From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>, Sakari Ailus <sakari.ailus@iki.fi>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
Hans Verkuil <hans.verkuil@cisco.com>,
devicetree@vger.kernel.org
Subject: Re: [PATCH 3/4] [media] ad5820: DT new optional field enable-gpios
Date: Thu, 20 Sep 2018 23:23:43 +0300 [thread overview]
Message-ID: <2983018.WjSXnZMEY4@avalon> (raw)
In-Reply-To: <1939782.bRt5jKDIiS@avalon>
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
next prev parent reply other threads:[~2018-09-21 2:08 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-20 16:19 [PATCH 1/4] [media] ad5820: Define entity function Ricardo Ribalda Delgado
2018-09-20 16:19 ` [PATCH 2/4] [media] ad5820: Add support for enable pin Ricardo Ribalda Delgado
2018-09-20 18:40 ` Sakari Ailus
2018-09-20 18:47 ` Ricardo Ribalda Delgado
2018-09-20 18:45 ` [PATCH v2 " Ricardo Ribalda Delgado
2018-09-20 18:54 ` Pavel Machek
2018-09-20 19:06 ` Ricardo Ribalda Delgado
2018-09-20 19:08 ` Pavel Machek
2018-09-20 19:12 ` Ricardo Ribalda Delgado
2018-09-20 20:04 ` Laurent Pinchart
2018-09-20 20:04 ` Laurent Pinchart
2018-09-20 20:14 ` Pavel Machek
2018-09-20 20:21 ` Pavel Machek
2018-09-20 20:32 ` Ricardo Ribalda Delgado
2018-09-20 16:19 ` [PATCH 3/4] [media] ad5820: DT new optional field enable-gpios Ricardo Ribalda Delgado
2018-09-20 20:21 ` Laurent Pinchart
2018-09-20 20:23 ` Laurent Pinchart [this message]
2018-09-20 20:25 ` Ricardo Ribalda Delgado
2018-09-20 20:28 ` Pavel Machek
2018-09-20 16:19 ` [PATCH 4/4] [media] ad5820: Add support for of-autoload Ricardo Ribalda Delgado
2018-09-20 18:31 ` [PATCH v2 " Ricardo Ribalda Delgado
2018-09-20 18:55 ` Pavel Machek
2018-09-20 20:10 ` Laurent Pinchart
2018-09-20 20:18 ` Sakari Ailus
2018-09-20 20:22 ` [PATCH 1/4] [media] ad5820: Define entity function Laurent Pinchart
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