[PATCH 2/3] drm/exynos: add dt-binding documentation for rotator

[Inki Dae]

> -----Original Message-----
> From: Mark Rutland [mailto:mark.rutland at arm.com]
> Sent: Monday, July 22, 2013 5:48 PM
> To: Chanho Park
> Cc: inki.dae at samsung.com; kgene.kim at samsung.com; linux-samsung-
> soc at vger.kernel.org; jy0922.shim at samsung.com; devicetree-
> discuss at lists.ozlabs.org; sw0312.kim at samsung.com; dri-
> devel at lists.freedesktop.org; kyungmin.park at samsung.com; linux-arm-
> kernel at lists.infradead.org
> Subject: Re: [PATCH 2/3] drm/exynos: add dt-binding documentation for
> rotator
> 
> On Mon, Jul 22, 2013 at 07:49:26AM +0100, Chanho Park wrote:
> > This patch adds a dt-binding document for exynos rotator. It describes
> which
> > nodes should be defined to use the rotator.
> >
> > Signed-off-by: Chanho Park <chanho61.park at samsung.com>
> > Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
> > ---
> >  .../bindings/drm/exynos/samsung-rotator.txt        |   35
> ++++++++++++++++++++
> >  1 file changed, 35 insertions(+)
> >  create mode 100644
> Documentation/devicetree/bindings/drm/exynos/samsung-rotator.txt
> >
> > diff --git a/Documentation/devicetree/bindings/drm/exynos/samsung-
> rotator.txt b/Documentation/devicetree/bindings/drm/exynos/samsung-
> rotator.txt
> > new file mode 100644
> > index 0000000..6b1d704
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/drm/exynos/samsung-rotator.txt
> > @@ -0,0 +1,35 @@
> > +* Samsung Image Rotator
> > +
> > +Required properties:
> > +  - compatible : value should be the "samsung,exynos4210".

Please, add more compatible strings for other SoC.

> > +  - reg : Physical base address of the IP registers and length of
> memory
> > +	  mapped region.
> > +  - interrupts : interrupt number to the CPU.
> > +  - clocks : clock number of exynos4 rotator clock.
> > +  - clocks : clock name of rotator
> 
> clock-names?
> 
> > +  - status : "okay" or "disabled"
> > +  - limit table for image formats : min_w/min_h/max_w/max_h for min/max
> of image
> 
> Limit table? This doesn't seem to be a well-defined binding, and it
> seems like a relatively generic thing to describe.
> 
> > +
> > +Example:
> > +	rotator: rotator at 12810000 {
> > +		compatible = "samsung,exynos4210-rotator";
> > +		reg = <0x12810000 0x1000>;
> > +		interrupts = <0 83 0>;
> > +		clocks = <&clock 278>;
> > +		clock-names = "rotator";
> > +		status = "disabled";
> > +		ycbcr420_2p {
> 
> Which names are allowed for these subnodes?
> 
> > +			min_w = <32>;
> > +			min_h = <32>;
> > +			max_w = <32768>;
> > +			max_h = <32768>;
> > +			align = <3>;
> 
> min-width, min-height, max-width, max-height? What units are they in?
> 
> What does alignment specify exactly?
> 
> Are these a configurable part of the rotator hardware, or are these
> values always the same?

Right, that seems like configurable part. At least, min_w/h and max_w/h can
be different values according to SoC and pixel formats so they should be
described enough in this dt-binding document file.

Thanks,
Inki Dae

> If thery're always the same, there's no need to
> describe in in the devicetree.
> 
> Thanks,
> Mark.
> 
> > +		};
> > +		rgb888 {
> > +			min_w = <8>;
> > +			min_h = <8>;
> > +			max_w = <8192>;
> > +			max_h = <8192>;
> > +			align = <2>;
> > +		};
> > +	};
> > --
> > 1.7.9.5
> >
> >
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> >