:: Re: [maemo-leste] Backlight on Droi…
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Autor: Pavel Machek
Data:  
A: Jean-Jacques Hiblot
CC: Sebastian Reichel, tomi.valkeinen, Tony Lindgren, Merlijn Wajer, maemo-leste, Ivaylo Dimitrov
Assumpte: Re: [maemo-leste] Backlight on Droid4 -- was Re: Droid 4 in 5.3-rc1, development boards
Hi!

> >Hmm, I guess I should try to get it to work.
> >
> >I came up with this, and ... it does not work. If you see something
> >obviously wrong, tell me.
>
> The dts changes look OK to me.
>
> You should be able to use the SYSFS to check if the LED is working as
> expected (the backlight driver does not remove sysfs control over
>the LED)


I verified the LED works, yes.

> ALSO can you check if it is working without a defined brightness-levels in
> the DTS. The behavior of the LED may not be linear at all. On my test board
> the LED is black until the LED level reaches 240 or so.


Hmm... what board is that? Maybe we should fix that.

That should not be a problem, either. I added some printks, and
realized code can not parse leds = <> reference. (I also had backlight
in wrong place, but I fixed that). Probe fails, so table is not used
at all.

Can you post working example of the dts?

Thanks,
                                Pavel



> >+++ b/arch/arm/boot/dts/omap4-droid4-xt894.dts
> >@@ -202,12 +202,22 @@
> >          };
> >      };
> >+    backlight: backlight {
> >+             compatible = "led-backlight";
> >+
> >+         leds = <&backlight_led>;
> >+         brightness-levels = <0 4 8 16 32 64 128 255>;
> >+         default-brightness-level = <6>;
> >+    };
> >+
> >      lcd0: display {
> >          compatible = "panel-dsi-cm";
> >          label = "lcd0";
> >          vddi-supply = <&lcd_regulator>;
> >          reset-gpios = <&gpio4 5 GPIO_ACTIVE_HIGH>;    /* gpio101 */
> >+        backlight = <&backlight>;
> >+
> >          width-mm = <50>;
> >          height-mm = <89>;
> >@@ -417,12 +427,11 @@
> >          ramp-up-us = <1024>;
> >          ramp-down-us = <8193>;
> >-        led@0 {
> >+        backlight_led: led@0 {
> >              reg = <0>;
> >              led-sources = <2>;
> >              ti,led-mode = <0>;
> >              label = ":backlight";
> >-            linux,default-trigger = "backlight";
> >          };
> >          led@1 {

> >
> >


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