[PATCH v3 0/3] iio: accel: bmc150: DMA-safe buffers and use iio_push_to_buffers_with_ts()

From: Yash Suthar

Date: Tue Aug 25 2026 - 04:52:21 EST


The trigger path used a plain s16 buffer while the FIFO path already had
a properly typed scan member (__le16 + aligned timestamp). Those two
buffers did the same job, and s16 does not represent little-endian data.
Drop the duplicate, keep scan at the end of struct bmc150_accel_data with
IIO_DMA_MINALIGN, and use it for both the trigger and FIFO paths.

The FIFO and read_raw buffers are passed to regmap bulk/raw reads, which
is not DMA-safe. Move them into struct bmc150_accel_data after the aligned
scan buffer. Because all buffers are serialized by data->mutex, placing
them after scan ensures DMA safety without needing separate alignment.

Finally, replace the deprecated iio_push_to_buffers_with_timestamp() with
iio_push_to_buffers_with_ts() so the push sites pass an explicit buffer
size.

This supersedes the earlier standalone patches:
Link: https://lore.kernel.org/linux-iio/20260808220236.421832-1-yashsuthar983@xxxxxxxxx/
Link: https://lore.kernel.org/linux-iio/20260809111303.496393-1-yashsuthar983@xxxxxxxxx/

Link to v1: https://lore.kernel.org/all/20260814101845.301769-1-yashsuthar983@xxxxxxxxx/
Link to v2: https://lore.kernel.org/linux-iio/20260815175728.99541-1-yashsuthar983@xxxxxxxxx/

Changes in v3:
- patch 1: hold mutex for both the read and push to guarantee DMA safety
- patch 1: drop unused AXIS_MAX and use sizeof(data->scan.channels)
- patch 2: remove redundant __aligned(IIO_DMA_MINALIGN) from fifo_buff
and regval, as the mutex serializes access
- patch 2: fix comma typo in commit message

Changes in v2:
- patch 1: restore early error check flow
- patch 2: keep fifo_buff declaration in one line

Yash Suthar (3):
iio: accel: bmc150: use aligned scan buffer for both trigger and fifo
iio: accel: bmc150: use DMA-safe buffers for regmap bulk reads
iio: accel: bmc150: use iio_push_to_buffers_with_ts()

drivers/iio/accel/bmc150-accel-core.c | 28 +++++++++++++--------------
drivers/iio/accel/bmc150-accel.h | 19 +++++++++---------
2 files changed, 23 insertions(+), 24 deletions(-)

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2.43.0