音效卡驅動dts.
======
    wm8960:[email protected]1a{
            compatible="wlf,wm8960";
            reg = <0x1a>;
    };

    i2s0:[email protected]03830000 {
         compatible = "samsung,exynos4412-i2s";
         reg = <0x03830000 0x100>;
         dmas = <&pdma0 10
                 &pdma0 9
 

                 &pdma0 8>;
         dma-names = "tx", "rx", "tx-sec";
         clocks = <&clock_audss EXYNOS_I2S_BUS>,
                  <&clock_audss EXYNOS_I2S_BUS>,
                  <&clock_audss EXYNOS_SCLK_I2S>;
         clock-names = "iis", "i2s_opclk0", "i2s_opclk1"
 
;
         samsung,supports-6ch;
         samsung,supports-rstclr;
         samsung,supports-secdai;
         samsung,idma-addr = <0x03000000>;
         pinctrl-names = "default";
         pinctrl-0 = <&pinctrl_0>;
     };
     sound {
         compatible = "bva,implant-bva"
         samsung,i2s-controller = <&i2s0>;
         samsung,audio-codec = <&wm8960>;
     };
============


static
 
 int soc_bind_dai_link(struct snd_soc_card *card, int num)
{

    /* Find CPU DAI from registered DAIs*/
    list_for_each_entry(cpu_dai, &dai_list, list) {
        if (dai_link->cpu_of_node &&
            (cpu_dai->dev->of_node != dai_link->cpu_of_node))
            continue;
        if (dai_link->cpu_name &&
            strcmp(dev_name(cpu_dai->dev), dai_link->cpu_name))
            continue;
        if (dai_link->cpu_dai_name &&
            strcmp(cpu_dai->name, dai_link->cpu_dai_name))
            continue;

        rtd->cpu_dai = cpu_dai;
    }
    printk("\n=========soc_bind_dai_link=============\n");//soc-core.c P903

    /* Find CODEC from registered CODECs */
    list_for_each_entry(codec, &codec_list, list) {
        if (dai_link->codec_of_node) {
            if (codec->dev->of_node != dai_link->codec_of_node)
                continue;
        } else {
            if (strcmp(codec->name, dai_link->codec_name))
                continue;
        }

        rtd->codec = codec;

        /*
         * CODEC found, so find CODEC DAI from registered DAIs from
         * this CODEC
         */
        printk("\n=========list_for_each_entry 903=============\n");
        list_for_each_entry(codec_dai, &dai_list, list) {
        printk("\n===%s=====%s======\n",codec_dai->name,dai_link->codec_dai_name);
            if (codec->dev == codec_dai->dev &&
                !strcmp(codec_dai->name,
                    dai_link->codec_dai_name)) {

                rtd->codec_dai = codec_dai;
            }
        }

        if (!rtd->codec_dai) {
            dev_err(card->dev, "ASoC: CODEC DAI %s not registered\n",
                dai_link->codec_dai_name);
            return -EPROBE_DEFER;
        }
    }

}








問題:

[    1.915000] wm8960 0-001a: (wm8960_probe)No platform data supplied
解決：
註冊裝置驅動的匯流排號應該用0而不是4


[    1.925000] wm8960 0-001a: Failed to issue reset
[    1.930000] Failed to issue reset  ret=-6
[    1.930000] wm8960 0-001a: ASoC: failed to probe CODEC -6
[    1.935000] soc-audio soc-audio: ASoC: failed to instantiate card -6

#define ENXIO        6  /* No such device or address */


[    1.965000] regulator-dummy: disabling



[    1.600000] ==codec->dev!=NULL   snd_soc_register_codec      ==
[    1.605000] ==codec->dev.platform_data!=NULL   snd_soc_register_codec      ==

[    1.805000] soc-audio soc-audio: ASoC: CODEC wm8960.0-001a not registered
[    1.810000] platform soc-audio: Driver soc-audio requests probe deferral
[    1.910000] soc-audio: probe of soc-audio failed with error -22



1、如何檢視linux核心中註冊了那些i2c裝置。
2、i2c裝置和i2c驅動的匹配。
static int wm8960_probe(struct snd_soc_codec *codec)
{
    ret = snd_soc_codec_set_cache_io(codec, 7, 9, wm8960->control_type);//設定codec的讀寫等函式
                    ||
                codec->write = hw_write;//soc-io.c   98
                codec->read = hw_read;
                codec->control_data = regmap_init_i2c(to_i2c_client(codec->dev),&config);
                                    ||
                    struct regmap *regmap_init_i2c(struct i2c_client *i2c,const struct regmap_config *config)//regmap-i2c.c  110
                    {
                        return regmap_init(&i2c->dev, &regmap_i2c, &i2c->dev, config);
                    }
                                    ||
                        struct regmap *regmap_init(struct device *dev,const struct regmap_bus *bus,void *bus_context,const struct regmap_config *config)//regmap.c  395
                        {
                            map->bus = bus;//443
                            if (map->format.format_write) {//639 
                                map->defer_caching = false;
                                map->reg_write = _regmap_bus_formatted_write;//在這裡設定了下面要使用的map->reg_write函式。
                                printk("map->reg_write = _regmap_bus_formatted_write;\n");
                            } else if (map->format.format_val) {
                                map->defer_caching = true;
                                map->reg_write = _regmap_bus_raw_write;
                                printk("map->reg_write = _regmap_bus_raw_write;\n");

