On Thu, Jul 12, 2012 at 10:21:01AM +0200, Simon Glass wrote:
Hi Thierry,
On Wed, Jul 11, 2012 at 7:48 AM, Thierry Reding thierry.reding@avionic-design.de wrote:
On Wed, Jul 11, 2012 at 06:44:10AM +0200, Simon Glass wrote:
Hi Stephen,
On Fri, Jun 15, 2012 at 1:32 AM, Stephen Warren swarren@wwwdotorg.orgwrote:
On 06/13/2012 10:19 AM, Simon Glass wrote:
Add LCD definitions and also a proposed binding for LCD displays.
The PWFM is in progress on the device-tree-discuss list, so only a very basic binding is offered here.
I believe we have settled on a final representation, it just hasn't been added into linux-next yet. See:
http://gitorious.org/linux-pwm/linux-pwm/commit/d3ce73e5dc86646a6302f2b0f7dd...
Thanks for the pointer. I suppose this doesn't address clocks as yet, but that's fine.
I was waiting for the common clock framework and DT bindings to get ready. This should happen RSN for Tegra so I will probably look at adding support for it in.
OK, are you looking at adding it in U-Boot?
No. I don't have much time to spend on U-Boot right now.
[...]
I also need a place to put the pwm and GPIOs for the panel itself. Something like this:
nvidia,pwm = <&pwm 2 0>; nvidia,backlight-enable-gpios = <&gpio 28 0>; /* PD4 */ nvidia,lvds-shutdown-gpios = <&gpio 10 0>; /* PB2 */ nvidia,backlight-vdd-gpios = <&gpio 176 0>; /* PW0 */ nvidia,panel-vdd-gpios = <&gpio 22 0>; /* PC6 */ nvidia,panel-timings = <4 203 17 15>; (number of ms before turningon the next gpio) nvidia,bits-per-pixel = <16>; (er, TBD)
I am thinking of something like a phandle in your rgb node:
host1x { dc@54200000 { rgb { nvidia-panel = <&lcd_panel>; ...
lcd_panel: panel { nvidia,pwm = <&pwm 2 0>; ... }
Or have you already solved this problem another way?
Linux has a generic PWM backlight driver. This is currently solved by using this in the DT:
backlight { compatible = "pwm-backlight"; pwms = <&pwm 0 5000000>;
brightness-levels = <0 4 8 16 32 64 128 255>; default-brightness-level = <6>; };
Alex Courbot (Cc'd) has been working on adding a generic way to add GPIO and regulator support to that. I don't know exactly what the lvds-shutdown-gpios and panel-vdd-gpios properties do. If they control hardware connected behind the display controller I suppose they could go into the rgb node.
The panel alternative that you propose sounds interesting as well. Maybe the panel should itself contain either a phandle or a subnode for the backlight and collect the properties that you listed above.
Thierry