From 80bc64201e78f18248343c8986a55fe342a19e17 Mon Sep 17 00:00:00 2001 From: Marek Vasut Date: Wed, 6 Nov 2024 19:59:04 +0100 Subject: [PATCH] dt-bindings: hwmon: pwm-fan: Document start from stopped state properties Delta AFC0612DB-F00 fan has to be set to at least 30% PWM duty cycle to spin up from a stopped state, and can be afterward throttled down to lower PWM duty cycle. Introduce support for operating such fans which need to start at higher PWM duty cycle first and can slow down next. Document two new DT properties, "fan-stop-to-start-percent" and "fan-stop-to-start-usec". The former describes the minimum percent of fan RPM at which it will surely spin up from stopped state. This value can be found in the fan datasheet and can be converted to PWM duty cycle easily. The "fan-stop-to-start-usec" describes the minimum time in microseconds for which the fan has to be set to stopped state start RPM for the fan to surely spin up. Signed-off-by: Marek Vasut Acked-by: Conor Dooley Message-ID: <20241106185925.223736-1-marex@denx.de> Signed-off-by: Guenter Roeck --- Documentation/devicetree/bindings/hwmon/pwm-fan.yaml | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml index 4e5abf7580cc6..8b4ed5ee962fb 100644 --- a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml @@ -31,6 +31,16 @@ properties: it must be self resetting edge interrupts. maxItems: 1 + fan-stop-to-start-percent: + description: + Minimum fan RPM in percent to start when stopped. + minimum: 0 + maximum: 100 + + fan-stop-to-start-us: + description: + Time to wait in microseconds after start when stopped. + pulses-per-revolution: description: Define the number of pulses per fan revolution for each tachometer