[PATCH v3 1/8] dt-bindings: clock: imx8m-clock: support spread spectrum clocking

Dario Binacchi
2024-11-06T09:30:48Z

The patch adds the DT bindings for enabling and tuning spread spectrum
clocking generation.

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>

---

Changes in v3:
- Added in v3
- The dt-bindings have been moved from fsl,imx8m-anatop.yaml to
imx8m-clock.yaml. The anatop device (fsl,imx8m-anatop.yaml) is
indeed more or less a syscon, so it represents a memory area
accessible by ccm (imx8m-clock.yaml) to setup the PLLs.

.../bindings/clock/imx8m-clock.yaml | 46 +++++++++++++++++++
1 file changed, 46 insertions(+)

diff --git a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml
index c643d4a81478..7920393e518e 100644
--- a/Documentation/devicetree/bindings/clock/imx8m-clock.yaml
+++ b/Documentation/devicetree/bindings/clock/imx8m-clock.yaml
@@ -43,6 +43,40 @@ properties:
ID in its "clocks" phandle cell. See include/dt-bindings/clock/imx8m-clock.h
for the full list of i.MX8M clock IDs.

+ fsl,ssc-clocks:
+ $ref: /schemas/types.yaml#/definitions/phandle-array
+ description:
+ Phandles of the PLL with spread spectrum generation hardware capability.
+ minItems: 1
+ maxItems: 4
+
+ fsl,ssc-modfreq-hz:
+ description:
+ The values of modulation frequency (Hz unit) of spread spectrum
+ clocking for each PLL.
+ minItems: 1
+ maxItems: 4
+
+ fsl,ssc-modrate-percent:
+ description:
+ The percentage values of modulation rate of spread spectrum
+ clocking for each PLL.
+ minItems: 1
+ maxItems: 4
+
+ fsl,ssc-modmethod:
+ $ref: /schemas/types.yaml#/definitions/string-array
+ description:
+ The modulation techniques of spread spectrum clocking for
+ each PLL.
+ minItems: 1
+ maxItems: 4
+ items:
+ enum:
+ - down-spread
+ - up-spread
+ - center-spread
+
required:
- compatible
- reg
@@ -76,6 +110,11 @@ allOf:
- const: clk_ext2
- const: clk_ext3
- const: clk_ext4
+ fsl,ssc-clocks: false
+ fsl,ssc-modfreq-hz: false
+ fsl,ssc-modrate-percent: false
+ fsl,ssc-modmethod: false
+
else:
properties:
clocks:
@@ -101,6 +140,8 @@ additionalProperties: false
examples:
# Clock Control Module node:
- |
+ #include <dt-bindings/clock/imx8mm-clock.h>
+
clock-controller@30380000 {
compatible = "fsl,imx8mm-ccm";
reg = <0x30380000 0x10000>;
@@ -109,6 +150,11 @@ examples:
<&clk_ext3>, <&clk_ext4>;
clock-names = "osc_32k", "osc_24m", "clk_ext1", "clk_ext2",
"clk_ext3", "clk_ext4";
+ fsl,ssc-clocks = <&clk IMX8MM_AUDIO_PLL1>,
+ <&clk IMX8MM_VIDEO_PLL1>;
+ fsl,ssc-modfreq-hz = <6818>, <2419>;
+ fsl,ssc-modrate-percent = <3>, <7>;
+ fsl,ssc-modmethod = "down-spread", "center-spread";
};

- |
--
2.43.0