Re: [PATCH v5 2/3] iio: light: ltr390: Add ALS channel and support for gain and resolution
From: Abhash jha
Date: Tue Aug 06 2024 - 13:20:31 EST
> Hi Abhash,
>
> I think I managed to confuse things with earlier reviews.
>
> We want a light channel here, but because the scaling is just linear
> we want to provide it as in_illuminance_raw and in_illumiance_scale,
> not a processed channel.
>
> Sometimes we have no alternative to a processed channel (typically non
> linear maths) but when we can present the scaling via _scale (and
> if needed _offset) then we do that. This avoids a bunch of future
> problems:
> 1 - Processed channels are a pain for buffered capture because they
> often need a lot more bits to store.
> 2 - Any events on this channel tend to require fiddly reverse lookups
> to get from processed to the raw value that needs to be written
> to the device.
>
> Also note we very rarely provide both processed and raw for a channel.
> The only exceptions are corner cases such as having to maintain ABI
> that we should have never have introduced in the first place.
>
> A few other comments inline.
>
>
> Jonathan
>
Hi Jonathan,
I have made the changes, can you look it over and tell me if it looks good.
Link for v7:
https://lore.kernel.org/linux-iio/20240804142321.54586-1-abhashkumarjha123@xxxxxxxxx/T/#t
Thanks,
Abhash