HID: sony: Handle multiple touch events input record

Read the touch history field in the HID descriptor and use this value
to determine how many touch events to read from the report. As part
of this patch, we did a first attempt of making the offset calculation
code less magical.
Signed-off-by: Roderick Colenbrander <roderick.colenbrander@sony.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-sony.c

@@ -1030,6 +1030,12 @@ struct motion_output_report_02 {
 #define SIXAXIS_REPORT_0xF5_SIZE 8
 #define MOTION_REPORT_0x02_SIZE 49
 
+/* Offsets relative to USB input report (0x1). Bluetooth (0x11) requires an
+ * additional +2.
+ */
+#define DS4_INPUT_REPORT_BATTERY_OFFSET  30
+#define DS4_INPUT_REPORT_TOUCHPAD_OFFSET 33
+
 static DEFINE_SPINLOCK(sony_dev_list_lock);
 static LIST_HEAD(sony_device_list);
 static DEFINE_IDA(sony_device_id_allocator);
@@ -1226,19 +1232,17 @@ static void dualshock4_parse_report(struct sony_sc *sc, u8 *rd, int size)
 						struct hid_input, list);
 	struct input_dev *input_dev = hidinput->input;
 	unsigned long flags;
-	int n, offset;
+	int n, m, offset, num_touch_data, max_touch_data;
 	u8 cable_state, battery_capacity, battery_charging;
 
-	/*
-	 * Battery and touchpad data starts at byte 30 in the USB report and
-	 * 32 in Bluetooth report.
-	 */
-	offset = (sc->quirks & DUALSHOCK4_CONTROLLER_USB) ? 30 : 32;
+	/* When using Bluetooth the header is 2 bytes longer, so skip these. */
+	int data_offset = (sc->quirks & DUALSHOCK4_CONTROLLER_USB) ? 0 : 2;
 
 	/*
-	 * The lower 4 bits of byte 30 contain the battery level
+	 * The lower 4 bits of byte 30 (or 32 for BT) contain the battery level
 	 * and the 5th bit contains the USB cable state.
 	 */
+	offset = data_offset + DS4_INPUT_REPORT_BATTERY_OFFSET;
 	cable_state = (rd[offset] >> 4) & 0x01;
 	battery_capacity = rd[offset] & 0x0F;
 
@@ -1265,30 +1269,52 @@ static void dualshock4_parse_report(struct sony_sc *sc, u8 *rd, int size)
 	sc->battery_charging = battery_charging;
 	spin_unlock_irqrestore(&sc->lock, flags);
 
-	offset += 5;
-
 	/*
-	 * The Dualshock 4 multi-touch trackpad data starts at offset 35 on USB
-	 * and 37 on Bluetooth.
-	 * The first 7 bits of the first byte is a counter and bit 8 is a touch
-	 * indicator that is 0 when pressed and 1 when not pressed.
-	 * The next 3 bytes are two 12 bit touch coordinates, X and Y.
-	 * The data for the second touch is in the same format and immediatly
-	 * follows the data for the first.
+	 * The Dualshock 4 multi-touch trackpad data starts at offset 33 on USB
+	 * and 35 on Bluetooth.
+	 * The first byte indicates the number of touch data in the report.
+	 * Trackpad data starts 2 bytes later (e.g. 35 for USB).
 	 */
-	for (n = 0; n < 2; n++) {
-		u16 x, y;
+	offset = data_offset + DS4_INPUT_REPORT_TOUCHPAD_OFFSET;
+	max_touch_data = (sc->quirks & DUALSHOCK4_CONTROLLER_USB) ? 3 : 4;
+	if (rd[offset] > 0 && rd[offset] <= max_touch_data)
+		num_touch_data = rd[offset];
+	else
+		num_touch_data = 1;
+	offset += 1;
 
-		x = rd[offset+1] | ((rd[offset+2] & 0xF) << 8);
-		y = ((rd[offset+2] & 0xF0) >> 4) | (rd[offset+3] << 4);
+	for (m = 0; m < num_touch_data; m++) {
+		/* Skip past timestamp */
+		offset += 1;
 
-		input_mt_slot(input_dev, n);
-		input_mt_report_slot_state(input_dev, MT_TOOL_FINGER,
-					!(rd[offset] >> 7));
-		input_report_abs(input_dev, ABS_MT_POSITION_X, x);
-		input_report_abs(input_dev, ABS_MT_POSITION_Y, y);
+		/*
+		 * The first 7 bits of the first byte is a counter and bit 8 is
+		 * a touch indicator that is 0 when pressed and 1 when not
+		 * pressed.
+		 * The next 3 bytes are two 12 bit touch coordinates, X and Y.
+		 * The data for the second touch is in the same format and
+		 * immediately follows the data for the first.
+		 */
+		for (n = 0; n < 2; n++) {
+			u16 x, y;
+			bool active;
+
+			x = rd[offset+1] | ((rd[offset+2] & 0xF) << 8);
+			y = ((rd[offset+2] & 0xF0) >> 4) | (rd[offset+3] << 4);
+
+			active = !(rd[offset] >> 7);
+			input_mt_slot(input_dev, n);
+			input_mt_report_slot_state(input_dev, MT_TOOL_FINGER, active);
 
-		offset += 4;
+			if (active) {
+				input_report_abs(input_dev, ABS_MT_POSITION_X, x);
+				input_report_abs(input_dev, ABS_MT_POSITION_Y, y);
+			}
+
+			offset += 4;
+		}
+		input_mt_sync_frame(input_dev);
+		input_sync(input_dev);
 	}
 }