液晶背光外设配置
PanGu开发板支持对LCD液晶屏的背光控制,降低背光可以减少产品整体的功耗,也保护液晶长时间高亮带来的损耗情况。Linux kernel中对于背光的控制支持多种方式,GPIO控制,PWM控制。PanGu开发板使用PWM方式控制LCD液晶的背光亮度,对应的驱动是pwm-backlight,使用pwm2产品PWM波形来控制背光亮度。
PWM控制LCD背光的dts代码如下,
panel_backlight: panel-backlight {
compatible = "pwm-backlight";
pwms = <&pwm2 0 5000000>;
brightness-levels = <0 4 8 16 32 64 128 255>;
default-brightness-level = <6>;
status = "okay";
};
&pinctrl {
pwm2_pins_b: pwm2-0 {
pins {
pinmux = <STM32_PINMUX('A', 5, AF1)>; /* TIM2_CH1 */
bias-pull-down;
drive-push-pull;
slew-rate = <0>;
};
};
pwm2_sleep_pins_b: pwm2-sleep-0 {
pins {
pinmux = <STM32_PINMUX('A', 5, ANALOG)>; /* TIM2_CH1 */
};
};
};
&timers2 {
status = "okay";
/* spare dmas for other usage */
/delete-property/dmas;
/delete-property/dma-names;
pwm2: pwm {
pinctrl-0 = <&pwm2_pins_b>;
pinctrl-1 = <&pwm2_sleep_pins_b>;
pinctrl-names = "default", "sleep";
#pwm-cells = <2>;
status = "okay";
};
timer@1 {
status = "disabled";
};
};
作者:SteveChen 创建时间:2024-09-18 14:48
最后编辑:SteveChen 更新时间:2024-09-18 14:48
最后编辑:SteveChen 更新时间:2024-09-18 14:48