On Tue, Apr 23, 2024 at 03:45:12PM +0700, Chanh Nguyen wrote: > > > On 16/04/2024 11:52, Chanh Nguyen wrote: > > > > > > On 14/04/2024 13:07, Krzysztof Kozlowski wrote: > > > On 14/04/2024 06:22, Chanh Nguyen wrote: > > > > The max31790 supports six pins, which are dedicated PWM outputs. > > > > Any of the > > > > six PWM outputs can also be configured to serve as tachometer inputs, > > > > allowing for up to 12 tachometer fans to be monitored. > > > > > > > > Add a new vendor-specific property, 'maxim,pwmout-pin-as-tach-input', > > > > to allow PWMOUT to become a TACH input. > > > > > > > > An array of six integers responds to six PWM channels for configuring > > > > the PWM to TACH mode. When set to 0, the associated PWMOUT produces > > > > a PWM waveform for control of fan speed. When set to 1, PWMOUT becomes > > > > a TACH input. > > > > > > > > Signed-off-by: Chanh Nguyen <chanh@xxxxxxxxxxxxxxxxxxxxxx> > > > > --- > > > > Changes in v2: > > > > - Update the vendor property name to > > > > "maxim,pwmout-pin-as-tach-input" [Rob] > > > > - Update commit > > > > message > > > > [Krzysztof] > > > > > > Please put binding before its user. > > > > > > > Hi Krzysztof, I'll drop this [Path 3/3] in the patch series v3. > > > > My patch series will only be two patches. They are "dt-bindings: hwmon: > > Add maxim max31790" and "hwmon: (max31790): Support config PWM output > > becomes TACH" > > > > > > --- > > > > .../devicetree/bindings/hwmon/maxim,max31790.yaml | 11 +++++++++++ > > > > 1 file changed, 11 insertions(+) > > > > > > > > diff --git > > > > a/Documentation/devicetree/bindings/hwmon/maxim,max31790.yaml > > > > b/Documentation/devicetree/bindings/hwmon/maxim,max31790.yaml > > > > index a561e5a3e9e4..2d4f50bc7c41 100644 > > > > --- a/Documentation/devicetree/bindings/hwmon/maxim,max31790.yaml > > > > +++ b/Documentation/devicetree/bindings/hwmon/maxim,max31790.yaml > > > > @@ -30,6 +30,16 @@ properties: > > > > resets: > > > > maxItems: 1 > > > > + maxim,pwmout-pin-as-tach-input: > > > > + description: | > > > > + An array of six integers responds to six PWM channels for > > > > + configuring the pwm to tach mode. > > > > + When set to 0, the associated PWMOUT produces a PWM waveform for > > > > + control of fan speed. When set to 1, PWMOUT becomes a TACH input > > > > + $ref: /schemas/types.yaml#/definitions/uint8-array > > > > + maxItems: 6 > > > > + minItems: 6 > > > > > > tach-ch solves your case. You define which inputs should be used for > > > tach. > > > > > > > Agree Krzysztof. I'll use the tach-ch property from the fan-common.yaml > > to solve my case. So I will not need to define a new vendor property as > > "maxim,pwmout-pin-as-tach-input". I'll drop this [Path 3/3] in the patch > > series v3. > > > > > > > Best regards, > > > Krzysztof > > > > > > Hi Krzysztof, > > I checked in the > Documentation/devicetree/bindings/hwmon/fan-common.yaml. I found the > tach-ch property, but it seems define the tach channel used for fan. > > tach-ch: > description: > The tach channel used for the fan. > $ref: /schemas/types.yaml#/definitions/uint8-array > > > In my purpose, I would like to configure the pwm output pins to become > tachometer input pins by setting bit[0] in the Configuration Register. > > > I think a vendor property is suitable for this purpose. It is only available > on specific MAX31790 fan controllers and not on other fan controller > devices. So I think we can't use the "tach-ch" in fan-common.yaml. Can you explain why you think that only MAX31790 fan controllers are capable of an arbitrary mapping of PWM outputs to TACH inputs?
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