Re: [PATCH v2] iio: accel: bmc150: use IIO_DECLARE_BUFFER_WITH_TS

[Yash Suthar <yashsuthar983@gmail.com>]

On Mon, Aug 10, 2026 at 12:00:05PM +0300, Andy Shevchenko wrote:
> > So what is going on here?
>
> AI slop?

No. I only intended to convert buffer to IIO_DECLARE_BUFFER_WITH_TS() and dont
want to mix it with the existing scan member. Really sorry for that i should 
have asked.

On Mon, Aug 10, 2026 at 12:18:52AM +0100, Jonathan Cameron wrote:
> Given the data alignment is fixed, if we were going to do this it would
> be clearer as
> struct {
> 	s16 chans[3]; //see later, I believe this should be __le16
> 	aligned_s64 timestamp;
> };
>
> But that is very similar to the structure that follows immediately after
> this, but that has __le16 chans[]
>
> So what is going on here?
> ...
> The chan spec is little endian so the scan one is more correct.
>
> So I think the fix for this issue is move the scan element to the end of
> struct bmc150_accel_data and mark it with __aligned(IIO_DMA_MINALIGN);
>
> Then use that for both the bmc150_accel_trigger_handler() and
> __bmc150_accel_fifo_flush() paths.  A second fix will resolve the local
> buffer in __bmc150_accel_fifo_flush() that is being used for a bulk
> regmap transfer that may need a dma safe buffer.
>
> Please combine these two fixes (if you agree with my analysis) with a
> follow up to do the iio_push_to_buffers_with_ts() all in one series
> as they will be touching the same code.

Thanks, Jonathan.
I agree with your analysis.

On type, kept s16 because that was the originally used.
I'll keep __le16 and will merge buffer and scan together as you suggested.
Will move scan to the end with __aligned(IIO_DMA_MINALIGN) and use it for both
trigger handler and fifo flush.
A separate patch for the FIFO stack buffer and keep the
iio_push_to_buffers_with_ts() change in the same.

Yash Suthar