The LCD backlight on the A23/A33 Q8 format tablets is enabled with a GPIO controlled regulator, and brightness controlled with the SoC's PWM controller.
The backlight is powered from the AXP223 PMIC's DC1SW output, which is not supported yet. A proper bootloader is required to enable it. The brightness levels are arbitrary. The FEX files do not have such information. As such, actual brightness levels may differ from device to device. Signed-off-by: Chen-Yu Tsai <w...@csie.org> --- arch/arm/boot/dts/sun8i-q8-common.dtsi | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/arch/arm/boot/dts/sun8i-q8-common.dtsi b/arch/arm/boot/dts/sun8i-q8-common.dtsi index 4c2d0b459d6f..8a56ff567911 100644 --- a/arch/arm/boot/dts/sun8i-q8-common.dtsi +++ b/arch/arm/boot/dts/sun8i-q8-common.dtsi @@ -41,11 +41,24 @@ */ #include "sunxi-q8-common.dtsi" +#include <dt-bindings/pwm/pwm.h> + / { aliases { serial0 = &r_uart; }; + backlight: backlight { + compatible = "pwm-backlight"; + pinctrl-names = "default"; + pinctrl-0 = <&bl_en_pin_q8>; + pwms = <&pwm 0 50000 PWM_POLARITY_INVERTED>; + brightness-levels = <0 10 20 30 40 50 60 70 80 90 100>; + default-brightness-level = <8>; + enable-gpios = <&pio 7 6 GPIO_ACTIVE_HIGH>; /* PH6 */ + /* backlight is powered by AXP223 DC1SW */ + }; + chosen { stdout-path = "serial0:115200n8"; }; @@ -62,6 +75,13 @@ }; &pio { + bl_en_pin_q8: bl_en_pin@0 { + allwinner,pins = "PH6"; + allwinner,function = "gpio_in"; + allwinner,drive = <SUN4I_PINCTRL_10_MA>; + allwinner,pull = <SUN4I_PINCTRL_NO_PULL>; + }; + mmc0_cd_pin_q8: mmc0_cd_pin@0 { allwinner,pins = "PB4"; allwinner,function = "gpio_in"; -- 2.5.1 -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to linux-sunxi+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.