On Tue, Sep 03, 2013 at 12:52:36PM -0600, Stephen Warren wrote:
On 08/30/2013 09:25 AM, Thierry Reding wrote:
Add a driver for simple panels. Such panels can have a regulator that provides the supply voltage and a separate GPIO to enable the panel. Optionally the panels can have a backlight associated with them so it can be enabled or disabled according to the panel's power management mode.
diff --git a/Documentation/devicetree/bindings/panel/panel-simple.txt b/Documentation/devicetree/bindings/panel/panel-simple.txt
+Simple display panel
+Required properties: +- compatible: should be one of:
- "auo,b101aw03": AU Optronics Corporation 10.1" WSVGA TFT LCD panel
- "cptt,claa101wb03": Chunghwa Picture Tubes Ltd. 10.1" WXGA TFT LCD panel
- "pc,vvx10f004b00": Panasonic Corporation 10.1" WUXGA TFT LCD panel
+Optional properties: +- ddc-i2c-bus: phandle of an I2C controller used for DDC EDID probing +- power-supply: regulator to provide the supply voltage +- enable-gpios: GPIO pin to enable or disable the panel +- backlight: phandle of the backlight device attached to the panel
Do we need to represent the timing requirements e.g. between panel enable and backlight enable, or do you expect the driver to hard-code this based on the compatible value?
Yes, I'd expect the driver to hard-code that, similar to how the video mode is hardcoded. ddc-i2c-bus support hasn't even been implemented yet. I was planning to do that because one of the panels (the Chunghwa I think) actually is connected via DDC. What I was going to do was prefer a hardcoded mode over EDID to allow a driver to override a faulty EDID.
Looking at the driver code, it seems that it has direct knowledge of the video mode that each panel supports, so DDC is actually optional unlike what I asserted/assumed in my previous response. As such, I guess we should have a separate DT binding document for each of the three panels (compatible values) listed above that pretty much just says "go look at simple-panel.txt".
Okay, I suppose that makes sense.
Thierry