Re: [PATCH v3 1/5] dt-bindings: pwm: Add a new binding for rockchip,rk3576-pwm

[Damon Ding <damon.ding@rock-chips.com>]

Hi Nicolas,

On 10/28/2025 1:11 AM, Nicolas Frattaroli wrote:
> The Rockchip RK3576 SoC has a newer PWM controller IP revision than
> previous Rockchip SoCs. This IP, called "PWMv4" by Rockchip, introduces
> several new features, and consequently differs in its bindings.
> 
> Instead of expanding the ever-growing rockchip-pwm binding that already
> has an if-condition, add an entirely new binding to handle this.
> 
> There are two additional clocks, "osc" and "rc". These are available for
> every PWM instance, and the PWM hardware can switch between the "pwm",
> "osc" and "rc" clock at runtime.
> 
> The PWM controller also comes with an interrupt now. This interrupt is
> used to signal various conditions.
> 
> Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
> Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
> Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
> ---
>   .../bindings/pwm/rockchip,rk3576-pwm.yaml          | 77 ++++++++++++++++++++++
>   MAINTAINERS                                        |  7 ++
>   2 files changed, 84 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/pwm/rockchip,rk3576-pwm.yaml b/Documentation/devicetree/bindings/pwm/rockchip,rk3576-pwm.yaml
> new file mode 100644
> index 000000000000..48d5055c8b06
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pwm/rockchip,rk3576-pwm.yaml
> @@ -0,0 +1,77 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/pwm/rockchip,rk3576-pwm.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Rockchip PWMv4 controller
> +
> +maintainers:
> +  - Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
> +
> +description: |
> +  The Rockchip PWMv4 controller is a PWM controller found on several Rockchip
> +  SoCs, such as the RK3576.
> +
> +  It supports both generating and capturing PWM signals.
> +
> +allOf:
> +  - $ref: pwm.yaml#
> +
> +properties:
> +  compatible:
> +    items:
> +      - const: rockchip,rk3576-pwm
> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    items:
> +      - description: Used to derive the PWM signal.
> +      - description: Used as the APB bus clock.
> +      - description: Used as an alternative to derive the PWM signal.
> +      - description: Used as another alternative to derive the PWM signal.
> +
> +  clock-names:
> +    items:
> +      - const: pwm
> +      - const: pclk
> +      - const: osc
> +      - const: rc
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  "#pwm-cells":
> +    const: 3
> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - clock-names
> +  - interrupts
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/rockchip,rk3576-cru.h>
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +
> +    soc {
> +        #address-cells = <2>;
> +        #size-cells = <2>;
> +
> +        pwm@2add0000 {
> +            compatible = "rockchip,rk3576-pwm";
> +            reg = <0x0 0x2add0000 0x0 0x1000>;
> +            clocks = <&cru CLK_PWM1>, <&cru PCLK_PWM1>, <&cru CLK_OSC_PWM1>,
> +                     <&cru CLK_RC_PWM1>;
> +            clock-names = "pwm", "pclk", "osc", "rc";
> +            interrupts = <GIC_SPI 102 IRQ_TYPE_LEVEL_HIGH>;
> +            #pwm-cells = <3>;
> +        };
> +    };
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 252b06d4240c..baecabab35a2 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -22366,6 +22366,13 @@ F:	Documentation/userspace-api/media/v4l/metafmt-rkisp1.rst
>   F:	drivers/media/platform/rockchip/rkisp1
>   F:	include/uapi/linux/rkisp1-config.h
>   
> +ROCKCHIP MFPWM
> +M:	Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
> +L:	linux-rockchip@lists.infradead.org
> +L:	linux-pwm@vger.kernel.org
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/pwm/rockchip,rk3576-pwm.yaml
> +
>   ROCKCHIP RK3568 RANDOM NUMBER GENERATOR SUPPORT
>   M:	Daniel Golle <daniel@makrotopia.org>
>   M:	Aurelien Jarno <aurelien@aurel32.net>
> 

The RK3506 and RV1126B platforms that are about to be upstream also use 
this PWM IP. Would it be better to name the yaml file 
"pwm-rockchip-v4.yaml"? Then subsequent platforms only need to expand 
the compatible property.

Best regards,
Damon