection (Application),               */
+	0x85, UCLOGIC_RDESC_V1_FRAME_ID,
+			    /*      Report ID,                          */
+	0x05, 0x0D,         /*      Usage Page (Digitizer),             */
+	0x09, 0x39,         /*      Usage (Tablet Function Keys),       */
+	0xA0,               /*      Collection (Physical),              */
+	0x75, 0x01,         /*          Report Size (1),                */
+	0x95, 0x08,         /*          Report Count (8),               */
+	0x81, 0x01,         /*          Input (Constant),               */
+	0x05, 0x09,         /*          Usage Page (Button),            */
+	0x19, 0x01,         /*          Usage Minimum (01h),            */
+	UCLOGIC_RDESC_FRAME_PH_BTN,
+			    /*          Usage Maximum (PLACEHOLDER),    */
+	0x95, 0x0A,         /*          Report Count (10),              */
+	0x14,               /*          Logical Minimum (0),            */
+	0x25, 0x01,         /*          Logical Maximum (1),            */
+	0x81, 0x02,         /*          Input (Variable),               */
+	0x95, 0x46,         /*          Report Count (70),              */
+	0x81, 0x01,         /*          Input (Constant),               */
+	0xC0,               /*      End Collection,                     */
+	0xC0                /*  End Collection                          */
+};
+const size_t uclogic_rdesc_ugee_v2_frame_btn_template_size =
+			sizeof(uclogic_rdesc_ugee_v2_frame_btn_template_arr);
+
 /* Fixed report descriptor for Ugee EX07 frame */
 const __u8 uclogic_rdesc_ugee_ex07_frame_arr[] = {
 	0x05, 0x01,             /*  Usage Page (Desktop),                   */

drivers/hid/hid-uclogic-rdesc.h

···
 /* Device ID byte offset in v2 frame dial reports */
 #define UCLOGIC_RDESC_V2_FRAME_DIAL_DEV_ID_BYTE	0x4
 
+/* Fixed report descriptor template for UGEE v2 pen reports */
+extern const __u8 uclogic_rdesc_ugee_v2_pen_template_arr[];
+extern const size_t uclogic_rdesc_ugee_v2_pen_template_size;
+
+/* Fixed report descriptor template for UGEE v2 frame reports (buttons only) */
+extern const __u8 uclogic_rdesc_ugee_v2_frame_btn_template_arr[];
+extern const size_t uclogic_rdesc_ugee_v2_frame_btn_template_size;
+
 /* Fixed report descriptor for Ugee EX07 frame */
 extern const __u8 uclogic_rdesc_ugee_ex07_frame_arr[];
 extern const size_t uclogic_rdesc_ugee_ex07_frame_size;