Linux版LVGL v8 底层输入配置

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该代码实现了一个Linux输入设备驱动程序，用于处理Evdev接口。`evdev_init()`函数初始化Evdev接口，而`evdev_set_file()`函数允许重新配置设备文件。`evdev_read()`函数读取设备事件，处理鼠标、触摸屏等输入设备的坐标和按键状态。支持LVGL库的输入设备类型包括指针、键盘和按钮。

/**
 * @file evdev.c
 *
 */

/*********************
 *      INCLUDES
 *********************/
#include "evdev.h"
#if USE_EVDEV != 0 || USE_BSD_EVDEV

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#if USE_BSD_EVDEV
#include <dev/evdev/input.h>
#else
#include <linux/input.h>
#endif

/*********************
 *      DEFINES
 *********************/

/**********************
 *      TYPEDEFS
 **********************/

/**********************
 *  STATIC PROTOTYPES
 **********************/
int map(int x, int in_min, int in_max, int out_min, int out_max);

/**********************
 *  STATIC VARIABLES
 **********************/
int evdev_fd;
int evdev_root_x;
int evdev_root_y;
int evdev_button;

int evdev_key_val;

/**********************
 *      MACROS
 **********************/

/**********************
 *   GLOBAL FUNCTIONS
 **********************/

/**
 * Initialize the evdev interface
 */
void evdev_init(void)
{
#if USE_BSD_EVDEV
    evdev_fd = open(EVDEV_NAME, O_RDWR | O_NOCTTY);// #  define EVDEV_NAME 
  "/dev/input/event1" 
#else
    evdev_fd = open(EVDEV_NAME, O_RDWR | O_NOCTTY | O_NDELAY);
#endif
    if(evdev_fd == -1) {
        perror("unable open evdev interface:");
        return;
    }

#if USE_BSD_EVDEV
    fcntl(evdev_fd, F_SETFL, O_NONBLOCK);
#else
    fcntl(evdev_fd, F_SETFL, O_ASYNC | O_NONBLOCK);
#endif

    evdev_root_x = 0;
    evdev_root_y = 0;
    evdev_key_val = 0;
    evdev_button = LV_INDEV_STATE_REL;
}
/**
 * reconfigure the device file for evdev
 * @param dev_name set the evdev device filename
 * @return true: the device file set complete
 *         false: the device file doesn't exist current system
 */
bool evdev_set_file(char* dev_name)
{ 
     if(evdev_fd != -1) {
        close(evdev_fd);
     }
#if USE_BSD_EVDEV
     evdev_fd = open(dev_name, O_RDWR | O_NOCTTY);
#else
     evdev_fd = open(dev_name, O_RDWR | O_NOCTTY | O_NDELAY);
#endif

     if(evdev_fd == -1) {
        perror("unable open evdev interface:");
        return false;
     }

#if USE_BSD_EVDEV
     fcntl(evdev_fd, F_SETFL, O_NONBLOCK);
#else
     fcntl(evdev_fd, F_SETFL, O_ASYNC | O_NONBLOCK);
#endif

     evdev_root_x = 0;
     evdev_root_y = 0;
     evdev_key_val = 0;
     evdev_button = LV_INDEV_STATE_REL;

     return true;
}
/**
 * Get the current position and state of the evdev
 * @param data store the evdev data here
 * @return false: because the points are not buffered, so no more data to be read
 */
void evdev_read(lv_indev_drv_t * drv, lv_indev_data_t * data)
{
    struct input_event in;

