rv1106 PWM控制

修改设备树

修改设备树，添加PWM0_M0 ， PWM3_IR_M1， PWM7_IR_M1
注意 rv1106g2-ipc.dtsi的vdd-arm已经占用PWM0_M0，要将其取消

vdd_arm: vdd-arm {
		// compatible = "pwm-regulator";
		// pwms = <&pwm0 0 5000 1>;
		compatible = "regulator-fixed";
		regulator-name = "vdd_arm";
		regulator-min-microvolt = <724000>;
		regulator-max-microvolt = <1078000>;
		regulator-init-microvolt = <950000>;
		regulator-always-on;
		regulator-boot-on;
		regulator-settling-time-up-us = <250>;
	};

在rv1106g2-ipc.dts中添加各个pwm

&pinctrl {
	sdmmc {
		/omit-if-no-ref/
		sdmmc_pwren: sdmmc-pwren {
			rockchip,pins = <0 RK_PA1 RK_FUNC_GPIO &pcfg_pull_none>;
		};
	};

	pwm0 {
		/omit-if-no-ref/
		pwm0m0_pins: pwm0m0-pins {
			rockchip,pins =
				/* pwm0_m0 */
				<1 RK_PA2 1 &pcfg_pull_none>;
		};
	};

	pwm3 {

		/omit-if-no-ref/
		pwm3m1_pins: pwm3m1-pins {
			rockchip,pins =
				/* pwm3_ir_m1 */
				<1 RK_PB0 2 &pcfg_pull_none>;
		};
	};

	pwm7 {

		/omit-if-no-ref/
		pwm7m1_pins: pwm7m1-pins {
			rockchip,pins =
				/* pwm7_ir_m1 */
				<1 RK_PB1 2 &pcfg_pull_none>;
		};
	};
};

&pwm0 {
	status = "okay";
	pinctrl-0 = <&pwm0m1_pins>;
};

&pwm3 {
	status = "okay";
	pinctrl-0 = <&pwm3m1_pins>;
};

&pwm7 {
	status = "okay";
	pinctrl-0 = <&pwm7m1_pins>;
};

重新生成固件，烧录后进入sys

[root@luckfox root]# cd /sys/class/pwm/
[root@luckfox pwm]# ls
pwmchip0  pwmchip3  pwmchip7

已经可以见到pwm0，pwm3， pwm7

通过sysfs对pwm操作

导出pwm0m0

[root@luckfox pwm]# echo 0 > ./pwmchip0/export
[root@luckfox pwm]# ls ./pwmchip0/
device     export     npwm       power      pwm0       subsystem  uevent     unexport

可见pwm0的pwm0已经导出

[root@luckfox pwm0]# ls ./ -al
total 0
drwxr-xr-x    3 root     root             0 Mar 13 17:44 .
drwxr-xr-x    4 root     root             0 Mar 13 17:44 ..
-r--r--r--    1 root     root          4096 Mar 13 17:46 capture
-rw-r--r--    1 root     root          4096 Mar 13 17:46 duty_cycle
-rw-r--r--    1 root     root          4096 Mar 13 17:46 enable
-r--r--r--    1 root     root          4096 Mar 13 17:46 output_type
-rw-r--r--    1 root     root          4096 Mar 13 17:46 period
-rw-r--r--    1 root     root          4096 Mar 13 17:46 polarity
drwxr-xr-x    2 root     root             0 Mar 13 17:46 power
-rw-r--r--    1 root     root          4096 Mar 13 17:46 uevent

[root@luckfox pwm0]# cat ./capture
cat: read error: Function not implemented
[root@luckfox pwm0]# cat ./duty_cycle
0  #1的时间
[root@luckfox pwm0]# cat ./enable
0  #开启
[root@luckfox pwm0]# cat ./output_type
fixed
[root@luckfox pwm0]# cat ./period
0    #周期时间 ns计算 如1000hz周期时间为1000000
[root@luckfox pwm0]# cat ./polarity
inversed   #极性 反相，值越大，高电平越少

测试

[root@luckfox pwm0]# echo 1000000 > ./period #设置频率为1KHZ
[root@luckfox pwm0]# echo normal > ./polarity #设置极性为正常，duty_cycle越大越亮
[root@luckfox pwm0]# echo 1 > ./enable #打开PWM0M0输出
[root@luckfox pwm0]# echo 300000 > ./duty_cycle # %30占空比
[root@luckfox pwm0]# echo 500000 > ./duty_cycle # %50占空比
[root@luckfox pwm0]# echo 700000 > ./duty_cycle # %70占空比
[root@luckfox pwm0]# echo 900000 > ./duty_cycle # %90占空比
[root@luckfox pwm0]# echo 1000000 > ./duty_cycle # %100占空比

随着duty_cycle的变大，LED越亮。

注意RKIPC已经占用PWM3，RKIPC初始化时会亮灯