On Mon, Oct 26, 2020 at 01:16:50AM +0300, Dmitry Osipenko wrote:
> The SoC core voltage can't be changed without taking into account the
> clock rate of External Memory Controller. Document OPP table that will
> be used for dynamic voltage frequency scaling, taking into account EMC
> voltage requirement. Document optional core voltage regulator, which is
> optional because some boards may have a fixed core regulator and still
> frequency scaling may be desired to have.
You need to document that property is optional in the binding.
Best regards,
Krzysztof
>
> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
> ---
> .../memory-controllers/nvidia,tegra20-emc.txt | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt
> index 0a53adc6ccba..8d09b228ac42 100644
> --- a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt
> +++ b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt
> @@ -14,11 +14,23 @@ Properties:
> - clocks : Should contain EMC clock.
> - nvidia,memory-controller : Phandle of the Memory Controller node.
> - #interconnect-cells : Should be 0.
> +- core-supply: Phandle of voltage regulator of the SoC "core" power domain.
> +- operating-points-v2: See ../bindings/opp/opp.txt for details.
>
> Child device nodes describe the memory settings for different configurations and clock rates.
>
> Example:
>
> + emc_icc_dvfs_opp_table: emc_opp_table0 {
> + compatible = "operating-points-v2";
> +
> + opp@36000000 {
> + opp-microvolt = <950000 950000 1300000>;
> + opp-hz = /bits/ 64 <36000000>;
> + };
> + ...
> + };
> +
> memory-controller@7000f400 {
> #address-cells = < 1 >;
> #size-cells = < 0 >;
> @@ -28,6 +40,8 @@ Example:
> interrupts = <0 78 0x04>;
> clocks = <&tegra_car TEGRA20_CLK_EMC>;
> nvidia,memory-controller = <&mc>;
> + core-supply = <&core_vdd_reg>;
> + operating-points-v2 = <&emc_icc_dvfs_opp_table>;
> }
>
>
> --
> 2.27.0
>
