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

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

[Ricardo Ribalda Delgado]

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. If specified, it will be
+     asserted when VANA-supply is enabled.
+
 Example:
 
        ad5820: coil@c {
@@ -15,5 +20,6 @@ Example:
                reg = <0x0c>;
 
                VANA-supply = <&vaux4>;
+               enable-gpios = <&msmgpio 26 GPIO_ACTIVE_HIGH>;
        };
 
-- 
2.18.0

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

[Laurent Pinchart]

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).

> If specified, it will be
> +     asserted when VANA-supply is enabled.

That documents a driver behaviour, is it needed in DT ?


>  Example:
> 
>         ad5820: coil@c {
> @@ -15,5 +20,6 @@ Example:
>                 reg = <0x0c>;
> 
>                 VANA-supply = <&vaux4>;
> +               enable-gpios = <&msmgpio 26 GPIO_ACTIVE_HIGH>;
>         };

-- 
Regards,

Laurent Pinchart

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

[Laurent Pinchart]

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).

Or alternatively you could name the property xshutdown-gpios, as explained in 
my (incorrect) review of 2/4.

> > If specified, it will be
> > +     asserted when VANA-supply is enabled.
> 
> That documents a driver behaviour, is it needed in DT ?
> 
> >  Example:
> >         ad5820: coil@c {
> > 
> > @@ -15,5 +20,6 @@ Example:
> >                 reg = <0x0c>;
> >                 VANA-supply = <&vaux4>;
> > 
> > +               enable-gpios = <&msmgpio 26 GPIO_ACTIVE_HIGH>;
> >         };


-- 
Regards,

Laurent Pinchart

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

[Ricardo Ribalda Delgado]

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.

>
> > > If specified, it will be
> > > +     asserted when VANA-supply is enabled.
> >
> > That documents a driver behaviour, is it needed in DT ?
> >
> > >  Example:
> > >         ad5820: coil@c {
> > >
> > > @@ -15,5 +20,6 @@ Example:
> > >                 reg = <0x0c>;
> > >                 VANA-supply = <&vaux4>;
> > >
> > > +               enable-gpios = <&msmgpio 26 GPIO_ACTIVE_HIGH>;
> > >         };
>
>
> --
> Regards,
>
> Laurent Pinchart
>
>
>


-- 
Ricardo Ribalda

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

[Pavel Machek]

[-- Attachment #1: Type: text/plain, Size: 2210 bytes --]

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

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]