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

Damon Ding
2025-10-28T03:06:26Z

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