Re: [PATCH v2 1/3] dt-bindings: adc-joystick: add adc-joystick,polled option

[Chris Morgan <macromorgan@hotmail.com>]

On Thu, Jun 02, 2022 at 11:56:10AM +0200, Krzysztof Kozlowski wrote:
> On 01/06/2022 22:49, Chris Morgan wrote:
> > From: Chris Morgan <macromorgan@hotmail.com>
> > 
> > Add documentation for adc-joystick,polled. New device-tree properties
> > have been added.
> > 
> > - adc-joystick,polled: A boolean value noting the joystick device
> > 		       should be polled rather than use a triggered
> > 		       buffer.
> > 
> > Signed-off-by: Maya Matuszczyk <maccraft123mc@gmail.com>
> > Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
> > ---
> >  .../devicetree/bindings/input/adc-joystick.yaml          | 9 ++++++++-
> >  1 file changed, 8 insertions(+), 1 deletion(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/input/adc-joystick.yaml b/Documentation/devicetree/bindings/input/adc-joystick.yaml
> > index 2ee04e03bc22..4f49a1a5772e 100644
> > --- a/Documentation/devicetree/bindings/input/adc-joystick.yaml
> > +++ b/Documentation/devicetree/bindings/input/adc-joystick.yaml
> > @@ -12,12 +12,19 @@ maintainers:
> >  
> >  description: >
> >    Bindings for joystick devices connected to ADC controllers supporting
> > -  the Industrial I/O subsystem.
> > +  the Industrial I/O subsystem. Supports both polled devices where no
> > +  iio trigger is available and non-polled devices which are triggered
> > +  by iio.
> >  
> >  properties:
> >    compatible:
> >      const: adc-joystick
> >  
> > +  adc-joystick,polled:
> > +    type: boolean
> > +    description:
> > +      If the device does not support triggered buffers and needs to be polled.
> 

What would your recommendation be? I'm basically proposing polling
instead of utilizing a triggered buffer, so instead of the driver
relying on a hardware trigger or a software trigger being set up to
fill the buffer that is read by the input subsystem we use the input
subsystem polling function directly (this is useful for my use-case
where the Rockchip SARADC doesn't have a hardware trigger).

Thank you for your help.

> You described desired Linux feature or behavior, not the actual
> hardware. The bindings are about the latter, so instead you need to
> rephrase the property and it's description to match actual hardware
> capabilities/features/configuration etc.
> 
> 
> Best regards,
> Krzysztof