MLK-18042-02 arm: dts: update the backlight brightness on imx7ulp evk

On the i.MX7ULP EVK Rev.B baord, the backlight brigntness driver circuit
is updated. A RC filter is added on the MP3301's EN pin. So the PWM's frequency
should be change to 20KHZ. for EN pin, A DC voltage from 0.7V to 1.4V can control
the LED current from 0% to 100%. the backlight brightness level also need to be
updated.

Signed-off-by: Bai Ping <ping.bai@nxp.com>
Reviewed-by: Anson Huang <Anson.Huang@nxp.com>
(cherry picked from commit 82555e15a5f958c09492d0103425dc30bc7cd927)

diff --git a/arch/arm/boot/dts/imx7ulp-evk.dts b/arch/arm/boot/dts/imx7ulp-evk.dts
index 028d297..3cc46ca 100644 (file)
--- a/arch/arm/boot/dts/imx7ulp-evk.dts
+++ b/arch/arm/boot/dts/imx7ulp-evk.dts
@@ -1,6 +1,6 @@
 /*
  * Copyright 2016 Freescale Semiconductor, Inc.
- * Copyright 2017 NXP.
+ * Copyright 2017-2018 NXP.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -32,8 +32,8 @@
 
        backlight {
                compatible = "pwm-backlight";
-               pwms = <&pwm0 1 5000000>;
-               brightness-levels = <0 4 8 16 32 64 128 255>;
+               pwms = <&pwm0 1 50000>;
+               brightness-levels = <0 20 25 30 35 40 100>;
                default-brightness-level = <6>;
                status = "okay";
        };