Re: [PATCH v6 2/6] dt-bindings: arm: msm: Convert and split kpss-acc driver Documentation to yaml

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

On 10/01/2023 20:32, Christian Marangi wrote:
> Convert kpss-acc driver Documentation to yaml.
> The original Documentation was wrong all along. Fix it while we are
> converting it.
> The example was wrong as kpss-acc-v2 should only expose the regs but we
> don't have any driver that expose additional clocks. The kpss-acc driver
> is only specific to v1. For this exact reason, split the Documentation
> to 2 different schema, v1 as clock-controller and v2 for
> power-controller as per msm-3.10 specification, the exposed regs handle
> power domains.
> 
> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> ---
>   .../bindings/arm/msm/qcom,kpss-acc.txt        | 49 -------------
>   .../bindings/clock/qcom,kpss-acc-v1.yaml      | 72 +++++++++++++++++++
>   .../bindings/power/qcom,kpss-acc-v2.yaml      | 47 ++++++++++++
>   3 files changed, 119 insertions(+), 49 deletions(-)
>   delete mode 100644 Documentation/devicetree/bindings/arm/msm/qcom,kpss-acc.txt
>   create mode 100644 Documentation/devicetree/bindings/clock/qcom,kpss-acc-v1.yaml
>   create mode 100644 Documentation/devicetree/bindings/power/qcom,kpss-acc-v2.yaml
> 
> diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,kpss-acc.txt b/Documentation/devicetree/bindings/arm/msm/qcom,kpss-acc.txt
> deleted file mode 100644
> index 7f696362a4a1..000000000000
> --- a/Documentation/devicetree/bindings/arm/msm/qcom,kpss-acc.txt
> +++ /dev/null
> @@ -1,49 +0,0 @@
> -Krait Processor Sub-system (KPSS) Application Clock Controller (ACC)
> -
> -The KPSS ACC provides clock, power domain, and reset control to a Krait CPU.
> -There is one ACC register region per CPU within the KPSS remapped region as
> -well as an alias register region that remaps accesses to the ACC associated
> -with the CPU accessing the region.
> -
> -PROPERTIES
> -
> -- compatible:
> -	Usage: required
> -	Value type: <string>
> -	Definition: should be one of:
> -			"qcom,kpss-acc-v1"
> -			"qcom,kpss-acc-v2"
> -
> -- reg:
> -	Usage: required
> -	Value type: <prop-encoded-array>
> -	Definition: the first element specifies the base address and size of
> -		    the register region. An optional second element specifies
> -		    the base address and size of the alias register region.
> -
> -- clocks:
> -        Usage: required
> -        Value type: <prop-encoded-array>
> -        Definition: reference to the pll parents.
> -
> -- clock-names:
> -        Usage: required
> -        Value type: <stringlist>
> -        Definition: must be "pll8_vote", "pxo".
> -
> -- clock-output-names:
> -	Usage: optional
> -	Value type: <string>
> -	Definition: Name of the output clock. Typically acpuX_aux where X is a
> -		    CPU number starting at 0.
> -
> -Example:
> -
> -	clock-controller@2088000 {
> -		compatible = "qcom,kpss-acc-v2";
> -		reg = <0x02088000 0x1000>,
> -		      <0x02008000 0x1000>;
> -		clocks = <&gcc PLL8_VOTE>, <&gcc PXO_SRC>;
> -		clock-names = "pll8_vote", "pxo";
> -		clock-output-names = "acpu0_aux";
> -	};
> diff --git a/Documentation/devicetree/bindings/clock/qcom,kpss-acc-v1.yaml b/Documentation/devicetree/bindings/clock/qcom,kpss-acc-v1.yaml
> new file mode 100644
> index 000000000000..a466e4e8aacd
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/qcom,kpss-acc-v1.yaml
> @@ -0,0 +1,72 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/clock/qcom,kpss-acc-v1.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Krait Processor Sub-system (KPSS) Application Clock Controller (ACC) v1
> +
> +maintainers:
> +  - Christian Marangi <ansuelsmth@gmail.com>
> +
> +description:
> +  The KPSS ACC provides clock, power domain, and reset control to a Krait CPU.
> +  There is one ACC register region per CPU within the KPSS remapped region as
> +  well as an alias register region that remaps accesses to the ACC associated
> +  with the CPU accessing the region. ACC v1 is currently used as a
> +  clock-controller for enabling the cpu and hanling the aux clocks.
> +
> +properties:
> +  compatible:
> +    const: qcom,kpss-acc-v1
> +
> +  reg:
> +    items:
> +      - description: Base address and size of the register region
> +      - description: Optional base address and size of the alias register region
> +    minItems: 1
> +
> +  clocks:
> +    minItems: 2
> +    maxItems: 2
> +
> +  clock-names:
> +    items:
> +      - const: pll8_vote
> +      - const: pxo
> +
> +  clock-output-names:
> +    description: Name of the aux clock. Krait can have at most 4 cpu.
> +    enum:
> +      - acpu0_aux
> +      - acpu1_aux
> +      - acpu2_aux
> +      - acpu3_aux
> +
> +  '#clock-cells':
> +    const: 0
> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - clock-names
> +  - clock-output-names
> +  - '#clock-cells'
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/qcom,gcc-ipq806x.h>
> +
> +    clock-controller@2088000 {
> +      compatible = "qcom,kpss-acc-v1";
> +      reg = <0x02088000 0x1000>, <0x02008000 0x1000>;
> +      clocks = <&gcc PLL8_VOTE>, <&pxo_board>;
> +      clock-names = "pll8_vote", "pxo";
> +      clock-output-names = "acpu0_aux";
> +      #clock-cells = <0>;
> +    };
> +
> +...
> diff --git a/Documentation/devicetree/bindings/power/qcom,kpss-acc-v2.yaml b/Documentation/devicetree/bindings/power/qcom,kpss-acc-v2.yaml
> new file mode 100644
> index 000000000000..91af95569ae6
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/power/qcom,kpss-acc-v2.yaml
> @@ -0,0 +1,47 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/power/qcom,kpss-acc-v2.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Krait Processor Sub-system (KPSS) Application Clock Controller (ACC) v2
> +
> +maintainers:
> +  - Christian Marangi <ansuelsmth@gmail.com>
> +
> +description:
> +  The KPSS ACC provides clock, power domain, and reset control to a Krait CPU.
> +  There is one ACC register region per CPU within the KPSS remapped region as
> +  well as an alias register region that remaps accesses to the ACC associated
> +  with the CPU accessing the region. ACC v2 is currently used as a
> +  power-controller for enabling the cpu.
> +
> +properties:
> +  compatible:
> +    const: qcom,kpss-acc-v2
> +
> +  reg:
> +    items:
> +      - description: Base address and size of the register region
> +      - description: Optional base address and size of the alias register region
> +    minItems: 1
> +
> +  '#power-domain-cells':
> +    const: 0
> +
> +required:
> +  - compatible
> +  - reg
> +  - '#power-domain-cells'

This dictates that if at some point we implement the kps-acc-v2 driver, 
it will return a single power domain. I can not confirm that this would 
be the case. I see that you want to migrate from the clock-controller as 
the acc-v2 doesn't provide clocks. I'd suggest instead using the neutral 
`power-manager@...` node name. It doesn't demand anything, so we can 
drop the (unused and unsupported) #power-domain-cells property.

> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    power-controller@f9088000 {
> +      compatible = "qcom,kpss-acc-v2";
> +      reg = <0xf9088000 0x1000>,
> +            <0xf9008000 0x1000>;
> +      #power-domain-cells = <0>;
> +    };
> +...

-- 
With best wishes
Dmitry