IIC 设备Dump 寄存器方法 （kernel 4.4）

废话不多说，直接上代码：

1.添加IIC读写寄存器方法：

static struct class *cls = NULL;

static struct i2c_client *rt5640_i2c_g = NULL;

#define XYP_IIC_ADDR_LENGTH             1
s32 xyp_i2c_read(struct i2c_client *client, u8 *buf, s32 len)
{
    struct i2c_msg msgs[2];
    s32 ret=-1;
    s32 retries = 0;

    msgs[0].flags = !I2C_M_RD;
    msgs[0].addr  = client->addr;
    msgs[0].len   = XYP_IIC_ADDR_LENGTH;
    msgs[0].buf   = &buf[0];
#ifdef CONFIG_I2C_ROCKCHIP_COMPAT
    msgs[0].scl_rate=200 * 1000;
#endif
    msgs[1].flags = I2C_M_RD;
    msgs[1].addr  = client->addr;
    msgs[1].len   = len - XYP_IIC_ADDR_LENGTH;
    msgs[1].buf   = &buf[XYP_IIC_ADDR_LENGTH];
#ifdef CONFIG_I2C_ROCKCHIP_COMPAT
    msgs[1].scl_rate=200 * 1000;
#endif

    while(retries < 5)
    {
        ret = i2c_transfer(client->adapter, msgs, 2);
        if(ret == 2)break;
        retries++;
    }
    return ret;
}



s32 xyp_i2c_write(struct i2c_client *client,u8 *buf,s32 len)
{
    struct i2c_msg msg;
    s32 ret = -1;
    s32 retries = 0;

    msg.flags = !I2C_M_RD;
    msg.addr  = client->addr;
    msg.len   = len;
    msg.buf   = buf;
#ifdef CONFIG_I2C_ROCKCHIP_COMPAT
    msg.scl_rate=200 * 1000;
#endif
    while(retries < 5)
    {
        ret = i2c_transfer(client->adapter, &msg, 1);
        if (ret == 1)break;
        retries++;
    }
    return ret;
}


static ssize_t show_rt5640_reg(
        struct device *dev, struct device_attribute *attr, char *buf)
{
        PAGE_SIZE;
        int i = 0, count = 0;
        u8 t_buf[4] = {0};
        for(i = 0; i < 0xff; i++)
        {
                t_buf[0] = i;
                xyp_i2c_read(rt5640_i2c_g, t_buf, 3);
                printk("XYP_DEBUG read 0x%02x = 0x%02x \n", i, t_buf[1]);
                count += sprintf(buf + count, "0x%02x = 0x%04x\n", i, t_buf[1] << 8 | t_buf[2]);
        }
        return count;
}


static ssize_t store_rt5640_reg(struct class *dev,
               struct class_attribute *attr, const char *buf, size_t count)
{
        int reg, value, ret;
        u8 t_buf[4] = {0};

        sscanf(buf, "0x%x = 0x%x", &reg, &value);
        printk("XYP_DEBUG reg = 0x%02x, value = 0x%02x \n", reg, value);
        t_buf[0] = reg;
        t_buf[1] = (value & 0xff00) >> 8;
        t_buf[2] = value & 0xff;
        xyp_i2c_write(rt5640_i2c_g, t_buf, 3);

        return count;
}
static struct class_attribute attr[] = {
       __ATTR(rt5640_debug_reg, 0770, show_rt5640_reg, store_rt5640_reg),
       __ATTR_NULL,
};

2、在probe函数中创建/sys/class下的节点，并且创建相应的属性文件。

cls = class_create(THIS_MODULE, "XYP_DEBUG_CODEC");
class_create_file(cls, attr);
rt5640_i2c_g = i2c;