Re: [PATCH v4 2/4] iio: light: add support for veml6031x00 ALS series

[Javier Carrasco]

On Tue Jun 2, 2026 at 4:29 PM CEST, Jonathan Cameron wrote:
> On Tue, 02 Jun 2026 14:40:47 +0200
> "Javier Carrasco" <javier.carrasco.cruz@xxxxxxxxx> wrote:
>
>> On Tue Jun 2, 2026 at 2:38 PM CEST, Jonathan Cameron wrote:
>> >> >> +/*
>> >> >> + * The gain selector encodes (PD_D4 << 2) | GAIN to identify each gain setting.
>> >> >> + * Gains are multiplied by 8 to work with integers. The values in the iio-gts
>> >> >> + * tables don't need corrections because the maximum value of the scale refers
>> >> >> + * to GAIN = x1, and the rest of the values are obtained from the resulting
>> >> >> + * linear function.
>> >> >> + * TODO: add support for MILLI_GAIN_X165 and MILLI_GAIN_X660
>> >> >> + */
>> >> >> +#define VEML6031X00_SEL_MILLI_GAIN_X125  0x07
>> >> >> +#define VEML6031X00_SEL_MILLI_GAIN_X250  0x04
>> >> >> +#define VEML6031X00_SEL_MILLI_GAIN_X500  0x03
>> >> >> +#define VEML6031X00_SEL_MILLI_GAIN_X1000 0x00
>> >> >> +#define VEML6031X00_SEL_MILLI_GAIN_X2000 0x01
>> >> >
>> >> > Not sure if these one-time use definitions improve or not the readability
>> >> > of the code. Up to Jonathan.
>> >> >
>> >>
>> >> I prefer these definitions, and a similar pattern is used in multiple
>> >> drivers in IIO, but I have no strong feelings about it.
>> >
>> > Looking again at this, what do the numbers in the defines actually mean?
>> > Seems a bit odd to have the base gain of 1 being called X125.
>> > Maybe a comment on that would be useful.  I don't mind either way
>> > on defines for this but if that number is useful to have I'd rather
>> > have a define than a comment on each line.
>> >
>>
>> I thought that MILLI_GAIN was already documenting what x125 is: 0.125 =
>> 125 milli. More than the base gain of 1, it is the lowest gain you can
>> configure.
>
> Ah. The X location maybe what meant I didn't figure it out.
> For similar the past we've done _0_125 .... _2_000
> which might be less confusing?
>
> There isn't really a perfect answer for this stuff.
>
> J

If that has been done in the past, I am fine with dropping _MILLI_ and
using _0_125 and so on for V5.

Best regards,
Javier