音频驱动

本文档以 es8388 驱动为例。

电路原理

es8388 电路设计：

es8388 支持多种输入模式，可以直通输入也可以差分输入，这个需要针对实际情况对芯片寄存器进行配置。以上LIN1和RLIN1是直通，连接耳机。LIN2和RLIN2是差分输入，连接板载麦克风。

设备树分析

声音卡配置

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es8388_sound: es8388-sound {
	status = "okay";
	compatible = "rockchip,multicodecs-card";
	rockchip,card-name = "rockchip-es8388";
	hp-det-gpio = <&gpio1 RK_PC4 GPIO_ACTIVE_HIGH>;
	io-channels = <&saradc 3>;
	io-channel-names = "adc-detect";
	keyup-threshold-microvolt = <1800000>;
	poll-interval = <100>;
	spk-con-gpio = <&gpio4 RK_PA3 GPIO_ACTIVE_HIGH>;
	hp-con-gpio = <&gpio4 RK_PA4 GPIO_ACTIVE_HIGH>;
	rockchip,format = "i2s";
	rockchip,mclk-fs = <256>;
	rockchip,cpu = <&i2s0_8ch>;
	rockchip,codec = <&es8388>;
	rockchip,audio-routing =
		"Headphone", "LOUT1",
		"Headphone", "ROUT1",
		"Speaker", "LOUT2",
		"Speaker", "ROUT2",
		"Headphone", "Headphone Power",
		"Headphone", "Headphone Power",
		"Speaker", "Speaker Power",
		"Speaker", "Speaker Power",
		"LINPUT1", "Headset Mic",
		"LINPUT2", "Main Mic",
		"RINPUT1", "Main Mic",
		"RINPUT2", "Main Mic";
	pinctrl-names = "default";
	pinctrl-0 = <&hp_det>;
	play-pause-key {
		label = "playpause";
		linux,code = <KEY_PLAYPAUSE>;
		press-threshold-microvolt = <2000>;
	};
};

label解释：
hp-det-gpio ：检测耳机插入状态的GPIO
io-channels ：检测耳机插入状态的ADC通道
io-channel-names ：检测耳机插入状态的ADC通道名称
keyup-threshold-microvolt ：检测耳机插入状态的阈值
poll-interval ：检测耳机插入状态的间隔时间
spk-con-gpio ：耳机输出控制的GPIO
hp-con-gpio ：耳机输入控制的GPIO
rockchip,format ：音频数据格式
rockchip,mclk-fs ：音频数据采样率
rockchip,codec ：音频数据采集的CODEC
rockchip,audio-routing ：音频数据采集的路由
pinctrl-0 ：检测脚设置
play-pause-key ：耳机播放暂停的按键

芯片挂载在I2C7总线上，对应设备树如下：

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&i2c7 {
	status = "okay";
	es8388: es8388@11 {
		status = "okay";
		#sound-dai-cells = <0>;
		compatible = "everest,es8388", "everest,es8323";
		reg = <0x11>;
		clocks = <&mclkout_i2s0>;
		clock-names = "mclk";
		assigned-clocks = <&mclkout_i2s0>;
		assigned-clock-rates = <12288000>;
		pinctrl-names = "default";
		pinctrl-0 = <&i2s0_mclk>;
	};
};

HiFi.conf中定义声卡名称

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# Use case for devices on rockchip,rk809-codec card.

SectionVerb {
	EnableSequence [
		cdev "hw:rockchiprk809co"
	]

	DisableSequence [
		cdev "hw:rockchiprk809co"
	]
}

SectionDevice."Headphone" {
	Comment "Headphones Playback"

	EnableSequence [
		cdev "hw:rockchiprk809co"

		cset "name='Playback Path' HP"
	]

	DisableSequence [
		cdev "hw:rockchiprk809co"

		cset "name='Playback Path' OFF"
	]

	Value {
		PlaybackPCM "hw:rockchiprk809co"
		PlaybackChannels "2"
		PlaybackPriority "1"
		JackControl "Headphones Jack"
		JackHWMute "Speaker"
	}
}

SectionDevice."Speaker" {
	Comment "Speaker Playback"

	EnableSequence [
		cdev "hw:rockchiprk809co"

		cset "name='Playback Path' SPK"
	]

	DisableSequence [
		cdev "hw:rockchiprk809co"

		cset "name='Playback Path' OFF"
	]

	Value {
		PlaybackPCM "hw:rockchiprk809co"
		PlaybackChannels "2"
		PlaybackPriority "2"
	}
}


SectionDevice."Headset" {
	Comment "Headset Mic"
	ConflictingDevice [
		"MainMic"
	]
	EnableSequence [
		cdev "hw:rockchiprk809co"
		cset "name='Capture MIC Path' Hands Free Mic"
	]

	DisableSequence [
		cdev "hw:rockchiprk809co"
		cset "name='Capture MIC Path' MIC OFF"
	]

	Value {
		CapturePCM "hw:rockchiprk809co"
		CaptureChannels "2"
		JackControl "Mic Jack"
		JackHWMute "MainMic"
	}
}

SectionDevice."MainMic" {
	Comment "Main Mic"
	ConflictingDevice [
		"Headset"
	]
	EnableSequence [
		cdev "hw:rockchiprk809co"
		cset "name='Capture MIC Path' Main Mic"
	]

