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

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Message-ID: <20241106090549.3684963-2-dario.binacchi@amarulasolutions.com>
Date: Wed,  6 Nov 2024 09:57:57 +0100
From: Dario Binacchi <dario.binacchi@...rulasolutions.com>
To: linux-kernel@...r.kernel.org
Cc: linux-amarula@...rulasolutions.com,
	Dario Binacchi <dario.binacchi@...rulasolutions.com>,
	Abel Vesa <abelvesa@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Fabio Estevam <festevam@...il.com>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Michael Turquette <mturquette@...libre.com>,
	Peng Fan <peng.fan@....com>,
	Pengutronix Kernel Team <kernel@...gutronix.de>,
	Rob Herring <robh@...nel.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Shawn Guo <shawnguo@...nel.org>,
	Stephen Boyd <sboyd@...nel.org>,
	devicetree@...r.kernel.org,
	imx@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org,
	linux-clk@...r.kernel.org
Subject: [PATCH v3 1/8] dt-bindings: clock: imx8m-clock: support spread spectrum clocking

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

Signed-off-by: Dario Binacchi <dario.binacchi@...rulasolutions.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@...80000 {
         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