tda7313是一款立体声音频处理器件，支持3路输入通道和i2c串行总线支持。

I2C命令：

我们可以看到该芯片i2c命令是由 start信号+地址+ N个DATA + STOP信号组成

DATA：

例1.Volume control -45db组成是：00100100

例2.Audio switch stereo2(输入端口2) LOUDNESS ON +7.5db组成是：01001001

由于我得板子是i2s1接 RK809 ，输出spkout接 tda7313的 L1 R1

i2s1接 RK809的spkout 可以参考官方的

记得屏蔽ucart3 ucart5不然跟i2s1会冲突

Linux i2C driver：

tda7313挂载在i2c5下，地址为0x88 但是i2c只支持7bit的地址所以要右移一位得0x44

设备树描述：

#if 1
&i2c5 {status = "okay";tda7313: tda7313@44 {status = "okay";compatible = "st,tda7313";reg = <0x44>;tda7313pwr-gpios = <&gpio0 RK_PA6 GPIO_ACTIVE_HIGH>;pwr2-gpios = <&gpio3 RK_PC4 GPIO_ACTIVE_LOW>;#sound-dai-cells = <0>;};
};
#endif

tda7313pwr-gpios是板子上得电源引脚，没有得话可以不写

测试驱动代码：

#include <linux/init.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/device.h>#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_gpio.h>#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/uaccess.h>
#include <linux/delay.h> // mdelay()#define MYMA 300
#define COUNT 1
static struct device_node *work_device_node;static int gpio_0;
static int gpio_1;
static int gpio_fm;
static int value = 0;
static int bassvalue = 0;
static int audioSwitch = 0;#define VOLUME_2BIT 0
#define AUDIO_SWITCH_3BIT 2
#define SPEAKER_LF_3BIT 4
#define SPEAKER_RF_3BIT 5
#define SPEAKER_LR_3BIT 6
#define SPEAKER_RR_3BIT 7#define STEREO_1 0
#define STEREO_2 1
#define STEREO_3 2
#define STEREO_ALL 3
#define STEREO_VALUE STEREO_2#define BASS_4BIT 6
#define TEBLE_4BIT 7
#define OFFSET_3BIT 5
#define OFFSET_4BIT 4#define LOUDNESS 0 // 0x4
typedef struct
{struct mutex mutex;struct cdev cdev;struct i2c_client *cli;struct class *cls;
} dht12_data_t;struct file_operations fops = {.owner = THIS_MODULE,};int myprobe(struct i2c_client *cli, const struct i2c_device_id *id)
{struct device_node *np;struct device *dev;static int mi = 0; // 记录次设备号dht12_data_t *data;dev_t devid;int ret;// 注册设备号devid = MKDEV(MYMA, mi);ret = register_chrdev_region(devid, COUNT, cli->name);if (ret < 0)goto err0;// 准备每个匹配设备的数据data = kzalloc(sizeof(*data), GFP_KERNEL);if (NULL == data){ret = -ENOMEM;goto err1;}// 字符设备初始化cdev_init(&data->cdev, &fops);data->cdev.owner = THIS_MODULE;ret = cdev_add(&data->cdev, devid, COUNT);if (ret < 0)goto err2;// 初始化互斥锁mutex_init(&data->mutex);// 创建设备文件data->cls = class_create(THIS_MODULE, cli->name);device_create(data->cls, NULL, devid, NULL, "%s.%d", cli->name, mi++);data->cli = cli;i2c_set_clientdata(cli, data);dev = &cli->dev;if (!dev)return -ENODEV;np = dev->of_node;gpio_0 = of_get_named_gpio(np, "tda7313pwr-gpios", 0);if (gpio_0 < 0){printk("0 of_get_namd_gpio is error \n");return -1;}gpio_1 = of_get_named_gpio(np, "pwr2-gpios", 0);if (gpio_1 < 0){printk("1 of_get_namd_gpio is error \n");return -1;}gpio_fm = of_get_named_gpio(np, "fm-gpios", 0);if (gpio_fm < 0){printk("fm of_get_namd_gpio is error \n");return -1;}gpio_direction_output(gpio_0, 1);gpio_direction_output(gpio_1, 1);gpio_direction_output(gpio_fm, 1);mdelay(100);struct i2c_msg msgs[2];char data_rcv[5], addr[2] = {0x24 ,                  // volue -45db0x48, // .Audio switch stereo1(输入端口2)  LOUDNESS ON +7.5db组成是：01001001}// 上锁，防止重入mutex_lock(&data->mutex);msgs[0].addr = cli->addr;msgs[0].flags = 0;msgs[0].len = 2;msgs[0].buf = addr;ret = i2c_transfer(cli->adapter, msgs, 1);if (ret != 1){printk("error %d\n", ret);// goto out;}printk("ret %d\n", ret);mutex_unlock(&data->mutex);printk("myprobe--------------------------------------------------------------n\n");return 0;
err2:kfree(data);
err1:unregister_chrdev_region(devid, COUNT);
err0:return ret;
}int myremove(struct i2c_client *cli)
{dht12_data_t *data = i2c_get_clientdata(cli); // dev_get_drvdata(&cli->dev);// 移除设备文件device_destroy(data->cls, data->cdev.dev);class_destroy(data->cls);cdev_del(&data->cdev);unregister_chrdev_region(data->cdev.dev, COUNT);kfree(data);return 0;
}struct i2c_device_id ids[] = {{"st,tda7313", 0},{},
};
MODULE_DEVICE_TABLE(i2c, ids);
static const struct of_device_id tda7313_of_match[] = {{.compatible = "st,tda7313"},{},
};struct i2c_driver mydrv = {.probe = myprobe,.remove = myremove,.driver = {.name = "tda7313",.of_match_table = tda7313_of_match,.owner = THIS_MODULE,},.id_table = ids,
};module_i2c_driver(mydrv);
MODULE_LICENSE("GPL");

struct i2c_msg msgs[2];
char data_rcv[5], addr[2] = {0x24 ,                  // volue -45db0x4a, // .Audio switch stereo2(输入端口2)  LOUDNESS ON +7.5db组成是：01001001}msgs[0].addr = cli->addr;//设备地址msgs[0].flags = 0;//0为写msgs[0].len = 2;//2个DATA数据msgs[0].buf = addr;//DATA数据地址
ret = i2c_transfer(cli->adapter, msgs, 1) 执行一次会发出start信号+设备地址+len个数据+stop信号