    while(read(evdev_fd, &in, sizeof(struct input_event)) > 0) {
        if(in.type == EV_REL) {
            if(in.code == REL_X)
				#if EVDEV_SWAP_AXES
					evdev_root_y += in.value;
				#else
					evdev_root_x += in.value;
				#endif
            else if(in.code == REL_Y)
				#if EVDEV_SWAP_AXES
					evdev_root_x += in.value;
				#else
					evdev_root_y += in.value;
				#endif
        } else if(in.type == EV_ABS) {
            if(in.code == ABS_X)
				#if EVDEV_SWAP_AXES
					evdev_root_y = in.value;
				#else
					evdev_root_x = in.value;
				#endif
            else if(in.code == ABS_Y)
				#if EVDEV_SWAP_AXES
					evdev_root_x = in.value;
				#else
					evdev_root_y = in.value;
				#endif
            else if(in.code == ABS_MT_POSITION_X)
                                #if EVDEV_SWAP_AXES
                                        evdev_root_y = in.value;
                                #else
                                        evdev_root_x = in.value;
                                #endif
            else if(in.code == ABS_MT_POSITION_Y)
                                #if EVDEV_SWAP_AXES
                                        evdev_root_x = in.value;
                                #else
                                        evdev_root_y = in.value;
                                #endif
            else if(in.code == ABS_MT_TRACKING_ID)
                                if(in.value == -1)
                                    evdev_button = LV_INDEV_STATE_REL;
                                else if(in.value == 0)
                                    evdev_button = LV_INDEV_STATE_PR;
        } else if(in.type == EV_KEY) {
            if(in.code == BTN_MOUSE || in.code == BTN_TOUCH) {
                if(in.value == 0)
                    evdev_button = LV_INDEV_STATE_REL;
                else if(in.value == 1)
                    evdev_button = LV_INDEV_STATE_PR;
            } else if(drv->type == LV_INDEV_TYPE_KEYPAD) {
		data->state = (in.value) ? LV_INDEV_STATE_PR : LV_INDEV_STATE_REL;
		switch(in.code) {
			case KEY_BACKSPACE:
				data->key = LV_KEY_BACKSPACE;
				break;
			case KEY_ENTER:
				data->key = LV_KEY_ENTER;
				break;
			case KEY_UP:
				data->key = LV_KEY_UP;
				break;
			case KEY_LEFT:
				data->key = LV_KEY_PREV;
				break;
			case KEY_RIGHT:
				data->key = LV_KEY_NEXT;
				break;
			case KEY_DOWN:
				data->key = LV_KEY_DOWN;
				break;
			default:
				data->key = 0;
				break;
		}
		evdev_key_val = data->key;
		evdev_button = data->state;
		return ;
	    }
        }
    }

    if(drv->type == LV_INDEV_TYPE_KEYPAD) {
        /* No data retrieved */
        data->key = evdev_key_val;
	data->state = evdev_button;
	return ;
    }
    if(drv->type != LV_INDEV_TYPE_POINTER)
        return ;
    /*Store the collected data*/

#if EVDEV_CALIBRATE
    data->point.x = map(evdev_root_x, EVDEV_HOR_MIN, EVDEV_HOR_MAX, 0, drv->disp->driver->hor_res);
    data->point.y = map(evdev_root_y, EVDEV_VER_MIN, EVDEV_VER_MAX, 0, drv->disp->driver->ver_res);
#else
    data->point.x = evdev_root_x;
    data->point.y = evdev_root_y;
#endif

    data->state = evdev_button;

    if(data->point.x < 0)
      data->point.x = 0;
    if(data->point.y < 0)
      data->point.y = 0;
    if(data->point.x >= drv->disp->driver->hor_res)
      data->point.x = drv->disp->driver->hor_res - 1;
    if(data->point.y >= drv->disp->driver->ver_res)
      data->point.y = drv->disp->driver->ver_res - 1;

    return ;
}

/**********************
 *   STATIC FUNCTIONS
 **********************/
int map(int x, int in_min, int in_max, int out_min, int out_max)
{
  return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}

#endif

同时支持如下多个输入设备：

/** Possible input device types*/
typedef enum {
    LV_INDEV_TYPE_NONE,    /**< Uninitialized state*/
    LV_INDEV_TYPE_POINTER, /**< Touch pad, mouse, external button*/
    LV_INDEV_TYPE_KEYPAD,  /**< Keypad or keyboard*/
    LV_INDEV_TYPE_BUTTON,  /**< External (hardware button) which is assigned to a specific point of the screen*/
    LV_INDEV_TYPE_ENCODER, /**< Encoder with only Left, Right turn and a Button*/
} lv_indev_type_t;

在main函数下加入如下代码可以直接使用对应输入设备：

	evdev_init();
	
	lv_indev_drv_t indev_drv;
	
	lv_indev_drv_init(&indev_drv);
	
	indev_drv.type =LV_INDEV_TYPE_POINTER;
	
	indev_drv.read_cb =evdev_read;
	
	lv_indev_drv_register(&indev_drv);