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imx6q 音频芯片驱动开发--相关设备树以及代码中的对应设置_imx6q 声卡 时钟

作者：在线问答5 | 2024-08-05 16:35:58

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imx6q 声卡 时钟

首先就不介绍asoc框架了，网上好的资料很多，推荐DroidPhone大神的，写的很全，知识面基本都介绍到了，不过由于写的比较早，没有使用设备树，最近也正好在调相关驱动，写点东西记录一下。

https://blog.csdn.net/droidphone/category_1118446.html

源码我也上传了 有需要的可以下载

https://download.csdn.net/download/qq_17270067/13721398

 

 

mpu：imx6q

linux-kernel：4.1.15

 

1、machine驱动

使用的是设备树中的sound节点

  1. sound {
  2. 	compatible = "fsl,imx-audio-tas2505";
  3. 	model = "tas2505-audio";
  4. 	cpu-dai = <&ssi1>; 
  5. 	audio-codec = <&codec>;
  6.  
  7. 	audio-routing = 
  8. 	  "Speaker Driver", "DAC Channel" ,
  9. 	  "Speaker", "Speaker Driver" ;                 
  10.  
  11. 	mux-int-port = <1>;
  12. 	mux-ext-port = <3>;
  13. };

cpu-dai：使用的platform节点

audio-codec：使用的codec节点

audio-routing：音频设备连接路径，每两个为一组，第一个为sink，第二个为source。

mux-int-port ：使用了内部的哪个ssi。内部ssi接口ssi1，ssi2，ssi3， 分别对应 mux-int-port = <1>，mux-int-port = <2>，mux-int-port = <7>

mux-ext-port：使用了哪个外部AUD接口，有 AUD3，AUD4，AUD5，AUD6，分别对应mux-ext-port = <3>，mux-ext-port = <4>，mux-ext-port = <5>，mux-ext-port = <6>

 

在修改完了使用的AUDX接口之后，我们也需要将audmux的pinctrl修改成对应的接口

  1. pinctrl_audmux: audmuxgrp {
  2. 			fsl,pins = <
  3. 				MX6QDL_PAD_CSI0_DAT4__AUD3_TXC          0x130b0
  4. 				MX6QDL_PAD_CSI0_DAT5__AUD3_TXD          0x110b0
  5. 				MX6QDL_PAD_CSI0_DAT6__AUD3_TXFS         0x130b0
  6. 				MX6QDL_PAD_CSI0_DAT7__AUD3_RXD          0x130b0
  7. 			>;
  8. 		};
  9.  
  10. &audmux {
  11. 	pinctrl-names = "default";
  12. 	pinctrl-0 = <&pinctrl_audmux>;
  13. 	status = "okay";
  14. };

 

