Linux驱动——ALSA
小狼@http://blog.csdn.net/xiaolangyangyang
Control宏定义：
SOC_SINGLE_VALUE
SOC_SINGLE_VALUE_EXT
SOC_SINGLE
SOC_SINGLE_TLV
SOC_DOUBLE
SOC_DOUBLE_R
SOC_DOUBLE_TLV
SOC_DOUBLE_R_TLV
SOC_DOUBLE_S8_TLV
SOC_ENUM_DOUBLE
SOC_ENUM_SINGLE
SOC_ENUM_SINGLE_EXT
SOC_VALUE_ENUM_DOUBLE
SOC_VALUE_ENUM_SINGLE
SOC_ENUM
SOC_VALUE_ENUM
SOC_SINGLE_EXT
SOC_DOUBLE_EXT
SOC_SINGLE_EXT_TLV
SOC_DOUBLE_EXT_TLV
SOC_DOUBLE_R_EXT_TLV
SOC_SINGLE_BOOL_EXT
SOC_ENUM_EXT
SOC_DOUBLE_R_SX_TLV
SOC_ENUM_DOUBLE_DECL
SOC_ENUM_SINGLE_DECL
SOC_ENUM_SINGLE_EXT_DECL
SOC_VALUE_ENUM_DOUBLE_DECL
SOC_VALUE_ENUM_SINGLE_DECLDAPM宏定义：
SND_SOC_DAPM_VMID
SND_SOC_DAPM_INPUT
SND_SOC_DAPM_OUTPUT
SND_SOC_DAPM_MIC
SND_SOC_DAPM_HP
SND_SOC_DAPM_SPK
SND_SOC_DAPM_LINE
SND_SOC_DAPM_PGA
SND_SOC_DAPM_OUT_DRV
SND_SOC_DAPM_MIXER
SND_SOC_DAPM_MIXER_NAMED_CTL
SND_SOC_DAPM_MICBIAS
SND_SOC_DAPM_SWITCH
SND_SOC_DAPM_MUX
SND_SOC_DAPM_VIRT_MUX
SND_SOC_DAPM_VALUE_MUX
SOC_PGA_ARRAY
SOC_MIXER_ARRAY
SOC_MIXER_NAMED_CTL_ARRAY
SND_SOC_DAPM_PGA_E
SND_SOC_DAPM_OUT_DRV_E
SND_SOC_DAPM_MIXER_E
SND_SOC_DAPM_MIXER_NAMED_CTL_E
SND_SOC_DAPM_MICBIAS_E
SND_SOC_DAPM_SWITCH_E
SND_SOC_DAPM_MUX_E
SND_SOC_DAPM_VIRT_MUX_E
SND_SOC_DAPM_PGA_S
SND_SOC_DAPM_SUPPLY_S
SOC_PGA_E_ARRAY
SOC_MIXER_E_ARRAY
SOC_MIXER_NAMED_CTL_E_ARRAY
SND_SOC_DAPM_PRE
SND_SOC_DAPM_POST
SND_SOC_DAPM_AIF_IN
SND_SOC_DAPM_AIF_IN_E
SND_SOC_DAPM_AIF_OUT
SND_SOC_DAPM_AIF_OUT_E
SND_SOC_DAPM_DAC
SND_SOC_DAPM_DAC_E
SND_SOC_DAPM_ADC
SND_SOC_DAPM_ADC_E
SND_SOC_DAPM_REG
SND_SOC_DAPM_SUPPLY
SOC_DAPM_SINGLE
SOC_DAPM_SINGLE_TLV
SOC_DAPM_ENUM
SOC_DAPM_ENUM_VIRT
SOC_DAPM_VALUE_ENUM
SOC_DAPM_PIN_SWITCH
static const struct snd_kcontrol_new wmxx_mix1_controls[] = {SOC_DAPM_SINGLE("SW1", WMXX_REG_SW, 1, 1, 0),SOC_DAPM_SINGLE("SW2", WMXX_REG_SW, 2, 0, 0),SOC_DAPM_SINGLE("SW3", WMXX_REG_SW, 3, 0, 0),SOC_DAPM_SINGLE("SW4", WMXX_REG_SW, 4, 0, 0)
};static const struct snd_kcontrol_new wmxx_mix2_controls[] = {SOC_DAPM_SINGLE("SW5", WMXX_REG_SW, 5, 1, 0),SOC_DAPM_SINGLE("SW6", WMXX_REG_SW, 6, 0, 0),SOC_DAPM_SINGLE("SW7", WMXX_REG_SW, 7, 0, 0),SOC_DAPM_SINGLE("SW8", WMXX_REG_SW, 8, 0, 0)
};static const struct snd_soc_dapm_widget wm8900_dapm_widgets[] = {SND_SOC_DAPM_MIXER("MIX1", WMXX_REG_MIX, 1, 0, wmxx_mix1_controls, ARRAY_SIZE(wmxx_mix1_controls)),SND_SOC_DAPM_MIXER("MIX2", WMXX_REG_MIX, 2, 0, wmxx_mix2_controls, ARRAY_SIZE(wmxx_mix2_controls))
};static const struct snd_soc_dapm_route audio_map[] = {{"MIX1", "SW2", "ADC"},{"MIX2", "SW6", "MIX1"},
};播放器代码
#include <alsa/asoundlib.h>
#include <stdio.h>
#include <termios.h>
#include <unistd.h>
#include <stdlib.h>#define int8_t char
#define int16_t short
#define int32_t int
#define int64_t long
#define uint8_t unsigned char
#define uint16_t unsigned short
#define uint32_t unsigned int
#define uint64_t unsigned long/* para of wav file */
typedef struct {uint32_t dwSize;uint16_t wFormatTag;uint16_t wChannels;uint32_t dwSamplesPerSec;uint32_t dwAvgBytesPerSec;uint16_t wBlockAlign;uint16_t wBitsPerSample;
} WAVEFORMAT;/* format of wav file header */
typedef struct {uint8_t RiffID [4];uint32_t RiffSize;uint8_t WaveID[4];uint8_t FmtID[4];uint32_t FmtSize;uint16_t wFormatTag;uint16_t nChannels;uint32_t nSamplesPerSec;uint32_t nAvgBytesPerSec;uint16_t nBlockAlign;uint16_t wBitsPerSample;uint8_t DataID[4];uint32_t nDataBytes;
} WAVE_HEADER;/* set hwparams */
