| Message ID | 20190502225336.206885-1-dianders@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/5] dt-bindings: drm/bridge/synopsys: dw-hdmi: Add "unwedge" for ddc bus | expand |
On Thu, 2 May 2019 15:53:32 -0700, Douglas Anderson wrote: > In certain situations it was seen that we could wedge up the DDC bus > on the HDMI adapter on rk3288. The only way to unwedge was to mux one > of the pins over to GPIO output-driven-low temporarily and then > quickly mux back. Full details can be found in the patch > ("drm/bridge/synopsys: dw-hdmi: Add "unwedge" for ddc bus"). > > Since unwedge requires remuxing the pins, we first need to add to the > bindings so that we can specify what state the pins should be in for > unwedging. > > Signed-off-by: Douglas Anderson <dianders@chromium.org> > --- > > .../bindings/display/rockchip/dw_hdmi-rockchip.txt | 7 +++++++ > 1 file changed, 7 insertions(+) > Reviewed-by: Rob Herring <robh@kernel.org>
On Thu, May 02, 2019 at 03:53:32PM -0700, Douglas Anderson wrote: > In certain situations it was seen that we could wedge up the DDC bus > on the HDMI adapter on rk3288. The only way to unwedge was to mux one > of the pins over to GPIO output-driven-low temporarily and then > quickly mux back. Full details can be found in the patch > ("drm/bridge/synopsys: dw-hdmi: Add "unwedge" for ddc bus"). > > Since unwedge requires remuxing the pins, we first need to add to the > bindings so that we can specify what state the pins should be in for > unwedging. Pushed to drm-misc-next along with patch 2. I'll let Heiko land the dts patches. Thanks! Sean > > Signed-off-by: Douglas Anderson <dianders@chromium.org> > --- > > .../bindings/display/rockchip/dw_hdmi-rockchip.txt | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/Documentation/devicetree/bindings/display/rockchip/dw_hdmi-rockchip.txt b/Documentation/devicetree/bindings/display/rockchip/dw_hdmi-rockchip.txt > index 39143424a474..8346bac81f1c 100644 > --- a/Documentation/devicetree/bindings/display/rockchip/dw_hdmi-rockchip.txt > +++ b/Documentation/devicetree/bindings/display/rockchip/dw_hdmi-rockchip.txt > @@ -38,6 +38,13 @@ Optional properties > - phys: from general PHY binding: the phandle for the PHY device. > - phy-names: Should be "hdmi" if phys references an external phy. > > +Optional pinctrl entry: > +- If you have both a "unwedge" and "default" pinctrl entry, dw_hdmi > + will switch to the unwedge pinctrl state for 10ms if it ever gets an > + i2c timeout. It's intended that this unwedge pinctrl entry will > + cause the SDA line to be driven low to work around a hardware > + errata. > + > Example: > > hdmi: hdmi@ff980000 { > -- > 2.21.0.1020.gf2820cf01a-goog >
diff --git a/Documentation/devicetree/bindings/display/rockchip/dw_hdmi-rockchip.txt b/Documentation/devicetree/bindings/display/rockchip/dw_hdmi-rockchip.txt index 39143424a474..8346bac81f1c 100644 --- a/Documentation/devicetree/bindings/display/rockchip/dw_hdmi-rockchip.txt +++ b/Documentation/devicetree/bindings/display/rockchip/dw_hdmi-rockchip.txt @@ -38,6 +38,13 @@ Optional properties - phys: from general PHY binding: the phandle for the PHY device. - phy-names: Should be "hdmi" if phys references an external phy. +Optional pinctrl entry: +- If you have both a "unwedge" and "default" pinctrl entry, dw_hdmi + will switch to the unwedge pinctrl state for 10ms if it ever gets an + i2c timeout. It's intended that this unwedge pinctrl entry will + cause the SDA line to be driven low to work around a hardware + errata. + Example: hdmi: hdmi@ff980000 {
In certain situations it was seen that we could wedge up the DDC bus on the HDMI adapter on rk3288. The only way to unwedge was to mux one of the pins over to GPIO output-driven-low temporarily and then quickly mux back. Full details can be found in the patch ("drm/bridge/synopsys: dw-hdmi: Add "unwedge" for ddc bus"). Since unwedge requires remuxing the pins, we first need to add to the bindings so that we can specify what state the pins should be in for unwedging. Signed-off-by: Douglas Anderson <dianders@chromium.org> --- .../bindings/display/rockchip/dw_hdmi-rockchip.txt | 7 +++++++ 1 file changed, 7 insertions(+)