PandaBoard Button
UserSpace Access
the push button can be accessed via the sysfs interface as well as a shell script functionality. the sysfs entry for the push button can be found in the directory marked /sys/devices/platform/ . each button will be listed as gpio-keys follow by a number.
Adding New PushButtons
the gpio buttons are defined in the linux kernel machine file. in this case for pandaboard it would be in arch/arm/mach-omap2/board-omap4panda.c file. each button requires that the gpio be defined, a name, and key scan code associated with it. in addition standard platform data and platform device have to be defined.
static struct gpio_keys_button gpio_keys_buttons[] = { [0] = { .code = 0x26, .gpio = 39, .active_low = 0, .desc = "PB0", }, }; static struct gpio_keys_platform_data gpio_keys_data = { .buttons = gpio_keys_buttons, .nbuttons = ARRAY_SIZE(gpio_keys_buttons), }; static struct platform_device pandaboard_buttons = { .name = "gpio-keys", .id = 0, .dev = { .platform_data = &gpio_keys_data, }, };