The MediaTek MT8196 SoC has new cpufreq hardware, with added memory
register ranges to control Dynamic-Voltage-Frequency-Scaling.
The DVFS hardware is controlled through a set of registers referred to
as "FDVFS"; one is a location from which a magic number is read to
ensure DVFS should be used, the other is a region to set the desired
target frequency that DVFS should aim towards for each performance
domain.
Instead of working around the old binding and its already established
meanings for the reg items, add a new binding. The FDVFS register memory
regions are at the beginning, which allows us to easily expand this
binding for future SoCs which may have more than 3 performance domains.
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
.../cpufreq/mediatek,mt8196-cpufreq-hw.yaml | 86 ++++++++++++++++++++++
1 file changed, 86 insertions(+)
diff --git a/Documentation/devicetree/bindings/cpufreq/mediatek,mt8196-cpufreq-hw.yaml b/Documentation/devicetree/bindings/cpufreq/mediatek,mt8196-cpufreq-hw.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..26bf21e05888646b4d1bdac95bfba0f36e037ffd
--- /dev/null
+++ b/Documentation/devicetree/bindings/cpufreq/mediatek,mt8196-cpufreq-hw.yaml
@@ -0,0 +1,86 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/cpufreq/mediatek,mt8196-cpufreq-hw.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek CPUFreq for MT8196 and related SoCs
+
+maintainers:
+ - Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
+
+description:
+ MT8196 uses CPUFreq management hardware that supports dynamic voltage
+ frequency scaling (dvfs), and can support several performance domains.
+
+properties:
+ compatible:
+ const: mediatek,mt8196-cpufreq-hw
+
+ reg:
+ items:
+ - description: FDVFS magic number register region
+ - description: FDVFS control register region
+ - description: OPP tables and control for performance domain 0
+ - description: OPP tables and control for performance domain 1
+ - description: OPP tables and control for performance domain 2
+
+ "#performance-domain-cells":
+ description:
+ Number of cells in a performance domain specifier. Must be 1.
+ const: 1
+
+required:
+ - compatible
+ - reg
+ - "#performance-domain-cells"
+
+additionalProperties: false
+
+examples:
+ - |
+ cpus {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ cpu0: cpu@0 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a720";
+ enable-method = "psci";
+ performance-domains = <&performance 0>;
+ reg = <0x000>;
+ };
+
+ /* ... */
+
+ cpu6: cpu@600 {
+ device_type = "cpu";
+ compatible = "arm,cortex-x4";
+ enable-method = "psci";
+ performance-domains = <&performance 1>;
+ reg = <0x600>;
+ };
+
+ cpu7: cpu@700 {
+ device_type = "cpu";
+ compatible = "arm,cortex-x925";
+ enable-method = "psci";
+ performance-domains = <&performance 2>;
+ reg = <0x700>;
+ };
+ };
+
+ /* ... */
+
+ soc {
+ #address-cells = <2>;
+ #size-cells = <2>;
+
+ performance: performance-controller@c2c2034 {
+ compatible = "mediatek,mt8196-cpufreq-hw";
+ reg = <0 0xc2c2034 0 0x4>, <0 0xc220400 0 0x20>,
+ <0 0xc2c0f20 0 0x120>, <0 0xc2c1040 0 0x120>,
+ <0 0xc2c1160 0 0x120>;
+ #performance-domain-cells = <1>;
+ };
+ };
--
2.50.1Il 14/07/25 16:08, Nicolas Frattaroli ha scritto:
> The MediaTek MT8196 SoC has new cpufreq hardware, with added memory
> register ranges to control Dynamic-Voltage-Frequency-Scaling.
>
> The DVFS hardware is controlled through a set of registers referred to
> as "FDVFS"; one is a location from which a magic number is read to
> ensure DVFS should be used, the other is a region to set the desired
> target frequency that DVFS should aim towards for each performance
> domain.
>
> Instead of working around the old binding and its already established
> meanings for the reg items, add a new binding. The FDVFS register memory
> regions are at the beginning, which allows us to easily expand this
> binding for future SoCs which may have more than 3 performance domains.
>
> Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
> ---
> .../cpufreq/mediatek,mt8196-cpufreq-hw.yaml | 86 ++++++++++++++++++++++
> 1 file changed, 86 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/cpufreq/mediatek,mt8196-cpufreq-hw.yaml b/Documentation/devicetree/bindings/cpufreq/mediatek,mt8196-cpufreq-hw.yaml
> new file mode 100644
> index 0000000000000000000000000000000000000000..26bf21e05888646b4d1bdac95bfba0f36e037ffd
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/cpufreq/mediatek,mt8196-cpufreq-hw.yaml
> @@ -0,0 +1,86 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/cpufreq/mediatek,mt8196-cpufreq-hw.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: MediaTek CPUFreq for MT8196 and related SoCs
title: MediaTek Hybrid CPUFreq for MT8196/MT6991 series SoCs
> +
> +maintainers:
> + - Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
> +
> +description:
> + MT8196 uses CPUFreq management hardware that supports dynamic voltage
> + frequency scaling (dvfs), and can support several performance domains.
