Bit by bit analysis Linkit™smart 7688 button operation

using the ProCD and Gpio-button-hotplug sampling buttons

There are many ways to do a button operation in OpenWrt. I think one method is easier. Reference 1.3. The method is controlled by the Gpio-button-hotplug (openwrt/package/kernel/gpio-button-hotplug) module.

Specific steps: Modify the Target/linux/ramips/dts/linkit7688.dts. Configure the relevant buttons as gpio-button-hotplug approved buttons. Compile the system reference Https://wiki.openwrt.org/doc/howto/hardware.button?s[]=button&s[]=hotplug document for operation.
So easy. If you use the ProCD method

You need to create a script to the/etc/rc.button/directory. Each script corresponds to the specified button. If you use Gpio-button-hotplug, you need to create a script to/etc/hotplug.d/button/00-button that handles the button information. Refer to OpenWrt website information.

root@mylinkit:/# 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?

Script GPIO Control//gpio Application Layer Control

Https://wiki.openwrt.org/doc/howto/hardware.button
Https://wiki.openwrt.org/doc/hardware/port.gpio?s[]=kmod&s[]=leds&s[]=gpio
Https://wiki.openwrt.org/doc/howto/hardware.button#preliminary.steps

http://wiki.wrtnode.cc/index.php?title= User-space Gpio calls

1 GPIO39 pin control led

Export GPIO39 Pin

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

Defining the GPIO39 Output

  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
  

Modifying the GPIO39 output level

  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 Detecting a button input

Export Gpio

  root@mylinkit:/sys/class/gpio# echo ">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#

Define GPIO39 Input

  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
  

Detect button status High/low level

  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