rk3399调试alc5651(audio模块)之simple-card framework机制分析

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我是靠谱客的博主繁荣画笔，这篇文章主要介绍rk3399调试alc5651(audio模块)之simple-card framework机制分析，现在分享给大家，希望可以做个参考。

这是“rk3399调试alc5651”的第二篇，这篇以源码分析simple-card framework机制。

在《rk3399调试alc5651之操作方法》讲述了如何移植alc5651，现在我们分析从源码simple-card framework框架。
本篇博文不展示asoc调用过程（因为笔记内容有点多），如想获取其asoc调用过程请从这里下载本人的笔记。

环境：
硬件：realtek alc5651
内核：Linux4.4

分析一个复杂的子系统代码需要找到入口，明确自己想要的东西。
先抓住主要的函数调用流，理清思路。为日后深入分析打下基础。现在有了设备树之后，我们可以从设备树上开始我们的研究。

参考文档：
Documentation/devicetree/bindings/sound/rockchip-rt5645.txt
Documentation/devicetree/bindings/sound/rockchip-i2s.txt

复制代码

rt5651-sound {			//machine 匹配层的驱动节点。
	status = "okay";	//默认打开
	compatible = "simple-audio-card";	//simple-card framework框架
	simple-audio-card,format = "i2s";
	simple-audio-card,name = "realtek,rt5651-codec";
	simple-audio-card,mclk-fs = <256>;	//主控供给编解码芯片用的时钟
	simple-audio-card,widgets =		//指定相关组件
		"Microphone", "Mic Jack",	//mic
		"Headphone", "Headphone Jack";	//耳机
		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";
	simple-audio-card,cpu {
		sound-dai = <&i2s0>;	//指定cpu接入音频编解码的dai(数字化接口)
	};
	simple-audio-card,codec {
		sound-dai = <&rt5651>;	//指定编解码音频接入cpu的dai(数字化接口)
	};
};

rt5651: rt5651@1a {
	#sound-dai-cells = <0>;
	compatible = "rockchip,rt5651";
	reg = <0x1a>;		//控制音频芯片i2c通道的设备地址
	clocks = <&cru SCLK_I2S_8CH_OUT>;
	clock-names = "mclk";
	pinctrl-names = "default";
	pinctrl-0 = <&i2s_8ch_mclk>;
	spk-con-gpio = <&gpio0 11 GPIO_ACTIVE_HIGH>;
	hp-det-gpio = <&gpio4 28 GPIO_ACTIVE_LOW>;
};

i2s0: i2s@ff880000 {
	compatible = "rockchip,rk3399-i2s", "rockchip,rk3066-i2s";
	reg = <0x0 0xff880000 0x0 0x1000>;
	rockchip,grf = <&grf>;
	interrupts = <0 39 4 0>;
	dmas = <&dmac_bus 0>, <&dmac_bus 1>;
	dma-names = "tx", "rx";
	clock-names = "i2s_clk", "i2s_hclk";
	clocks = <&cru 86>, <&cru 468>;
	pinctrl-names = "default";
	pinctrl-0 = <&i2s0_8ch_bus>;
	power-domains = <&power 28>;
	status = "disabled";
 };

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rt5651-sound {			//machine 匹配层的驱动节点。
	status = "okay";	//默认打开
	compatible = "simple-audio-card";	//simple-card framework框架
	simple-audio-card,format = "i2s";
	simple-audio-card,name = "realtek,rt5651-codec";
	simple-audio-card,mclk-fs = <256>;	//主控供给编解码芯片用的时钟
	simple-audio-card,widgets =		//指定相关组件
		"Microphone", "Mic Jack",	//mic
		"Headphone", "Headphone Jack";	//耳机
		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";
	simple-audio-card,cpu {
		sound-dai = <&i2s0>;	//指定cpu接入音频编解码的dai(数字化接口)
	};
	simple-audio-card,codec {
		sound-dai = <&rt5651>;	//指定编解码音频接入cpu的dai(数字化接口)
	};
};

rt5651: rt5651@1a {
	#sound-dai-cells = <0>;
	compatible = "rockchip,rt5651";
	reg = <0x1a>;		//控制音频芯片i2c通道的设备地址
	clocks = <&cru SCLK_I2S_8CH_OUT>;
	clock-names = "mclk";
	pinctrl-names = "default";
	pinctrl-0 = <&i2s_8ch_mclk>;
	spk-con-gpio = <&gpio0 11 GPIO_ACTIVE_HIGH>;
	hp-det-gpio = <&gpio4 28 GPIO_ACTIVE_LOW>;
};

i2s0: i2s@ff880000 {
	compatible = "rockchip,rk3399-i2s", "rockchip,rk3066-i2s";
	reg = <0x0 0xff880000 0x0 0x1000>;
	rockchip,grf = <&grf>;
	interrupts = <0 39 4 0>;
	dmas = <&dmac_bus 0>, <&dmac_bus 1>;
	dma-names = "tx", "rx";
	clock-names = "i2s_clk", "i2s_hclk";
	clocks = <&cru 86>, <&cru 468>;
	pinctrl-names = "default";
	pinctrl-0 = <&i2s0_8ch_bus>;
	power-domains = <&power 28>;
	status = "disabled";
 };