| Message ID | 20191209145016.227784-4-hsinyi@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm: bridge: anx7688 and an optional feature | expand |
On Mon, Dec 9, 2019 at 10:55 PM Laurent Pinchart <laurent.pinchart@ideasonboard.com> wrote: > > Hi Hsin-Yi, > > Thank you for the patch. > > On Mon, Dec 09, 2019 at 10:50:15PM +0800, Hsin-Yi Wang wrote: > > Support optional feature: bypass GPIO. > > > > Some SoC (eg. mt8173) have a hardware mux that connects to 2 ports: > > anx7688 and hdmi. When the GPIO is active, the bridge is bypassed. > > This doesn't look like the right place to fix this, as the mux is > unrelated to the bridge. You would have to duplicate this logic in every > bridge driver otherwise. > > Could you describe the hardware topology in a bit more details ? I can > then try to advise on how to best support it. > Hi Laurent, The mt8173 layout is: MT8173 HDMI bridge-- hardware mux --- HDMI | ------------ anx7688 There's a hardware mux that takes mt8173 hdmi as input and has 2 output port: native hdmi and anx7688 bridge. If gpio is active, we would like it to go to HDMI. Previous approach is to make hardware mux a generic gpio mux bridge, but this is probably a very rare use case that is only for mt8173.(https://lore.kernel.org/lkml/57723AD2.8020806@codeaurora.org/) We merge the mux and anx7688 to a single bridge and leave this as an optional feature in this time. Thanks.
On Mon, Dec 9, 2019 at 11:32 PM Laurent Pinchart <laurent.pinchart@ideasonboard.com> wrote: > Hi Laurent, > You may have used a proportional font when writing this, the | doesn't > align with anything using a fixed font. Do I assume correctly that the > hardware multiplexer is actually a demultiplexer with one input and two > outputs ? > +-----------+ > +---------+ +------+ /--> | HDMI | > | MT8173 | HDMI | -->| --/ | Connector | > | HDMI | ------> |--/ | +-----------+ > | Encoder | | ->| --\ +-----------+ +-----------+ > +---------+ +------+ \--> | ANX7688 | ---> | USB-C | > | Bridge | | Connector | > +-----------+ +-----------+ > Sorry for not noticing the font issue, this graph is correct. > > There's a hardware mux that takes mt8173 hdmi as input and has 2 > > output port: native hdmi and anx7688 bridge. > > If gpio is active, we would like it to go to HDMI. > > > > Previous approach is to make hardware mux a generic gpio mux bridge, > > but this is probably a very rare use case that is only for > > mt8173.(https://lore.kernel.org/lkml/57723AD2.8020806@codeaurora.org/) > > We merge the mux and anx7688 to a single bridge and leave this as an > > optional feature in this time. > > I think that's a better approach, at least at the DT level. The HDMI > demultiplexer should be represented as a DT node with 3 ports (one input > and two outputs) with a control GPIO. > I've resend the original gpio mux driver. So for anx7688 there's 1 input and 1 output. Thanks
diff --git a/Documentation/devicetree/bindings/display/bridge/anx7688.txt b/Documentation/devicetree/bindings/display/bridge/anx7688.txt index 78b55bdb18f7..44185dcac839 100644 --- a/Documentation/devicetree/bindings/display/bridge/anx7688.txt +++ b/Documentation/devicetree/bindings/display/bridge/anx7688.txt @@ -15,10 +15,13 @@ Required properties: Optional properties: - Video port for HDMI input, using the DT bindings defined in [1]. + - bypass-gpios : External GPIO. If this GPIO is active, we assume + the bridge is bypassed (e.g. by a mux). + - pinctrl-0, pinctrl-names: the pincontrol settings to configure bypass GPIO. [1]: Documentation/devicetree/bindings/media/video-interfaces.txt -Example: +Example 1: anx7688: anx7688@2c { compatible = "analogix,anx7688"; @@ -30,3 +33,38 @@ Example: }; }; }; + +Example 2: + + anx7688: anx7688@2c { + compatible = "analogix,anx7688"; + status = "okay"; + reg = <0x2c>; + ddc-i2c-bus = <&hdmiddc0>; + + bypass-gpios = <&pio 36 GPIO_ACTIVE_HIGH>; + pinctrl-names = "default"; + pinctrl-0 = <&hdmi_mux_pins>; + + ports { + #address-cells = <1>; + #size-cells = <0>; + + port@0 { /* input */ + reg = <0>; + + anx7688_in: endpoint { + remote-endpoint = <&hdmi_out_anx>; + }; + }; + + port@1 { /* output */ + reg = <1>; + + anx7688_out: endpoint { + remote-endpoint = <&hdmi_connector_in>; + }; + }; + }; + }; +
Support optional feature: bypass GPIO. Some SoC (eg. mt8173) have a hardware mux that connects to 2 ports: anx7688 and hdmi. When the GPIO is active, the bridge is bypassed. Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org> --- .../bindings/display/bridge/anx7688.txt | 40 ++++++++++++++++++- 1 file changed, 39 insertions(+), 1 deletion(-)