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

[Rob Herring <robh@kernel.org>]

On Tue, Feb 2, 2021 at 4:36 AM Damien Le Moal <damien.lemoal@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@sifive.com>
> Cc: Rob Herring <robh@kernel.org>
> Cc: devicetree@vger.kernel.org
> Signed-off-by: Damien Le Moal <damien.lemoal@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).

Rob