root/include/linux/gpio_keys.h

#ifndef _GPIO_KEYS_H
#define _GPIO_KEYS_H

struct gpio_keys_button {
        /* Configuration parameters */
        int code;               /* input event code (KEY_*, SW_*) */
        int gpio;
        int active_low;
        char *desc;
        int type;               /* input event type (EV_KEY, EV_SW) */
        int wakeup;             /* configure the button as a wake-up source */
        int debounce_interval;  /* debounce ticks interval in msecs */
};

struct gpio_keys_platform_data {
        struct gpio_keys_button *buttons;
        int nbuttons;
};

#endif