struct snd_soc_dai_link {
[...省略]
struct snd_soc_dai_link_component *codecs;
[...省略]
struct snd_soc_dai_link_component *platform;
[...省略]
}如上可以，struct snd_soc_dai_link将codec和platform连接在了一起，这也就是link的意思了；
int snd_soc_register_card(struct snd_soc_card *card)
{
[...省略]
mutex_lock(&client_mutex);
for_each_card_prelinks(card, i, link) {
ret = soc_init_dai_link(card, link); // <---- snd_soc_register_card调用
if (ret) {
dev_err(card->dev, "ASoC: failed to init link %s\n",
link->name);
mutex_unlock(&client_mutex);
return ret;
}
}
mutex_unlock(&client_mutex);
[...省略]
return snd_soc_bind_card(card);
}
EXPORT_SYMBOL_GPL(snd_soc_register_card);static int soc_init_dai_link(struct snd_soc_card *card,
struct snd_soc_dai_link *link)
{
int i, ret;
struct snd_soc_dai_link_component *codec;
ret = snd_soc_init_platform(card, link); // 创建platform component
if (ret) {
dev_err(card->dev, "ASoC: failed to init multiplatform\n");
return ret;
}
ret = snd_soc_init_multicodec(card, link); // 创建codec component
if (ret) {
dev_err(card->dev, "ASoC: failed to init multicodec\n");
return ret;
}
for_each_link_codecs(link, i, codec) { // codec名称和设备树不用同时设定，DAI名字要设定
/*
* Codec must be specified by 1 of name or OF node,
* not both or neither.
*/
if (!!codec->name ==
!!codec->of_node) {
dev_err(card->dev, "ASoC: Neither/both codec name/of_node are set for %s\n",
link->name);
return -EINVAL;
}
/* Codec DAI name must be specified */
/**
* priv->dai_link[0].codec_dai_name = "cs42888"
* priv->dai_link[1].codec_dai_name = "snd-soc-dummy-dai"
* priv->dai_link[2].codec_dai_name = "cs42888"
*/
if (!codec->dai_name) {
dev_err(card->dev, "ASoC: codec_dai_name not set for %s\n",
link->name);
return -EINVAL;
}
}
/*
* Platform may be specified by either name or OF node, but
* can be left unspecified, and a dummy platform will be used.
* platform的名字和设备树节点只能设定一个
*/
if (link->platform->name && link->platform->of_node) {
dev_err(card->dev,
"ASoC: Both platform name/of_node are set for %s\n",
link->name);
return -EINVAL;
}
/*
* Defer card registartion if platform dai component is not added to
* component list.
*/
if ((link->platform->of_node || link->platform->name) &&
!soc_find_component(link->platform->of_node, link->platform->name))
return -EPROBE_DEFER;
/*
* CPU device may be specified by either name or OF node, but
* can be left unspecified, and will be matched based on DAI
* name alone..
* cpu的名字和设备树节点只能设定一个
*/
if (link->cpu_name && link->cpu_of_node) {
dev_err(card->dev,
"ASoC: Neither/both cpu name/of_node are set for %s\n",
link->name);
return -EINVAL;
}
/*
* Defer card registartion if cpu dai component is not added to
* component list.
*/
if ((link->cpu_of_node || link->cpu_name) &&
!soc_find_component(link->cpu_of_node, link->cpu_name))
return -EPROBE_DEFER;
/*
* At least one of CPU DAI name or CPU device name/node must be
* specified
*/
if (!link->cpu_dai_name &&
!(link->cpu_name || link->cpu_of_node)) {
dev_err(card->dev,
"ASoC: Neither cpu_dai_name nor cpu_name/of_node are set for %s\n",
link->name);
return -EINVAL;
}
return 0;
}- platform snd_soc_dai_link_component
static int snd_soc_init_platform(struct snd_soc_card *card, struct snd_soc_dai_link *dai_link) { struct snd_soc_dai_link_component *platform = dai_link->platform; /* * FIXME * * this function should be removed in the future */ /* convert Legacy platform link */ if (!platform || dai_link->legacy_platform) { platform = devm_kzalloc(card->dev, sizeof(struct snd_soc_dai_link_component), GFP_KERNEL); if (!platform) return -ENOMEM; dai_link->platform = platform; dai_link->legacy_platform = 1; platform->name = dai_link->platform_name; platform->of_node = dai_link->platform_of_node; platform->dai_name = NULL; } /* if there's no platform we match on the empty platform */ if (!platform->name && !platform->of_node) platform->name = "snd-soc-dummy"; return 0; }
- codec snd_soc_dai_link_component
static int snd_soc_init_multicodec(struct snd_soc_card *card, struct snd_soc_dai_link *dai_link) { /* Legacy codec/codec_dai link is a single entry in multicodec */ if (dai_link->codec_name || dai_link->codec_of_node || dai_link->codec_dai_name) { dai_link->num_codecs = 1; dai_link->codecs = devm_kzalloc(card->dev, sizeof(struct snd_soc_dai_link_component), GFP_KERNEL); if (!dai_link->codecs) return -ENOMEM; dai_link->codecs[0].name = dai_link->codec_name; dai_link->codecs[0].of_node = dai_link->codec_of_node; dai_link->codecs[0].dai_name = dai_link->codec_dai_name; } if (!dai_link->codecs) { dev_err(card->dev, "ASoC: DAI link has no CODECs\n"); return -EINVAL; } return 0; }
static struct snd_soc_dai_link fsl_asoc_card_dai[] = {
/* Default ASoC DAI Link*/
{
.name = "HiFi",
.stream_name = "HiFi",
.ops = &fsl_asoc_card_ops,
.cpu_of_node = cpu_np,
.codec_dai_name = codec_dai_name,
.codec_of_node = codec_np,
.platform_of_node = cpu_np,
.dai_fmt = priv->dai_fmt,
.dai_link->legacy_platform = 1,
.platform = {
.of_node = cpu_np,
},
.codecs = [{
.of_node = codec_np,
.dai_name = codec_dai_name,
},],
},
/* DPCM Link between Front-End and Back-End (Optional) */
{
.name = "HiFi-ASRC-FE",
.stream_name = "HiFi-ASRC-FE",
.codec_name = "snd-soc-dummy",
.codec_dai_name = "snd-soc-dummy-dai",
.dpcm_playback = 1,
.dpcm_capture = 1,
.dynamic = 1,
.cpu_of_node = asrc_np,
.platform_of_node = asrc_np,
.dai_link->legacy_platform = 1,
.platform = {
.of_node = asrc_np,
},
.codecs = [{
.dai_name = "snd-soc-dummy-dai",
},],
},
{
.name = "HiFi-ASRC-BE",
.stream_name = "HiFi-ASRC-BE",
.platform_name = "snd-soc-dummy",
.be_hw_params_fixup = be_hw_params_fixup,
.ops = &fsl_asoc_card_ops,
.dpcm_playback = 1,
.dpcm_capture = 1,
.no_pcm = 1,
.codec_dai_name = codec_dai_name,
.codec_of_node = codec_np,
.cpu_of_node = cpu_np,
.dai_fmt = priv->dai_fmt,
.dai_link->legacy_platform = 1,
.platform = {
.name = "snd-soc-dummy",
},
.codecs = [{
.of_node = codec_np,
.dai_name = codec_dai_name,
},],
},
};