[PATCH 6/7] HID: sony: Report hardware timestamp for DS4 sensor values

[Roderick Colenbrander <roderick@gaikai.com>]

From: Roderick Colenbrander <roderick.colenbrander@sony.com>

Report the hardware timestamp inside each HID report through
MSC_TIMESTAMP for motion sensor values.

Signed-off-by: Roderick Colenbrander <roderick.colenbrander@sony.com>
---
 drivers/hid/hid-sony.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/hid/hid-sony.c b/drivers/hid/hid-sony.c
index a7a3692..9f79d1b 100644
--- a/drivers/hid/hid-sony.c
+++ b/drivers/hid/hid-sony.c
@@ -781,6 +781,7 @@ struct motion_output_report_02 {
  * additional +2.
  */
 #define DS4_INPUT_REPORT_BUTTON_OFFSET    5
+#define DS4_INPUT_REPORT_TIMESTAMP_OFFSET 10
 #define DS4_INPUT_REPORT_GYRO_X_OFFSET   13
 #define DS4_INPUT_REPORT_BATTERY_OFFSET  30
 #define DS4_INPUT_REPORT_TOUCHPAD_OFFSET 33
@@ -838,6 +839,11 @@ struct sony_sc {
 	u8 led_delay_on[MAX_LEDS];
 	u8 led_delay_off[MAX_LEDS];
 	u8 led_count;
+
+	bool timestamp_initialized;
+	u16 prev_timestamp;
+	unsigned int timestamp_us;
+
 	bool ds4_dongle_connected;
 	/* DS4 calibration data */
 	struct ds4_calibration_data ds4_calib_data[6];
@@ -1032,6 +1038,7 @@ static void dualshock4_parse_report(struct sony_sc *sc, u8 *rd, int size)
 	unsigned long flags;
 	int n, m, offset, num_touch_data, max_touch_data;
 	u8 cable_state, battery_capacity, battery_charging;
+	u16 timestamp;
 
 	/* When using Bluetooth the header is 2 bytes longer, so skip these. */
 	int data_offset = (sc->quirks & DUALSHOCK4_CONTROLLER_USB) ? 0 : 2;
@@ -1040,6 +1047,24 @@ static void dualshock4_parse_report(struct sony_sc *sc, u8 *rd, int size)
 	offset = data_offset + DS4_INPUT_REPORT_BUTTON_OFFSET;
 	input_report_key(sc->touchpad, BTN_LEFT, rd[offset+2] & 0x2);
 
+	/* Convert timestamp (in 5.33us unit) to timestamp_us */
+	offset = data_offset + DS4_INPUT_REPORT_TIMESTAMP_OFFSET;
+	timestamp = get_unaligned_le16(&rd[offset]);
+	if (!sc->timestamp_initialized) {
+		sc->timestamp_us = ((unsigned int)timestamp * 16) / 3;
+		sc->timestamp_initialized = true;
+	} else {
+		u16 delta;
+
+		if (sc->prev_timestamp > timestamp)
+			delta = (U16_MAX - sc->prev_timestamp + timestamp + 1);
+		else
+			delta = timestamp - sc->prev_timestamp;
+		sc->timestamp_us += (delta * 16) / 3;
+	}
+	sc->prev_timestamp = timestamp;
+	input_event(sc->sensor_dev, EV_MSC, MSC_TIMESTAMP, sc->timestamp_us);
+
 	offset = data_offset + DS4_INPUT_REPORT_GYRO_X_OFFSET;
 	for (n = 0; n < 6; n++) {
 		/* Store data in int for more precision during mult_frac. */
@@ -1386,6 +1411,8 @@ static int sony_register_sensors(struct sony_sc *sc)
 	input_abs_set_res(sc->sensor_dev, ABS_RY, DS4_GYRO_RES_PER_DEG_S);
 	input_abs_set_res(sc->sensor_dev, ABS_RZ, DS4_GYRO_RES_PER_DEG_S);
 
+	__set_bit(EV_MSC, sc->sensor_dev->evbit);
+	__set_bit(MSC_TIMESTAMP, sc->sensor_dev->mscbit);
 	__set_bit(INPUT_PROP_ACCELEROMETER, sc->sensor_dev->propbit);
 
 	ret = input_register_device(sc->sensor_dev);
-- 
2.7.4