                            }
                        }

    ret = wm8960_reset(codec);//wm8960.c  1019
}
        ||
unsigned int snd_soc_write(struct snd_soc_codec *codec,
               unsigned int reg, unsigned int val)
{
    dev_dbg(codec->dev, "write %x = %x\n", reg, val);
    trace_snd_soc_reg_write(codec, reg, val);
    return codec->write(codec, reg, val);//soc-core.c 2349
}
               ||
static int hw_write(struct snd_soc_codec *codec, unsigned int reg,
            unsigned int value)
{
    ret=regmap_write(codec->control_data, reg, value);//soc-io.c  45
}
        ||
int regmap_write(struct regmap *map, unsigned int reg, unsigned int val)
{
    ret = _regmap_write(map, reg, val);//regmap.c  1348
}
        ||
int _regmap_write(struct regmap *map, unsigned int reg,
          unsigned int val)
{
    ret=map->reg_write(context, reg, val);//regmap.c  1322
}
        ||
static int _regmap_bus_formatted_write(void *context, unsigned int reg,
                       unsigned int val)
{

    ret = map->bus->write(map->bus_context, map->work_buf,map->format.buf_size);//regmap.c  1268
}   
        ||
static int regmap_i2c_write(void *context, const void *data, size_t count)//regmap-i2c.c  18
{
    ret = i2c_master_send(i2c, data, count);
}
        ||
int i2c_master_send(const struct i2c_client *client, const char *buf, int count)//i2c-core.c  1807
{
    ret = i2c_transfer(adap, &msg, 1);//<<====  ret=-6
}
        ||
int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
       ret = __i2c_transfer(adap, msgs, num);//i2c-core.c  1788
}
        ||
int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
    ret = adap->algo->master_xfer(adap, msgs, num);//i2c-core.c  1725
}
        ||
static const struct i2c_algorithm s3c24xx_i2c_algorithm = {//drivers/i2c/busses/i2c-s3c2410.c
    .master_xfer        = s3c24xx_i2c_xfer,
    .functionality      = s3c24xx_i2c_func,
};
        ||
static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
            struct i2c_msg *msgs, int num)
{
    for (retry = 0; retry < adap->retries; retry++) {

        ret = s3c24xx_i2c_doxfer(i2c, msgs, num);//第一次就等於-6
    }
}
        ||
static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
                  struct i2c_msg *msgs, int num)
{

    timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);//drivers/i2c/busses/i2c-s3c2410.c  733
    ret = i2c->msg_idx;在這裡將ret=-6

}
        ||
static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret)
{
        i2c->msg_idx = ret;//drivers/i2c/busses/i2c-s3c2410.c  195
}
        ||
static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c,
                      struct i2c_msg *msg)
{
            i2c_s3c_irq_nextbyte(i2c, stat);//drivers/i2c/busses/i2c-s3c2410.c  300   
}
------------------------------------------------------------
static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id)
{
    struct s3c24xx_i2c *i2c = dev_id;
    unsigned long status;
    unsigned long tmp;

    status = readl(i2c->regs + S3C2410_IICSTAT);//問題出在這裡，status=0xf1低4位應該為0
    printk("\n--%s-----%d-----stat=0x%x\n",__FUNCTION__,__LINE__,status);

    if (status & S3C2410_IICSTAT_ARBITR) {
        /* deal with arbitration loss */
        dev_err(i2c->dev, "deal with arbitration loss\n");
    }

    if (i2c->state == STATE_IDLE) {
        dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");

        tmp = readl(i2c->regs + S3C2410_IICCON);
        tmp &= ~S3C2410_IICCON_IRQPEND;
        writel(tmp, i2c->regs +  S3C2410_IICCON);
        goto out;
    }

    /* pretty much this leaves us with the fact that we've
     * transmitted or received whatever byte we last sent */
    printk("\n--%s-----%d-----stat=0x%x\n",__FUNCTION__,__LINE__,status);//問題出在這裡，status應該為0，但在這裡變為非零，導致下面的if語句成立。
    i2c_s3c_irq_nextbyte(i2c, status);

 out:
    return IRQ_HANDLED;
}


        ||
static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
{
    case STATE_START:
        if (iicstat & S3C2410_IICSTAT_LASTBIT &&!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
            /* ack was not received... */
            dev_dbg(i2c->dev, "ack was not received\n");
            s3c24xx_i2c_stop(i2c, -ENXIO);                     //drivers/i2c/busses/i2c-s3c2410.c  435
            printk("--%s-----%d-----\n",__FUNCTION__,__LINE__);// -ENXIO=-6最終在這裡出錯
            goto out_ack;
        }
}