在fsl-imx8qm-mek.dtsi添加如下内容:
步骤1;
gen_backlight0: gen_backlight@0 {
compatible = "pwm-backlight";
pwms = <&pwm0 0 100000 0>;
brightness-levels = < 0 1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19
20 21 22 23 24 25 26 27 28 29
30 31 32 33 34 35 36 37 38 39
40 41 42 43 44 45 46 47 48 49
50 51 52 53 54 55 56 57 58 59
60 61 62 63 64 65 66 67 68 69
70 71 72 73 74 75 76 77 78 79
80 81 82 83 84 85 86 87 88 89
90 91 92 93 94 95 96 97 98 99
100>;
default-brightness-level = <60>;
};
};
步骤2:
pinctrl_pwm0_lsio: pwm0grp {
fsl,pins = <
//SC_P_UART1_TX_LSIO_PWM0_OUT 0x0000020
SC_P_MIPI_DSI0_GPIO0_00_MIPI_DSI0_PWM0_OUT 0x00000020 //20200910
>;
};
步骤3:
&pwm0{
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_pwm0_lsio>;
status = "okay";
};
串口消息:
[ 1.412894] pwm-backlight gen_backlight@0: gen_backlight@0 supply power not found, using dummy regulator
[ 1.422349] pwm-backlight gen_backlight@0: Linked as a consumer to regulator.0
[ 1.440864] Bus freq driver module loaded
串口输入命令:
root@imx8qmmek:/sys/class/backlight/gen_backlight@0# ls
actual_brightness brightness max_brightness subsystem uevent
bl_power device power type
root@imx8qmmek:/sys/class/backlight/gen_backlight@0#
root@imx8qmmek:/sys/class/backlight/gen_backlight@0#
root@imx8qmmek:/sys/class/backlight/gen_backlight@0# echo 50 >brightness
root@imx8qmmek:/sys/class/backlight/gen_backlight@0# cat brightness 50
According to the pads-imx8qm.h, the name of the pin should be
IMX8QM_MIPI_DSI0_GPIO0_00_MIPI_DSI0_PWM0_OUT