linux-kernel - Re: [PATCH v5 21/25] dt-bindings: media: imx258: Add binding for powerdown-gpio

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Date: Mon, 20 May 2024 14:20:28 +0100
From: Dave Stevenson <dave.stevenson@...pberrypi.com>
To: Ondřej Jirman <megi@....cz>, 
	Sakari Ailus <sakari.ailus@...ux.intel.com>, git@...gi311.com, 
	linux-media@...r.kernel.org, dave.stevenson@...pberrypi.com, 
	jacopo.mondi@...asonboard.com, mchehab@...nel.org, robh@...nel.org, 
	krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org, shawnguo@...nel.org, 
	s.hauer@...gutronix.de, kernel@...gutronix.de, festevam@...il.com, 
	devicetree@...r.kernel.org, imx@...ts.linux.dev, 
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	pavel@....cz, phone-devel@...r.kernel.org, 
	Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Subject: Re: [PATCH v5 21/25] dt-bindings: media: imx258: Add binding for powerdown-gpio

Hi Ondřej

On Mon, 20 May 2024 at 13:55, Ondřej Jirman <megi@....cz> wrote:
>
> On Fri, May 17, 2024 at 08:31:35AM GMT, Sakari Ailus wrote:
> > Hi Luis,
> >
> > On Wed, May 01, 2024 at 09:24:38AM -0600, git@...gi311.com wrote:
> > > From: Ondrej Jirman <megi@....cz>
> > >
> > > Add powerdown-gpio binding as it is required for some boards.
> >
> > I thought the conclusion was that this wasn't a property of the sensor? If
> > it needs to be controlled, then this should take place somewhere else than
> > in the sensor driver.
>
> It's a property of the sensor modules. It's just optional on
> some, eg. (pin 8):
>
>   https://assets-global.website-files.com/63b65bd4974577341e1fe194/654290d4d0fb173e87f754ed_IMX_258_FF_drawing.png
>
> Where else should it be so that the module is described properly in the
> DT and the powerdown signal can be used as part of powerup/down sequence
> of the sensor?

>From v3 [1] Luis reported testing dropping the powerdown-gpio on a PPP
and it working fine.

I linked to the IMX258 datasheet in the same thread[2], and that
datasheet does not include such a signal on the imx258 sensor itself.

If your module has a powerdown gpio, then you'll have to ask the
module vendor what it is actually connected to. Potentially it relates
to the VCM driver rather than the sensor.

  Dave

[1] https://www.spinics.net/lists/linux-media/msg252519.html
[2] https://www.spinics.net/lists/linux-media/msg252496.html

> regards,
>         o.
>
> > >
> > > Signed-off-by: Ondrej Jirman <megi@....cz>
> > > Signed-off-by: Luis Garcia <git@...gi311.com>
> > > Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
> > > Reviewed-by: Pavel Machek <pavel@....cz>
> > > ---
> > >  Documentation/devicetree/bindings/media/i2c/sony,imx258.yaml | 4 ++++
> > >  1 file changed, 4 insertions(+)
> > >
> > > diff --git a/Documentation/devicetree/bindings/media/i2c/sony,imx258.yaml b/Documentation/devicetree/bindings/media/i2c/sony,imx258.yaml
> > > index c978abc0cdb3..33338139e6e8 100644
> > > --- a/Documentation/devicetree/bindings/media/i2c/sony,imx258.yaml
> > > +++ b/Documentation/devicetree/bindings/media/i2c/sony,imx258.yaml
> > > @@ -36,6 +36,10 @@ properties:
> > >    reg:
> > >      maxItems: 1
> > >
> > > +  powerdown-gpios:
> > > +    description:
> > > +      Reference to the GPIO connected to the PWDN pin, if any.
> > > +
> > >    reset-gpios:
> > >      description: |-
> > >        Reference to the GPIO connected to the XCLR pin, if any.
> >
> > --
> > Regards,
> >
> > Sakari Ailus