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

[Lucas Stach]

Am Montag, den 22.07.2013, 21:37 +0900 schrieb 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.
> 
Is there really this much configurability? Could each of those values be
a different on different SoCs, or could you just extract those values
from the SoC/rotator hardware version and thus the DT compatible string?

> 
> > 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
> > >
> > >
> > > _______________________________________________
> > > linux-arm-kernel mailing list
> > > linux-arm-kernel at lists.infradead.org
> > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> > >
> 
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