iio: hid-sensor-gyro-3d: Add timestamp channel

Each sample has a timestamp field with this change. This timestamp may
be from the sensor hub when present or local kernel timestamp. And the
unit of timestamp is nanosecond.
Signed-off-by: Ye Xiang <xiang.ye@intel.com>
Link: https://lore.kernel.org/r/20210105093515.19135-3-xiang.ye@intel.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/gyro/hid-sensor-gyro-3d.c

@@ -23,15 +23,20 @@ enum gyro_3d_channel {
 	GYRO_3D_CHANNEL_MAX,
 };
 
+#define CHANNEL_SCAN_INDEX_TIMESTAMP GYRO_3D_CHANNEL_MAX
 struct gyro_3d_state {
 	struct hid_sensor_hub_callbacks callbacks;
 	struct hid_sensor_common common_attributes;
 	struct hid_sensor_hub_attribute_info gyro[GYRO_3D_CHANNEL_MAX];
-	u32 gyro_val[GYRO_3D_CHANNEL_MAX];
+	struct {
+		u32 gyro_val[GYRO_3D_CHANNEL_MAX];
+		u64 timestamp __aligned(8);
+	} scan;
 	int scale_pre_decml;
 	int scale_post_decml;
 	int scale_precision;
 	int value_offset;
+	s64 timestamp;
 };
 
 static const u32 gyro_3d_addresses[GYRO_3D_CHANNEL_MAX] = {
@@ -72,7 +77,8 @@ static const struct iio_chan_spec gyro_3d_channels[] = {
 		BIT(IIO_CHAN_INFO_SAMP_FREQ) |
 		BIT(IIO_CHAN_INFO_HYSTERESIS),
 		.scan_index = CHANNEL_SCAN_INDEX_Z,
-	}
+	},
+	IIO_CHAN_SOFT_TIMESTAMP(CHANNEL_SCAN_INDEX_TIMESTAMP)
 };
 
 /* Adjust channel real bits based on report descriptor */
@@ -178,14 +184,6 @@ static const struct iio_info gyro_3d_info = {
 	.write_raw = &gyro_3d_write_raw,
 };
 
-/* Function to push data to buffer */
-static void hid_sensor_push_data(struct iio_dev *indio_dev, const void *data,
-	int len)
-{
-	dev_dbg(&indio_dev->dev, "hid_sensor_push_data\n");
-	iio_push_to_buffers(indio_dev, data);
-}
-
 /* Callback handler to send event after all samples are received and captured */
 static int gyro_3d_proc_event(struct hid_sensor_hub_device *hsdev,
 				unsigned usage_id,
@@ -195,10 +193,15 @@ static int gyro_3d_proc_event(struct hid_sensor_hub_device *hsdev,
 	struct gyro_3d_state *gyro_state = iio_priv(indio_dev);
 
 	dev_dbg(&indio_dev->dev, "gyro_3d_proc_event\n");
-	if (atomic_read(&gyro_state->common_attributes.data_ready))
-		hid_sensor_push_data(indio_dev,
-				gyro_state->gyro_val,
-				sizeof(gyro_state->gyro_val));
+	if (atomic_read(&gyro_state->common_attributes.data_ready)) {
+		if (!gyro_state->timestamp)
+			gyro_state->timestamp = iio_get_time_ns(indio_dev);
+
+		iio_push_to_buffers_with_timestamp(indio_dev, &gyro_state->scan,
+						   gyro_state->timestamp);
+
+		gyro_state->timestamp = 0;
+	}
 
 	return 0;
 }
@@ -219,10 +222,15 @@ static int gyro_3d_capture_sample(struct hid_sensor_hub_device *hsdev,
 	case HID_USAGE_SENSOR_ANGL_VELOCITY_Y_AXIS:
 	case HID_USAGE_SENSOR_ANGL_VELOCITY_Z_AXIS:
 		offset = usage_id - HID_USAGE_SENSOR_ANGL_VELOCITY_X_AXIS;
-		gyro_state->gyro_val[CHANNEL_SCAN_INDEX_X + offset] =
-						*(u32 *)raw_data;
+		gyro_state->scan.gyro_val[CHANNEL_SCAN_INDEX_X + offset] =
+				*(u32 *)raw_data;
 		ret = 0;
 	break;
+	case HID_USAGE_SENSOR_TIME_TIMESTAMP:
+		gyro_state->timestamp =
+			hid_sensor_convert_timestamp(&gyro_state->common_attributes,
+						     *(s64 *)raw_data);
+	break;
 	default:
 		break;
 	}