[PATCH v2 1/4] dt-bindings: cpufreq: Add mediatek,mt8196-cpufreq-hw binding

[Nicolas Frattaroli]

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 at 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 at 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 at 0 {
+                device_type = "cpu";
+                compatible = "arm,cortex-a720";
+                enable-method = "psci";
+                performance-domains = <&performance 0>;
+                reg = <0x000>;
+            };
+
+            /* ... */
+
+            cpu6: cpu at 600 {
+                device_type = "cpu";
+                compatible = "arm,cortex-x4";
+                enable-method = "psci";
+                performance-domains = <&performance 1>;
+                reg = <0x600>;
+            };
+
+            cpu7: cpu at 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 at 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>;
+        };
+    };

-- 
2.50.1