linux-kernel - Re: [RFC PATCH v2 3/6] dt-bindings: ufs: common: add OPP table

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Date:   Thu, 14 Apr 2022 10:25:17 -0500
From:   Rob Herring <robh@...nel.org>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Alim Akhtar <alim.akhtar@...sung.com>,
        Avri Altman <avri.altman@....com>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Taniya Das <tdas@...eaurora.org>,
        linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, linux-scsi@...r.kernel.org
Subject: Re: [RFC PATCH v2 3/6] dt-bindings: ufs: common: add OPP table

On Mon, Apr 11, 2022 at 05:43:44PM +0200, Krzysztof Kozlowski wrote:
> Except scaling UFS and bus clocks, it's necessary to scale also the
> voltages of regulators or power domain performance state levels.  Adding
> Operating Performance Points table allows to adjust power domain
> performance state, depending on the UFS clock speed.
> 
> OPPv2 deprecates previous property limited to clock scaling:
> freq-table-hz.
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
> 
> ---
> 
> Not adding Rob's review tag because patch changed significantly.
> ---
>  .../devicetree/bindings/ufs/ufs-common.yaml   | 34 +++++++++++++++++--
>  1 file changed, 31 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/ufs/ufs-common.yaml b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
> index 47a4e9e1a775..d7d2c8a136bb 100644
> --- a/Documentation/devicetree/bindings/ufs/ufs-common.yaml
> +++ b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
> @@ -20,11 +20,24 @@ properties:
>        items:
>          - description: Minimum frequency for given clock in Hz
>          - description: Maximum frequency for given clock in Hz
> +    deprecated: true
>      description: |
> +      Preferred is operating-points-v2.
> +
>        Array of <min max> operating frequencies in Hz stored in the same order
> -      as the clocks property. If this property is not defined or a value in the
> -      array is "0" then it is assumed that the frequency is set by the parent
> -      clock or a fixed rate clock source.
> +      as the clocks property. If either this property or operating-points-v2 is
> +      not defined or a value in the array is "0" then it is assumed that the
> +      frequency is set by the parent clock or a fixed rate clock source.
> +
> +  operating-points-v2:
> +    description:
> +      Preferred over freq-table-hz.
> +      If present, each OPP must contain array of frequencies stored in the same
> +      order for each clock.  If clock frequency in the array is "0" then it is
> +      assumed that the frequency is set by the parent clock or a fixed rate
> +      clock source.
> +
> +  opp-table: true
>  
>    interrupts:
>      maxItems: 1
> @@ -75,8 +88,23 @@ properties:
>  
>  dependencies:
>    freq-table-hz: [ 'clocks' ]
> +  operating-points-v2: [ 'clocks', 'clock-names' ]
>  
>  required:
>    - interrupts
>  
> +allOf:
> +  - if:
> +      required:
> +        - freq-table-hz
> +    then:
> +      properties:
> +        operating-points-v2: false
> +  - if:
> +      required:
> +        - operating-points-v2
> +    then:
> +      properties:
> +        freq-table-hz: false

You could also express this as:

oneOf:
  - required: [ freq-table-hz ]
  - required: [ operating-points-v2 ]
  - not:
      required: [ freq-table-hz, operating-points-v2 ]


> +
>  additionalProperties: true
> -- 
> 2.32.0
> 
>