static int32_t set_hwparams(snd_pcm_t *handle, snd_pcm_hw_params_t *params, snd_pcm_access_t access, uint32_t ch, snd_pcm_format_t format, uint32_t rate, snd_pcm_sframes_t *period_size)
{snd_pcm_uframes_t size;uint32_t rrate;int32_t err, dir;uint32_t buffer_time = 500000; /* ring buffer length in us */uint32_t period_time = 100000; /* period time in us */int32_t resample = 1; /* enable alsa-lib resampling *//* choose all parameters */err = snd_pcm_hw_params_any(handle, params);if (err < 0){printf("Broken configuration for playback: no configurations available: %s\n", snd_strerror(err));return err;}/* set hardware resampling */err = snd_pcm_hw_params_set_rate_resample(handle, params, resample);if (err < 0){printf("Resampling setup failed for playback: %s\n", snd_strerror(err));return err;}/* set the interleaved read/write format */err = snd_pcm_hw_params_set_access(handle, params, access);if (err < 0){printf("Access type not available for playback: %s\n", snd_strerror(err));return err;}/* set the sample format */err = snd_pcm_hw_params_set_format(handle, params, format);if (err < 0){printf("Sample format not available for playback: %s\n", snd_strerror(err));return err;}/* set the count of channels */err = snd_pcm_hw_params_set_channels(handle, params, ch);if (err < 0){printf("Channels count (%u) not available for playbacks: %s\n", ch, snd_strerror(err));return err;}/* set the stream rate */rrate = rate;err = snd_pcm_hw_params_set_rate_near(handle, params, &rrate, 0);if (err < 0){printf("Rate %uHz not available for playback: %s\n", rate, snd_strerror(err));return err;}if (rrate != rate){printf("Rate doesn't match (requested %uHz, get %iHz)\n", rate, err);return -EINVAL;}/* set the buffer time */err = snd_pcm_hw_params_set_buffer_time_near(handle, params, &buffer_time, &dir);if (err < 0){printf("Unable to set buffer time %u for playback: %s\n", buffer_time, snd_strerror(err));return err;}err = snd_pcm_hw_params_get_buffer_size(params, &size);if (err < 0){printf("Unable to get buffer size for playback: %s\n", snd_strerror(err));return err;}printf("buffer_size = %ld\n", size);/* set the period time */ err = snd_pcm_hw_params_set_period_time_near(handle, params, &period_time, &dir);if (err < 0){printf("Unable to set period time %u for playback: %s\n", period_time, snd_strerror(err));return err;}err = snd_pcm_hw_params_get_period_size(params, &size, &dir);if (err < 0){printf("Unable to get period size for playback: %s\n", snd_strerror(err));return err;}*period_size = size;printf("period_size = %ld\n", size);/* write the parameters to device */err = snd_pcm_hw_params(handle, params);if (err < 0){printf("Unable to set hw params for playback: %s\n", snd_strerror(err));return err;}return 0;
}/* read wav file header*/
FILE * open_and_print_file_params(int8_t *file_name, WAVE_HEADER *g_wave_header)
