Messages in this thread | | | Subject | Re: [PATCH v2 1/2] dt-bindings: hwmon: add binding documentation for adt7475 | From | Guenter Roeck <> | Date | Sun, 18 Nov 2018 14:56:56 -0800 |
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On 11/17/18 7:29 AM, Rob Herring wrote: > On Fri, Nov 09, 2018 at 11:56:06AM +1300, Chris Packham wrote: >> With the addition of the invert-pwm property the adt7475 needs its own >> binding documentation rather being captured under trivial-devices.txt. >> >> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> >> --- >> Changes in v2: >> - use pwm-polarity attiribute to indicate normal or inverted polarity. >> >> .../devicetree/bindings/hwmon/adt7475.txt | 24 +++++++++++++++++++ >> .../devicetree/bindings/trivial-devices.txt | 4 ---- >> 2 files changed, 24 insertions(+), 4 deletions(-) >> create mode 100644 Documentation/devicetree/bindings/hwmon/adt7475.txt >> >> diff --git a/Documentation/devicetree/bindings/hwmon/adt7475.txt b/Documentation/devicetree/bindings/hwmon/adt7475.txt >> new file mode 100644 >> index 000000000000..d9212b5e9036 >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/hwmon/adt7475.txt >> @@ -0,0 +1,24 @@ >> +*ADT7475 hwmon sensor. >> + >> +Required properties: >> +- compatible: One of >> + "adi,adt7473" >> + "adi,adt7475" >> + "adi,adt7476" >> + "adi,adt7490" >> + >> +- reg: I2C address >> + >> +optional properties: >> + >> +- pwm-polarity: This configures the polarity of the PWM. 0 >> + (PWM_POLARITY_NORMAL) uses logic high for 100% duty cycle. 1 >> + (PWM_POLARITY_INVERSED) uses logic low for 100% duty cycle. > > So we're using part of the PWM binding, but none of the rest of it? What > is the PWM connection here? > The chip has a built-in PWM controller to control fan speeds. PWM frequency as well as PWM polarity are configurable. I had suggested to use the terminology from Documentation/devicetree/bindings/pwm/pwm.txt. Other than terminology there is no connection to a standard pwm controller.
Another option/possibility would be to use a boolean, such as pwm-polarity-inverted. We are open to suggestions.
> It sounds like this is common for sensors, so this should be documented > somewhere common. > Sure, no problem. Any suggestion where ?
Thanks, Guenter
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