Re: [PATCH 3/6] dt-bindings: perf: Add devicetree binding for custom PPMU

[Krzysztof Kozlowski <krzk@kernel.org>]

On 08/07/2025 12:32, Vivek Yadav wrote:
> Add the dt-binding documentation for the Samsung specific
> Platform Performance Monitoring Unit (PPMU) driver which provides
> performance statistics for AXI bus masters such as MFC.

A nit, subject: drop second/last, redundant "devicetree bindings". The
"dt-bindings" prefix is already stating that these are bindings.
See also:
https://elixir.bootlin.com/linux/v6.7-rc8/source/Documentation/devicetree/bindings/submitting-patches.rst#L18

> 
> Signed-off-by: Ravi Patel <ravi.patel@samsung.com>
> Signed-off-by: Vivek Yadav <vivek.2311@samsung.com>
> ---
>  .../bindings/perf/samsung,ppmu-v2.yaml        | 62 +++++++++++++++++++
>  1 file changed, 62 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/perf/samsung,ppmu-v2.yaml
> 
> diff --git a/Documentation/devicetree/bindings/perf/samsung,ppmu-v2.yaml b/Documentation/devicetree/bindings/perf/samsung,ppmu-v2.yaml
> new file mode 100644
> index 000000000000..d137d06b7034
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/perf/samsung,ppmu-v2.yaml
> @@ -0,0 +1,62 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/perf/samsung,ppmu-v2.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Samsung PPMU (Platform Performance Monitoring Unit)
> +
> +maintainers:
> +  - Vivek Yadav <vivek.2311@samsung.com>
> +  - Ravi Patel <ravi.patel@samsung.com>
> +
> +description:
> +  PPMU (Platform Performance Monitoring Unit) provides performance statistics
> +  such as bandwidth, read and write request, transactions count for AXI masters
> +  like MFC.
> +
> +properties:
> +  compatible:
> +    const: samsung,ppmu-v2

What is wrong with existing bindings? Anyway, this must be SoC specific.

> +
> +  reg:
> +    maxItems: 1
> +    description: Memory-mapped register address
> +
> +  clocks:
> +    items:
> +      - description: AXI bus clock
> +      - description: Peripheral clock
> +
> +  clock-names:
> +    items:
> +      - const: aclk
> +      - const: pclk
> +
> +  interrupts:
> +    items:
> +      - description: Overflow interrupt for Counters
> +      - description: Conditional Interrupt Generation (CIG)
> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - clock-names
> +  - interrupts
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/fsd-clk.h>
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +    ppmu@12840000 {

Node names should be generic. See also an explanation and list of
examples (not exhaustive) in DT specification:
https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#generic-names-recommendation


> +        compatible = "samsung,ppmu-v2";
> +        reg = <0x12840000 0x1000>;
> +        interrupts = <GIC_SPI 133 IRQ_TYPE_LEVEL_HIGH>,
> +                     <GIC_SPI 134 IRQ_TYPE_LEVEL_HIGH>;
> +        clocks = <&clock_mfc MFC_PPMU_MFCD0_IPCLKPORT_ACLK>,
> +                 <&clock_mfc MFC_PPMU_MFCD0_IPCLKPORT_PCLK>;
> +        clock-names = "aclk", "pclk";
> +     };


Best regards,
Krzysztof