[PATCH] iio: accel: hid-sensor-accel-3d: Add timestamp

[Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>]

Added timestamp channel. With this change, each sample has a timestamp.
This timestamp can be from the sensor hub when present or local kernel
timestamp. HID sensors can send timestamp with input data using usage id
HID_USAGE_SENSOR_TIME_TIMESTAMP.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 drivers/iio/accel/hid-sensor-accel-3d.c | 29 +++++++++++++++++++++--------
 include/linux/hid-sensor-ids.h          |  1 +
 2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/drivers/iio/accel/hid-sensor-accel-3d.c b/drivers/iio/accel/hid-sensor-accel-3d.c
index ab1e238..41215b6 100644
--- a/drivers/iio/accel/hid-sensor-accel-3d.c
+++ b/drivers/iio/accel/hid-sensor-accel-3d.c
@@ -42,11 +42,13 @@ struct accel_3d_state {
 	struct hid_sensor_hub_callbacks callbacks;
 	struct hid_sensor_common common_attributes;
 	struct hid_sensor_hub_attribute_info accel[ACCEL_3D_CHANNEL_MAX];
-	u32 accel_val[ACCEL_3D_CHANNEL_MAX];
+	/* Reserve for 3 channels + padding + timestamp */
+	u32 accel_val[ACCEL_3D_CHANNEL_MAX + 3];
 	int scale_pre_decml;
 	int scale_post_decml;
 	int scale_precision;
 	int value_offset;
+	int64_t timestamp;
 };
 
 static const u32 accel_3d_addresses[ACCEL_3D_CHANNEL_MAX] = {
@@ -87,7 +89,8 @@ static const struct iio_chan_spec accel_3d_channels[] = {
 		BIT(IIO_CHAN_INFO_SAMP_FREQ) |
 		BIT(IIO_CHAN_INFO_HYSTERESIS),
 		.scan_index = CHANNEL_SCAN_INDEX_Z,
-	}
+	},
+	IIO_CHAN_SOFT_TIMESTAMP(3)
 };
 
 /* Adjust channel real bits based on report descriptor */
@@ -192,11 +195,11 @@ static const struct iio_info accel_3d_info = {
 };
 
 /* Function to push data to buffer */
-static void hid_sensor_push_data(struct iio_dev *indio_dev, const void *data,
-	int len)
+static void hid_sensor_push_data(struct iio_dev *indio_dev, void *data,
+				 int len, int64_t timestamp)
 {
 	dev_dbg(&indio_dev->dev, "hid_sensor_push_data\n");
-	iio_push_to_buffers(indio_dev, data);
+	iio_push_to_buffers_with_timestamp(indio_dev, data, timestamp);
 }
 
 /* Callback handler to send event after all samples are received and captured */
@@ -208,10 +211,17 @@ static int accel_3d_proc_event(struct hid_sensor_hub_device *hsdev,
 	struct accel_3d_state *accel_state = iio_priv(indio_dev);
 
 	dev_dbg(&indio_dev->dev, "accel_3d_proc_event\n");
-	if (atomic_read(&accel_state->common_attributes.data_ready))
+	if (atomic_read(&accel_state->common_attributes.data_ready)) {
+		if (!accel_state->timestamp)
+			accel_state->timestamp = iio_get_time_ns(indio_dev);
+
 		hid_sensor_push_data(indio_dev,
-				accel_state->accel_val,
-				sizeof(accel_state->accel_val));
+				     accel_state->accel_val,
+				     sizeof(accel_state->accel_val),
+				     accel_state->timestamp);
+
+		accel_state->timestamp = 0;
+	}
 
 	return 0;
 }
@@ -236,6 +246,9 @@ static int accel_3d_capture_sample(struct hid_sensor_hub_device *hsdev,
 						*(u32 *)raw_data;
 		ret = 0;
 	break;
+	case HID_USAGE_SENSOR_TIME_TIMESTAMP:
+		accel_state->timestamp = *(int64_t *)raw_data;
+	break;
 	default:
 		break;
 	}
diff --git a/include/linux/hid-sensor-ids.h b/include/linux/hid-sensor-ids.h
index f2ee90a..9a3a9db 100644
--- a/include/linux/hid-sensor-ids.h
+++ b/include/linux/hid-sensor-ids.h
@@ -95,6 +95,7 @@
 #define HID_USAGE_SENSOR_TIME_HOUR				0x200525
 #define HID_USAGE_SENSOR_TIME_MINUTE				0x200526
 #define HID_USAGE_SENSOR_TIME_SECOND				0x200527
+#define HID_USAGE_SENSOR_TIME_TIMESTAMP				0x200529
 
 /* Units */
 #define HID_USAGE_SENSOR_UNITS_NOT_SPECIFIED			0x00
-- 
2.7.4