On Thu, Oct 01, 2026 at 08:40:53PM +0800, Long Zhao via B4 Relay wrote:
> From: Long Zhao <longzhao@ambarella.com>
> 
> The CV75 GPIO banks sit on the AMBA PrimeCell bus but are not
> register-compatible with the ARM PL061. Each bank is 32-bit and 32
> lines, with extra mask/enable registers, so arm,pl061 must not be used
> as a fallback compatible.

What has this got in common with the pl061 beyond using the PrimeCell
bus? Current reason for putting them together is a bit tenuous to me.

Cheers,
Conor.

> 
> The AMBA core matches the PL061 driver by PrimeCell ID, not by the DT
> compatible string. These blocks do not implement the standard PL061 ID
> (0x00041061) in the ID registers, so arm,primecell-periphid is required
> and is fixed to 0x000e8061; the driver uses that ID to select the
> Ambarella layout. gpio-ranges is required because each bank is a slice
> of the SoC pinctrl pin space.
> 
> Signed-off-by: Long Zhao <longzhao@ambarella.com>
> ---
>  .../devicetree/bindings/gpio/pl061-gpio.yaml       | 25 +++++++++++++++++++---
>  1 file changed, 22 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/gpio/pl061-gpio.yaml b/Documentation/devicetree/bindings/gpio/pl061-gpio.yaml
> index 4d970e55104b..c22dd8a1d2c1 100644
> --- a/Documentation/devicetree/bindings/gpio/pl061-gpio.yaml
> +++ b/Documentation/devicetree/bindings/gpio/pl061-gpio.yaml
> @@ -15,7 +15,9 @@ select:
>    properties:
>      compatible:
>        contains:
> -        const: arm,pl061
> +        enum:
> +          - arm,pl061
> +          - ambarella,cv75-gpio
>    required:
>      - compatible
>  
> @@ -25,7 +27,9 @@ properties:
>  
>    compatible:
>      items:
> -      - const: arm,pl061
> +      - enum:
> +          - ambarella,cv75-gpio
> +          - arm,pl061
>        - const: arm,primecell
>  
>    reg:
> @@ -64,6 +68,21 @@ required:
>    - "#gpio-cells"
>    - gpio-controller
>  
> -additionalProperties: false
> +allOf:
> +  - $ref: /schemas/arm/primecell.yaml#
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: ambarella,cv75-gpio
> +    then:
> +      properties:
> +        arm,primecell-periphid:
> +          const: 0x000e8061
> +      required:
> +        - arm,primecell-periphid
> +        - gpio-ranges
> +
> +unevaluatedProperties: false
>  
>  ...
> 
> -- 
> 2.34.1
> 
>