Re: [PATCH] iio: adc: ad7606: explicit timestamp alignment

["Nuno Sá" <noname.nuno@gmail.com>]

On Mon, 2025-04-28 at 21:17 -0500, David Lechner wrote:
> Use struct with aligned_s64 timestamp to make timestamp alignment
> explicit. Technically, what we have works because for all known
> architectures, IIO_DMA_MINALIGN is a multiple of __alignof__(s64).
> But this way, we don't have to make people read the comments to know
> why there are extra elements in each buffer.
> 
> ---

Reviewed-by: Nuno Sá <nuno.sa@analog.com>

>  drivers/iio/adc/ad7606.h | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/iio/adc/ad7606.h b/drivers/iio/adc/ad7606.h
> index
> 89d49551eaf515bab9706c12bff056dfcb707b67..441e62c521bcbea69b4f70bb2d55f65334d2
> 2276 100644
> --- a/drivers/iio/adc/ad7606.h
> +++ b/drivers/iio/adc/ad7606.h
> @@ -155,12 +155,15 @@ struct ad7606_state {
>  	/*
>  	 * DMA (thus cache coherency maintenance) may require the
>  	 * transfer buffers to live in their own cache lines.
> -	 * 16 * 16-bit samples + 64-bit timestamp - for AD7616
> -	 * 8 * 32-bit samples + 64-bit timestamp - for AD7616C-18 (and
> similar)
> +	 * 16 * 16-bit samples for AD7616
> +	 * 8 * 32-bit samples for AD7616C-18 (and similar)
>  	 */
> -	union {
> -		u16 buf16[20];
> -		u32 buf32[10];
> +	struct {
> +		union {
> +			u16 buf16[16];
> +			u32 buf32[8];
> +		};
> +		aligned_s64 timestamp;
>  	} data __aligned(IIO_DMA_MINALIGN);
>  	__be16				d16[2];
>  };
> 
> ---
> base-commit: b475195fecc79a1a6e7fb0846aaaab0a1a4cb2e6
> change-id: 20250428-iio-adc-ad7606-fix-buffer-alignment-9fcde71687dc
> 
> Best regards,