Re: [PATCH 3/4] [media] ad5820: DT new optional field enable-gpios

Pavel Machek
2018-09-21T02:13:57Z

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On Thu 2018-09-20 22:25:54, Ricardo Ribalda Delgado wrote:
> Hi
> On Thu, Sep 20, 2018 at 10:23 PM Laurent Pinchart
> <laurent.pinchart@ideasonboard.com> wrote:
> >
> > On Thursday, 20 September 2018 23:21:28 EEST Laurent Pinchart wrote:
> > > Hi Ricardo,
> > >
> > > Thank you for the patch.
> > >
> > > On Thursday, 20 September 2018 19:19:11 EEST Ricardo Ribalda Delgado wrote:
> > > > Document new enable-gpio field. It can be used to disable the part
> > > > without turning down its regulator.
> > > >
> > > > Cc: devicetree@vger.kernel.org
> > > > Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
> > > > ---
> > > >
> > > > Documentation/devicetree/bindings/media/i2c/ad5820.txt | 6 ++++++
> > > > 1 file changed, 6 insertions(+)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/media/i2c/ad5820.txt
> > > > b/Documentation/devicetree/bindings/media/i2c/ad5820.txt index
> > > > 5940ca11c021..07d577bb37f7 100644
> > > > --- a/Documentation/devicetree/bindings/media/i2c/ad5820.txt
> > > > +++ b/Documentation/devicetree/bindings/media/i2c/ad5820.txt
> > > >
> > > > @@ -8,6 +8,11 @@ Required Properties:
> > > > - VANA-supply: supply of voltage for VANA pin
> > > >
> > > > +Optional properties:
> > > > +
> > > > + - enable-gpios : GPIO spec for the XSHUTDOWN pin.
> > >
> > > xshutdown is active-low, so enable is active-high. Should this be documented
> > > explicitly, to avoid polarity errors ? Maybe something along the lines of
> > >
> > > - enable-gpios: GPIO spec for the XSHUTDOWN pin. Note that the polarity of
> > > the enable GPIO is the opposite of the XSHUTDOWN pin (asserting the enable
> > > GPIO deasserts the XSHUTDOWN signal and vice versa).
>
> Agreed
>
> >
> > Or alternatively you could name the property xshutdown-gpios, as explained in
> > my (incorrect) review of 2/4.
>
> I have double negatives :). If there is no other option I will rename
> it xshutdown, but I want to give it a try to enable.

I think enable is fine.

Pavel

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