alsa device ioctl

利用 device 的 hwdep 介面 call ioctl:

	#include <fcntl.h>
	#include <sys/ioctl.h>
	#include <hwdep.h>
	#include <error.h>
	#include <stdio.h>
	#include "rt56xx_ioctl.h"
	int main()
	{
	snd_hwdep_t *hwdep;
	int err;
	int i;
	struct rt56xx_cmd cmd;
	int buf[0x80];
	cmd.buf = &buf;
	if ((err = snd_hwdep_open(&hwdep, "hw:3,0", O_RDWR)) < 0) {
	printf("snd_hwdep open failed! %s\n",snd_strerror(err));
	return -1;
	}
	if ((err = snd_hwdep_ioctl(hwdep,RT_READ_ALL_CODEC_REG_IOCTL, &cmd)) < 0 ) {
	printf("snd_hwdep ioctl failed! %s\n",snd_strerror(err));
	return -1;
	}
	for(i=0;i<0x80;i++){
	printf("%03X, %08X\n",i,buf[i]);
	}
	return 0;
	}

view raw asound_ioctl.c hosted with ❤ by GitHub

Android.mk ：

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_CFLAGS := \
        -fPIC -D_POSIX_SOURCE \
        -DALSA_CONFIG_DIR=\"/system/usr/share/alsa\" \
        -DALSA_PLUGIN_DIR=\"/system/usr/lib/alsa-lib\" \
        -DALSA_DEVICE_DIRECTORY=\"/dev/snd/\"

LOCAL_C_INCLUDES := \
        external/alsa-lib/include

LOCAL_SRC_FILES := \
        asound_ioctl.c


LOCAL_MODULE_TAGS := eng
LOCAL_MODULE := asound_ioctl

LOCAL_SHARED_LIBRARIES := \
        libaudio \
        libasound \
        libc

include $(BUILD_EXECUTABLE)

要給alsa-lib 的 path

...
...
其中 rt56xx_ioctl.h 就是 alsa device rt56xx 的 driver header, 從 kernel code copy 出來的..

#include <linux/ioctl.h>

struct rt56xx_cmd {
        size_t number;
        int *buf;
};

enum {
        RT_READ_CODEC_REG_IOCTL = _IOR('R', 0x01, struct rt56xx_cmd),
        RT_WRITE_CODEC_REG_IOCTL = _IOW('R', 0x01, struct rt56xx_cmd),
        RT_READ_ALL_CODEC_REG_IOCTL = _IOR('R', 0x02, struct rt56xx_cmd),
        RT_READ_CODEC_INDEX_IOCTL = _IOR('R', 0x03, struct rt56xx_cmd),
        RT_WRITE_CODEC_INDEX_IOCTL = _IOW('R', 0x03, struct rt56xx_cmd),
        RT_READ_CODEC_DSP_IOCTL = _IOR('R', 0x04, struct rt56xx_cmd),
        RT_WRITE_CODEC_DSP_IOCTL = _IOW('R', 0x04, struct rt56xx_cmd),
        RT_SET_CODEC_HWEQ_IOCTL = _IOW('R', 0x05, struct rt56xx_cmd),
        RT_GET_CODEC_HWEQ_IOCTL = _IOR('R', 0x05, struct rt56xx_cmd),
        RT_SET_CODEC_SPK_VOL_IOCTL = _IOW('R', 0x06, struct rt56xx_cmd),
        RT_GET_CODEC_SPK_VOL_IOCTL = _IOR('R', 0x06, struct rt56xx_cmd),
        RT_SET_CODEC_MIC_GAIN_IOCTL = _IOW('R', 0x07, struct rt56xx_cmd),
        RT_GET_CODEC_MIC_GAIN_IOCTL = _IOR('R', 0x07, struct rt56xx_cmd),
        RT_SET_CODEC_3D_SPK_IOCTL = _IOW('R', 0x08, struct rt56xx_cmd),
        RT_GET_CODEC_3D_SPK_IOCTL = _IOR('R', 0x08, struct rt56xx_cmd),
        RT_SET_CODEC_MP3PLUS_IOCTL = _IOW('R', 0x09, struct rt56xx_cmd),
        RT_GET_CODEC_MP3PLUS_IOCTL = _IOR('R', 0x09, struct rt56xx_cmd),
        RT_SET_CODEC_3D_HEADPHONE_IOCTL = _IOW('R', 0x0a, struct rt56xx_cmd),
        RT_GET_CODEC_3D_HEADPHONE_IOCTL = _IOR('R', 0x0a, struct rt56xx_cmd),
        RT_SET_CODEC_BASS_BACK_IOCTL = _IOW('R', 0x0b, struct rt56xx_cmd),
        RT_GET_CODEC_BASS_BACK_IOCTL = _IOR('R', 0x0b, struct rt56xx_cmd),
        RT_SET_CODEC_DIPOLE_SPK_IOCTL = _IOW('R', 0x0c, struct rt56xx_cmd),
        RT_GET_CODEC_DIPOLE_SPK_IOCTL = _IOR('R', 0x0c, struct rt56xx_cmd),
        RT_SET_CODEC_DRC_AGC_ENABLE_IOCTL = _IOW('R', 0x0d, struct rt56xx_cmd),
        RT_GET_CODEC_DRC_AGC_ENABLE_IOCTL = _IOR('R', 0x0d, struct rt56xx_cmd),
        RT_SET_CODEC_DSP_MODE_IOCTL = _IOW('R', 0x0e, struct rt56xx_cmd),
        RT_GET_CODEC_DSP_MODE_IOCTL = _IOR('R', 0x0e, struct rt56xx_cmd),
        RT_SET_CODEC_WNR_ENABLE_IOCTL = _IOW('R', 0x0f, struct rt56xx_cmd),
        ....