dt-bindings: display: xlnx: mixer: Inconsistent pixel format terminology in dt docs

[Hyun Kwon]

Hi Kenneth,

> -----Original Message-----
> From: Kenneth Sloat <ksloat at designlinxhs.com>
> Sent: Thursday, August 20, 2020 2:18 PM
> To: Hyun Kwon <hyunk at xilinx.com>; linux-arm-kernel at lists.infradead.org
> Cc: Michal Simek <michals at xilinx.com>; dri-devel at lists.freedesktop.org; linux-
> kernel at vger.kernel.org; laurent.pinchart at ideasonboard.com;
> devicetree at vger.kernel.org; linux-kernel at vger.kernel.org;
> mark.rutland at arm.com
> Subject: dt-bindings: display: xlnx: mixer: Inconsistent pixel format terminology
> in dt docs
> 
> Hello,
> 
> The Xilinx Video mixer IP uses the DRM fourcc string as a device tree binding in
> order to describe the format for a specific DRM layer/plane. Currently, in the
> device tree doc in
> "Documentation/devicetree/bindings/dma/xilinx/xilinx_frmbuf.txt" there is a list
> called "VIDEO FORMATS" with a table containing "Mixer IP Format" and
> associated "Driver supported Format String" (fourcc). In general, this table is not
> helpful, because "Mixer IP Format" does not match the Xilinx IP datasheet
> terminology for formats but rather some other commonly used nomenclature.
> This is also inconsistent from other Xilinx dts binding docs which specify the
> actual correct IP name and at times list other format nomenclature where
> helpful (i.e. xilinx_frmbuf.txt)
> 
> My suggestion is to remove the current "Mixer IP Format" strings in the doc and
> replace them with the actual IP names in the datasheet (which also match those
> used in Xilinx's Vivado FPGA tool). Otherwise, the programmer must cross
> reference other dts documentation or the code in order to figure these out. I am
> happy to provide a patch for this but wanted to throw out the suggestion first.

I agree. The bindings should be in sync with datasheet and not rely on
software definitions. Since the driver is only in Xilinx vendor tree,
please send directly to git at xilinx.com.

Thanks!

-hyun

> 
> Thanks
> 
> Sincerely,
> Ken Sloat