Difference between revisions of "PWM"
From FriendlyELEC WiKi
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| − | [[PWM/zh|查看中文]]< | + | [[PWM/zh|查看中文]] |
| − | + | ===H3上配置SYS_PWM=== | |
| + | ====先确定内核已经打了这个补丁==== | ||
| + | <syntaxhighlight lang="bash"> | ||
| + | https://github.com/torvalds/linux/commit/179a79fd740b6b2f66b64bae5cb6ecd483987d20 | ||
| + | </syntaxhighlight> | ||
| + | 注: FriendlyELEC的内核源代码分支 https://github.com/friendlyarm/linux/tree/sunxi-4.14.y 已包含此提交。 | ||
| + | ====修改内核dts配置, 启用SYS_PWM (在NanoPi NEO上, 引脚与POWER LED复用)==== | ||
| + | 参考以下补丁, 配置POWER LED对应的引脚为PWM功能，然后编译并测试: | ||
| + | <syntaxhighlight lang="bash"> | ||
| + | diff --git a/arch/arm/boot/dts/sun8i-h3-nanopi-neo.dts b/arch/arm/boot/dts/sun8i-h3-nanopi-neo.dts | ||
| + | index b9826c150c0a..ca62502ad9a3 100644 | ||
| + | --- a/arch/arm/boot/dts/sun8i-h3-nanopi-neo.dts | ||
| + | +++ b/arch/arm/boot/dts/sun8i-h3-nanopi-neo.dts | ||
| + | @@ -45,6 +45,10 @@ | ||
| + | / { | ||
| + | model = "FriendlyElec NanoPi-NEO"; | ||
| + | compatible = "friendlyelec,nanopi-neo", "allwinner,sun8i-h3"; | ||
| + | + | ||
| + | + aliases { | ||
| + | + pwm1 = &r_pwm; | ||
| + | + }; | ||
| + | }; | ||
| + | |||
| + | &emac { | ||
| + | @@ -52,4 +56,14 @@ | ||
| + | phy-mode = "mii"; | ||
| + | allwinner,leds-active-low; | ||
| + | status = "okay"; | ||
| + | -}; | ||
| + | \ No newline at end of file | ||
| + | +}; | ||
| + | + | ||
| + | +&gpio_leds { | ||
| + | + pinctrl-0 = <&leds_npi>; | ||
| + | + | ||
| + | + /delete-node/ pwr; | ||
| + | +}; | ||
| + | + | ||
| + | +&r_pwm { | ||
| + | + status = "okay"; | ||
| + | +}; | ||
| + | diff --git a/arch/arm/boot/dts/sun8i-h3-nanopi.dtsi b/arch/arm/boot/dts/sun8i-h3-nanopi.dtsi | ||
| + | index 5eeb41744735..1802f8ca2c56 100644 | ||
| + | --- a/arch/arm/boot/dts/sun8i-h3-nanopi.dtsi | ||
| + | +++ b/arch/arm/boot/dts/sun8i-h3-nanopi.dtsi | ||
| + | @@ -89,7 +89,7 @@ | ||
| + | }; | ||
| + | }; | ||
| + | |||
| + | - leds { | ||
| + | + gpio_leds: leds { | ||
| + | compatible = "gpio-leds"; | ||
| + | pinctrl-names = "default"; | ||
| + | pinctrl-0 = <&leds_npi>, <&leds_r_npi>; | ||
| + | </syntaxhighlight> | ||
| + | ====测试脚本==== | ||
| + | 在NanoPi NEO上测试, 可看到POWER LED以淡出效果闪烁10次: | ||
| + | <syntaxhighlight lang="bash"> | ||
| + | #!/bin/bash | ||
| + | |||
| + | sys_pwm=/sys/class/pwm/pwmchip0 | ||
| + | |||
| + | [ -d $sys_pwm ] || exit 1 | ||
| + | |||
| + | if [ ! -d $sys_pwm/pwm0 ]; then | ||
| + | echo 0 > $sys_pwm/export | ||
| + | fi | ||
| + | |||
| + | echo 1000 > $sys_pwm/pwm0/period | ||
| + | echo 1 > $sys_pwm/pwm0/enable | ||
| + | |||
| + | for n in $(seq 10); do | ||
| + | for d in $(seq 0 50 1000); do | ||
| + | echo $d > $sys_pwm/pwm0/duty_cycle | ||
| + | sleep .02 | ||
| + | done | ||
| + | sleep 1 | ||
| + | done | ||
| + | </syntaxhighlight> | ||
Revision as of 03:50, 6 January 2022
Contents
1 H3上配置SYS_PWM
1.1 先确定内核已经打了这个补丁
https://github.com/torvalds/linux/commit/179a79fd740b6b2f66b64bae5cb6ecd483987d20
注: FriendlyELEC的内核源代码分支 https://github.com/friendlyarm/linux/tree/sunxi-4.14.y 已包含此提交。
1.2 修改内核dts配置, 启用SYS_PWM (在NanoPi NEO上, 引脚与POWER LED复用)
参考以下补丁, 配置POWER LED对应的引脚为PWM功能，然后编译并测试:
diff --git a/arch/arm/boot/dts/sun8i-h3-nanopi-neo.dts b/arch/arm/boot/dts/sun8i-h3-nanopi-neo.dts index b9826c150c0a..ca62502ad9a3 100644 --- a/arch/arm/boot/dts/sun8i-h3-nanopi-neo.dts +++ b/arch/arm/boot/dts/sun8i-h3-nanopi-neo.dts @@ -45,6 +45,10 @@ / { model = "FriendlyElec NanoPi-NEO"; compatible = "friendlyelec,nanopi-neo", "allwinner,sun8i-h3"; + + aliases { + pwm1 = &r_pwm; + }; }; &emac { @@ -52,4 +56,14 @@ phy-mode = "mii"; allwinner,leds-active-low; status = "okay"; -}; \ No newline at end of file +}; + +&gpio_leds { + pinctrl-0 = <&leds_npi>; + + /delete-node/ pwr; +}; + +&r_pwm { + status = "okay"; +}; diff --git a/arch/arm/boot/dts/sun8i-h3-nanopi.dtsi b/arch/arm/boot/dts/sun8i-h3-nanopi.dtsi index 5eeb41744735..1802f8ca2c56 100644 --- a/arch/arm/boot/dts/sun8i-h3-nanopi.dtsi +++ b/arch/arm/boot/dts/sun8i-h3-nanopi.dtsi @@ -89,7 +89,7 @@ }; }; - leds { + gpio_leds: leds { compatible = "gpio-leds"; pinctrl-names = "default"; pinctrl-0 = <&leds_npi>, <&leds_r_npi>;
1.3 测试脚本
在NanoPi NEO上测试, 可看到POWER LED以淡出效果闪烁10次:
#!/bin/bash sys_pwm=/sys/class/pwm/pwmchip0 [ -d $sys_pwm ] || exit 1 if [ ! -d $sys_pwm/pwm0 ]; then echo 0 > $sys_pwm/export fi echo 1000 > $sys_pwm/pwm0/period echo 1 > $sys_pwm/pwm0/enable for n in $(seq 10); do for d in $(seq 0 50 1000); do echo $d > $sys_pwm/pwm0/duty_cycle sleep .02 done sleep 1 done
