高通Audio中ASOC的machine驱动（一）
原文链接： https://www.cnblogs.com/linhaostudy/p/8419231.html#_label0_0
正文
ASoC被分为Machine、Platform和Codec三大部分，其中的Machine驱动负责Platform和Codec之间的耦合以及部分和设备或板子特定的代码，再次引用上一节的内容：Machine驱动负责处理机器特有的一些控件和音频事件（例如，当播放音频时，需要先行打开一个放大器）；单独的Platform和Codec驱动是不能工作的，它必须由Machine驱动把它们结合在一起才能完成整个设备的音频处理工作。
ASoC的一切都从Machine驱动开始，包括声卡的注册，绑定Platform和Codec驱动等等；（linux内核版本为3.10.28）
回到顶部
1. 注册Platform driver:
ASoC把声卡注册为Platform Device：
1 static int msm8x16_asoc_machine_probe(struct platform_device *pdev)
2 {
3 struct snd_soc_card *card;
4 struct msm8916_asoc_mach_data *pdata = NULL;
5 struct pinctrl *pinctrl;
6 const char *card_dev_id = "qcom,msm-snd-card-id";
7 const char *codec_type = "qcom,msm-codec-type";
8 const char *hs_micbias_type = "qcom,msm-hs-micbias-type";
9 const char *ext_pa = "qcom,msm-ext-pa";
10 const char *mclk = "qcom,msm-mclk-freq";
11 const char *spk_ext_pa = "qcom,msm-spk-ext-pa";
12 const char *ptr = NULL;
13 const char *type = NULL;
14 const char *ext_pa_str = NULL;
15 int num_strings;
16 int ret, id, i;
17
18 pr_err("'msm8x16_asoc_machine_probe ......");
19 pdata = devm_kzalloc(&pdev->dev,
20 sizeof(struct msm8916_asoc_mach_data), GFP_KERNEL);
21 if (!pdata) {
22 dev_err(&pdev->dev, "Can't allocate msm8x16_asoc_mach_data\n");
23 ret = -ENOMEM;
24 goto err1;
25 }
26
27 pdata->vaddr_gpio_mux_spkr_ctl =
28 ioremap(LPASS_CSR_GP_IO_MUX_SPKR_CTL , 4);
29 if (!pdata->vaddr_gpio_mux_spkr_ctl) {
30 pr_err("%s ioremap failure for addr %x",
31 __func__, LPASS_CSR_GP_IO_MUX_SPKR_CTL);
32 ret = -ENOMEM;
33 goto err;
34 }
35 pdata->vaddr_gpio_mux_mic_ctl =
36 ioremap(LPASS_CSR_GP_IO_MUX_MIC_CTL , 4);
37 if (!pdata->vaddr_gpio_mux_mic_ctl) {
38 pr_err("%s ioremap failure for addr %x",
39 __func__, LPASS_CSR_GP_IO_MUX_MIC_CTL);
40 ret = -ENOMEM;
41 goto err;
42 }
43
44 pdata->vaddr_gpio_mux_pcm_ctl =
45 ioremap(LPASS_CSR_GP_LPAIF_PRI_PCM_PRI_MODE_MUXSEL, 4);
46 if (!pdata->vaddr_gpio_mux_pcm_ctl) {
47 pr_err("%s ioremap failure for addr %x",
48 __func__,
49 LPASS_CSR_GP_LPAIF_PRI_PCM_PRI_MODE_MUXSEL);
50 ret = -ENOMEM;
51 goto err;
52 }
53 ret = of_property_read_u32(pdev->dev.of_node, card_dev_id, &id);
54 if (ret) {
55 dev_err(&pdev->dev,
56 "%s: missing %s in dt node\n", __func__, card_dev_id);
57 goto err;
58 }
59
60 pdev->id = id;
61 if (!pdev->dev.of_node) {
62 dev_err(&pdev->dev, "No platform supplied from device tree\n");
63 ret = -EINVAL;
64 goto err;
65 }
66
67 ret = of_property_read_u32(pdev->dev.of_node, mclk, &id);
68 if (ret) {
69 dev_err(&pdev->dev,
70 "%s: missing %s in dt node\n", __func__, mclk);
71 id = DEFAULT_MCLK_RATE;
72 }
73 pdata->mclk_freq = id;
74
75 pdata->spk_ext_pa_gpio = of_get_named_gpio(pdev->dev.of_node,
76 spk_ext_pa, 0);
77 if (pdata->spk_ext_pa_gpio < 0) {
78 dev_dbg(&pdev->dev,
79 "%s: missing %s in dt node\n", __func__, spk_ext_pa);
80 } else {
