/*
 * vaio.c - brightness (and maybe volume) control for Sony Vaio PCG-C1VE
 *  and other related PCs.
 * Copyright (C) Nick Brown (nick.brown@coe.int), 2001.
 * GNU Public License applies (of course).
 *
 * Derived from GVaioControls by Drew Bertola
 *  (http://gvaiocontrols.serialhacker.net/) 
 * This version is command-line only, but can be run with setuid privileges.
 *
 * Revision history:
 * 2001-04-02	First release
 *
 * To build (wot, no Makefile ?):
 * gcc -o yourexename vaio.c
 */

#define BRIGHTNESS_REQ 0x96
#define BRIGHTNESS_DATA_REG 0x62
#define BRIGHTNESS_CST_REG  0x66

#include <sys/io.h>
#include <stdio.h>

typedef unsigned short u16;

static int verbose = 0;
static int relative = 0;
static int dump = 0;
static int brightness = 0;

static
void
brightness_set (u16 value)
{
/*
 * Next statement was in GVaioControls but condition doesn't always seem
 *  to be met, so program can loop forever.
 */
#if 0
  while (inw(BRIGHTNESS_CST_REG) & 3) {
    usleep(1);
  }
#endif

  outw(0x81, BRIGHTNESS_CST_REG);

  while (inw(BRIGHTNESS_CST_REG) & 2) {
    usleep(1);
  }
  outw(BRIGHTNESS_REQ, BRIGHTNESS_DATA_REG);

  while (inw(BRIGHTNESS_CST_REG) & 2) {
    usleep(1);
  }
  outw(value, BRIGHTNESS_DATA_REG);

  while (inw(BRIGHTNESS_CST_REG) & 2) {
    usleep(1);
  }
}

static
u16
brightness_get (void)
{
/*
 * Next statement was in GVaioControls but condition doesn't always seem
 *  to be met, so program can loop forever.
 */
#if 0
  while (inw(BRIGHTNESS_CST_REG) & 3) {
    usleep(1);
  }
#endif

  outb(0x80, BRIGHTNESS_CST_REG);

  while (inw(BRIGHTNESS_CST_REG) & 2) {
    usleep(1);
  }
  outb(BRIGHTNESS_REQ, BRIGHTNESS_DATA_REG);

  while (inw(BRIGHTNESS_CST_REG) & 2) {
    usleep(1);
  }
  return (inw(BRIGHTNESS_DATA_REG) & 255);
}

/*
 * Complain about command line syntax, and exit.
 */
static
void
usage (void)
{
  fprintf(stderr, "Usage: VAIO -b [-r] [-R] [-v] [-d] [brightness-value]\n");
  fprintf(stderr, "-b: specify brightness (mandatory; later versions may use other flags)\n");
  fprintf(stderr, "-d: write current value to stdout, brightness-value ignored\n");
  fprintf(stderr, "-r: brightness-value is relative positive (default is absolute)\n");
  fprintf(stderr, "-R: brightness-value is relative negative (default is absolute)\n");
  fprintf(stderr, "-v: verbose\n");
  fprintf(stderr, "brightness-value: brightness value, in range 0-255\n");

  exit(0);
}

/*
 * Here we go...
 */
int
main (int argc, char *argv [])
{
  int i;
  int n_parm = 0;
  u16 current = 0;
  int value;

  for (i = 1; i < argc; i++) {
    char *argp;

    if ((argp = argv[i])[0] == '-') {
      while (*++argp) {
        switch (*argp) {
          case 'b': {
            brightness = 1;
            break;
          }

          case 'd': {
            dump = 1;
            break;
          }

          case 'r': {
            relative = 1;
            break;
          }

          case 'R': {
            relative = -1;
            break;
          }

          case 'v': {
            verbose = 1;
            break;
          }

          default: {
            usage();
            break;
          }
        }
      }
    }
    else {
      switch (n_parm++) {
        case 0: {
          if ((sscanf(argv[i], "%d", &value)) != 1) {
            usage();
          }

          break;
        }

        default: {
          break;
        }
      }
    }
  }

  if (n_parm > 1) {
    usage();
  }

  if ((n_parm == 0) && (! dump)) {
    usage();
  }

  if (! brightness) {
    usage();
  }

  if (verbose) {
    fprintf(stderr, "Setting I/O permissions\n");
  }

  ioperm(BRIGHTNESS_DATA_REG, 0x08, 1);

  if (dump || relative) {
    if (verbose) {
      fprintf(stderr, "Getting current brightness value...");
    }

    current = brightness_get();

    if (verbose) {
      fprintf(stderr, " current value %d\n", current);
    }
  }

  if (dump) {
    printf("%d\n", current);
  }
  else {
    int new;

    if (relative) {
      new = ((value * relative) + current);
    }
    else {
      new = value;
    }

    if (new > 255) {
      new = 255;
    }
    else if (new < 0) {
      new = 0;
    }

    if (verbose) {
      fprintf(stderr, "Setting new brightness value %d...", (u16)new);
    }
  
    brightness_set(new);
  
    if (verbose) {
      fprintf(stderr, " done\n");
    }
  }

  return 1;
}