	DisableSequence [
		cdev "hw:rockchiprk809co"
		cset "name='Capture MIC Path' MIC OFF"
	]

	Value {
		CapturePCM "hw:rockchiprk809co"
		CaptureChannels "2"
	}
}


从配置上可以看出配置了两个 jack ， “Headphone” 和 “MainMic” 。
Headphone 是用来区分耳机和喇叭播放，MainMic区分板载麦克风和耳机麦克风

数据手册

调整耳机录音增益寄存器，电路图连接的是左声道in，所以调整左声道增益就行。


寄存器10对应的输入通道选择LIN1或者LIN2.
DSR = 0: 选择LINPUT1 - RINPUT1作为差分输入对（默认）。
DSR = 1: 选择LINPUT2 - RINPUT2作为差分输入对

寄存器11则是使用差分模式输入，DS切换需要设置成1.

驱动代码分析

代码节选：

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static int es8323_probe(struct snd_soc_component *component)
{
	struct es8323_priv *es8323 = snd_soc_component_get_drvdata(component);
	int ret = 0;

	es8323->mclk = devm_clk_get(component->dev, "mclk");
	if (IS_ERR(es8323->mclk)) {
		dev_err(component->dev, "%s mclk is missing or invalid\n", __func__);
		return PTR_ERR(es8323->mclk);
	}
	ret = clk_prepare_enable(es8323->mclk);
	if (ret)
		return ret;
	es8323->component = component;

	ret = es8323_reset(component);
	if (ret < 0) {
		dev_err(component->dev, "Failed to issue reset\n");
		clk_disable_unprepare(es8323->mclk);
		return ret;
	}
	// 设置默认值
	snd_soc_component_write(component, 0x01, 0x60);
	snd_soc_component_write(component, 0x02, 0xF3);
	snd_soc_component_write(component, 0x02, 0xF0);
	snd_soc_component_write(component, 0x2B, 0x80);
	snd_soc_component_write(component, 0x00, 0x36);
	snd_soc_component_write(component, 0x08, 0x00);
	snd_soc_component_write(component, 0x04, 0x00);
	snd_soc_component_write(component, 0x06, 0xC3);
	snd_soc_component_write(component, 0x19, 0x02);
	snd_soc_component_write(component, 0x09, 0x88);
	snd_soc_component_write(component, 0x0A, 0x5C);
	snd_soc_component_write(component, 0x0B, 0x82);
	snd_soc_component_write(component, 0x0C, 0x4C);
	snd_soc_component_write(component, 0x0D, 0x02);
	snd_soc_component_write(component, 0x10, 0x00);
	snd_soc_component_write(component, 0x11, 0x00);
	snd_soc_component_write(component, 0x12, 0xea);
	snd_soc_component_write(component, 0x13, 0xc0);
	snd_soc_component_write(component, 0x14, 0x05);
	snd_soc_component_write(component, 0x15, 0x06);
	snd_soc_component_write(component, 0x16, 0x53);

	snd_soc_component_write(component, 0x17, 0x18);
	snd_soc_component_write(component, 0x18, 0x02);
	snd_soc_component_write(component, 0x1A, 0x00);
	snd_soc_component_write(component, 0x1B, 0x00);
	snd_soc_component_write(component, 0x27, 0xB8);
	snd_soc_component_write(component, 0x2A, 0xB8);
	snd_soc_component_write(component, 0x35, 0xA0);
	usleep_range(18000, 20000);
	snd_soc_component_write(component, 0x2E, 0x1E);
	snd_soc_component_write(component, 0x2F, 0x1E);
	snd_soc_component_write(component, 0x30, 0x1E);
	snd_soc_component_write(component, 0x31, 0x1E);
	snd_soc_component_write(component, 0x03, 0x09);
	snd_soc_component_write(component, 0x02, 0x00);
	usleep_range(18000, 20000);
	snd_soc_component_write(component, 0x04, 0x3C);

	es8323_set_bias_level(component, SND_SOC_BIAS_STANDBY);
	return 0;
}

在probe阶段，会设置寄存器默认值，根据手册修改0x09增加录音增益。修改 0x0A和0x0B，设置默认录音路径。

问题

  • 切换录音默认路径问题

参考数据手册中寄存器10和11设置，结合代码分析。
es8388 寄存器驱动默认配置LIN1为录音设备，硬件电路板载麦克风为LIN2，如需要调试板载，需要切换以下寄存器配置值。
Left PGA Mux 32
Right PGA Mux 33
Differential Mux 34

测试

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#  安装audacity 录音工具 桌面版软件
apt-get install audacity
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# 查看音频设备状态
amixer -c 0 contents
# 查看声卡信息
cat /proc/asound/cards
# 设置声卡参数 如id:34
amixer cset numid=34 1
  • 指令录音
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# 录音 
arecord -D hw:0,0 -d 10 -f cd -r 44100 -c 2 -t wav test.wav
-d 10表示录制10秒声音，test.wav是保存的文件名称

-D hw:x  表示指定第几个声卡 

-r 指定采样率，-f 指定每个采样点的位数--样本大小

指令错误

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查看参数设置，排查指令错误
arecord -D hw:0,0 --dump-hw-params

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# 播放
aplay -D hw:0,0 test.wav