On Fri, Apr 26, 2019 at 2:20 PM Ondřej Jirman megous@megous.com wrote:
On Fri, Apr 26, 2019 at 01:23:37PM -0500, Rob Herring wrote:
On Sat, Apr 13, 2019 at 06:54:15PM +0200, megous@megous.com wrote:
From: Ondrej Jirman megous@megous.com
Some Allwinner SoC using boards (Orange Pi 3 for example) need to enable on-board voltage shifting logic for the DDC bus to be usable. Use ddc-supply on the hdmi-connector to model this.
Add binding documentation for optional ddc-supply property.
Signed-off-by: Ondrej Jirman megous@megous.com
.../devicetree/bindings/display/connector/hdmi-connector.txt | 1 + 1 file changed, 1 insertion(+)
diff --git a/Documentation/devicetree/bindings/display/connector/hdmi-connector.txt b/Documentation/devicetree/bindings/display/connector/hdmi-connector.txt index 508aee461e0d..33085aeb0bb9 100644 --- a/Documentation/devicetree/bindings/display/connector/hdmi-connector.txt +++ b/Documentation/devicetree/bindings/display/connector/hdmi-connector.txt @@ -9,6 +9,7 @@ Optional properties:
- label: a symbolic name for the connector
- hpd-gpios: HPD GPIO number
- ddc-i2c-bus: phandle link to the I2C controller used for DDC EDID probing
+- ddc-supply: the power supply for the DDC bus
It's not just for DDC. It powers the chips in bridge dongles for example. Pretty much every diagram I find just calls it 5V or +5V.
So how about '5V-supply' or 'v5V-supply'?
Just to be sure, the schematic that inspired this change looks like this:
https://megous.com/dl/tmp/33b2971de6943e9d.png
HDMI-5V is always on, and what is really being enabled here are mosfets connected to DDC_CEC_EN and not the HDMI-5V power supply. So in this case it really is just for DDC. It is conceivable that some boards may need both to enable 5V for HDMI circuitry and some separate power shifting logic for DDC bus.
Okay, not what I thought you were defining. DDC_CEC_EN is a GPIO line? I wouldn't characterize this as a voltage rail, so I don't think it should be a supply. Perhaps 'ddc-en-gpios'?
We certainly want to make it clear this is not the 5V supply.
Rob