fmlib.c

   1 /* fmlib.c - simple V4L2 compatible tuner for radio cards
   2
   3    Copyright (C) 2009, 2012 Ben Pfaff <blp@cs.stanford.edu>
   4
   5    This program is free software; you can redistribute it and/or modify it
   6    under the terms of the GNU General Public License as published by the Free
   7    Software Foundation; either version 2 of the License, or (at your option)
   8    any later version.
   9
  10    This program is distributed in the hope that it will be useful, but WITHOUT
  11    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13    more details.
  14
  15    You should have received a copy of the GNU General Public License along with
  16    this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19 #include "fmlib.h"
  20 #include <assert.h>
  21 #include <errno.h>
  22 #include <fcntl.h>
  23 #include <stdarg.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <sys/ioctl.h>
  28 #include <unistd.h>
  29
  30 struct tuner_test {
  31         int freq;               /* In 1/16 MHz. */
  32         int volume;             /* Between 1000 and 2000. */
  33         bool mute;              /* Muted? */
  34 };
  35
  36 char *program_name;
  37
  38 static void query_control(const struct tuner *, uint32_t id,
  39                           struct v4l2_queryctrl *);
  40 static int32_t get_control(const struct tuner *, uint32_t id);
  41 static void set_control(const struct tuner *, uint32_t id, int32_t value);
  42 static void query_tuner(const struct tuner *, struct v4l2_tuner *);
  43
  44 void
  45 fatal(int error, const char *msg, ...)
  46 {
  47         va_list args;
  48
  49         fprintf(stderr, "%s: ", program_name);
  50
  51         va_start(args, msg);
  52         vfprintf(stderr, msg, args);
  53         va_end(args);
  54
  55         if (error)
  56                 fprintf(stderr, ": %s", strerror(error));
  57         putc('\n', stderr);
  58
  59         exit(EXIT_FAILURE);
  60 }
  61
  62 static void *
  63 xmalloc(size_t n)
  64 {
  65         void *p = malloc(n ? n : 1);
  66         if (!p)
  67                 fatal(0, "out of memory");
  68         return p;
  69 }
  70
  71 void
  72 tuner_open(struct tuner *tuner, const char *device, int index)
  73 {
  74         memset(tuner, 0, sizeof *tuner);
  75
  76         if (!device)
  77                 device = "/dev/radio0";
  78         else if (!strcmp(device, "test") || !strncmp(device, "test ", 5)) {
  79                 double volume;
  80                 int mute;
  81                 int n;
  82
  83                 n = sscanf(device, "test %lf %d", &volume, &mute);
  84                 if (n < 1)
  85                         volume = 50;
  86                 if (n < 2)
  87                         mute = 0;
  88
  89                 tuner->test = xmalloc(sizeof *tuner->test);
  90                 tuner->test->freq = 90 * 16;
  91                 tuner->test->volume = volume >= 0 ? volume * 10 + 1000.5 : 0;
  92                 tuner->test->mute = mute != 0;
  93
  94                 device = "/dev/null";
  95         }
  96
  97         tuner->fd = open(device, O_RDONLY);
  98         if (tuner->fd < 0)
  99                 fatal(errno, "Unable to open %s", device);
 100         tuner->index = index;
 101
 102         query_control(tuner, V4L2_CID_AUDIO_VOLUME, &tuner->volume_ctrl);
 103         query_tuner(tuner, &tuner->tuner);
 104 }
 105
 106 void
 107 tuner_close(struct tuner *tuner)
 108 {
 109         close(tuner->fd);
 110 }
 111
 112 bool
 113 tuner_is_muted(const struct tuner *tuner)
 114 {
 115         return get_control(tuner, V4L2_CID_AUDIO_MUTE);
 116 }
 117
 118 void
 119 tuner_set_mute(struct tuner *tuner, bool mute)
 120 {
 121         set_control(tuner, V4L2_CID_AUDIO_MUTE, mute);
 122 }
 123
 124 bool
 125 tuner_has_volume_control(const struct tuner *tuner)
 126 {
 127         const struct v4l2_queryctrl *vqc = &tuner->volume_ctrl;
 128         return vqc->maximum > vqc->minimum;
 129 }
 130
 131 double
 132 tuner_get_volume(const struct tuner *tuner)
 133 {
 134         if (tuner_has_volume_control(tuner)) {
 135                 const struct v4l2_queryctrl *vqc = &tuner->volume_ctrl;
 136                 int volume = get_control(tuner, V4L2_CID_AUDIO_VOLUME);
 137                 return (100.0
 138                         * (volume - vqc->minimum)
 139                         / (vqc->maximum - vqc->minimum));
 140         } else {
 141                 return 100.0;
 142         }
 143 }
 144
 145 void
 146 tuner_set_volume(struct tuner *tuner, double volume)
 147 {
 148         if (tuner_has_volume_control(tuner)) {
 149                 struct v4l2_queryctrl *vqc = &tuner->volume_ctrl;
 150                 set_control(tuner, V4L2_CID_AUDIO_VOLUME,
 151                             (volume / 100.0 * (vqc->maximum - vqc->minimum)
 152                              + vqc->minimum));
 153         }
 154 }
 155
 156 long long int
 157 tuner_get_min_freq(const struct tuner *tuner)
 158 {
 159         long long int rangelow = tuner->tuner.rangelow;
 160         if (!(tuner->tuner.capability & V4L2_TUNER_CAP_LOW))
 161                 rangelow *= 1000;
 162         return rangelow;
 163 }
 164
 165 long long int
 166 tuner_get_max_freq(const struct tuner *tuner)
 167 {
