Difference between revisions of "PWM"

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(updated by API)
(updated by API)
 
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[[PWM/zh|查看中文]]
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[[PWM/zh|查看中文]]<br>
===H3上配置SYS_PWM===
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TODO
====先确定内核已经打了这个补丁====
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<syntaxhighlight lang="bash">
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https://github.com/torvalds/linux/commit/179a79fd740b6b2f66b64bae5cb6ecd483987d20
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</syntaxhighlight>
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====编译内核配置 SYS_PWM (在NanoPi NEO上, 引脚与POWER LED复用)====
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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:
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<syntaxhighlight lang="bash">
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diff --git a/arch/arm/boot/dts/sun8i-h3-nanopi-neo.dts b/arch/arm/boot/dts/sun8i-h3-nanopi-neo.dts
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index b9826c150c0a..ca62502ad9a3 100644
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--- a/arch/arm/boot/dts/sun8i-h3-nanopi-neo.dts
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+++ b/arch/arm/boot/dts/sun8i-h3-nanopi-neo.dts
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@@ -45,6 +45,10 @@
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/ {
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        model = "FriendlyElec NanoPi-NEO";
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        compatible = "friendlyelec,nanopi-neo", "allwinner,sun8i-h3";
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+
+
+      aliases {
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+              pwm1 = &r_pwm;
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+      };
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};
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+
&emac {
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@@ -52,4 +56,14 @@
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        phy-mode = "mii";
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        allwinner,leds-active-low;
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        status = "okay";
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-};
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\ No newline at end of file
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+};
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+
+
+&gpio_leds {
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+      pinctrl-0 = <&leds_npi>;
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+
+
+      /delete-node/ pwr;
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+};
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+
+
+&r_pwm {
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+      status = "okay";
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+};
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diff --git a/arch/arm/boot/dts/sun8i-h3-nanopi.dtsi b/arch/arm/boot/dts/sun8i-h3-nanopi.dtsi
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index 5eeb41744735..1802f8ca2c56 100644
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--- a/arch/arm/boot/dts/sun8i-h3-nanopi.dtsi
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+++ b/arch/arm/boot/dts/sun8i-h3-nanopi.dtsi
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@@ -89,7 +89,7 @@
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                };
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        };
+
       
+
-      leds {
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+      gpio_leds: leds {
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                compatible = "gpio-leds";
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                pinctrl-names = "default";
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                pinctrl-0 = <&leds_npi>, <&leds_r_npi>;
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</syntaxhighlight>
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====在NanoPi NEO上测试, 可看到 POWER LED闪烁====
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<syntaxhighlight lang="bash">
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#!/bin/bash
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sys_pwm=/sys/class/pwm/pwmchip0
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[ -d $sys_pwm ] || exit 1
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if [ ! -d $sys_pwm/pwm0 ]; then
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    echo 0 > $sys_pwm/export
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fi
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echo 1000 > $sys_pwm/pwm0/period
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echo 1 > $sys_pwm/pwm0/enable
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for n in $(seq 10); do
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    for d in $(seq 0 50 1000); do
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        echo $d > $sys_pwm/pwm0/duty_cycle
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        sleep .02
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    done
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    sleep 1
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done
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</syntaxhighlight>
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Latest revision as of 03:52, 6 January 2022

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TODO