[PATCH v14 07/16] dt-bindings: fix sifive gpio properties

[Rob Herring]

On Wed, Feb 3, 2021 at 6:52 AM Damien Le Moal <Damien.LeMoal at wdc.com> wrote:
>
> On Tue, 2021-02-02 at 13:02 -0600, Rob Herring wrote:
> > On Tue, Feb 2, 2021 at 4:36 AM Damien Le Moal <damien.lemoal at wdc.com> wrote:
> > >
> > > The sifive gpio IP block supports up to 32 GPIOs. Reflect that in the
> > > interrupts property description and maxItems. Also add the standard
> > > ngpios property to describe the number of GPIOs available on the
> > > implementation.
> > >
> > > Also add the "canaan,k210-gpiohs" compatible string to indicate the use
> > > of this gpio controller in the Canaan Kendryte K210 SoC. If this
> > > compatible string is used, do not define the clocks property as
> > > required as the K210 SoC does not have a software controllable clock
> > > for the Sifive gpio IP block.
> > >
> > > Cc: Paul Walmsley <paul.walmsley at sifive.com>
> > > Cc: Rob Herring <robh at kernel.org>
> > > Cc: devicetree at vger.kernel.org
> > > Signed-off-by: Damien Le Moal <damien.lemoal at wdc.com>
> > > ---
> > >  .../devicetree/bindings/gpio/sifive,gpio.yaml | 21 ++++++++++++++++---
> > >  1 file changed, 18 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/Documentation/devicetree/bindings/gpio/sifive,gpio.yaml b/Documentation/devicetree/bindings/gpio/sifive,gpio.yaml
> > > index ab22056f8b44..2cef18ca737c 100644
> > > --- a/Documentation/devicetree/bindings/gpio/sifive,gpio.yaml
> > > +++ b/Documentation/devicetree/bindings/gpio/sifive,gpio.yaml
> > > @@ -16,6 +16,7 @@ properties:
> > >        - enum:
> > >            - sifive,fu540-c000-gpio
> > >            - sifive,fu740-c000-gpio
> > > +          - canaan,k210-gpiohs
> > >        - const: sifive,gpio0
> > >
> > >    reg:
> > > @@ -23,9 +24,9 @@ properties:
> > >
> > >    interrupts:
> > >      description:
> > > -      interrupt mapping one per GPIO. Maximum 16 GPIOs.
> > > +      interrupt mapping one per GPIO. Maximum 32 GPIOs.
> > >      minItems: 1
> > > -    maxItems: 16
> > > +    maxItems: 32
> > >
> > >    interrupt-controller: true
> > >
> > > @@ -38,6 +39,10 @@ properties:
> > >    "#gpio-cells":
> > >      const: 2
> > >
> > > +  ngpios:
> > > +    minimum: 1
> > > +    maximum: 32
> >
> > What's the default as obviously drivers already assume something.
> >
> > Does a driver actually need to know this? For example, does the
> > register stride change or something?
> >
> > Please don't add it if the only purpose is error check your DT (IOW,
> > if it just checks the max cell value in gpios phandles).
>
> If I remove that, make dtbs_check complains. Looking at othe gpio controller
> bindings, they all have it. So isn't it better to be consistent, and avoid make
> dtbs_check errors ?

That would mean you are already using 'ngpios' and it is undocumented
(for this binding). If already in use and possibly having users then
that changes things, but that's not what the commit msg says.

Not *all* gpio controllers have ngpios. It's a good number, but
probably more than need it though. If we wanted it everywhere, there
would be a schema enforcing that.

Rob