Re: [PATCH v3 3/5] dt-bindings: input: Add poll-interval property

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Thu, Oct 10, 2019 at 02:40:36PM -0500, Rob Herring wrote:
> On Thu, Oct 03, 2019 at 08:12:54AM +0200, Michal Vokáč wrote:
> > Add an option to periodicaly poll the device to get state of the inputs
> > as the interrupt line may not be used on some platforms.
> > 
> > Signed-off-by: Michal Vokáč <michal.vokac@ysoft.com>
> > ---
> > Changes since v2:
> >  - None
> > 
> > Changes since v1:
> >  - Use poll-interval instead of linux,poll-interval.
> >  - Place the poll-interval binding into the common schema.
> >  - Properly describe that either interrupts or poll-interval property is
> >    required.
> >  - Fix the example to pass validation.
> > 
> >  .../bindings/input/fsl,mpr121-touchkey.yaml        | 25 +++++++++++++++++++++-
> >  Documentation/devicetree/bindings/input/input.yaml |  4 ++++
> >  2 files changed, 28 insertions(+), 1 deletion(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/input/fsl,mpr121-touchkey.yaml b/Documentation/devicetree/bindings/input/fsl,mpr121-touchkey.yaml
> > index c6fbcdf78556..035b2fee4491 100644
> > --- a/Documentation/devicetree/bindings/input/fsl,mpr121-touchkey.yaml
> > +++ b/Documentation/devicetree/bindings/input/fsl,mpr121-touchkey.yaml
> > @@ -17,6 +17,10 @@ description: |
> >  allOf:
> >    - $ref: input.yaml#
> >  
> > +oneOf:
> 
> It should be valid to have both properties present, right?

The poll does not really sense and does not have any effect when
interrupt is supplied.

> The h/w description can't know what the OS supports.

It also has no idea what OS does at all and whether it even pays
attention to any of these properties. We are just trying to say here "I
do not have an interrupt wired, so for this device's primary use case
(that is coupled with a certain $PRIMARY OS) we need to poll the
controller ever so often to handle our use case".

> In that case, we should use 'anyOf' here instead.
> 
> With that,
> 
> Reviewed-by: Rob Herring <robh@kernel.org>
> 
> > +  - required: [ interrupts ]
> > +  - required: [ poll-interval ]
> > +
> >  properties:
> >    compatible:
> >      const: fsl,mpr121-touchkey
> > @@ -41,12 +45,12 @@ properties:
> >  required:
> >    - compatible
> >    - reg
> > -  - interrupts
> >    - vdd-supply
> >    - linux,keycodes
> >  
> >  examples:
> >    - |
> > +    // Example with interrupts
> >      #include "dt-bindings/input/input.h"
> >      i2c {
> >          #address-cells = <1>;
> > @@ -64,3 +68,22 @@ examples:
> >                               <KEY_8>, <KEY_9>, <KEY_A>, <KEY_B>;
> >          };
> >      };
> > +
> > +  - |
> > +    // Example with polling
> > +    #include "dt-bindings/input/input.h"
> > +    i2c {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        mpr121@5a {
> > +            compatible = "fsl,mpr121-touchkey";
> > +            reg = <0x5a>;
> > +            poll-interval = <20>;
> > +            autorepeat;
> > +            vdd-supply = <&ldo4_reg>;
> > +            linux,keycodes = <KEY_0>, <KEY_1>, <KEY_2>, <KEY_3>,
> > +                             <KEY_4>, <KEY_5>, <KEY_6>, <KEY_7>,
> > +                             <KEY_8>, <KEY_9>, <KEY_A>, <KEY_B>;
> > +        };
> > +    };
> > diff --git a/Documentation/devicetree/bindings/input/input.yaml b/Documentation/devicetree/bindings/input/input.yaml
> > index ca8fe84a2e62..6d519046b3af 100644
> > --- a/Documentation/devicetree/bindings/input/input.yaml
> > +++ b/Documentation/devicetree/bindings/input/input.yaml
> > @@ -24,6 +24,10 @@ properties:
> >            minimum: 0
> >            maximum: 0xff
> >  
> > +  poll-interval:
> > +    description: Poll interval time in milliseconds.
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +
> >    power-off-time-sec:
> >      description:
> >        Duration in seconds which the key should be kept pressed for device to
> > -- 
> > 2.1.4
> > 

-- 
Dmitry