2021-01-30

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我是靠谱客的博主炙热汉堡，最近开发中收集的这篇文章主要介绍2021-01-30，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

关于linux ak4495声卡的驱动编译，从零开始

设备树

/ { <-------/表法根目录
compatible = "rockchip,pro3288-act8846", "rockchip,rk3288";

ak449x-sound {
status = "okay";
compatible = "simple-audio-card";//simple-card framework框架
simple-audio-card,format = "i2s";
simple-audio-card,name = "rockchip,ak449x-codec";//<------simple-audio-card,name：用户指定的音频声卡名称。
simple-audio-card,mclk-fs = <256>;//主控供给编解码芯片用的时钟

// simple-audio-card,widgets：指定音频编解码器DAPM小部件(widgets),

// 每个条目都是一对字符串:“template-wname”，“user-supplied-wname”。
// “ template-wname”是模板小部件名称，可选为：“Microphone”, “Line”, “Headphone”, “Speaker”.
// “user-supplied-wname”是用户指定的窗口小部件名称。

// simple-audio-card,widgets =
// "Microphone", "Mic Jack",
// "Headphone", "Headphone Jack",
// "Speaker", "Speaker";

   //simple-audio-card,routing：音频组件之间的连接列表。
   //每个条目都是一对字符串，第一个是目的(sink)，第二个是源(source)。
//simple-audio-card,routing =    //音频路径,如mic输入、耳机输出走那些通路
// "Mic Jack", "MICBIAS1",
// "IN1P", "Mic Jack",
// "Headphone Jack", "HPOL",
// "Headphone Jack", "HPOR",
// "Speaker", "SPOLP",
// "Speaker", "SPOLN",
// "Speaker", "SPORP",
// "Speaker", "SPORN";

//用于dai-link里指定CPU和CODEC子节点。
simple-audio-card,dai-link@0 {

   //可选格式为：
   //“ i2s”，“ right_j”，“ left_j”，“ dsp_a”
   //“ dsp_b”，“ ac97”，“ pdm”，“ msb”，“ lsb”。
format = "i2s";
cpu {
sound-dai = <&i2s>;
};

codec {
sound-dai = <&ak449x>;
};
};
};

}；//end of /

&i2c4 {
status = "okay";

ak449x: ak449x@1a {
#sound-dai-cells = <0>;
compatible = "AudioX,ak449x";
reg = <0x1a>;
status = "okay";//1573 add
chip = "AK4495";//1573 add
clocks = <&cru SCLK_I2S0_OUT>;
clock-names = "mclk";
pinctrl-names = "default";
pinctrl-0 = <&i2s0_mclk>;
io-channels = <&saradc 4>;
// hp-det-adc-value = <500>;
//realtek,in1-differential;
};
};

匹配优先顺序：https://blog.csdn.net/mcgrady_tracy/article/details/38980991?utm_medium=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-1.control&depth_1-utm_source=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-1.control

设备树中
compatible = “AudioX,ak449x”
匹配优先级
of_match_table>id_table
of_match_table表中的厂商和设备树中条目compatible(包含供应商字符串) 的厂商“myvendor”不匹配，则会用id_table去匹配设备树条目compatible (不包含供应商字符串)。

of_match_table > acpi_driver > id_table.

static const struct of_device_id ak449x_of_match[] = {
   { .compatible = "AudioX,ak449x", },
   { },
};
static const struct i2c_device_id ak449x_i2c_id[] = {
   { "ak449x", 0 },
   { "rt5639", 0 },
   { "rt5642", 0 },
   { }
};
MODULE_DEVICE_TABLE(i2c, ak449x_i2c_id);
static struct i2c_driver ak449x_i2c_driver = {
   .driver = {
       .name = "ak449x",
       .pm = &ak449x_pm,
       .of_match_table = ak449x_of_match,

//未用 .acpi_match_table = ACPI_PTR(rt5640_acpi_match),
       },
   .probe = ak449x_i2c_probe,//match成功后调用
   .remove = ak449x_i2c_remove,
   .id_table = ak449x_i2c_id,
};

module_i2c_driver(ak449x_i2c_driver);

i2c总线查看

i2cdetect -l