81 if (gpio_is_valid(pdata->spk_ext_pa_gpio)) {
82 ret = gpio_request(pdata->spk_ext_pa_gpio, "spk_ext_pa_gpio");
83 if(ret) {
84 pr_err("spk ext pa gpio request failed");
85 goto err;
86 }
87
88 ret = gpio_direction_output(pdata->spk_ext_pa_gpio, 1);
89 if(ret) {
90 pr_err("set_direction for spk ext pa gpio failed\n");
91 goto err;
92 }
93 } else {
94 pr_err("%s: Invaild external_speaker gpio: %d", __func__, pdata->spk_ext_pa_gpio);
95 ret = -EINVAL;
96 goto err;
97 }
98
99 }
100
101 ret = of_property_read_string(pdev->dev.of_node, codec_type, &ptr);
102 if (ret) {
103 dev_err(&pdev->dev,
104 "%s: missing %s in dt node\n", __func__, codec_type);
105 goto err;
106 }
107 if (pdev->id >= MAX_SND_CARDS) {
108 dev_err(&pdev->dev, "Sound Card parsed is wrong, id=%d\n",
109 pdev->id);
110 ret = -EINVAL;
111 goto err;
112 }
113 if (!strcmp(ptr, "external")) {
114 dev_info(&pdev->dev, "external codec is configured\n");
115 pdata->codec_type = 1;
116 /*Populate external codec TLMM configs*/
117 ret = populate_ext_snd_card_dt_data(pdev);
118 if (ret < 0) {
119 dev_err(&pdev->dev, "error finding the DT\n"
120 "params ret=%d\n", ret);
121 goto err;
122 }
123 card = populate_ext_snd_card_dailinks(pdev);
124 if (!card) {
125 dev_err(&pdev->dev, "%s: Card uninitialized\n",
126 __func__);
127 ret = -EPROBE_DEFER;
128 goto err;
129 }
130 } else {
131 card = populate_ext_snd_card_dailinks(pdev);
132 if (!card) {
133 dev_err(&pdev->dev, "%s: Card uninitialized\n",
134 __func__);
135 ret = -EPROBE_DEFER;
136 goto err;
137 }
138 dev_info(&pdev->dev, "default codec configured\n");
139 pdata->codec_type = 0;
140 num_strings = of_property_count_strings(pdev->dev.of_node,
141 ext_pa);
142 if (num_strings < 0) {
143 dev_err(&pdev->dev,
144 "%s: missing %s in dt node or length is incorrect\n",
145 __func__, ext_pa);
146 goto err;
147 }
148 for (i = 0; i < num_strings; i++) {
149 ret = of_property_read_string_index(pdev->dev.of_node,
150 ext_pa, i, &ext_pa_str);
151 if (ret) {
152 dev_err(&pdev->dev,
153 "%s:of read string %s i %d error %d\n",
154 __func__, ext_pa, i, ret);
155 goto err;
156 }
157 if (!strcmp(ext_pa_str, "primary"))
158 pdata->ext_pa = (pdata->ext_pa | PRI_MI2S_ID);
159 else if (!strcmp(ext_pa_str, "secondary"))
160 pdata->ext_pa = (pdata->ext_pa | SEC_MI2S_ID);
161 else if (!strcmp(ext_pa_str, "tertiary"))
162 pdata->ext_pa = (pdata->ext_pa | TER_MI2S_ID);
163 else if (!strcmp(ext_pa_str, "quaternary"))
164 pdata->ext_pa = (pdata->ext_pa | QUAT_MI2S_ID);
165 }
166 pr_debug("%s: ext_pa = %d\n", __func__, pdata->ext_pa);
167 pinctrl = devm_pinctrl_get(&pdev->dev);
168 if (IS_ERR(pinctrl)) {
169 pr_err("%s: Unable to get pinctrl handle\n",
170 __func__);
171 return -EINVAL;
172 }
173 pinctrl_info.pinctrl = pinctrl;
174 ret = get_cdc_gpio_lines(pinctrl, pdata->ext_pa);
175 if (ret < 0) {