{FILE * fp = fopen(file_name, "r");if (fp == NULL){printf("can't open wav file\n");return NULL;}memset(g_wave_header, 0, sizeof(WAVE_HEADER));fread(g_wave_header, 1, sizeof(WAVE_HEADER), fp);printf(">> RiffID : %c%c%c%c\n", g_wave_header->RiffID[0], g_wave_header->RiffID[1], g_wave_header->RiffID[2], g_wave_header->RiffID[3]);printf(">> RiffSize : %d\n", g_wave_header->RiffSize);printf(">> WaveID : %c%c%c%c\n", g_wave_header->WaveID[0], g_wave_header->WaveID[1], g_wave_header->WaveID[2], g_wave_header->WaveID[3]);printf(">> FmtID : %c%c%c%c\n", g_wave_header->FmtID[0], g_wave_header->FmtID[1], g_wave_header->FmtID[2], g_wave_header->FmtID[3]);printf(">> FmtSize : %d\n", g_wave_header->FmtSize);printf(">> wFormatTag : %d\n", g_wave_header->wFormatTag);printf(">> nChannels : %d\n", g_wave_header->nChannels);printf(">> nSamplesPerSec : %d\n", g_wave_header->nSamplesPerSec);printf(">> nAvgBytesPerSec : %d\n", g_wave_header->nAvgBytesPerSec);printf(">> nBlockAlign : %d\n", g_wave_header->nBlockAlign);printf(">> wBitsPerSample : %d\n", g_wave_header->wBitsPerSample);printf(">> DataID : %c%c%c%c\n", g_wave_header->DataID[0], g_wave_header->DataID[1], g_wave_header->DataID[2], g_wave_header->DataID[3]);printf(">> nDataBytes : %d\n", g_wave_header->nDataBytes);return fp;
}char * sctrlstr = "Digital Playback Volume";int32_t main()
{int8_t *infile = "Back_to_Earth.wav";int8_t *device = "hw:0,0";snd_pcm_t *handle;snd_pcm_hw_params_t *hwparams;WAVE_HEADER g_wave_header;snd_pcm_format_t format;uint32_t ch;uint32_t rate;snd_pcm_sframes_t period_size;int16_t *samples;int32_t music_sec;int32_t err;int32_t size;int32_t rc;FILE *fp = open_and_print_file_params(infile, &g_wave_header);if (fp == NULL){printf("open_and_print_file_params error\n");return -1;}/* set sample rate */rate = g_wave_header.nSamplesPerSec;/* set sample bit */if (8 == g_wave_header.FmtSize){format = SND_PCM_FORMAT_U8;}else if (16 == g_wave_header.FmtSize){format = SND_PCM_FORMAT_S16_LE;}else if (24 == g_wave_header.FmtSize){format = SND_PCM_FORMAT_U24_LE;}else if (32 == g_wave_header.FmtSize){format = SND_PCM_FORMAT_U32_LE;}else{printf("SND_PCM_FORMAT_UNKNOWN.\n");format = SND_PCM_FORMAT_UNKNOWN;return -1; }/* set channel */ch = g_wave_header.nChannels;/* music time */music_sec = g_wave_header.nDataBytes / g_wave_header.nAvgBytesPerSec;printf("music_time : %d : %d\n", (int32_t)music_sec / 60, music_sec % 60);printf("Playback device is %s\n", device);printf("Stream parameters are %uHz, %s, %u channels\n", rate, snd_pcm_format_name(format), ch);err = snd_pcm_open(&handle, device, SND_PCM_STREAM_PLAYBACK, 0);if (err < 0) {printf("Playback open error: %s\n", snd_strerror(err));return 0;}snd_pcm_hw_params_alloca(&hwparams);err = set_hwparams(handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED, ch, format, rate, &period_size);if (err < 0) {printf("Setting of hwparams failed: %s\n", snd_strerror(err));return 0;}size = (period_size * ch * snd_pcm_format_physical_width(format)) / 8;samples = (int16_t *)malloc(size);while (1) {rc = fread(samples, sizeof(int16_t), size, fp);if (rc == 0){printf("end of file on input\n");break;} else if (rc != size){printf("short read: read %d bytes\n", rc);}rc = snd_pcm_writei(handle, samples, size);if (rc == -EPIPE){printf("underrun occurred\n");err = snd_pcm_prepare(handle);if( err < 0){printf("can not recover from underrun: %s\n", snd_strerror(err));}} else if (rc < 0){printf("error from writei: %s\n", snd_strerror(rc));} else if (rc != (int32_t)size){printf("short write, write %d frames\n", rc);}}if (samples != NULL){free(samples);}snd_pcm_close(handle);return 0;
}# arm-fsl-linux-gnueabi-gcc player.c -o player -lasound -lm -I /var/alsa/include/ -L /var/alsa/lib/
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