On Tue, Nov 05, 2024 at 02:52:15PM +0100, Marek Vasut wrote: > Delta AFC0612DB-F00 fan has to be set to at least 30% PWM duty cycle > to spin up from a dead stop, 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-dead-stop-start-percent" and > "fan-dead-stop-start-usec". The former describes the minimum percent > of fan RPM at which it will surely spin up from dead stop. This value > can be found in the fan datasheet and can be converted to PWM duty > cycle easily. The "fan-dead-stop-start-usec" describes the minimum > time in microseconds for which the fan has to be set to dead stop > start RPM for the fan to surely spin up. > > Signed-off-by: Marek Vasut <marex@xxxxxxx> > --- > Cc: Conor Dooley <conor+dt@xxxxxxxxxx> > Cc: Guenter Roeck <linux@xxxxxxxxxxxx> > Cc: Jean Delvare <jdelvare@xxxxxxxx> > Cc: Krzysztof Kozlowski <krzk+dt@xxxxxxxxxx> > Cc: Rob Herring <robh@xxxxxxxxxx> > Cc: devicetree@xxxxxxxxxxxxxxx > Cc: linux-hwmon@xxxxxxxxxxxxxxx > --- > Documentation/devicetree/bindings/hwmon/pwm-fan.yaml | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml > index 4e5abf7580cc6..f1042471b5176 100644 > --- a/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml > +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.yaml > @@ -31,6 +31,17 @@ properties: > it must be self resetting edge interrupts. > maxItems: 1 > > + fan-dead-stop-start-percent: > + description: > + Minimum fan RPM in percent to start from dead stop. > + minimum: 0 > + maximum: 100 > + > + fan-dead-stop-start-usec: s/usec/us/ and you get the type from property-units.yaml automagically. > + description: > + Time to wait in microseconds after start from dead stop. > + $ref: /schemas/types.yaml#/definitions/uint32 > + > pulses-per-revolution: > description: > Define the number of pulses per fan revolution for each tachometer > -- > 2.45.2 >
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