From ab16dfb99cb565fb21ddf29320890c7bad35024c Mon Sep 17 00:00:00 2001 From: Christian Marangi Date: Fri, 6 Dec 2024 22:11:24 +0100 Subject: [PATCH] dt-bindings: cpufreq: Document support for Airoha EN7581 CPUFreq On newer Airoha SoC, CPU Frequency is scaled indirectly with SMC commands to ATF. A virtual clock is exposed. This virtual clock is a get-only clock and is used to expose the current global CPU clock. The frequency info comes by the output of the SMC command that reports the clock in MHz. The SMC sets the CPU clock by providing an index, this is modelled as performance states in a power domain. CPUs can't be individually scaled as the CPU frequency is shared across all CPUs and is global. Signed-off-by: Christian Marangi Reviewed-by: Ulf Hansson Reviewed-by: Rob Herring (Arm) Signed-off-by: Viresh Kumar --- .../cpufreq/airoha,en7581-cpufreq.yaml | 55 +++++++++++++++++++ 1 file changed, 55 insertions(+) create mode 100644 Documentation/devicetree/bindings/cpufreq/airoha,en7581-cpufreq.yaml diff --git a/Documentation/devicetree/bindings/cpufreq/airoha,en7581-cpufreq.yaml b/Documentation/devicetree/bindings/cpufreq/airoha,en7581-cpufreq.yaml new file mode 100644 index 0000000000000..7d4510b3219ca --- /dev/null +++ b/Documentation/devicetree/bindings/cpufreq/airoha,en7581-cpufreq.yaml @@ -0,0 +1,55 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/cpufreq/airoha,en7581-cpufreq.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Airoha EN7581 CPUFreq + +maintainers: + - Christian Marangi + +description: | + On newer Airoha SoC, CPU Frequency is scaled indirectly with SMC commands + to ATF. + + A virtual clock is exposed. This virtual clock is a get-only clock and + is used to expose the current global CPU clock. The frequency info comes + by the output of the SMC command that reports the clock in MHz. + + The SMC sets the CPU clock by providing an index, this is modelled as + performance states in a power domain. + + CPUs can't be individually scaled as the CPU frequency is shared across + all CPUs and is global. + +properties: + compatible: + const: airoha,en7581-cpufreq + + '#clock-cells': + const: 0 + + '#power-domain-cells': + const: 0 + + operating-points-v2: true + +required: + - compatible + - '#clock-cells' + - '#power-domain-cells' + - operating-points-v2 + +additionalProperties: false + +examples: + - | + performance-domain { + compatible = "airoha,en7581-cpufreq"; + + operating-points-v2 = <&cpu_smcc_opp_table>; + + #power-domain-cells = <0>; + #clock-cells = <0>; + }; -- 2.39.5