[PATCH 4/5] iio: accel: adxl313: Add timestamp to FIFO data

[Md Shofiqul Islam]

The driver pushes FIFO samples using iio_push_to_buffers() which does
not attach a hardware timestamp to the data.  Add a scan buffer struct
with an aligned_s64 timestamp field to struct adxl313_data (in
adxl313.h), capture a timestamp with iio_get_time_ns() at the start of
adxl313_fifo_push(), and switch the push loop to
iio_push_to_buffers_with_timestamp().  The ADXL313 always scans all
three axes together so the scan buffer layout is fixed.

Signed-off-by: Md Shofiqul Islam <shofiqtest@xxxxxxxxx>
---
 drivers/iio/accel/adxl313.h      | 4 ++++
 drivers/iio/accel/adxl313_core.c | 8 ++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/accel/adxl313.h b/drivers/iio/accel/adxl313.h
index 75ef54b60f..ea5792fae2 100644
--- a/drivers/iio/accel/adxl313.h
+++ b/drivers/iio/accel/adxl313.h
@@ -94,6 +94,10 @@ struct adxl313_data {
 	u8 watermark;
 	__le16		transf_buf __aligned(IIO_DMA_MINALIGN);
 	__le16		fifo_buf[ADXL313_NUM_AXIS * ADXL313_FIFO_SIZE + 1];
+	struct {
+		__le16 channels[ADXL313_NUM_AXIS];
+		aligned_s64 ts;
+	} scan;
 };
 
 struct adxl313_chip_info {
diff --git a/drivers/iio/accel/adxl313_core.c b/drivers/iio/accel/adxl313_core.c
index bcc11dabdf..bd45b90c42 100644
--- a/drivers/iio/accel/adxl313_core.c
+++ b/drivers/iio/accel/adxl313_core.c
@@ -1013,6 +1013,7 @@ static const struct iio_buffer_setup_ops adxl313_buffer_ops = {
 static int adxl313_fifo_push(struct iio_dev *indio_dev, int samples)
 {
 	struct adxl313_data *data = iio_priv(indio_dev);
+	s64 ts = iio_get_time_ns(indio_dev);
 	unsigned int i;
 	int ret;
 
@@ -1020,8 +1021,11 @@ static int adxl313_fifo_push(struct iio_dev *indio_dev, int samples)
 	if (ret)
 		return ret;
 
-	for (i = 0; i < ADXL313_NUM_AXIS * samples; i += ADXL313_NUM_AXIS)
-		iio_push_to_buffers(indio_dev, &data->fifo_buf[i]);
+	for (i = 0; i < ADXL313_NUM_AXIS * samples; i += ADXL313_NUM_AXIS) {
+		memcpy(data->scan.channels, &data->fifo_buf[i],
+		       sizeof(data->scan.channels));
+		iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, ts);
+	}
 
 	return 0;
 }
-- 
2.54.0.windows.1