mixer_alsa.c

   1 /*
   2  * Copyright 2004-2005 Timo Hirvonen
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation; either version 2 of the
   7  * License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  17  * 02111-1307, USA.
  18  */
  19
  20 #include "mixer.h"
  21 #include "op.h"
  22 #include "xmalloc.h"
  23 #include "debug.h"
  24
  25 #define ALSA_PCM_NEW_HW_PARAMS_API
  26 #define ALSA_PCM_NEW_SW_PARAMS_API
  27
  28 #include <alsa/asoundlib.h>
  29
  30 static snd_mixer_t *alsa_mixer_handle;
  31 static snd_mixer_elem_t *mixer_elem = NULL;
  32 static long mixer_vol_min, mixer_vol_max;
  33
  34 /* configuration */
  35 static char *alsa_mixer_device = NULL;
  36 static char *alsa_mixer_element = NULL;
  37
  38 static int alsa_mixer_init(void)
  39 {
  40         if (alsa_mixer_device == NULL)
  41                 alsa_mixer_device = xstrdup("default");
  42         if (alsa_mixer_element == NULL)
  43                 alsa_mixer_element = xstrdup("PCM");
  44         /* FIXME: check device */
  45         return 0;
  46 }
  47
  48 static int alsa_mixer_exit(void)
  49 {
  50         free(alsa_mixer_device);
  51         alsa_mixer_device = NULL;
  52         free(alsa_mixer_element);
  53         alsa_mixer_element = NULL;
  54         return 0;
  55 }
  56
  57 static int alsa_mixer_open(int *volume_max)
  58 {
  59         snd_mixer_selem_id_t *sid;
  60         snd_mixer_elem_t *elem;
  61         int count;
  62         int rc;
  63
  64         snd_mixer_selem_id_alloca(&sid);
  65
  66         rc = snd_mixer_open(&alsa_mixer_handle, 0);
  67         if (rc < 0)
  68                 goto error;
  69         rc = snd_mixer_attach(alsa_mixer_handle, alsa_mixer_device);
  70         if (rc < 0)
  71                 goto error;
  72         rc = snd_mixer_selem_register(alsa_mixer_handle, NULL, NULL);
  73         if (rc < 0)
  74                 goto error;
  75         rc = snd_mixer_load(alsa_mixer_handle);
  76         if (rc < 0)
  77                 goto error;
  78         count = snd_mixer_get_count(alsa_mixer_handle);
  79         if (count == 0) {
  80                 d_print("error: mixer does not have elements\n");
  81                 return -2;
  82         }
  83         elem = snd_mixer_first_elem(alsa_mixer_handle);
  84         while (elem) {
  85                 const char *name;
  86                 int has_vol, has_switch;
  87
  88                 snd_mixer_selem_get_id(elem, sid);
  89                 name = snd_mixer_selem_id_get_name(sid);
  90                 d_print("name = %s\n", name);
  91                 d_print("has playback volume = %d\n", snd_mixer_selem_has_playback_volume(elem));
  92                 d_print("has playback switch = %d\n", snd_mixer_selem_has_playback_switch(elem));
  93                 if (strcasecmp(name, alsa_mixer_element)) {
  94                         elem = snd_mixer_elem_next(elem);
  95                         continue;
  96                 }
  97                 has_vol = snd_mixer_selem_has_playback_volume(elem);
  98                 if (!has_vol) {
  99                         d_print("mixer element `%s' does not have playback volume\n", name);
 100                         return -2;
 101                 }
 102                 snd_mixer_selem_get_playback_volume_range(elem,
 103                                 &mixer_vol_min, &mixer_vol_max);
 104                 has_switch = snd_mixer_selem_has_playback_switch(elem);
 105                 /* FIXME: get number of channels */
 106                 mixer_elem = elem;
 107                 *volume_max = mixer_vol_max - mixer_vol_min;
 108                 return 0;
 109         }
 110         d_print("error: mixer element `%s' not found\n", alsa_mixer_element);
 111         return -2;
 112 error:
 113         d_print("error: %s\n", snd_strerror(rc));
 114         return -1;
 115 }
 116
 117 static int alsa_mixer_close(void)
 118 {
 119         snd_mixer_close(alsa_mixer_handle);
 120         return 0;
 121 }
 122
 123 static int alsa_mixer_set_volume(int l, int r)
 124 {
 125         if (mixer_elem == NULL) {
 126                 return -1;
 127         }
 128         l += mixer_vol_min;
 129         r += mixer_vol_min;
 130         if (l > mixer_vol_max)
 131                 d_print("error: left volume too high (%d > %ld)\n",
 132                                 l, mixer_vol_max);
 133         if (r > mixer_vol_max)
 134                 d_print("error: right volume too high (%d > %ld)\n",
 135                                 r, mixer_vol_max);
 136         snd_mixer_selem_set_playback_volume(mixer_elem, SND_MIXER_SCHN_FRONT_LEFT, l);
 137         snd_mixer_selem_set_playback_volume(mixer_elem, SND_MIXER_SCHN_FRONT_RIGHT, r);
 138         return 0;
 139 }
 140
 141 static int alsa_mixer_get_volume(int *l, int *r)
 142 {
 143         long lv, rv;
 144
 145         if (mixer_elem == NULL)
 146                 return -1;
 147         snd_mixer_handle_events(alsa_mixer_handle);
 148         snd_mixer_selem_get_playback_volume(mixer_elem, SND_MIXER_SCHN_FRONT_LEFT, &lv);
 149         snd_mixer_selem_get_playback_volume(mixer_elem, SND_MIXER_SCHN_FRONT_RIGHT, &rv);
 150         *l = lv - mixer_vol_min;
 151         *r = rv - mixer_vol_min;
 152         return 0;
 153 }
 154
 155 static int alsa_mixer_set_option(int key, const char *val)
 156 {
 157         switch (key) {
 158         case 0:
 159                 free(alsa_mixer_element);
 160                 alsa_mixer_element = xstrdup(val);
 161                 break;
 162         case 1:
 163                 free(alsa_mixer_device);
 164                 alsa_mixer_device = xstrdup(val);
 165                 break;
 166         default:
 167                 return -OP_ERROR_NOT_OPTION;
 168         }
 169         return 0;
 170 }
 171
 172 static int alsa_mixer_get_option(int key, char **val)
 173 {
 174         switch (key) {
 175         case 0:
 176                 if (alsa_mixer_element)
 177                         *val = xstrdup(alsa_mixer_element);
 178                 break;
 179         case 1:
 180                 if (alsa_mixer_device)
 181                         *val = xstrdup(alsa_mixer_device);
 182                 break;
 183         default:
 184                 return -OP_ERROR_NOT_OPTION;
 185         }
 186         return 0;
 187 }
 188
 189 const struct mixer_plugin_ops op_mixer_ops = {
 190         .init = alsa_mixer_init,
 191         .exit = alsa_mixer_exit,
 192         .open = alsa_mixer_open,
 193         .close = alsa_mixer_close,
 194         .set_volume = alsa_mixer_set_volume,
 195         .get_volume = alsa_mixer_get_volume,
 196         .set_option = alsa_mixer_set_option,
 197         .get_option = alsa_mixer_get_option
 198 };
 199
 200 const char * const op_mixer_options[] = {
 201         "channel",
 202         "device",
 203         NULL
 204 };