Gpio control for keys and lights in the OpenWrt

Based on the Barrierbreaker version, the description is based on the AR9331 AP121 demo veneer

1. Lamp

A. In mach-ap121.c, the definition of the gpio corresponding to the lamp is defined:

#define Ap121_gpio_led_wlan0

#define Ap121_gpio_led_usb1

and defines the GPIO structure object for the lamp:

static struct gpio_led ap121_leds_gpio[] __initdata = {{. Name= "Ap121:green:usb",. Gpio= Ap121_gpio_led_usb,. active_low= 0,},{. Name= "Ap121:green:wlan",. Gpio= Ap121_gpio_led_wlan,. active_low= 0,},

}

In the initialization function: ap121_setup  , using the Span style= "line-height:1.5;" >ath79_register_leds_gpio ( -1, Array_size (Ap121_leds_gpio),   ap121_ Leds_gpio), enabling the registration of LED device. After this function is called, a device of type platform is created, and the leds-gpio driver (LEDS-GPIO.C) implements Bindings. In this way, the control directory for the corresponding LED lights is generated in the /sys/devices/platform/leds-gpio/directory:

Drwxr-xr-x    2 root     root             0 Jan  1  1970  Ap121:green:usbdrwxr-xr-x    2 root     root             0 Jan  1 & Nbsp;1970 ap121:green:wlanb. Enter any of the above directories, such as: Ap121:green:wlan, will have the following files:-rw-r--r--   1 root     Root          4096 Jan 06:19 brightness lrwxrwxrwx    1 root     root             0 Jan 06:04 device. /.. /.. /leds-gpio-r--r--r--   1 root     root          4096 Jan 06:04 max_bright nesslrwxrwxrwx    1 root     root             0 Jan 06:04 Subsystem- >.. /.. /.. /.. /.. /class/leds-rw-r--r--   1 root     root          4096 Jan 06:04 trigger-r w-r--r--   1 root     root         4096 Jan 06:04 uevent

With echo 1 > Brightness, you can control the lights, echo 0 > brightness,

2. Keys

A. In Mach-ap121.c, a gpio and a data structure object are defined for the keystrokes:

#define Ap121_gpio_btn_jumpstart11

#define Ap121_gpio_btn_reset12

And

static struct Gpio_keys_button ap121_gpio_keys[] __initdata = {{. desc= "Jumpstart Button",. type= Ev_key,. Code= Key_wps_button,//defined in GPIO-BUTTON-HOTPLUG.C. Debounce_interval = Ap121_keys_debounce_interval,. Gpio= Ap121_gpio_btn_jumpstart,. active_low= 1,},{. desc= "reset Button",. type= Ev_key,. Code= Key_restart,//defined in GPIO-BUTTON-HOTPLUG.C. Debounce_interval = Ap121_keys_debounce_interval,. Gpio= Ap121_gpio_btn_reset,. active_low= 1,},

}

in the initialization function: Ap121_setup , the use of

Ath79_register_gpio_keys_polled ( -1, Ap121_keys_poll_interval,array_size (Ap121_gpio_keys),Ap121_gpio_keys);

the registration of key device is implemented. After this function is called, the platform type device is created, and the gpio-keys-polled driver (gpio-button-hotplug.c
) implements the binding.

B.

When the key is pressed, the Button_hotplug_event function (GPIO-BUTTON-HOTPLUG.C) is triggered: Call Button_hotplug_create_event to generate Uevent event, call Button_hotplug _fill_even fills the event (in JSON format) and eventually calls Button_hotplug_work to issue uevent broadcast above broadcast, being PROCD in the process of Hotplug_handler (PROCD/PLUG/HOTPLUG.C) Receive and navigate to the corresponding execution function according to the pre-defined JSON content matching criteria in Etc/hotplug.json, as follows:["If",["and",["Has", "button"],["EQ", "SUBSYSTEM", "button"],],["Exec", "/etc/rc.button/%button%"]], and["If",["EQ", "SUBSYSTEM",["NET", "input", "USB", "ieee1394", "Block", "ATM", "Zaptel", "TTY", "button"]],["Exec", "/sbin/hotplug-call", "%subsystem%"]],

Gpio control for keys and lights in the OpenWrt