diff options
| -rw-r--r-- | include/tinyalsa/asoundlib.h | 26 | ||||
| -rw-r--r-- | pcm.c | 144 |
2 files changed, 170 insertions, 0 deletions
diff --git a/include/tinyalsa/asoundlib.h b/include/tinyalsa/asoundlib.h index bdb4b7a..a4ebec8 100644 --- a/include/tinyalsa/asoundlib.h +++ b/include/tinyalsa/asoundlib.h @@ -98,6 +98,23 @@ struct pcm_config { unsigned int silence_threshold; }; +/* PCM parameters */ +enum pcm_param +{ + PCM_PARAM_SAMPLE_BITS, + PCM_PARAM_FRAME_BITS, + PCM_PARAM_CHANNELS, + PCM_PARAM_RATE, + PCM_PARAM_PERIOD_TIME, + PCM_PARAM_PERIOD_SIZE, + PCM_PARAM_PERIOD_BYTES, + PCM_PARAM_PERIODS, + PCM_PARAM_BUFFER_TIME, + PCM_PARAM_BUFFER_SIZE, + PCM_PARAM_BUFFER_BYTES, + PCM_PARAM_TICK_TIME, +}; + /* Mixer control types */ enum mixer_ctl_type { MIXER_CTL_TYPE_BOOL, @@ -117,6 +134,15 @@ struct pcm *pcm_open(unsigned int card, unsigned int device, int pcm_close(struct pcm *pcm); int pcm_is_ready(struct pcm *pcm); +/* Obtain the parameters for a PCM */ +struct pcm_params *pcm_params_get(unsigned int card, unsigned int device, + unsigned int flags); +void pcm_params_free(struct pcm_params *pcm_params); +unsigned int pcm_params_get_min(struct pcm_params *pcm_params, + enum pcm_param param); +unsigned int pcm_params_get_max(struct pcm_params *pcm_params, + enum pcm_param param); + /* Set and get config */ int pcm_get_config(struct pcm *pcm, struct pcm_config *config); int pcm_set_config(struct pcm *pcm, struct pcm_config *config); @@ -93,6 +93,24 @@ static void param_set_min(struct snd_pcm_hw_params *p, int n, unsigned int val) } } +static unsigned int param_get_min(struct snd_pcm_hw_params *p, int n) +{ + if (param_is_interval(n)) { + struct snd_interval *i = param_to_interval(p, n); + return i->min; + } + return 0; +} + +static unsigned int param_get_max(struct snd_pcm_hw_params *p, int n) +{ + if (param_is_interval(n)) { + struct snd_interval *i = param_to_interval(p, n); + return i->max; + } + return 0; +} + static void param_set_int(struct snd_pcm_hw_params *p, int n, unsigned int val) { if (param_is_interval(n)) { @@ -130,6 +148,9 @@ static void param_init(struct snd_pcm_hw_params *p) i->min = 0; i->max = ~0; } + p->rmask = ~0U; + p->cmask = 0; + p->info = ~0U; } #define PCM_ERROR_MAX 128 @@ -423,6 +444,129 @@ static struct pcm bad_pcm = { .fd = -1, }; +struct pcm_params *pcm_params_get(unsigned int card, unsigned int device, + unsigned int flags) +{ + struct snd_pcm_hw_params *params; + char fn[256]; + int fd; + + snprintf(fn, sizeof(fn), "/dev/snd/pcmC%uD%u%c", card, device, + flags & PCM_IN ? 'c' : 'p'); + + fd = open(fn, O_RDWR); + if (fd < 0) { + fprintf(stderr, "cannot open device '%s'\n", fn); + goto err_open; + } + + params = calloc(1, sizeof(struct snd_pcm_hw_params)); + if (!params) + goto err_calloc; + + param_init(params); + if (ioctl(fd, SNDRV_PCM_IOCTL_HW_REFINE, params)) { + fprintf(stderr, "SNDRV_PCM_IOCTL_HW_REFINE error (%d)\n", errno); + goto err_hw_refine; + } + + close(fd); + + return (struct pcm_params *)params; + +err_hw_refine: + free(params); +err_calloc: + close(fd); +err_open: + return NULL; +} + +void pcm_params_free(struct pcm_params *pcm_params) +{ + struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params; + + if (params) + free(params); +} + +static int pcm_param_to_alsa(enum pcm_param param) +{ + switch (param) { + case PCM_PARAM_SAMPLE_BITS: + return SNDRV_PCM_HW_PARAM_SAMPLE_BITS; + break; + case PCM_PARAM_FRAME_BITS: + return SNDRV_PCM_HW_PARAM_FRAME_BITS; + break; + case PCM_PARAM_CHANNELS: + return SNDRV_PCM_HW_PARAM_CHANNELS; + break; + case PCM_PARAM_RATE: + return SNDRV_PCM_HW_PARAM_RATE; + break; + case PCM_PARAM_PERIOD_TIME: + return SNDRV_PCM_HW_PARAM_PERIOD_TIME; + break; + case PCM_PARAM_PERIOD_SIZE: + return SNDRV_PCM_HW_PARAM_PERIOD_SIZE; + break; + case PCM_PARAM_PERIOD_BYTES: + return SNDRV_PCM_HW_PARAM_PERIOD_BYTES; + break; + case PCM_PARAM_PERIODS: + return SNDRV_PCM_HW_PARAM_PERIODS; + break; + case PCM_PARAM_BUFFER_TIME: + return SNDRV_PCM_HW_PARAM_BUFFER_TIME; + break; + case PCM_PARAM_BUFFER_SIZE: + return SNDRV_PCM_HW_PARAM_BUFFER_SIZE; + break; + case PCM_PARAM_BUFFER_BYTES: + return SNDRV_PCM_HW_PARAM_BUFFER_BYTES; + break; + case PCM_PARAM_TICK_TIME: + return SNDRV_PCM_HW_PARAM_TICK_TIME; + break; + + default: + return -1; + } +} + +unsigned int pcm_params_get_min(struct pcm_params *pcm_params, + enum pcm_param param) +{ + struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params; + int p; + + if (!params) + return 0; + + p = pcm_param_to_alsa(param); + if (p < 0) + return 0; + + return param_get_min(params, p); +} + +unsigned int pcm_params_get_max(struct pcm_params *pcm_params, + enum pcm_param param) +{ + struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params; + int p; + + if (!params) + return 0; + + p = pcm_param_to_alsa(param); + if (p < 0) + return 0; + + return param_get_max(params, p); +} + int pcm_close(struct pcm *pcm) { if (pcm == &bad_pcm) |