Input: focaltech - report finger width to userspace

Focaltech touchpads report finger width in packet[5] of absolute packet.
Range for width in raw format is 0x10 - 0x70. Second half-byte is always 0.
0xff is reported, when a large contact area is detected.
This can be handled in userspace.
Signed-off-by: Dmitry Tunin <hanipouspilot@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/mouse/focaltech.c

@@ -103,6 +103,16 @@ struct focaltech_hw_state {
 	 */
 	struct focaltech_finger_state fingers[FOC_MAX_FINGERS];
 
+	/*
+	 * Finger width 0-7 and 15 for a very big contact area.
+	 * 15 value stays until the finger is released.
+	 * Width is reported only in absolute packets.
+	 * Since hardware reports width only for last touching finger,
+	 * there is no need to store width for every specific finger,
+	 * so we keep only last value reported.
+	 */
+	unsigned int width;
+
 	/* True if the clickpad has been pressed. */
 	bool pressed;
 };
@@ -137,6 +147,7 @@ static void focaltech_report_state(struct psmouse *psmouse)
 			input_report_abs(dev, ABS_MT_POSITION_X, clamped_x);
 			input_report_abs(dev, ABS_MT_POSITION_Y,
 					 priv->y_max - clamped_y);
+			input_report_abs(dev, ABS_TOOL_WIDTH, state->width);
 		}
 	}
 	input_mt_report_pointer_emulation(dev, true);
@@ -187,6 +198,7 @@ static void focaltech_process_abs_packet(struct psmouse *psmouse,
 
 	state->fingers[finger].x = ((packet[1] & 0xf) << 8) | packet[2];
 	state->fingers[finger].y = (packet[3] << 8) | packet[4];
+	state->width = packet[5] >> 4;
 	state->fingers[finger].valid = true;
 }
 
@@ -331,6 +343,7 @@ static void focaltech_set_input_params(struct psmouse *psmouse)
 	__set_bit(EV_ABS, dev->evbit);
 	input_set_abs_params(dev, ABS_MT_POSITION_X, 0, priv->x_max, 0, 0);
 	input_set_abs_params(dev, ABS_MT_POSITION_Y, 0, priv->y_max, 0, 0);
+	input_set_abs_params(dev, ABS_TOOL_WIDTH, 0, 15, 0, 0);
 	input_mt_init_slots(dev, 5, INPUT_MT_POINTER);
 	__set_bit(INPUT_PROP_BUTTONPAD, dev->propbit);
 }