[PATCH] ARM: dts: droid4: Configure LED backlight for lm3532

From: Tony Lindgren
Date: Wed Feb 19 2020 - 14:25:27 EST


With the LED backlight changes merged, we still need the dts configured
to have backlight working for droid4. Based on an earlier patch from
Pavel Machek <pavel@xxxxxx>, let's configure the backlight but update
the value range to be more usable.

We have a range of 256 register values split into 8 steps, so we can
generate the brightness levels backwards with:

$ for i in 0 1 2 3 4 5 6 7; do echo "255 - ${i} * (256 / 8)" | bc; done

To avoid more confusion why the LCD backlight is still not on, let's
also enable LED backlight as a loadable module for omap2plus_defconfig.

Cc: Merlijn Wajer <merlijn@xxxxxxxxxx>
Cc: Pavel Machek <pavel@xxxxxx>
Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
---
arch/arm/boot/dts/motorola-mapphone-common.dtsi | 13 +++++++++++--
arch/arm/configs/omap2plus_defconfig | 1 +
2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/arm/boot/dts/motorola-mapphone-common.dtsi b/arch/arm/boot/dts/motorola-mapphone-common.dtsi
--- a/arch/arm/boot/dts/motorola-mapphone-common.dtsi
+++ b/arch/arm/boot/dts/motorola-mapphone-common.dtsi
@@ -182,6 +182,14 @@ vibrator {
pwm-names = "enable", "direction";
direction-duty-cycle-ns = <10000000>;
};
+
+ backlight: backlight {
+ compatible = "led-backlight";
+
+ leds = <&backlight_led>;
+ brightness-levels = <31 63 95 127 159 191 223 255>;
+ default-brightness-level = <6>;
+ };
};

&dss {
@@ -205,6 +213,8 @@ lcd0: display {
vddi-supply = <&lcd_regulator>;
reset-gpios = <&gpio4 5 GPIO_ACTIVE_HIGH>; /* gpio101 */

+ backlight = <&backlight>;
+
width-mm = <50>;
height-mm = <89>;

@@ -393,12 +403,11 @@ led-controller@38 {
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 {
diff --git a/arch/arm/configs/omap2plus_defconfig b/arch/arm/configs/omap2plus_defconfig
--- a/arch/arm/configs/omap2plus_defconfig
+++ b/arch/arm/configs/omap2plus_defconfig
@@ -375,6 +375,7 @@ CONFIG_BACKLIGHT_GENERIC=m
CONFIG_BACKLIGHT_PWM=m
CONFIG_BACKLIGHT_PANDORA=m
CONFIG_BACKLIGHT_GPIO=m
+CONFIG_BACKLIGHT_LED=m
CONFIG_FRAMEBUFFER_CONSOLE=y
CONFIG_FRAMEBUFFER_CONSOLE_ROTATION=y
CONFIG_LOGO=y
--
2.25.1