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

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 17 Mar 2025 13:24:07 +0200
Matti Vaittinen <mazziesaccount@gmail.com> wrote:

> On 16/03/2025 13:02, Jonathan Cameron wrote:
> > On Thu, 13 Mar 2025 09:19:03 +0200
> > Matti Vaittinen <mazziesaccount@gmail.com> wrote:  
> 
> ...
> 
> >> +static int bd79124_write_int_to_reg(struct bd79124_data *data, int reg,
> >> +				    unsigned int val)  
> > ..  
> >> +static int bd79124_read_event_config(struct iio_dev *iio_dev,
> >> +				     const struct iio_chan_spec *chan,
> >> +				     enum iio_event_type type,
> >> +				     enum iio_event_direction dir)
> >> +{
> >> +	struct bd79124_data *data = iio_priv(iio_dev);
> >> +
> >> +	if (chan->channel >= BD79124_MAX_NUM_CHANNELS)
> >> +		return -EINVAL;
> >> +
> >> +	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!

Jonathan

> 
> in v8.
> 
> 
> Yours,
> 	-- Matti