[嵌入式]arm linux 中littlevgl支持tslib的方法

1. 修改文件 lv_drv_conf.h，使用 linux下的触摸屏文件节点 /dev/input/event0

????????将 # ?define USE_EVDEV??0? ? ?改为? ??# ?define USE_EVDEV? ?1

2. 修改文件 lv_drivers/input/evdev.c，添加使用 tslib库代码。修改后的 evdev.c如下

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

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

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <linux/input.h>

//添加tslib头文件
#include "../../tslib.h"

/*********************
 *      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;

//添加tslib结构体
struct tsdev *ts;

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

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

/**
 * Initialize the evdev interface
 */
void evdev_init(void)
{
//使用tslib库
    ts = ts_setup(NULL, 1);
    if (!ts)
    {
        perror("ts_setup");
        return;;
    }

    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);
     }
     evdev_fd = open(dev_name, O_RDWR | O_NOCTTY | O_NDELAY);

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

     fcntl(evdev_fd, F_SETFL, O_ASYNC | O_NONBLOCK);

     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
 */
bool evdev_read(lv_indev_drv_t * drv, lv_indev_data_t * data)
{
    // tslib
    struct ts_sample samp;
    int ret;

    /* 修改自tslib ts_print.c */
    while (ts_read(ts, &samp, 1) == 1)
    {
        //printf("%ld.%06ld: %6d %6d %6d\n", samp.tv.tv_sec, samp.tv.tv_usec, samp.x, samp.y, samp.pressure);
        #if EVDEV_SWAP_AXES
            evdev_root_x = samp.y;
            evdev_root_y = samp.x;
        #else
            evdev_root_x = samp.x;
            evdev_root_y = samp.y;
        #endif

        if(samp.pressure == 0)
            evdev_button = LV_INDEV_STATE_REL;      //抬起
        else if(samp.pressure < 255 && samp.pressure > 0)
            evdev_button = LV_INDEV_STATE_PR;       //按下
    }


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

#if EVDEV_CALIBRATE
    data->point.x = map(evdev_root_x, EVDEV_HOR_MIN, EVDEV_HOR_MAX, 0, lv_disp_get_hor_res(drv->disp));
    data->point.y = map(evdev_root_y, EVDEV_VER_MIN, EVDEV_VER_MAX, 0, lv_disp_get_ver_res(drv->disp));
#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 >= lv_disp_get_hor_res(drv->disp))
      data->point.x = lv_disp_get_hor_res(drv->disp) - 1;
    if(data->point.y >= lv_disp_get_ver_res(drv->disp))
      data->point.y = lv_disp_get_ver_res(drv->disp) - 1;

    return false;
}

/**********************
 *   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