linux-kernel - [PATCH v2 1/2] dt-bindings: hwmon: Document adt7475 PWM initial duty cycle

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Date: Thu,  9 May 2024 09:55:03 +1200
From: Chris Packham <chris.packham@...iedtelesis.co.nz>
To: jdelvare@...e.com,
	linux@...ck-us.net,
	robh@...nel.org,
	krzk+dt@...nel.org,
	conor+dt@...nel.org
Cc: linux-hwmon@...r.kernel.org,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Chris Packham <chris.packham@...iedtelesis.co.nz>
Subject: [PATCH v2 1/2] dt-bindings: hwmon: Document adt7475 PWM initial duty cycle

Add documentation for the pwm-initial-duty-cycle and
pwm-initial-frequency properties. These allow the starting state of the
PWM outputs to be set to cater for hardware designs where undesirable
amounts of noise is created by the default hardware state.

Signed-off-by: Chris Packham <chris.packham@...iedtelesis.co.nz>
---

Notes:
    Changes in v2:
    - Document 0 as a valid value (leaves hardware as-is)

 .../devicetree/bindings/hwmon/adt7475.yaml    | 27 ++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/hwmon/adt7475.yaml b/Documentation/devicetree/bindings/hwmon/adt7475.yaml
index 051c976ab711..97deda082b4a 100644
--- a/Documentation/devicetree/bindings/hwmon/adt7475.yaml
+++ b/Documentation/devicetree/bindings/hwmon/adt7475.yaml
@@ -51,6 +51,30 @@ properties:
       enum: [0, 1]
       default: 1
 
+  adi,pwm-initial-duty-cycle:
+    description: |
+      Configures the initial duty cycle for the PWM outputs. The hardware
+      default is 100% but this may cause unwanted fan noise at startup. Set
+      this to a value from 0 (0% duty cycle) to 255 (100% duty cycle).
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    minItems: 3
+    maxItems: 3
+    items:
+      minimum: 0
+      maximum: 255
+      default: 255
+
+  adi,pwm-initial-frequency:
+    description: |
+      Configures the initial frequency for the PWM outputs. A value of 0
+      will leave the PWM frequency as-is.
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    minItems: 3
+    maxItems: 3
+    items:
+      enum: [0, 11, 14, 22, 29, 35, 44, 58, 88, 22500]
+      default: 35
+
 patternProperties:
   "^adi,bypass-attenuator-in[0-4]$":
     description: |
@@ -80,7 +104,6 @@ patternProperties:
       - therm#
       - smbalert#
       - gpio
-
 required:
   - compatible
   - reg
@@ -99,6 +122,8 @@ examples:
         adi,bypass-attenuator-in0 = <1>;
         adi,bypass-attenuator-in1 = <0>;
         adi,pwm-active-state = <1 0 1>;
+        adi,pwm-initial-duty-cycle = <128 0 128>;
+        adi,pwm-initial-frequency = <22500 0 22500>;
         adi,pin10-function = "smbalert#";
         adi,pin14-function = "tach4";
       };
-- 
2.43.2