Re: [PATCH v10 6/7] iio: adc: ad9467: convert to backend framework

[Andy Shevchenko <andy.shevchenko@gmail.com>]

On Fri, Feb 9, 2024 at 5:26 PM Nuno Sa <nuno.sa@analog.com> wrote:
>
> Convert the driver to use the new IIO backend framework. The device
> functionality is expected to be the same (meaning no added or removed
> features).
>
> Also note this patch effectively breaks ABI and that's needed so we can
> properly support this device and add needed features making use of the
> new IIO framework.
>
> Given the lack of features (and devices supported) in the ad9467 driver
> compared with the ADI out of tree version, we don't expect any user of
> the upstream driver so no one should notice the ABI breakage. However,
> if someone is affected by this, ADI will happily support transitioning
> to the backend framework.

...

>  struct ad9467_chip_info {
> -       struct adi_axi_adc_chip_info    axi_adc_info;
> -       unsigned int                    default_output_mode;
> -       unsigned int                    vref_mask;
> +       const char              *name;
> +       unsigned int            id;
> +       const struct            iio_chan_spec *channels;
> +       unsigned int            num_channels;
> +       const unsigned int      (*scale_table)[2];
> +       int                     num_scales;
> +       unsigned long           max_rate;
> +       unsigned int            default_output_mode;
> +       unsigned int            vref_mask;
>  };

Seems like you haven't checked this layout with `pahole`.

...

> +static int ad9467_iio_backend_get(struct ad9467_state *st)
> +{
> +       struct device *dev = &st->spi->dev;
> +       struct device_node *__back;
> +
> +       st->back = devm_iio_backend_get(&st->spi->dev, NULL);

Simply 'dev' as the first parameter?

...

> +       /* If not found, don't error out as we might have legacy DT property */

This seems related to ENOENT, correct?

> +       if (!IS_ERR(st->back))
> +               return 0;

And the above is about something else (found?) case, right?

> +       if (PTR_ERR(st->back) != -ENOENT)
> +               return PTR_ERR(st->back);

--
With Best Regards,
Andy Shevchenko