Re: [PATCH] iio: adc: ad4000: Avoid potential double data word read

[Andy Shevchenko]

On Tue, Apr 15, 2025 at 3:21 PM Marcelo Schmitt
<marcelo.schmitt@xxxxxxxxxx> wrote:
>
> Currently, SPI-Engine offload module always sends 32-bit data elements to
> DMA engine. Appropriately, when set for SPI offloading, the IIO driver uses
> 32 storagebits for IIO ADC channel buffer elements. However, setting SPI
> transfer length according to storagebits (32-bits in case of offload) can
> lead to unnecessarily long transfers for ADCs that are 16-bit or less
> precision. Adjust AD4000 single-shot read to run transfers of 2 bytes when
> that is enough to get all ADC data bits.

...

>         xfers[1].rx_buf = &st->scan.data;
> -       xfers[1].len = BITS_TO_BYTES(chan->scan_type.storagebits);
> +       xfers[1].len = chan->scan_type.realbits > 16 ? 4 : 2;

But wouldn't be logical to have

       xfers[1].len = BITS_TO_BYTES(chan->scan_type.realbits);

?

-- 
With Best Regards,
Andy Shevchenko