[PATCH v2 2/4] dt-bindings: clock: st,stm32-rcc: support spread spectrum clocking
From: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Date: 2025-01-09 21:19:21
Also in:
linux-clk, linux-devicetree, lkml
Subsystem:
common clk framework, open firmware and flattened device tree bindings, the rest · Maintainers:
Michael Turquette, Stephen Boyd, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds
The addition of DT bindings for enabling and tuning spread spectrum
clocking generation is available only for the main PLL of stm32f{4,7}
platforms.
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
---
Changes in v2:
- Update the commit message
- Change st,ssc-modmethod type from non-unique-string-array to string
.../bindings/clock/st,stm32-rcc.yaml | 36 +++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/Documentation/devicetree/bindings/clock/st,stm32-rcc.yaml b/Documentation/devicetree/bindings/clock/st,stm32-rcc.yaml
index 779e547700be..628bbbcf2875 100644
--- a/Documentation/devicetree/bindings/clock/st,stm32-rcc.yaml
+++ b/Documentation/devicetree/bindings/clock/st,stm32-rcc.yaml@@ -56,6 +56,26 @@ properties: Phandle to system configuration controller. It can be used to control the power domain circuitry. + st,ssc-modfreq-hz: + description: + The modulation frequency for main PLL (in Hz) + + st,ssc-moddepth-permyriad: + $ref: /schemas/types.yaml#/definitions/uint32 + description: + The modulation rate for main PLL (in permyriad, i.e. 0.01%) + minimum: 25 + maximum: 200 + + st,ssc-modmethod: + $ref: /schemas/types.yaml#/definitions/string + description: + The modulation techniques for main PLL. + items: + enum: + - center-spread + - down-spread + required: - compatible - reg
@@ -81,6 +101,10 @@ allOf: - description: high speed external (HSE) clock input - description: low speed external (LSE) clock input - description: Inter-IC sound (I2S) clock input + st,ssc-modfreq-hz: false + st,ssc-moddepth-permyriad: false + st,ssc-modmethod: false + else: properties: '#clock-cells':
@@ -98,6 +122,18 @@ additionalProperties: false examples: # Reset and Clock Control Module node: + - | + clock-controller@40023800 { + compatible = "st,stm32f42xx-rcc", "st,stm32-rcc"; + reg = <0x40023800 0x400>; + #clock-cells = <2>; + #reset-cells = <1>; + clocks = <&clk_hse>, <&clk_i2s_ckin>; + st,syscfg = <&pwrcfg>; + st,ssc-modfreq-hz = <10000>; + st,ssc-moddepth-permyriad = <200>; + st,ssc-modmethod = "center-spread"; + }; - | clock-controller@58024400 { compatible = "st,stm32h743-rcc", "st,stm32-rcc";
--
2.43.0