> +
> +properties:
> + compatible:
> + const: mediatek,mt8196-cpufreq-hw
> +
> + reg:
> + items:
> + - description: FDVFS magic number register region
As already said in the other commit, we might just be able to avoid adding the
magic number register region :-)
> + - description: FDVFS control register region
> + - description: OPP tables and control for performance domain 0
> + - description: OPP tables and control for performance domain 1
> + - description: OPP tables and control for performance domain 2
> +
> + "#performance-domain-cells":
> + description:
> + Number of cells in a performance domain specifier. Must be 1.
The description is redundant and doesn't add any real information, I think you
should drop it.
Bindings maintainers, please, opinions?
> + const: 1
> +
Everything else looks good to me.
Cheers,
Angelo
> +required:
> + - compatible
> + - reg
> + - "#performance-domain-cells"
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + cpus {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + cpu0: cpu@0 {
> + device_type = "cpu";
> + compatible = "arm,cortex-a720";
> + enable-method = "psci";
> + performance-domains = <&performance 0>;
> + reg = <0x000>;
> + };
> +
> + /* ... */
> +
> + cpu6: cpu@600 {
> + device_type = "cpu";
> + compatible = "arm,cortex-x4";
> + enable-method = "psci";
> + performance-domains = <&performance 1>;
> + reg = <0x600>;
> + };
> +
> + cpu7: cpu@700 {
> + device_type = "cpu";
> + compatible = "arm,cortex-x925";
> + enable-method = "psci";
> + performance-domains = <&performance 2>;
> + reg = <0x700>;
> + };
> + };
> +
> + /* ... */
> +
> + soc {
> + #address-cells = <2>;
> + #size-cells = <2>;
> +
> + performance: performance-controller@c2c2034 {
> + compatible = "mediatek,mt8196-cpufreq-hw";
> + reg = <0 0xc2c2034 0 0x4>, <0 0xc220400 0 0x20>,
> + <0 0xc2c0f20 0 0x120>, <0 0xc2c1040 0 0x120>,
> + <0 0xc2c1160 0 0x120>;
> + #performance-domain-cells = <1>;
> + };
> + };
>
On Mon, Jul 14, 2025 at 04:41:30PM +0200, AngeloGioacchino Del Regno wrote: > Il 14/07/25 16:08, Nicolas Frattaroli ha scritto: > > The MediaTek MT8196 SoC has new cpufreq hardware, with added memory > > register ranges to control Dynamic-Voltage-Frequency-Scaling. > > > > The DVFS hardware is controlled through a set of registers referred to > > as "FDVFS"; one is a location from which a magic number is read to > > ensure DVFS should be used, the other is a region to set the desired > > target frequency that DVFS should aim towards for each performance > > domain. > > > > Instead of working around the old binding and its already established > > meanings for the reg items, add a new binding. The FDVFS register memory > > regions are at the beginning, which allows us to easily expand this > > binding for future SoCs which may have more than 3 performance domains. > > > > Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com> > > --- > > .../cpufreq/mediatek,mt8196-cpufreq-hw.yaml | 86 ++++++++++++++++++++++ > > 1 file changed, 86 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/cpufreq/mediatek,mt8196-cpufreq-hw.yaml b/Documentation/devicetree/bindings/cpufreq/mediatek,mt8196-cpufreq-hw.yaml > > new file mode 100644 > > index 0000000000000000000000000000000000000000..26bf21e05888646b4d1bdac95bfba0f36e037ffd > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/cpufreq/mediatek,mt8196-cpufreq-hw.yaml > > @@ -0,0 +1,86 @@ > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > > +%YAML 1.2 > > +--- > > +$id: http://devicetree.org/schemas/cpufreq/mediatek,mt8196-cpufreq-hw.yaml# > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > + > > +title: MediaTek CPUFreq for MT8196 and related SoCs > > title: MediaTek Hybrid CPUFreq for MT8196/MT6991 series SoCs > > > + > > +maintainers: > > + - Nicolas Frattaroli <nicolas.frattaroli@collabora.com> > > + > > +description: > > + MT8196 uses CPUFreq management hardware that supports dynamic voltage > > + frequency scaling (dvfs), and can support several performance domains. > > + > > +properties: > > + compatible: > > + const: mediatek,mt8196-cpufreq-hw > > + > > + reg: > > + items: > > + - description: FDVFS magic number register region > > As already said in the other commit, we might just be able to avoid adding the > magic number register region :-) > > > + - description: FDVFS control register region > > + - description: OPP tables and control for performance domain 0 > > + - description: OPP tables and control for performance domain 1 > > + - description: OPP tables and control for performance domain 2 > > + > > + "#performance-domain-cells": > > + description: > > + Number of cells in a performance domain specifier. Must be 1. > > The description is redundant and doesn't add any real information, I think you > should drop it. > > Bindings maintainers, please, opinions? Drop. Rob
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