Re: [PATCH v5 6/9] iio: adc: ad7606: rework available attributes for SW channels

Jonathan Cameron
2024-09-07T15:04:05Z

On Sat, 7 Sep 2024 09:50:39 +0300
Alexandru Ardelean <aardelean@baylibre.com> wrote:

> For SW mode, the oversampling and scales attributes are always present.
> So, they can be implemented via a 'read_avail' hook in iio_info.
>
> For HW mode, it's a bit tricky, as these attributes get assigned based on
> GPIO definitions.
>
> So, for SW mode, we define a separate AD7606_SW_CHANNEL() macro, and use
> that for the SW channels.
> And 'ad7606_info_os_range_and_debug' can be renamed to
> 'ad7606_info_sw_mode' as it is only used for SW mode.
>
> For the 'read_avail' hook, we'll need to allocate the SW scales, so that
> they are just returned userspace without any extra processing.
> The allocation will happen when then ad7606_state struct is allocated.
> The oversampling available parameters don't need any extra processing; they
> can just be passed back to userspace (as they are).
>
> Signed-off-by: Alexandru Ardelean <aardelean@baylibre.com>

One question inline.

>
> int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
> diff --git a/drivers/iio/adc/ad7606.h b/drivers/iio/adc/ad7606.h
> index 635407c2acc0..fa175cff256c 100644
> --- a/drivers/iio/adc/ad7606.h
> +++ b/drivers/iio/adc/ad7606.h

> #define AD7616_CHANNEL(num) AD7606_SW_CHANNEL(num, 16)
>
> /**
> @@ -65,11 +84,15 @@ struct ad7606_chip_info {
> /**
> * struct ad7606_chan_scale - channel scale configuration
> * @scale_avail pointer to the array which stores the available scales
> + * @scale_avail_show a duplicate of 'scale_avail' which is readily formatted
> + * such that it can be read via the 'read_avail' hook
> * @num_scales number of elements stored in the scale_avail array
> * @range voltage range selection, selects which scale to apply
> */
> struct ad7606_chan_scale {
> +#define AD760X_MAX_SCALE_SHOW (AD760X_MAX_CHANNELS * 2)

Why is the number of scales dependent on the number of channels?

> const unsigned int *scale_avail;
> + int scale_avail_show[AD760X_MAX_SCALE_SHOW];
> unsigned int num_scales;
> unsigned int range;
> };