Re: [PATCH 5/5] staging: iio: ad9832: add sysfs documentation

[Jonathan Cameron]

On Thu, 18 Dec 2025 12:10:19 -0300
Marcelo Schmitt <marcelo.schmitt1@xxxxxxxxx> wrote:

> On 12/15, Tomas Borquez wrote:
> > Add sysfs ABI documentation for the AD9832/AD9835 Direct Digital
> > Synthesizer chips, documenting frequency, phase, output control,
> > and pin control attributes.
> > 
> > Signed-off-by: Tomas Borquez <tomasborquez13@xxxxxxxxx>
> > ---
> >  .../Documentation/sysfs-bus-iio-dds-ad9832    | 41 +++++++++++++++++++
> >  1 file changed, 41 insertions(+)
> >  create mode 100644 drivers/staging/iio/Documentation/sysfs-bus-iio-dds-ad9832
> > 
> > diff --git a/drivers/staging/iio/Documentation/sysfs-bus-iio-dds-ad9832 b/drivers/staging/iio/Documentation/sysfs-bus-iio-dds-ad9832
> > new file mode 100644
> > index 0000000000..5ceea57917
> > --- /dev/null
> > +++ b/drivers/staging/iio/Documentation/sysfs-bus-iio-dds-ad9832
> > @@ -0,0 +1,41 @@
> > +What:		/sys/bus/iio/devices/iio:deviceX/out_altcurrent0_frequencyY  
> To be more generic, I think we could use a capital letter for the channel number
> too and avoid the symbol postfix in the this attribute's name.
> +What:		/sys/bus/iio/devices/iio:deviceX/out_altcurrentY_frequency
> 
> > +KernelVersion:	6.19
> > +Contact:	linux-iio@xxxxxxxxxxxxxxx
> > +Description:
> > +    Frequency in Hz for frequency register Y (0-1). The active
> > +    frequency register is selected via out_altcurrent0_frequency_symbol.  
> Maybe, if we can keep only the 'Frequency in Hz for frequency channel Y.' part
> of the description, this is something that could actually go into sysfs-bus-iio
> when the driver graduates. Though, the 'register is selected via
> out_altcurrent0_frequency_symbol' part is trickier since it seems to be design
> specific. 

For now, these interfaces are specific enough I'd be tempted to put them in
sysfs-bus-iio-frequency or a driver specific file for now.

That lets us keep a little more track of how they are used. It's a lot
easier to make sure documentation is generic enough once there are a few users
(though as Marcelo suggests, make it as a general as possible from the start!)

Jonathan

> 
> What if we do something like
> +What:		/sys/bus/iio/devices/iio:deviceX/out_altcurrentY_frequency_symbolZ
> +KernelVersion:	6.19
> +Contact:	linux-iio@xxxxxxxxxxxxxxx
> +Description:
> +    Frequency in Hz for symbol Z of frequency Y channel. The active
> +    frequency symbol is selected via out_altcurrentY_frequency_symbol.
> ?
> 
> Same thoughts about out_altcurrent0_phaseY.