[PATCH v3 1/3] iio: accel: bmc150: use aligned scan buffer for both trigger and fifo

[Yash Suthar]

Drop buffer as duplicate and s16 is not correct we needed __le16 as little
endian, keep scan at the end of the bmc150_accel_data struct with
IIO_DMA_MINALIGN, and use it for both paths.

In trigger handle, replaced AXIS_MAX with sizeof(data->scan.channels).
Additionally, ensure mutex is held across both read and push to get
DMA safety for the scan buffer.

Fixes: bd7fe5b71918 ("iio: accel: BMC150 accel support")
Suggested-by: Jonathan Cameron <jic23@xxxxxxxxxx>
Signed-off-by: Yash Suthar <yashsuthar983@xxxxxxxxx>
---
 drivers/iio/accel/bmc150-accel-core.c |  8 ++++----
 drivers/iio/accel/bmc150-accel.h      | 14 +++++---------
 2 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/drivers/iio/accel/bmc150-accel-core.c b/drivers/iio/accel/bmc150-accel-core.c
index dc8a6285cf3d..1472e0d1ef65 100644
--- a/drivers/iio/accel/bmc150-accel-core.c
+++ b/drivers/iio/accel/bmc150-accel-core.c
@@ -131,7 +131,6 @@ enum bmc150_accel_axis {
 	AXIS_X,
 	AXIS_Y,
 	AXIS_Z,
-	AXIS_MAX,
 };
 
 enum bmc150_power_modes {
@@ -1191,14 +1190,15 @@ static irqreturn_t bmc150_accel_trigger_handler(int irq, void *p)
 
 	mutex_lock(&data->mutex);
 	ret = regmap_bulk_read(data->regmap, BMC150_ACCEL_REG_XOUT_L,
-			       data->buffer, AXIS_MAX * 2);
-	mutex_unlock(&data->mutex);
+			       data->scan.channels,
+			       sizeof(data->scan.channels));
 	if (ret < 0)
 		goto err_read;
 
-	iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
+	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
 					   pf->timestamp);
 err_read:
+	mutex_unlock(&data->mutex);
 	iio_trigger_notify_done(indio_dev->trig);
 
 	return IRQ_HANDLED;
diff --git a/drivers/iio/accel/bmc150-accel.h b/drivers/iio/accel/bmc150-accel.h
index e8f26198359f..9deff256aed5 100644
--- a/drivers/iio/accel/bmc150-accel.h
+++ b/drivers/iio/accel/bmc150-accel.h
@@ -64,15 +64,6 @@ struct bmc150_accel_data {
 	struct bmc150_accel_trigger triggers[BMC150_ACCEL_TRIGGERS];
 	struct mutex mutex;
 	u8 fifo_mode, watermark;
-	s16 buffer[8];
-	/*
-	 * Ensure there is sufficient space and correct alignment for
-	 * the timestamp if enabled
-	 */
-	struct {
-		__le16 channels[3];
-		aligned_s64 ts;
-	} scan;
 	u8 bw_bits;
 	u32 slope_dur;
 	u32 slope_thres;
@@ -85,6 +76,11 @@ struct bmc150_accel_data {
 	void (*resume_callback)(struct device *dev);
 	struct delayed_work resume_work;
 	struct iio_mount_matrix orientation;
+	/* Ensure correct alignment of timestamp and DMA safety */
+	struct {
+		__le16 channels[3];
+		aligned_s64 ts;
+	} scan __aligned(IIO_DMA_MINALIGN);
 };
 
 int bmc150_accel_core_probe(struct device *dev, struct regmap *regmap, int irq,
-- 
2.43.0