Re: [PATCH v7 06/10] iio: adc: Support ROHM BD79124 ADC

From: Andy Shevchenko
Date: Mon Mar 31 2025 - 03:37:20 EST


On Sun, Mar 30, 2025 at 05:04:36PM +0100, Jonathan Cameron wrote:
> On Mon, 17 Mar 2025 13:24:07 +0200
> Matti Vaittinen <mazziesaccount@xxxxxxxxx> wrote:
> > On 16/03/2025 13:02, Jonathan Cameron wrote:
> > > On Thu, 13 Mar 2025 09:19:03 +0200
> > > Matti Vaittinen <mazziesaccount@xxxxxxxxx> wrote:

...

> > >> + return (data->alarm_monitored[chan->channel] & BIT(dir));
> > >
> > > Drop the outer brackets as not adding anything.
> >
> > I just noticed that the integer returned from here is directly provided
> > to the user-space. I don't know the history, but it feels a bit off to
> > me. I mean, I would expect the read from sysfs file "*_en" to return '1'
> > or '0' - not 0x04.
> >
> > Oh well, I suppose it's too late to change this in the IIO core - but
> > I'll do:
> > return !!(data->alarm_monitored[chan->channel] & BIT(dir));
>
> Agreed it should be returning 1 or 0.
>
> This stuff is a little bit messy. I'd not be against that ABI
> cleanup if we squashed the values to 0,1 in the core as a follow up.
>
> I doubt anyone relies on getting 0x4 as that would be very driver
> specific userspace code!

FWIW, the time this discussion was held, I looked at the code and it seems
we have such drivers. I doubt we can change it without potential breakage of
(some) user space tools.

--
With Best Regards,
Andy Shevchenko