Re: [PATCH v2 1/2] dt-bindings: drm/bridge: anx7625: MIPI to DP transmitter binding
From: Xin Ji
Date: Sun Oct 13 2019 - 23:03:07 EST
Hi Laurent Pinchart, please check my comment below.
Thanks,
Xin
On Fri, Oct 11, 2019 at 03:54:18PM +0300, Laurent Pinchart wrote:
> Hi Andrzej,
>
> On Fri, Oct 11, 2019 at 01:21:43PM +0200, Andrzej Hajda wrote:
> > On 11.10.2019 04:21, Xin Ji wrote:
> > > The ANX7625 is an ultra-low power 4K Mobile HD Transmitter designed
> > > for portable device. It converts MIPI to DisplayPort 1.3 4K.
> > >
> > > You can add support to your board with binding.
> > >
> > > Example:
> > > anx7625_bridge: encoder@58 {
> > > compatible = "analogix,anx7625";
> > > reg = <0x58>;
> > > status = "okay";
> > > panel-flags = <1>;
> > > enable-gpios = <&pio 45 GPIO_ACTIVE_HIGH>;
> > > reset-gpios = <&pio 73 GPIO_ACTIVE_HIGH>;
> > > #address-cells = <1>;
> > > #size-cells = <0>;
> > >
> > > port@0 {
> > > reg = <0>;
> > > anx_1_in: endpoint {
> > > remote-endpoint = <&mipi_dsi>;
> > > };
> > > };
> > >
> > > port@3 {
> > > reg = <3>;
> > > anx_1_out: endpoint {
> > > remote-endpoint = <&panel_in>;
> > > };
> > > };
> > > };
> > >
> > > Signed-off-by: Xin Ji <xji@xxxxxxxxxxxxxxxx>
> > > ---
> > > .../bindings/display/bridge/anx7625.yaml | 96 ++++++++++++++++++++++
> > > 1 file changed, 96 insertions(+)
> > > create mode 100644 Documentation/devicetree/bindings/display/bridge/anx7625.yaml
> > >
> > > diff --git a/Documentation/devicetree/bindings/display/bridge/anx7625.yaml b/Documentation/devicetree/bindings/display/bridge/anx7625.yaml
> > > new file mode 100644
> > > index 0000000..fc84683
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/display/bridge/anx7625.yaml
> > > @@ -0,0 +1,96 @@
> > > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > > +# Copyright 2019 Analogix Semiconductor, Inc.
> > > +%YAML 1.2
> > > +---
> > > +$id: "http://devicetree.org/schemas/display/bridge/anx7625.yaml#";
> > > +$schema: "http://devicetree.org/meta-schemas/core.yaml#";
> > > +
> > > +title: Analogix ANX7625 SlimPort (4K Mobile HD Transmitter)
> > > +
> > > +maintainers:
> > > + - Xin Ji <xji@xxxxxxxxxxxxxxxx>
> > > +
> > > +description: |
> > > + The ANX7625 is an ultra-low power 4K Mobile HD Transmitter
> > > + designed for portable devices.
> > > +
> > > +properties:
> > > + "#address-cells": true
> > > + "#size-cells": true
> > > +
> > > + compatible:
> > > + items:
> > > + - const: analogix,anx7625
> > > +
> > > + reg:
> > > + maxItems: 1
> > > +
> > > + panel-flags:
> > > + description: indicate the panel is internal or external
> > > + maxItems: 1
> > > +
> > > + interrupts:
> > > + maxItems: 1
> > > +
> > > + enable-gpios:
> > > + description: used for power on chip control, POWER_EN pin D2.
> > > + maxItems: 1
> > > +
> > > + reset-gpios:
> > > + description: used for reset chip control, RESET_N pin B7.
> > > + maxItems: 1
> > > +
> > > + port@0:
> > > + type: object
> > > + description:
> > > + A port node pointing to MIPI DSI host port node.
> > > +
> > > + port@1:
> > > + type: object
> > > + description:
> > > + A port node pointing to MIPI DPI host port node.
> > > +
> > > + port@2:
> > > + type: object
> > > + description:
> > > + A port node pointing to external connector port node.
> > > +
> > > + port@3:
> > > + type: object
> > > + description:
> > > + A port node pointing to eDP port node.
> >
> >
> > Decrypting available product brief[1], there are following physical lines:
> >
> > Input:
> >
> > - MIPI DSI/DPI - video data, are DSI and DPI lines shared?
>
> It would be much easier if we could have access to more complete
> information. I believe the DSI and DPI pins could be muxed, but there
> should be more DPI pins than DSI pins.
Yes DPI pins more than DSI pins.
>
> >
> > - I2S - audio data,
> >
> > - I2C - control line,
> >
> > - ALERT/INTP - interrupt,
> >
> > - USB 3.1 SSRc/Tx - for USB forwarding,
> >
> > Output:
> >
> > - SS1, SS2,
> >
> > - SBU/AUX,
> >
> > - CC1/2.
> >
> >
> > Having this information I try to understand ports defined by you:
> >
> > - port@2 you have defined as pointing to external port, but here the
> > port should be rather subnode of ANX7625 - the chip has CC lines, see
> > beginning of [2].
> >
> > - port@3 describes SS1, SS2 and SBU/AUX lines together, am I right? In
> > USB-C binding SBU and SS lines are represented by different ports,
> > different approach, but maybe better in this case.
>
> I believe that, when connected to a DP display (either DP or eDP), the
> DisplayPort signals are output on SS1 and/or SS2. I this really wonder
> if we need two separate ports for this, it seems that port@2 and port@3
> should be merged.
OK, I will merge the port@2 and port@3, and use a flag to indicate
whether the control is external connector control or not.
>
> > Maybe it would be good to add 2nd example with USB-C port.
>
> That would help with the discussion, yes.
As we disabled USB-C feature in anx7625, we cannot define a USB-C port.
>
> > [1]:
> > https://www.analogix.com/system/files/AA-002291-PB-6-ANX7625_ProductBrief.pdf
> >
> > [2]: Documentation/devicetree/bindings/connector/usb-connector.txt
> >
> > > +
> > > +required:
> > > + - "#address-cells"
> > > + - "#size-cells"
> > > + - compatible
> > > + - reg
> > > + - port@0
> > > + - port@3
> > > +
> > > +example:
> > > + - |
> > > + anx7625_bridge: encoder@58 {
> > > + compatible = "analogix,anx7625";
> > > + reg = <0x58>;
> > > + status = "okay";
> > > + panel-flags = <1>;
> > > + enable-gpios = <&pio 45 GPIO_ACTIVE_HIGH>;
> > > + reset-gpios = <&pio 73 GPIO_ACTIVE_HIGH>;
> > > + #address-cells = <1>;
> > > + #size-cells = <0>;
> > > +
> > > + port@0 {
> > > + reg = <0>;
> > > + anx_1_in: endpoint {
> > > + remote-endpoint = <&mipi_dsi>;
> > > + };
> > > + };
> > > +
> > > + port@3 {
> > > + reg = <3>;
> > > + anx_1_out: endpoint {
> > > + remote-endpoint = <&panel_in>;
> > > + };
> > > + };
> > > + };
>
> --
> Regards,
>
> Laurent Pinchart