Re: [PATCH v3 18/25] dt-bindings: media: imx258: Add alternate compatible strings

From: Conor Dooley <conor@kernel.org>
To: Dave Stevenson <dave.stevenson@raspberrypi.com>
Cc: git@luigi311.com, linux-media@vger.kernel.org,
	jacopo.mondi@ideasonboard.com, mchehab@kernel.org,
	robh@kernel.org, krzysztof.kozlowski+dt@linaro.org,
	conor+dt@kernel.org, shawnguo@kernel.org, s.hauer@pengutronix.de,
	kernel@pengutronix.de, festevam@gmail.com,
	sakari.ailus@linux.intel.com, devicetree@vger.kernel.org,
	imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, pavel@ucw.cz,
	phone-devel@vger.kernel.org
Subject: Re: [PATCH v3 18/25] dt-bindings: media: imx258: Add alternate compatible strings
Date: Fri, 5 Apr 2024 17:24:55 +0100	[thread overview]
Message-ID: <20240405-citizen-rendering-a8345fc96fb0@spud> (raw)
In-Reply-To: <20240405-affair-cruelly-a7e9d23b597c@spud>

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On Fri, Apr 05, 2024 at 05:24:11PM +0100, Conor Dooley wrote:
> On Fri, Apr 05, 2024 at 11:25:50AM +0100, Dave Stevenson wrote:
> > Hi Conor
> > 
> > On Wed, 3 Apr 2024 at 17:14, Conor Dooley <conor@kernel.org> wrote:
> > >
> > > On Wed, Apr 03, 2024 at 09:03:47AM -0600, git@luigi311.com wrote:
> > > > From: Dave Stevenson <dave.stevenson@raspberrypi.com>
> > > >
> > > > There are a number of variants of the imx258 modules that can not
> > > > be differentiated at runtime, so add compatible strings for the
> > > > PDAF variant.
> > > >
> > > > Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
> > > > Signed-off-by: Luis Garcia <git@luigi311.com>
> > > > ---
> > > >  .../devicetree/bindings/media/i2c/sony,imx258.yaml       | 9 +++++++--
> > > >  1 file changed, 7 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/media/i2c/sony,imx258.yaml b/Documentation/devicetree/bindings/media/i2c/sony,imx258.yaml
> > > > index bee61a443b23..c978abc0cdb3 100644
> > > > --- a/Documentation/devicetree/bindings/media/i2c/sony,imx258.yaml
> > > > +++ b/Documentation/devicetree/bindings/media/i2c/sony,imx258.yaml
> > > > @@ -13,11 +13,16 @@ description: |-
> > > >    IMX258 is a diagonal 5.867mm (Type 1/3.06) 13 Mega-pixel CMOS active pixel
> > > >    type stacked image sensor with a square pixel array of size 4208 x 3120. It
> > > >    is programmable through I2C interface.  Image data is sent through MIPI
> > > > -  CSI-2.
> > > > +  CSI-2. The sensor exists in two different models, a standard variant
> > > > +  (IMX258) and a variant with phase detection autofocus (IMX258-PDAF).
> > > > +  The camera module does not expose the model through registers, so the
> > > > +  exact model needs to be specified.
> > > >
> > > >  properties:
> > > >    compatible:
> > > > -    const: sony,imx258
> > > > +    enum:
> > > > +      - sony,imx258
> > > > +      - sony,imx258-pdaf
> > >
> > > Does the pdaf variant support all of the features/is it register
> > > compatible with the regular variant? If it is, the regular variant
> > > should be a fallback compatible.
> > 
> > It has the same register set, but certain registers have to be
> > programmed differently so that the image is corrected for the
> > partially shielded pixels used for phase detect auto focus (PDAF).
> > Either compatible will "work" on either variant of the module, but
> > you'll get weird image artifacts when using the wrong one.
> 
> To paraphase, a fallback compatible is not suitable.

Whoops, I forgot this:
Acked-by: Conor Dooley <conor.dooley@microchip.com>

Cheers,
Conor.

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