採用procd和gpio-button-hotplug取樣按鈕

在openwrt中如何進行按鈕操作，有多中方法。我認為一種方法比較easy。參考1.3。該方法採用了gpio-button-hotplug (openwrt/package/kernel/gpio-button-hotplug)模組進行控制。

具體的步驟：

如果採用procd方式

需要建立指令碼到 /etc/rc.button/ 目錄。每個指令碼對應指定的按鈕。如果採用gpio-button-hotplug，需要建立指令碼到 /etc/hotplug.d/button/00-button，該指令碼處理按鈕資訊。參考openwrt網站資訊。

[email protected]:/# cat /sys/kernel/debug/gpio
GPIOs 0-31, platform/10000600.gpio, 10000600.gpio:
gpio-11  (bootstrap           ) out lo
gpio-14  (BTN_0               ) in  hi
gpio-15  (BTN_1               ) in  hi
gpio-16  (BTN_2               ) in  hi
gpio-17  (BNT_3               ) in  hi
gpio-18  (BTN_4               ) in
 
  hi
gpio-19  (BTN_5               ) in  hi

GPIOs 32-63, platform/10000600.gpio, 10000600.gpio:
gpio-38  (reset               ) in  hi

GPIOs 64-95, platform/10000600.gpio, 10000600.gpio:

GPIOs 127-127, platform/gpio-wifi, gpio-wifi:
gpio-127 (mediatek:orange:wifi) out ?

指令碼 GPIO 控制 //GPIO應用層控制

1 GPIO39引腳控制LED

匯出GPIO39引腳

  root@mylinkit:/sys/class/gpio# echo "39">export
  root@mylinkit:/sys/class/gpio# ls
  export       gpio39       gpiochip0    gpiochip127  gpiochip32   gpiochip64   unexport

定義GPIO39輸出

  root@mylinkit:/sys/class/gpio# cd gpio39
  root@mylinkit:/sys/devices/10000000.palmbus/10000600.gpio/gpio/gpio39# ls
  active_low  device      direction   edge        subsystem   uevent      value
  root@mylinkit:/sys/devices/10000000.palmbus/10000600.gpio/gpio/gpio39# cat direction
  in
  root@mylinkit:/sys/devices/10000000.palmbus/10000600.gpio/gpio/gpio39# echo "out" >direction
  root@mylinkit:/sys/devices/10000000.palmbus/10000600.gpio/gpio/gpio39# cat direction
  out

修改GPIO39輸出電平

  root@mylinkit:/sys/devices/10000000.palmbus/10000600.gpio/gpio/gpio39# cat value
  0
  root@mylinkit:/sys/devices/10000000.palmbus/10000600.gpio/gpio/gpio39# echo "1" > value
  root@mylinkit:/sys/devices/10000000.palmbus/10000600.gpio/gpio/gpio39# cat value
  1

1 檢測一個按鈕輸入

匯出GPIO

  root@mylinkit:/sys/class/gpio# echo "16">export
  root@mylinkit:/sys/class/gpio# ls
  export       gpio16       gpiochip0    gpiochip127  gpiochip32   gpiochip64   unexport
  root@mylinkit:/sys/class/gpio# cd gpio16
  root@mylinkit:/sys/devices/10000000.palmbus/10000600.gpio/gpio/gpio16# ls
  active_low  device      direction   edge        subsystem   uevent      value
  root@mylinkit:/sys/devices/10000000.palmbus/10000600.gpio/gpio/gpio16#

定義GPIO39輸入

  root@mylinkit:/sys/devices/10000000.palmbus/10000600.gpio/gpio/gpio16# cat direction
  in
  root@mylinkit:/sys/devices/10000000.palmbus/10000600.gpio/gpio/gpio16# echo "in">direction
  root@mylinkit:/sys/devices/10000000.palmbus/10000600.gpio/gpio/gpio16# cat direction
  in

檢測按鈕狀態 高電平/低電平

  root@mylinkit:/sys/devices/10000000.palmbus/10000600.gpio/gpio/gpio16# cat value
  1
  root@mylinkit:/sys/devices/10000000.palmbus/10000600.gpio/gpio/gpio16# cat value
  0