source: npl/mediabox/lcdproc_edwin/src/server/drivers/joy.c

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <termios.h>
#include <fcntl.h>
#include <string.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include <sys/types.h>


#define __u32 unsigned int
#define __u8 unsigned char
#include <linux/joystick.h>


#include "../../shared/debug.h"
#include "../../shared/str.h"

#define NAME_LENGTH 128



#include "lcd.h"
#include "joy.h"



//////////////////////////////////////////////////////////////////////////
////////////////////// Base "class" to derive from ///////////////////////
//////////////////////////////////////////////////////////////////////////

lcd_logical_driver *joy;

int fd;

struct js_event js;

char axes = 2;
char buttons = 2;
int jsversion = 0x000800;
char jsname[NAME_LENGTH] = "Unknown";

int *axis;
int *button;


// Configured for a Gravis Gamepad  (2 axis, 4 button)
char *axismap   = "EFGHIJKLMNOPQRST";
char *buttonmap = "BDACEFGHIJKLMNOP";


////////////////////////////////////////////////////////////
// init() should set up any device-specific stuff, and
// point all the function pointers.
int joy_init(struct lcd_logical_driver *driver, char *args) 
{
   char device[256];
   char *argv[64];
   int argc, i, j;
   
   joy = driver;

   
   strcpy(device, "/dev/js0");

   argc = get_args(argv, args, 64);

   for(i=0; i<argc; i++)
   {
      //printf("Arg(%i): %s\n", i, argv[i]);
      if(0 == strcmp(argv[i], "-d")  ||
         0 == strcmp(argv[i], "--device"))
      {
         if(i + 1 > argc) {
            fprintf(stderr, "joy_init: %s requires an argument\n",
                    argv[i]);
            return -1;
         }
         strcpy(device, argv[++i]);
      }
      else if(0 == strcmp(argv[i], "-a")  ||
         0 == strcmp(argv[i], "--axes"))
      {
         if(i + 1 > argc) {
            fprintf(stderr, "joy_init: %s requires an argument\n",
                    argv[i]);
            return -1;
         }
         strncpy(axismap, argv[++i], 16);
      }
      else if(0 == strcmp(argv[i], "-b")  ||
         0 == strcmp(argv[i], "--buttons"))
      {
         if(i + 1 > argc) {
            fprintf(stderr, "joy_init: %s requires an argument\n",
                    argv[i]);
            return -1;
         }
         strncpy(buttonmap, argv[++i], 16);
      }
      else if(0 == strcmp(argv[i], "-h")  ||
         0 == strcmp(argv[i], "--help"))
      {
         printf("LCDproc Joystick input driver\n"
                "\t-d\t--device\tSelect the input device to use [/dev/js0]\n"
                "\t-a\t--axes\t\tModify the axis map [%s]\n"
                "\t-b\t--buttons\tModify the button map [%s]\n"
                "\t-h\t--help\t\tShow this help information\n",
                axismap, buttonmap);
         return -1;
      }
      else
      {
         printf("Invalid parameter: %s\n", argv[i]);
      }
      
   }
   
   
   
   
   
   driver->getkey = joy_getkey;
   driver->close = joy_close;


   /*  FIXME:  This crashes!
   if(args)
   {
      if(strlen(args) > 0)
         strcpy(device, args);
   }
   */
   
   fd = open (device, O_RDONLY);
   fcntl(fd, F_SETFL, O_NONBLOCK);

   if(fd < 0) return -1;
   
   ioctl(fd, JSIOCGVERSION, &jsversion);
   ioctl(fd, JSIOCGAXES, &axes);
   ioctl(fd, JSIOCGBUTTONS, &buttons);
   ioctl(fd, JSIOCGNAME(NAME_LENGTH), jsname);
   
   debug("Joystick (%s) has %d axes and %d buttons. Driver version is %d.%d.%d.\n",
          jsname, axes, buttons,
          jsversion >> 16, (jsversion >> 8) & 0xff, jsversion & 0xff);
   
   axis = calloc(axes, sizeof(int));
   button = calloc(buttons, sizeof(char));

   return fd;  // 200 is arbitrary.  (must be 1 or more)
}


void joy_close() 
{
  if(joy->framebuf != NULL) free(joy->framebuf);
  close(fd);
  
  joy->framebuf = NULL;

  // Why do I have so much trouble getting memory freed without segfaults??
  //if(axis) free(axis);
  //if(button) free(button);
  
}


//////////////////////////////////////////////////////////////////////
// Tries to read a character from an input device...
//
// Return 0 for "nothing available".
//
char joy_getkey()
{
   int i;
   int err;
   
   err = read(fd, &js, sizeof(struct js_event));
   if (err <= 0) return 0;
   if (err != sizeof(struct js_event)) {
      fprintf(stderr, "\nerror reading joystick\n");
      return 0;
   }

//   if(js.type & JS_EVENT_INIT) return 0;
   
   switch(js.type & ~JS_EVENT_INIT) {
      case JS_EVENT_BUTTON:
         button[js.number] = js.value;
         break;
      case JS_EVENT_AXIS:
         axis[js.number] = js.value;
         break;
   }

   if (buttons) {
      //printf("Buttons: ");
      for (i = 0; i < buttons; i++)
         //printf("%2d:%s ", i, button[i] ? "on " : "off");
         if(button[i]) return buttonmap[i];
   }

   if (axes) {
      //printf("Axes: ");
      for (i = 0; i < axes; i++)
      {
         //printf("%2d:%6d ", i, axis[i]);
         // Eliminate noise...
         if(axis[i] > 20000) return axismap[(2*i) + 1];
         if(axis[i] < -20000) return axismap[(2*i)];
      }
   }
   
   return 0;
}