[v3,10/19] dt-bindings: clock: rockchip: Document RV1126 CRU

Commit Message

Jagan Teki Aug. 18, 2022, 12:41 p.m. UTC

Document dt-bindings for Rockchip RV1126 clock controller.

Cc: [e-mail]
Cc: Michael Turquette <[e-mail]>
Cc: Stephen Boyd <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Jagan Teki <[e-mail]>
---
Changes for v3:
- none
Changes for v2:
- fixed title
- remove '|' in description
- add one example

 .../bindings/clock/rockchip,rv1126-cru.yaml   | 62 +++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/clock/rockchip,rv1126-cru.yaml

Comments

Stephen Boyd Aug. 18, 2022, 9:29 p.m. UTC | #1

Quoting Jagan Teki (2022-08-18 05:41:23)
> +
> +  clocks:
> +    maxItems: 1
> +
> +  clock-names:
> +    const: xin24m
> +
> +  rockchip,grf:
> +    $ref: /schemas/types.yaml#/definitions/phandle
> +    description:
> +      Phandle to the syscon managing the "general register files" (GRF),
> +      if missing pll rates are not changeable, due to the missing pll
> +      lock status.
> +
> +required:
> +  - compatible
> +  - reg
> +  - "#clock-cells"
> +  - "#reset-cells"

Why aren't clocks required?

> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    cru: clock-controller@ff490000 {
> +      compatible = "rockchip,rv1126-cru";
> +      reg = <0xff490000 0x1000>;
> +      rockchip,grf = <&grf>;
> +      #clock-cells = <1>;
> +      #reset-cells = <1>;

Can you add 'clocks' property to the binding?

Jagan Teki Aug. 19, 2022, 9:20 p.m. UTC | #2

On Fri, 19 Aug 2022 at 02:59, Stephen Boyd <[e-mail]> wrote:
>
> Quoting Jagan Teki (2022-08-18 05:41:23)
> > +
> > +  clocks:
> > +    maxItems: 1
> > +
> > +  clock-names:
> > +    const: xin24m
> > +
> > +  rockchip,grf:
> > +    $ref: /schemas/types.yaml#/definitions/phandle
> > +    description:
> > +      Phandle to the syscon managing the "general register files" (GRF),
> > +      if missing pll rates are not changeable, due to the missing pll
> > +      lock status.
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - "#clock-cells"
> > +  - "#reset-cells"
>
> Why aren't clocks required?

I don't see any clocks being used by cru in rv1126 [1] so that is the
reason I didn't add any. Let me know if it is something that is
mandatory to add even if it's unused.
[1] https://github.com/rockchip-linux/kernel/blob/develop-4.19/arch/arm/boot/dts/rv1126.dtsi#L1074

Thanks,
Jagan.

Heiko Stübner Aug. 23, 2022, 5:59 p.m. UTC | #3

Am Freitag, 19. August 2022, 23:20:03 CEST schrieb Jagan Teki:
> On Fri, 19 Aug 2022 at 02:59, Stephen Boyd <[e-mail]> wrote:
> >
> > Quoting Jagan Teki (2022-08-18 05:41:23)
> > > +
> > > +  clocks:
> > > +    maxItems: 1
> > > +
> > > +  clock-names:
> > > +    const: xin24m
> > > +
> > > +  rockchip,grf:
> > > +    $ref: /schemas/types.yaml#/definitions/phandle
> > > +    description:
> > > +      Phandle to the syscon managing the "general register files" (GRF),
> > > +      if missing pll rates are not changeable, due to the missing pll
> > > +      lock status.
> > > +
> > > +required:
> > > +  - compatible
> > > +  - reg
> > > +  - "#clock-cells"
> > > +  - "#reset-cells"
> >
> > Why aren't clocks required?
> 
> I don't see any clocks being used by cru in rv1126 [1] so that is the
> reason I didn't add any. Let me know if it is something that is
> mandatory to add even if it's unused.
> [1] https://github.com/rockchip-linux/kernel/blob/develop-4.19/arch/arm/boot/dts/rv1126.dtsi#L1074

Our clock drivers normally just expect that xin24m to be present
but that xin24m _is_ a clock dependency for the cru and for a lot
of Rockchip SoCs Johan did update both the binding and the dtsi-s
to make that explicit when converting the binding over to yaml

See for example the rk3399.

Heiko

Patch

diff --git a/Documentation/devicetree/bindings/clock/rockchip,rv1126-cru.yaml b/Documentation/devicetree/bindings/clock/rockchip,rv1126-cru.yaml
new file mode 100644
index 000000000000..0998f8b922bd
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/rockchip,rv1126-cru.yaml
@@ -0,0 +1,62 @@ 
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/rockchip,rv1126-cru.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Rockchip RV1126 Clock and Reset Unit
+
+maintainers:
+  - Jagan Teki <[e-mail]>
+  - Finley Xiao <[e-mail]>
+  - Heiko Stuebner <[e-mail]>
+
+description:
+  The RV1126 clock controller generates the clock and also implements a
+  reset controller for SoC peripherals.
+
+properties:
+  compatible:
+    enum:
+      - rockchip,rv1126-cru
+      - rockchip,rv1126-pmucru
+
+  reg:
+    maxItems: 1
+
+  "#clock-cells":
+    const: 1
+
+  "#reset-cells":
+    const: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    const: xin24m
+
+  rockchip,grf:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Phandle to the syscon managing the "general register files" (GRF),
+      if missing pll rates are not changeable, due to the missing pll
+      lock status.
+
+required:
+  - compatible
+  - reg
+  - "#clock-cells"
+  - "#reset-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    cru: clock-controller@ff490000 {
+      compatible = "rockchip,rv1126-cru";
+      reg = <0xff490000 0x1000>;
+      rockchip,grf = <&grf>;
+      #clock-cells = <1>;
+      #reset-cells = <1>;
+    };