Re: [PATCH v12 14/17] counter: Implement *_component_id sysfs attributes

[David Lechner]

On 7/11/21 8:28 AM, Jonathan Cameron wrote:
> On Sat, 10 Jul 2021 12:06:53 -0500
> David Lechner <david@xxxxxxxxxxxxxx> wrote:
>
> > On 7/5/21 3:19 AM, William Breathitt Gray wrote:
> > > The Generic Counter chrdev interface expects users to supply component
> > > IDs in order to select extensions for requests. In order for users to
> > > know what component ID belongs to which extension this information must
> > > be exposed. The *_component_id attribute provides a way for users to
> > > discover what component ID belongs to which respective extension.
> > >
> > > Cc: David Lechner <david@xxxxxxxxxxxxxx>
> > > Cc: Gwendal Grignou <gwendal@xxxxxxxxxxxx>
> > > Cc: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> > > Signed-off-by: William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
> > > ---
> > >    Documentation/ABI/testing/sysfs-bus-counter | 16 ++++++++++-
> > >    drivers/counter/counter-sysfs.c             | 30 ++++++++++++++++-----
> > >    2 files changed, 39 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
> > > index 9809d8a47431..e0e99adb0ecc 100644
> > > --- a/Documentation/ABI/testing/sysfs-bus-counter
> > > +++ b/Documentation/ABI/testing/sysfs-bus-counter
> > > @@ -203,12 +203,26 @@ Description:
> > >    		both edges:
> > >    			Any state transition.
> > >    
> > > +What:		/sys/bus/counter/devices/counterX/countY/ceiling_component_id
> > > +What:		/sys/bus/counter/devices/counterX/countY/floor_component_id
> > > +What:		/sys/bus/counter/devices/counterX/countY/count_mode_component_id
> > > +What:		/sys/bus/counter/devices/counterX/countY/direction_component_id
> > > +What:		/sys/bus/counter/devices/counterX/countY/enable_component_id
> > > +What:		/sys/bus/counter/devices/counterX/countY/error_noise_component_id
> > > +What:		/sys/bus/counter/devices/counterX/countY/prescaler_component_id
> > > +What:		/sys/bus/counter/devices/counterX/countY/preset_component_id
> > > +What:		/sys/bus/counter/devices/counterX/countY/preset_enable_component_id
> > >    What:		/sys/bus/counter/devices/counterX/countY/signalZ_action_component_id
> > > +What:		/sys/bus/counter/devices/counterX/signalY/cable_fault_component_id
> > > +What:		/sys/bus/counter/devices/counterX/signalY/cable_fault_enable_component_id
> > > +What:		/sys/bus/counter/devices/counterX/signalY/filter_clock_prescaler_component_id
> > > +What:		/sys/bus/counter/devices/counterX/signalY/index_polarity_component_id
> > > +What:		/sys/bus/counter/devices/counterX/signalY/synchronous_mode_component_id
> >
> > Could we just write a single line?
> >
> > What:		/sys/bus/counter/devices/counterX/signalY/<component>_component_id
>
> Not nice for grepping so I think it's better to call them out explicitly.
>
> There has been a proposal to check this ABI doc against running kernels, and if we have
> too many wild cards that becomes very difficult to do.
>
> Jonathan
>
> > >    KernelVersion:	5.15

Makes sense. Do we start a new group of similar names with the same
description for each kernel release that includes new attributes then?

> > >    Contact:	linux-iio@xxxxxxxxxxxxxxx
> > >    Description:
> > >    		Read-only attribute that indicates the component ID of the
> > > -		respective Synapse of Count Y for Signal Z.
> > > +		respective extension or Synapse.
> > >