Re: [TEGRA194_CPUFREQ Patch v3 1/4] dt-bindings: arm: Add t194 ccplex compatible and bpmp property
From: Viresh Kumar
Date: Mon Jun 22 2020 - 03:22:54 EST
On 22-06-20, 03:04, Sumit Gupta wrote:
> To do frequency scaling on all CPUs within T194 CPU Complex, we need
> to query BPMP for data on valid operating points. Document a compatible
> string under 'cpus' node to represent the CPU Complex for binding drivers
> like cpufreq which don't have their node or CPU Complex node to bind to.
> Also, document a property to point to the BPMP device that can be queried
> for all CPUs.
You shouldn't be putting how linux is going to use this information and entries
shouldn't be made just so cpufreq can bind to a driver.
Though I see that this is a real hardware register which you can use to interact
with the firmware ? And so it makes sense to have it, maybe in different form
though.
I will let Rob explain what would be the right way of doing this though.
>
> Signed-off-by: Sumit Gupta <sumitg@xxxxxxxxxx>
> ---
> Documentation/devicetree/bindings/arm/cpus.yaml | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/arm/cpus.yaml b/Documentation/devicetree/bindings/arm/cpus.yaml
> index a018147..737b55e 100644
> --- a/Documentation/devicetree/bindings/arm/cpus.yaml
> +++ b/Documentation/devicetree/bindings/arm/cpus.yaml
> @@ -162,6 +162,7 @@ properties:
> - nvidia,tegra132-denver
> - nvidia,tegra186-denver
> - nvidia,tegra194-carmel
> + - nvidia,tegra194-ccplex
> - qcom,krait
> - qcom,kryo
> - qcom,kryo260
> @@ -255,6 +256,14 @@ properties:
>
> where voltage is in V, frequency is in MHz.
>
> + nvidia,bpmp:
> + $ref: '/schemas/types.yaml#/definitions/phandle'
> + descrption: |
> + Specifies the bpmp node that needs to be queried to get
> + operating point data for all CPUs.
> +
> + Optional for NVIDIA Tegra194 Carmel CPUs
> +
> power-domains:
> $ref: '/schemas/types.yaml#/definitions/phandle-array'
> description:
> --
> 2.7.4
--
viresh