 168         long long int rangehigh = tuner->tuner.rangehigh;
 169         if (!(tuner->tuner.capability & V4L2_TUNER_CAP_LOW))
 170                 rangehigh *= 1000;
 171         return rangehigh;
 172 }
 173
 174 void
 175 tuner_set_freq(const struct tuner *tuner, long long int freq,
 176                bool override_range)
 177 {
 178         long long int adj_freq;
 179         struct v4l2_frequency vf;
 180
 181         adj_freq = freq;
 182         if (!(tuner->tuner.capability & V4L2_TUNER_CAP_LOW))
 183                 adj_freq = (adj_freq + 500) / 1000;
 184
 185         if ((adj_freq < tuner->tuner.rangelow
 186              || adj_freq > tuner->tuner.rangehigh)
 187             && !override_range)
 188                 fatal(0, "Frequency %.1f MHz out of range (%.1f - %.1f MHz)",
 189                       freq / 16000.0,
 190                       tuner_get_min_freq(tuner) / 16000.0,
 191                       tuner_get_max_freq(tuner) / 16000.0);
 192
 193         memset(&vf, 0, sizeof vf);
 194         vf.tuner = tuner->index;
 195         vf.type = tuner->tuner.type;
 196         vf.frequency = adj_freq;
 197         if (tuner->test) {
 198                 tuner->test->freq = adj_freq;
 199         }
 200         else if (ioctl(tuner->fd, VIDIOC_S_FREQUENCY, &vf) == -1)
 201                 fatal(errno, "VIDIOC_S_FREQUENCY");
 202 }
 203
 204 int
 205 tuner_get_signal(const struct tuner *tuner)
 206 {
 207         struct v4l2_tuner vt;
 208
 209         query_tuner(tuner, &vt);
 210         return vt.signal;
 211 }
 212
 213 void
 214 tuner_usleep(const struct tuner *tuner, int usecs)
 215 {
 216         if (!tuner->test)
 217                 usleep(usecs);
 218 }
 219
 220 void
 221 tuner_sleep(const struct tuner *tuner, int secs)
 222 {
 223         if (!tuner->test)
 224                 sleep(secs);
 225 }
 226 \f
 227 /* Queries 'tuner' for a property with the given 'id' and fills in 'qc' with
 228  * the result.  If 'tuner' doesn't have such a property, clears 'qc' to
 229  * all-zeros. */
 230 static void
 231 query_control(const struct tuner *tuner, uint32_t id,
 232               struct v4l2_queryctrl *qc)
 233 {
 234         memset(qc, 0, sizeof *qc);
 235         qc->id = id;
 236         if (tuner->test) {
 237                 assert(id == V4L2_CID_AUDIO_VOLUME);
 238                 if (tuner->test->volume) {
 239                         qc->minimum = 1000;
 240                         qc->maximum = 2000;
 241                 }
 242         } else if (ioctl(tuner->fd, VIDIOC_QUERYCTRL, qc) != -1) {
 243                 /* Success. */
 244         } else if (errno == ENOTTY || errno == EINVAL) {
 245                 /* This tuner doesn't support either query operation
 246                  * or the specific control ('id') respectively */
 247                 memset(qc, 0, sizeof *qc);
 248         } else {
 249                 fatal(errno, "VIDIOC_QUERYCTRL");
 250         }
 251 }
 252
 253 static int32_t
 254 get_control(const struct tuner *tuner, uint32_t id)
 255 {
 256         struct v4l2_control control;
 257
 258         memset(&control, 0, sizeof control);
 259         control.id = id;
 260         if (tuner->test) {
 261                 if (id == V4L2_CID_AUDIO_VOLUME)
 262                         control.value = tuner->test->volume;
 263                 else if (id == V4L2_CID_AUDIO_MUTE)
 264                         control.value = tuner->test->mute;
 265                 else
 266                         abort();
 267         } else if (ioctl(tuner->fd, VIDIOC_G_CTRL, &control) == -1)
 268                 fatal(errno, "VIDIOC_G_CTRL");
 269         return control.value;
 270 }
 271
 272 static void
 273 set_control(const struct tuner *tuner, uint32_t id, int32_t value)
 274 {
 275         struct v4l2_control control;
 276
 277         memset(&control, 0, sizeof control);
 278         control.id = id;
 279         control.value = value;
 280         if (tuner->test) {
 281                 if (id == V4L2_CID_AUDIO_MUTE) {
 282                         assert(value == 0 || value == 1);
 283                         tuner->test->mute = value;
 284                 } else if (id == V4L2_CID_AUDIO_VOLUME) {
 285                         assert(value >= 1000 && value <= 2000);
 286                         tuner->test->volume = value;
 287                 } else {
 288                         abort();
 289                 }
 290         } else if (ioctl(tuner->fd, VIDIOC_S_CTRL, &control) == -1)
 291                 fatal(errno, "VIDIOC_S_CTRL");
 292 }
 293
 294 static void
 295 query_tuner(const struct tuner *tuner, struct v4l2_tuner *vt)
 296 {
 297         memset(vt, 0, sizeof *vt);
 298         vt->index = tuner->index;
 299         if (tuner->test) {
 300                 int freq = tuner->test->freq;
 301                 vt->rangelow = 16 * 89;
 302                 vt->rangehigh = 16 * 91;
 303                 vt->signal = (freq == (int) (16 * 89.6 + .5) ? 64000
 304                               : freq == (int) (16 * 90.4 + .5) ? 50000
 305                                : freq == (int) (16 * 90.5 + .5) ? 40000
 306                               : 1000);
 307         } else if (ioctl(tuner->fd, VIDIOC_G_TUNER, vt) == -1)
 308                 fatal(errno, "VIDIOC_G_TUNER");
 309 }