176 pr_err("%s: failed to ger the codec gpio's %d\n",
177 __func__, ret);
178 goto err;
179 }
180 }
181
182 ret = of_property_read_string(pdev->dev.of_node,
183 hs_micbias_type, &type);
184 if (ret) {
185 dev_err(&pdev->dev, "%s: missing %s in dt node\n",
186 __func__, hs_micbias_type);
187 goto err;
188 }
189 if (!strcmp(type, "external")) {
190 dev_dbg(&pdev->dev, "Headset is using external micbias\n");
191 mbhc_cfg.hs_ext_micbias = true;
192 } else {
193 dev_dbg(&pdev->dev, "Headset is using internal micbias\n");
194 mbhc_cfg.hs_ext_micbias = false;
195 }
196
197 /* initialize the mclk */
198 pdata->digital_cdc_clk.i2s_cfg_minor_version =
199 AFE_API_VERSION_I2S_CONFIG;
200 pdata->digital_cdc_clk.clk_val = pdata->mclk_freq;
201 pdata->digital_cdc_clk.clk_root = 5;
202 pdata->digital_cdc_clk.reserved = 0;
203 /* initialize the digital codec core clk */
204 pdata->digital_cdc_core_clk.clk_set_minor_version =
205 AFE_API_VERSION_I2S_CONFIG;
206 pdata->digital_cdc_core_clk.clk_id =
207 Q6AFE_LPASS_CLK_ID_INTERNAL_DIGITAL_CODEC_CORE;
208 pdata->digital_cdc_core_clk.clk_freq_in_hz =
209 pdata->mclk_freq;
210 pdata->digital_cdc_core_clk.clk_attri =
211 Q6AFE_LPASS_CLK_ATTRIBUTE_COUPLE_NO;
212 pdata->digital_cdc_core_clk.clk_root =
213 Q6AFE_LPASS_CLK_ROOT_DEFAULT;
214 pdata->digital_cdc_core_clk.enable = 1;
215 /* Initialize loopback mode to false */
216 pdata->lb_mode = false;
217
218 msm8x16_setup_hs_jack(pdev, pdata);
219 msm8x16_dt_parse_cap_info(pdev, pdata);
220
221 card->dev = &pdev->dev;
222 platform_set_drvdata(pdev, card);
223 snd_soc_card_set_drvdata(card, pdata);
224 ret = snd_soc_of_parse_card_name(card, "qcom,model");
225 if (ret)
226 goto err;
227 /* initialize timer */
228 INIT_DELAYED_WORK(&pdata->disable_mclk_work, disable_mclk);
229 mutex_init(&pdata->cdc_mclk_mutex);
230 atomic_set(&pdata->mclk_rsc_ref, 0);
231 atomic_set(&pdata->mclk_enabled, false);
232 atomic_set(&quat_mi2s_clk_ref, 0);
233 atomic_set(&auxpcm_mi2s_clk_ref, 0);
234
235 ret = snd_soc_of_parse_audio_routing(card,
236 "qcom,audio-routing");
237 if (ret)
238 goto err;
239
240 ret = msm8x16_populate_dai_link_component_of_node(card);
241 if (ret) {
242 ret = -EPROBE_DEFER;
243 goto err;
244 }
245
246 ret = snd_soc_register_card(card);
247 if (ret) {
248 dev_err(&pdev->dev, "snd_soc_register_card failed (%d)\n",
249 ret);
250 goto err;
251 }
252
253 ret = core_get_adsp_ver();
254 if (ret < 0) {
255 ret = -EPROBE_DEFER;
256 dev_info(&pdev->dev, "%s: Get adsp version failed (%d)\n",
257 __func__, ret);
258 goto err;
259 }
260
261 return 0;
262 err:
263 if (pdata->vaddr_gpio_mux_spkr_ctl)
264 iounmap(pdata->vaddr_gpio_mux_spkr_ctl);
265 if (pdata->vaddr_gpio_mux_mic_ctl)
266 iounmap(pdata->vaddr_gpio_mux_mic_ctl);
267 if (pdata->vaddr_gpio_mux_pcm_ctl)
268 iounmap(pdata->vaddr_gpio_mux_pcm_ctl);
269 if(gpio_is_valid(pdata->spk_ext_pa_gpio))
