Yocto Linux中ADS1174 ALSA驱动无法识别为音频设备求助

核心目标 #

使德州仪器ADS1274编解码器在Yocto Linux环境中可用。因Linux内核自带支持ADS1174的ads117x ALSA驱动，且ADS1174与ADS1274高度相似，先尝试集成该现有驱动，但目前无法让其显示为ALSA设备。

硬件环境 #

• 搭载Freescale i.MX6ULL处理器的Variscite DART-6UL开发板
• 编解码器优先连接至SAI3接口

已做配置 #

设备树修改 #

1. 根节点添加sound节点：

sound {
        compatible = "simple-audio-card";
        simple-audio-card,name = "ads1174audio";
        simple-audio-card,format ="left_j";  /* 左对齐，符合ADS1174数据手册规定 */
        simple-audio-card,bitclock-master = <&sound_master>;
        simple-audio-card,frame-master = <&sound_master>;

        simple-audio-card,widgets =
                "Line", "Channel1in",
                "Line", "Channel2in",
                "Line", "Channel3in",
                "Line", "Channel4in";

        simple-audio-card,routing =
                "Channel1in", "Input1",
                "Channel2in", "Input2",
                "Channel3in", "Input3",
                "Channel4in", "Input4";

        sound_master: simple-audio-card,cpu {
                sound-dai = <&sai3>;
                dai-tdm-slot-num = <4>;
                dai-tdm-slot-width = <24>;
        };

        simple-audio-card,codec {
                sound-dai = <&ads1174>;
                /*system-clock-frequency = <12288000>;*/
                /*clocks = <&codec_osc>;*/
        };
}

2. sai3节点添加ads1174子节点：

&sai3 {
        status = "okay";

        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_sai3>;
        ads1174: codec  {
                compatible = "ti,ads1174";
        };
};

注：不确定将ads1174节点添加至sai3下是否正确

Yocto配置 #

在layer.conf中设置驱动自动加载：

KERNEL_MODULE_AUTOLOAD += "ads117x"

现象 #

• Yocto编译正常，系统启动后ads117x驱动已加载
• 执行aplay -l无ALSA设备：

root@imx6ul-var-dart:~# aplay -l
aplay: device_list:274: no soundcards found...

• dmesg日志：

[    2.703831] ALSA device list:
[    2.709136]   No soundcards found.
...
[    9.611115] ads117x: loading out-of-tree module taints kernel.

请求协助 #

不确定问题出在驱动加载顺序，还是设备树配置缺失关键项，恳请协助排查解决。

内容的提问来源于stack exchange，提问作者jkow