Re: [PATCH v1 2/8] MT9M114: Add pad-slew-rate DT-binding

Conor Dooley
2025-02-28T19:11:36Z

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On Thu, Feb 27, 2025 at 10:14:02AM +0000, Sakari Ailus wrote:
> Hi Mathis,
>
> On Wed, Feb 26, 2025 at 04:39:23PM +0100, Mathis Foerst wrote:
> > The MT9M114 supports the different slew rates (0 to 7) on the output pads.
>
> "the output pads" probably means pixel data interface (DVP or CSI-2)
> signals in this cases? I suppose this is about clock modulation?
> It'd be good to say that.
>
> > At the moment, this is hardcoded to 7 (the fastest rate).
> > The user might want to change this values due to EMC requirements.
> >
> > Add the 'pad-slew-rate' property to the MT9M114 DT-bindings for selecting
> > the desired slew rate.
> >
> > Signed-off-by: Mathis Foerst <mathis.foerst@mt.com>
> > ---
> > .../devicetree/bindings/media/i2c/onnn,mt9m114.yaml | 6 ++++++
> > 1 file changed, 6 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/media/i2c/onnn,mt9m114.yaml b/Documentation/devicetree/bindings/media/i2c/onnn,mt9m114.yaml
> > index 72e258d57186..666afe10c538 100644
> > --- a/Documentation/devicetree/bindings/media/i2c/onnn,mt9m114.yaml
> > +++ b/Documentation/devicetree/bindings/media/i2c/onnn,mt9m114.yaml
> > @@ -74,6 +74,12 @@ properties:
> > description: Bypass the internal PLL of the sensor to use EXTCLK directly as SYSCLK.
> > type: boolean
> >
> > + onnn,slew-rate:
> > + $ref: /schemas/types.yaml#/definitions/uint8
>
> No need to make this 8-bit (i.e. just use 32 bits).
>
> > + description: Slew rate ot the output pads DOUT[7:0], LINE_VALID, FRAME_VALID and PIXCLK
>
> Please wrap at 80 characters.
>
> Is there more information on the effect than 7 is the fastest?
>
> > + minimum: 0
> > + maximum: 7
>
> Please also add a default.

It'd also be great (IMO) if it were given in terms of actual units, not
nebulous values that I assume to be the register values.

>
> > +
> > required:
> > - compatible
> > - reg
>
> --
> Regards,
>
> Sakari Ailus

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