270 gpio_free(pdata->spk_ext_pa_gpio);
271 devm_kfree(&pdev->dev, pdata);
272 err1:
273 return ret;
274 }
DTS：
1 sound {
2 compatible = "qcom,msm8x16-audio-codec";
3 qcom,model = "msm8x16-skui-snd-card";
4 qcom,msm-snd-card-id = <0>;
5 qcom,msm-ext-pa = "secondary";//"primary";
6 qcom,msm-codec-type = "internal";
7 qcom,msm-mbhc-hphl-swh = <0>;
8 qcom,msm-mbhc-gnd-swh = <1>;
9 qcom,msm-hs-micbias-type = "internal";
10 qcom,audio-routing =
11 "RX_BIAS", "MCLK",
12 "SPK_RX_BIAS", "MCLK",
13 "INT_LDO_H", "MCLK",
14 "MIC BIAS Internal1", "Handset Mic",
15 "MIC BIAS Internal2", "Headset Mic",
16 "MIC BIAS Internal1", "Secondary Mic",
17 "AMIC1", "MIC BIAS Internal1",
18 "AMIC2", "MIC BIAS Internal2",
19 "AMIC3", "MIC BIAS Internal1";
20 pinctrl-names = "cdc_lines_act",
21 "cdc_lines_sus",
22 "cdc_lines_sec_ext_act",
23 "cdc_lines_sec_ext_sus";
24 pinctrl-0 = <&cdc_pdm_lines_act>;
25 pinctrl-1 = <&cdc_pdm_lines_sus>;
26 pinctrl-2 = <&cdc_pdm_lines_act &cdc_ext_pa_act &cdc_ext_pa_ws_act>;
27 pinctrl-3 = <&cdc_pdm_lines_sus &cdc_ext_pa_sus &cdc_ext_pa_ws_sus>;
28 };
通过与DTS匹配，开始分析：
（1）、获取card的id：
1 ret = of_property_read_u32(pdev->dev.of_node, card_dev_id, &id);
（2）、设置card的名字：
1 pdev->id = id; 2 dev_set_name(&pdev->dev, "%s.%d", "msm-snd-card", id);
（3）、设置codec的类型为external还是internal的：
1 ret = of_property_read_string(pdev->dev.of_node, codec_type, &ptr);
2 if (ret) {
3 dev_err(&pdev->dev,
4 "%s: missing %s in dt node\n", __func__, codec_type);
5 goto err;
6 }
（4）、根据external还是internal的card，进入相应的处理函数中：
假设进入internal card：
1 card = &bear_cards[pdev->id]; 2 bear_cards[pdev->id].name = dev_name(&pdev->dev);
在这里，bear_cards是一个snd_soc_card的结构体，由设备树又可知，id=0：
1 static struct snd_soc_card bear_cards[MAX_SND_CARDS] = {
2 /* snd_soc_card_msm8x16 */
3 {
4 .name = "msm8x16-snd-card",
5 .dai_link = msm8x16_dai,
6 .num_links = ARRAY_SIZE(msm8x16_dai),
7 },
8 {
9 .name = "msm8x16-tapan-snd-card",
10 .dai_link = msm8x16_9306_dai_links,
11 .num_links = ARRAY_SIZE(msm8x16_9306_dai_links),
12 },
13 {
14 .name = "msm8x16-tapan9302-snd-card",
15 .dai_link = msm8x16_9302_dai_links,
16 .num_links = ARRAY_SIZE(msm8x16_9302_dai_links),
17 },
18 };
所以用到的只有msm8x16_dai；
snd_dai_link msm8x16_dai
其中，snd_soc_dai_link中，指定了Platform、Codec、codec_dai、cpu_dai的名字，稍后Machine驱动将会利用这些名字去匹配已经在系统中注册的platform，codec，dai，这些注册的部件都是在另外相应的Platform驱动和Codec驱动的代码文件中定义的，这样看来，Machine驱动的设备初始化代码无非就是选择合适Platform和Codec以及dai，用他们填充以上几个数据结构，然后注册Platform设备即可。
当然还要实现连接Platform和Codec的dai_link对应的ops实现；
msm8x16_sec_mi2s_be_ops的结构体是一个函数指针结构体，里面注册了相应的回调函数：
1 static struct snd_soc_ops msm8x16_mi2s_be_ops = {
2 .startup = msm_mi2s_snd_startup,
3 .hw_params = msm_mi2s_snd_hw_params,
4 .shutdown = msm_mi2s_snd_shutdown,
5 };
在高通平台中，这primary_mi2s这一路i2s，都是留给内部codec用的，所以，这路的dai_link上的codec_name和codec_dai_name，就是对应着内部codec的信息：
1 /* Backend I2S DAI Links */
