Re: [PATCH v2 2/4] dt-bindings: arm: mediatek: Add new bindings of MediaTek frequency hopping

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Il 14/09/22 14:45, Johnson Wang ha scritto:
Add the new binding documentation for MediaTek frequency hopping
and spread spectrum clocking control.

Co-developed-by: Edward-JW Yang <edward-jw.yang@xxxxxxxxxxxx>
Signed-off-by: Edward-JW Yang <edward-jw.yang@xxxxxxxxxxxx>
Signed-off-by: Johnson Wang <johnson.wang@xxxxxxxxxxxx>
---
  .../bindings/arm/mediatek/mediatek,fhctl.yaml | 47 +++++++++++++++++++
  1 file changed, 47 insertions(+)
  create mode 100644 Documentation/devicetree/bindings/arm/mediatek/mediatek,fhctl.yaml

diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,fhctl.yaml b/Documentation/devicetree/bindings/arm/mediatek/mediatek,fhctl.yaml
new file mode 100644
index 000000000000..7b0fd0889bb6
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,fhctl.yaml
@@ -0,0 +1,47 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arm/mediatek/mediatek,fhctl.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek frequency hopping and spread spectrum clocking control
+
+maintainers:
+  - Edward-JW Yang <edward-jw.yang@xxxxxxxxxxxx>
+
+description: |
+  Frequency hopping control (FHCTL) is a piece of hardware that control
+  some PLLs to adopt "hopping" mechanism to adjust their frequency.
+  Spread spectrum clocking (SSC) is another function provided by this hardware.
+
+properties:
+  compatible:
+    const: mediatek,mt8186-fhctl
+
+  reg:
+    maxItems: 1

There are still a few issues in this binding that I can immediately see...

+
+  clocks:
MT8195 has 23 PLLs, MT8186 has 14, but perhaps in the future we may see
something more than that on some newer SoC, so...

  clocks:
    maxItems: 30

+    description: Phandles of the PLL with FHCTL hardware capability.
+
+  mediatek,hopping-ssc-percents:
+    description: The percentage of spread spectrum clocking for one PLL.
+    $ref: /schemas/types.yaml#/definitions/uint32

This is an array, so...
$ref: /schemas/types.yaml#/definitions/uint32-array

...also, maxItems?

and you should also specify:

default: 0   <- because, by default, SSC is disabled
minimum: 0   <- because this is the minimum accepted value


Regards,
Angelo

+    maximum: 8
+
+required:
+  - compatible
+  - reg
+  - clocks
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/mt8186-clk.h>
+    fhctl: fhctl@1000ce00 {
+        compatible = "mediatek,mt8186-fhctl";
+        reg = <0x1000c000 0xe00>;
+        clocks = <&apmixedsys CLK_APMIXED_MSDCPLL>;
+        mediatek,hopping-ssc-percents = <3>;
+    };




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