| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20251215175436.wwlgzxionq55zu27@pengutronix.de>
Date: Mon, 15 Dec 2025 18:54:36 +0100
From: Marco Felsch <m.felsch@...gutronix.de>
To: Liu Ying <victor.liu@....com>
Cc: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>, Shawn Guo <shawnguo@...nel.org>,
Sascha Hauer <s.hauer@...gutronix.de>,
Pengutronix Kernel Team <kernel@...gutronix.de>,
Fabio Estevam <festevam@...il.com>, Peng Fan <peng.fan@....com>,
Andrzej Hajda <andrzej.hajda@...el.com>,
Neil Armstrong <neil.armstrong@...aro.org>,
Robert Foss <rfoss@...nel.org>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Jonas Karlman <jonas@...boo.se>,
Jernej Skrabec <jernej.skrabec@...il.com>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>,
Thomas Zimmermann <tzimmermann@...e.de>,
David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
devicetree@...r.kernel.org, imx@...ts.linux.dev,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH v7 1/3] dt-bindings: soc: imx93-media-blk-ctrl: Add PDFC
subnode to schema and example
Hi Liu,
sorry I didn't fully answer you please see below.
On 25-12-08, Liu Ying wrote:
> Hi Marco,
>
> On 12/02/2025, Marco Felsch wrote:
> > From: Liu Ying <victor.liu@....com>
> >
> > i.MX93 SoC mediamix blk-ctrl contains one DISPLAY_MUX register which
> > configures parallel display format by using the "PARALLEL_DISP_FORMAT"
> > field. Document the Parallel Display Format Configuration(PDFC) subnode
> > and add the subnode to example.
> >
> > Signed-off-by: Liu Ying <victor.liu@....com>
> > [m.felsch@...gutronix.de: port to v6.18-rc1]
> > [m.felsch@...gutronix.de: add bus-width]
> > Signed-off-by: Marco Felsch <m.felsch@...gutronix.de>
> > ---
> > .../bindings/soc/imx/fsl,imx93-media-blk-ctrl.yaml | 92 ++++++++++++++++++++++
> > 1 file changed, 92 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/soc/imx/fsl,imx93-media-blk-ctrl.yaml b/Documentation/devicetree/bindings/soc/imx/fsl,imx93-media-blk-ctrl.yaml
> > index 34aea58094e55365a2f9c86092f637e533f954ff..6e2d86d9341c75108b492bcbabc8a560d8e707cd 100644
> > --- a/Documentation/devicetree/bindings/soc/imx/fsl,imx93-media-blk-ctrl.yaml
> > +++ b/Documentation/devicetree/bindings/soc/imx/fsl,imx93-media-blk-ctrl.yaml
> > @@ -26,6 +26,12 @@ properties:
> > reg:
> > maxItems: 1
...
> > + properties:
> > + endpoint:
> > + $ref: /schemas/graph.yaml#/$defs/endpoint-base
> > + unevaluatedProperties: false
> > +
> > + properties:
> > + bus-width:
>
> In v1-v5, I thought the output bus format can be determined by the sink
> device(a panel or a bridge) hence properties like bus-width were not needed.
> But, if this property is really needed, then reference video-interfaces.yaml
> since bus-width is documented there. Should we reference bus-type defined
> in video-interfaces.yaml too?
You're right, the bus-width should be determined by the connected panel.
But there are cases where a 24-bit panel is connected but only the lower
18-bits are muxed. I added the bus-width property to handle this case.
In the end most users don't have to specify this since the correct
bus-width is coming from the panel bus-fmt.
> > + enum: [ 16, 18, 24 ]
>
> The PARALLEL_DISP_FORMAT field of DISPLAY_MUX register says this IP supports
> below formats. It seems that the enum here may tell RGB888, RGB666 and RGB565.
> How can we tell RGB555, YCbCr 24 bits and YUV444 then?
>
> 000b RGB888 -> RGB888
> 001b RGB888 -> RGB666
> 010b RGB565 -> RGB565
> 011b RGB555 -> RGB555
> 100b YUV -> YCbCr 24 bits
> 101b YUV -> YUV444
This enum is about the physical bus width. RGB565 == 16-bit, YUV ==
24-bit.
That said, I don't think that you need to specify the bus-fmt since this
is coming from the panel. As said above, my itension with the bus-width
property is to provide integrators (dts-writers) a possibility to limit
the physical available bus width.
> > + description:
> > + Specify the physical parallel bus width.
> > +
> > + This property is optional if the display bus-width
> > + matches the SoC bus-width, e.g. a 18-bit RGB666 (display)
> > + is connected and all 18-bit data lanes are muxed to the
>
> Per video-interfaces.yaml, s/data lanes/data lines/. "data lanes" is a
> value for MIPI DSI/CSI, afaik.
I can go with "lines" if this is the preferred naming convention for
DRM.
> > + parallel-output pads.
>
> How about just saying that this property is optional and by default it's 24?
I wanted to make it clear what this property does.
> > + This property must be set to 18 to cut only the LSBs
> > + instead of the MSBs in case a 24-bit RGB888 display is
> > + connected and only the lower 18-bit data lanes are muxed
> > + to the parallel-output pads.
>
> The __lower__ 18-bit? Isn't it the __MSB__ 6bit in each color component?
No, the LSB are cut, this is why it's so important to use this property
if you connected a external 24-bit display to the lower data
lines[17-0].
If you don't specify this property, the MSBs are cut/lost which is far
worse than using the LSB information.
Regards,
Marco
> > +
> > + required:
> > + - port@0
> > + - port@1
> > +
> > + required:
> > + - compatible
> > + - reg
> > + - ports
> > +
> > allOf:
> > - if:
> > properties:
> > @@ -81,9 +141,12 @@ allOf:
> > - const: isi
> > - const: csi
> > - const: dsi
> > +
> > required:
> > - compatible
> > - reg
> > + - '#address-cells'
> > + - '#size-cells'
> > - power-domains
> > - clocks
> > - clock-names
> > @@ -112,4 +175,33 @@ examples:
> > clock-names = "apb", "axi", "nic", "disp", "cam",
> > "pxp", "lcdif", "isi", "csi", "dsi";
> > #power-domain-cells = <1>;
> > + #address-cells = <1>;
> > + #size-cells = <1>;
> > +
> > + bridge@60 {
> > + compatible = "nxp,imx93-pdfc";
> > + reg = <0x60 0x4>;
> > +
> > + ports {
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + port@0 {
> > + reg = <0>;
> > +
> > + pdfc_from_lcdif: endpoint {
> > + remote-endpoint = <&lcdif_to_pdfc>;
> > + };
> > + };
> > +
> > + port@1 {
> > + reg = <1>;
> > +
> > + pdfc_to_panel: endpoint {
> > + remote-endpoint = <&panel_from_pdfc>;
> > + bus-width = <18>;
> > + };
> > + };
> > + };
> > + };
> > };
> >
>
>
> --
> Regards,
> Liu Ying
>
--
#gernperDu
#CallMeByMyFirstName
Pengutronix e.K. | |
Steuerwalder Str. 21 | https://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-9 |
Powered by blists - more mailing lists