2 {
3 .name = LPASS_BE_PRI_MI2S_RX,
4 .stream_name = "Primary MI2S Playback",
5 .cpu_dai_name = "msm-dai-q6-mi2s.0",
6 .platform_name = "msm-pcm-routing",
7 .codec_name = MSM8X16_CODEC_NAME,
8 .codec_dai_name = "msm8x16_wcd_i2s_rx1",
9 .no_pcm = 1,
10 .be_id = MSM_BACKEND_DAI_PRI_MI2S_RX,
11 .init = &msm_audrx_init,
12 .be_hw_params_fixup = msm_pri_rx_be_hw_params_fixup,
13 .ops = &msm8x16_mi2s_be_ops,
14 .ignore_suspend = 1,
15 },
从msm8x16_wcd_i2s_rx1我们便可以找到高通平台默认的msm8x16-wcd.c，在该文件中，注册了snd_soc_codec_driver：
（5）、匹配并注册相应的驱动：
如何匹配？
那这里就要谈论一个问题，在初始化的时候，如何凭借dai_link中的codec信息找到对应的codec，答案是codec_name。但注意，这里并不是通过这个名字直接寻找的，例如8916平台。
这下就来到重要的函数：
1 ret = snd_soc_register_card(card);
2 if (ret) {
3 dev_err(&pdev->dev, "snd_soc_register_card failed (%d)\n",
4 ret);
5 goto err;
6 }
snd_soc_register_card
将link指针遍历msm8x16_dai结构体数组的每一个成员：
1 for (i = 0; i < card->num_links; i++) {
2 struct snd_soc_dai_link *link = &card->dai_link[i];
这里定义了codec_name，名字为msm8x16_wcd_codec，所以不执行if的内容：
1 if (!!link->codec_name == !!link->codec_of_node) {
2 dev_err(card->dev, "ASoC: Neither/both codec"
3 " name/of_node are set for %s\n", link->name);
4 return -EINVAL;
5 }
同理，下面的函数也是一样：
View Code
继续向下看：
1 //设置声卡设备驱动信息 2 dev_set_drvdata(card->dev,card); 3 //初始化声卡设备列表 4 snd_soc_initialize_card_lists(card); 5 6 soc_init_card_debugfs(card); 7 //为声卡中的snd_soc_pcm_runtime数据结构分配内存空间 8 card->rtd= devm_kzalloc(card->dev, 9 sizeof(struct snd_soc_pcm_runtime) * 10 (card->num_links + card->num_aux_devs), 11 GFP_KERNEL); 12 if(card->rtd == NULL) 13 return-ENOMEM; 14 card->num_rtd= 0; 15 card->rtd_aux= &card->rtd[card->num_links]; 16 17 for(i = 0; i < card->num_links; i++) 18 card->rtd[i].dai_link= &card->dai_link[i]; 19 20 INIT_LIST_HEAD(&card->list); 21 INIT_LIST_HEAD(&card->dapm_dirty); 22 card->instantiated= 0; //表明声卡还没有被初始化 23 mutex_init(&card->mutex); 24 mutex_init(&card->dapm_mutex); 25 //初始化声卡 26 ret= snd_soc_instantiate_card(card); 27 if(ret != 0) 28 soc_cleanup_card_debugfs(card);
在snd_soc_instantiate_card函数中：
snd_soc_instantiate_card
1 /*bind DAIs */
2 for(i = 0; i < card->num_links; i++) {
3 //逐一绑定声卡的各类DAI链接，下面会详细介绍该函数
4 ret= soc_bind_dai_link(card, i);
5 if(ret != 0)
6 gotobase_error;
7 }
1 /* initialize the register cache for each available codec */
2 //遍历CODEC列表中的所有CODEC
3 list_for_each_entry(codec, &codec_list, list) {
4 //CODEC缓存是否已初始化
5 if (codec->cache_init)
6 continue;
7 /* by default we don't override the compress_type */
8 //设置压缩类型
9 compress_type = 0;
10 /* check to see if we need to override the compress_type */
11 for (i = 0; i < card->num_configs; ++i) {
12 codec_conf = &card->codec_conf[i];
13 if (!strcmp(codec->name, codec_conf->dev_name)) {
14 compress_type = codec_conf->compress_type;
15 if (compress_type && compress_type
16 != codec->compress_type)
17 break;
18 }
19 }
