RE: [PATCH v2] pwm_backlight: Add device tree support for LowThreshold Brightness

[Philip, Avinash]

Hi Stephen,

On Fri, Sep 21, 2012 at 10:46:45, Stephen Warren wrote:
> On 09/20/2012 10:51 PM, Philip, Avinash wrote:
> > Some backlights perform poorly when driven by a PWM with a short
> > duty-cycle. For such devices, the low threshold can be used to specify a
> > lower bound for the duty-cycle and should be chosen to exclude the
> > problematic range.
> > 
> > This patch adds support for an optional low-threshold-brightness
> > property.
> 
> > diff --git a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
> 
> >  Optional properties:
> >    - pwm-names: a list of names for the PWM devices specified in the
> >                 "pwms" property (see PWM binding[0])
> > +  - low-threshold-brightness: brightness threshold low level. Low threshold
> > +    brightness set to value so that backlight present on low end of
> > +    brightness.
> 
> For my education, why not just specify values above this value in the
> brightness-levels array; how do those two interact?

Please find details from 
https://lkml.org/lkml/2012/7/18/284

Thanks
Avinash

> It seems like any
> description of that is missing from the PWM documentation, and would be
> good to have in the DT binding too.
> 
> 

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