On Thu, Sep 18, 2014 at 11:20:40AM +0530, Ajay kumar wrote:
> Hi Tomi,
> 
> On Wed, Sep 17, 2014 at 9:52 PM, Tomi Valkeinen <tomi.valkeinen@ti.com> wrote:
> > On 17/09/14 17:29, Ajay kumar wrote:
> >> Hi Tomi,
> >>
> >> Thanks for your comments.
> >>
> >> On Wed, Sep 17, 2014 at 5:22 PM, Tomi Valkeinen <tomi.valkeinen@ti.com> wrote:
> >>> On 27/08/14 17:39, Ajay Kumar wrote:
> >>>> Add documentation for DT properties supported by ps8622/ps8625
> >>>> eDP-LVDS converter.
> >>>>
> >>>> Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
> >>>> ---
> >>>>  .../devicetree/bindings/video/bridge/ps8622.txt    |   20 ++++++++++++++++++++
> >>>>  1 file changed, 20 insertions(+)
> >>>>  create mode 100644 Documentation/devicetree/bindings/video/bridge/ps8622.txt
> >>>>
> >>>> diff --git a/Documentation/devicetree/bindings/video/bridge/ps8622.txt b/Documentation/devicetree/bindings/video/bridge/ps8622.txt
> >>>> new file mode 100644
> >>>> index 0000000..0ec8172
> >>>> --- /dev/null
> >>>> +++ b/Documentation/devicetree/bindings/video/bridge/ps8622.txt
> >>>> @@ -0,0 +1,20 @@
> >>>> +ps8622-bridge bindings
> >>>> +
> >>>> +Required properties:
> >>>> +     - compatible: "parade,ps8622" or "parade,ps8625"
> >>>> +     - reg: first i2c address of the bridge
> >>>> +     - sleep-gpios: OF device-tree gpio specification for PD_ pin.
> >>>> +     - reset-gpios: OF device-tree gpio specification for RST_ pin.
> >>>> +
> >>>> +Optional properties:
> >>>> +     - lane-count: number of DP lanes to use
> >>>> +     - use-external-pwm: backlight will be controlled by an external PWM
> >>>
> >>> What does this mean? That the backlight support from ps8625 is not used?
> >>> If so, maybe "disable-pwm" or something?
> >> "use-external-pwm" or "disable-bridge-pwm" would be better.
> >
> > Well, the properties are about the bridge. "use-external-pwm" means that
> > the bridge uses an external PWM, which, if I understood correctly, is
> > not what the property is about.
> >
> > "disable-bridge-pwm" is ok, but the "bridge" there is extra. The
> > properties are about the bridge, so it's implicit.
> Ok. I will use "disable-pwm".

Why is this even necessary? According to the datasheet this device has
circuitry for backlight control. If so, I'd expect it to expose either a
backlight device or a PWM device. That way unless somebody is using the
backlight/PWM exposed by the bridge the bridge can simply disable PWM.

Thierry