On Sun, 2023-01-29 at 12:46 +0100, Krzysztof Kozlowski wrote: > On 28/01/2023 04:47, Liu Ying wrote: > > NXP i.MX93 mediamix blk-ctrl contains one DISPLAY_MUX register > > which > > configures parallel display format by using the > > "PARALLEL_DISP_FORMAT" > > field. Add device tree bindings for the display format > > configuration. > > > > Signed-off-by: Liu Ying <victor.liu@xxxxxxx> > > --- > > .../display/bridge/nxp,imx93-pdfc.yaml | 78 > > +++++++++++++++++++ > > 1 file changed, 78 insertions(+) > > create mode 100644 > > Documentation/devicetree/bindings/display/bridge/nxp,imx93- > > pdfc.yaml > > > > diff --git > > a/Documentation/devicetree/bindings/display/bridge/nxp,imx93- > > pdfc.yaml > > b/Documentation/devicetree/bindings/display/bridge/nxp,imx93- > > pdfc.yaml > > new file mode 100644 > > index 000000000000..a84bfb46b01d > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/display/bridge/nxp,imx93- > > pdfc.yaml > > @@ -0,0 +1,78 @@ > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > > +%YAML 1.2 > > +--- > > +$id: > > https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdevicetree.org%2Fschemas%2Fdisplay%2Fbridge%2Fnxp%2Cimx93-pdfc.yaml%23&data=05%7C01%7Cvictor.liu%40nxp.com%7C7fb1b69849974435787008db01ee832c%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C638105896131701918%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=kkX5B45NTsmDKKzxjOiE6MaE4zkMVbMe4ILammVSwMc%3D&reserved=0 > > +$schema: > > https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdevicetree.org%2Fmeta-schemas%2Fcore.yaml%23&data=05%7C01%7Cvictor.liu%40nxp.com%7C7fb1b69849974435787008db01ee832c%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C638105896131701918%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=vIVpdEjIo6H3V8T7iTbDwz4Bmn0d%2BQB4BCJNJ0OzKJw%3D&reserved=0 > > + > > +title: NXP i.MX93 Parallel Display Format Configuration > > + > > +maintainers: > > + - Liu Ying <victor.liu@xxxxxxx> > > + > > +description: | > > + The i.MX93 mediamix blk-ctrl contains one DISPLAY_MUX register > > which > > + configures parallel display format by using the > > "PARALLEL_DISP_FORMAT" > > + field. > > + > > +properties: > > + compatible: > > + const: nxp,imx93-pdfc > > > Based on description, I have doubts this is a separate bridge device. > Why this is not part of display driver/bindings? The relevant display controller in i.MX93 SoC is LCDIF. From hardware design PoV, the parallel display format configuration logic is not a part of LCDIF. Instead, it's a part of i.MX93 mediamix blk-ctrl. The blk-ctrl includes controls for miscellaneous devices with small logics, like this parallel display format configuration, LVDS Display Bridge(LDB, see fsl,ldb.yaml) and so on. The below pipeline describes data flow of a parallel display LCD panel: DRAM -> LCDIF -> parallel display format configuration -> LCD panel So, the parallel display format configuration appears to be a separate bridge. > > We do not create usually devices for single registers, because they > are > not a devices. Devices are a bit more complex - have some pin > inputs/outputs, not a register only. Of course there are exception, > but > this one does not look like one. IMHO, this one is a standalone device although it is controlled by one single register. It's input pins connect to LCDIF and output pins connect to i.MX93 SoC's pins/pads. > > > + > > + reg: > > + maxItems: 1 > > Your driver tells different story: > > syscon_node_to_regmap(dev->of_node->parent); > > (which also points to fact this is not a separate device) This function call gets the parent device's(mediamix blk-ctrl's) regmap, like fsl-ldb.c does. Same to LDB, the parallel display format configuration device is a child device of the mediamix blk-ctrl device. Regards, Liu Ying > > Best regards, > Krzysztof >