20 /*初始化CODEC缓存，该函数最终调用sound/soc/soc-cache.c文件内的snd_soc_flat_cache_init函数，为缓存（reg_cache）开辟内存空间，并把codec->cache_init置为1*/
21 ret = snd_soc_init_codec_cache(codec, compress_type);
22 if (ret < 0)
23 goto base_error;
24 }
1 //创建声卡 2 ret= snd_card_create(SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1, 3 card->owner,0, &card->snd_card);
继续看soc_bind_dai_link函数，通过msm8x16-wcd.c中probe的of_device_id就可以知道：
554 pm8916_tombak_dig: msm8x16_wcd_codec@f000{
555 compatible = "qcom,wcd-spmi";
556 reg = <0xf000 0x100>;
557 interrupt-parent = <&spmi_bus>;
558 interrupts = <0x1 0xf0 0x0>,
559 <0x1 0xf0 0x1>,
560 <0x1 0xf0 0x2>,
561 <0x1 0xf0 0x3>,
562 <0x1 0xf0 0x4>,
563 <0x1 0xf0 0x5>,
564 <0x1 0xf0 0x6>,
565 <0x1 0xf0 0x7>;
566 interrupt-names = "spk_cnp_int",
567 "spk_clip_int",
568 "spk_ocp_int",
569 "ins_rem_det1",
570 "but_rel_det",
571 "but_press_det",
572 "ins_rem_det",
573 "mbhc_int";
而这个node节点正式codec驱动的设备树节点。在soc_bind_dai_link()函数中，会做出如下处理：
1 /*注册codec的时候，会将所有注册的codec链接到codec_list中*/
2 list_for_each_entry(codec, &codec_list, list) {
3 if (dai_link->codec_of_node) {
4 /*根据设备数节点句柄进行匹配*/
5 if (codec->dev->of_node != dai_link->codec_of_node)
6 continue;
7 } else {
8 /*如果句柄为空，根据,codec_name进行匹配，在这里不会走这里，其实codec_name是 wcd-spmi-core.1*/
9 if (strcmp(codec->name, dai_link->codec_name))
10 continue;
11 }
12
13 rtd->codec = codec;
14
15 /*找到codec之后，根据codec_dai的名字找到对应的codec_dai*/
16 list_for_each_entry(codec_dai, &dai_list, list) {
17 if (codec->dev == codec_dai->dev &&
18 !strcmp(codec_dai->name,
19 dai_link->codec_dai_name)) {
20
21 rtd->codec_dai = codec_dai;
22 }
23 }
24 }
所以，我们可以根据dai_link中的codec_dai的名字或者codec名字来找到对应的codec驱动。
另外，当播放音频的时候需要打开一个外部pa，所以probe函数中有一部分是external pa的初始化：
（6）、获取external pa:（也就是放大器）：
1 for (i = 0; i < num_strings; i++) {
2 ret = of_property_read_string_index(pdev->dev.of_node,
3 ext_pa, i, &ext_pa_str);
4 if (ret) {
5 dev_err(&pdev->dev, "%s:of read string %s i %d error %d\n",
6 __func__, ext_pa, i, ret);
7 goto err;
8 }
9 if (!strcmp(ext_pa_str, "primary"))
10 pdata->ext_pa = (pdata->ext_pa | PRI_MI2S_ID);
11 else if (!strcmp(ext_pa_str, "secondary"))
12 pdata->ext_pa = (pdata->ext_pa | SEC_MI2S_ID);
13 else if (!strcmp(ext_pa_str, "tertiary"))
14 pdata->ext_pa = (pdata->ext_pa | TER_MI2S_ID);
15 else if (!strcmp(ext_pa_str, "quaternary"))
16 pdata->ext_pa = (pdata->ext_pa | QUAT_MI2S_ID);
17 }
18 pr_err("%s: ext_pa = %d\n", __func__, pdata->ext_pa);
1 pinctrl_info.pinctrl = pinctrl;
2 ret = get_cdc_gpio_lines(pinctrl, pdata->ext_pa); //获取gpio状态
3 if (ret < 0) {
4 pr_err("%s: failed to ger the codec gpio's %d\n",
5 __func__, ret);
6 goto err;
7 }
可以根据高通手册来看，所以设备树上的配置为secondary：
1 qcom,msm-ext-pa = "secondary";//"primary";
回到顶部
2. 相应的资料：
其实以上便是linux3.10以上的audio内核machine架构，网上搜索相应资料便可找到；贴上借鉴的资料：
http://blog.csdn.net/zhaocj/article/details/20533369
网上大牛的架构：
http://www.cnblogs.com/linhaostudy/p/8169383.html