machine驱动文件中的probe函数如下：

  1. static int imx_tas2505_probe ( struct platform_device* pdev )
  2. {
  3. 	struct device_node* cpu_np, *codec_np,*gpr_np;
  4. 	struct device_node* np = pdev->dev.of_node;
  5. 	struct platform_device* cpu_pdev;
  6. 	struct imx_priv* priv = &card_priv;
  7. 	struct i2c_client* codec_dev;
  8. 	struct device_node* asrc_np;
  9. 	struct imx_tas2505_data* data = NULL;
  10. 	struct platform_device* asrc_pdev = NULL;
  11. 	int int_port, ext_port;
  12. 	int ret;
  13.  
  14.     //读取设备树中的mux-int-port属性的值
  15. 	ret = of_property_read_u32 ( np, "mux-int-port", &int_port );
  16. 	if ( ret )
  17. 	{
  18. 		dev_err ( &pdev->dev, "mux-int-port missing or invalid\n" );
  19. 		return ret;
  20. 	}
  21. 	
  22.     //读取设备树中的mux-ext-port属性的值
  23. 	ret = of_property_read_u32 ( np, "mux-ext-port", &ext_port );
  24. 	if ( ret )
  25. 	{
  26. 		dev_err ( &pdev->dev, "mux-ext-port missing or invalid\n" );
  27. 		return ret;
  28. 	}
  29.  
  30. 	/*
  31. 	 * The port numbering in the hardware manual starts at 1, while
  32. 	 * the audmux API expects it starts at 0.
  33. 	 */
  34. 	int_port--;
  35. 	ext_port--;
  36. 	//根据codec和cpu的主从关系 配置ssi和aud的连接以及各条线的输入输出 
  37. 	//本质是设置寄存器的值 具体参照数据手册Chapter 15 Digital Audio Multiplexer (AUDMUX)	
  38. 	ret = imx_audmux_v2_configure_port ( ext_port,
  39. 	                                     IMX_AUDMUX_V2_PTCR_SYN |
  40. 	                                     IMX_AUDMUX_V2_PTCR_TFSEL ( int_port ) |
  41. 	                                     IMX_AUDMUX_V2_PTCR_TCSEL ( int_port ) |
  42. 	                                     IMX_AUDMUX_V2_PTCR_TFSDIR |
  43. 	                                     IMX_AUDMUX_V2_PTCR_TCLKDIR,
  44. 	                                     IMX_AUDMUX_V2_PDCR_RXDSEL ( int_port ) );
  45. 	if ( ret )
  46. 	{
  47. 		dev_err ( &pdev->dev, "audmux internal port setup failed\n" );
  48. 		return ret;
  49. 	}
  50. 	ret = imx_audmux_v2_configure_port ( int_port,
  51. 	                                     IMX_AUDMUX_V2_PTCR_SYN,
  52. 	                                     IMX_AUDMUX_V2_PDCR_RXDSEL ( ext_port ) );
  53. 	if ( ret )
  54. 	{
  55. 		dev_err ( &pdev->dev, "audmux external port setup failed\n" );
  56. 		return ret;
  57. 	}
  58.  
  59.  
  60. 	priv->pdev = pdev;
  61.  
  62.     //获取platform和codec节点
  63. 	cpu_np = of_parse_phandle ( pdev->dev.of_node, "cpu-dai", 0 );
  64. 	codec_np = of_parse_phandle ( pdev->dev.of_node, "audio-codec", 0 );
  65. 	if ( !cpu_np || !codec_np )
  66. 	{
  67. 		dev_err ( &pdev->dev, "phandle missing or invalid\n" );
  68. 		ret = -EINVAL;
  69. 		goto fail;
  70. 	}
  71.  
  72. 	cpu_pdev = of_find_device_by_node ( cpu_np );
  73. 	if ( !cpu_pdev )
  74. 	{
  75. 		dev_err ( &pdev->dev, "failed to find SSI platform device\n" );
  76. 		ret = -EINVAL;
  77. 		goto fail;
  78. 	}
  79. 	codec_dev = of_find_i2c_device_by_node ( codec_np );
  80. 	if ( !codec_dev || !codec_dev->dev.driver )
  81. 	{
  82. 		dev_err ( &pdev->dev, "failed to find codec platform device\n" );
  83. 		ret = -EINVAL;
  84. 		goto fail;
  85. 	}
  86.  
  87. 	data = devm_kzalloc ( &pdev->dev, sizeof ( *data ), GFP_KERNEL );
  88. 	if ( !data )
  89. 	{
  90. 		ret = -ENOMEM;
  91. 		goto fail;
  92. 	}
  93.  
  94. 	//读取设备树codec-master 是否存在
  95. 	if ( of_property_read_bool ( pdev->dev.of_node,"codec-master" ) )
  96. 	{
  97. 		data->is_codec_master = true;
  98. 	}
  99.  
  100. 	//获取code时钟
  101. 	data->codec_clk = devm_clk_get ( &codec_dev->dev, "mclk" );
  102. 	if ( IS_ERR ( data->codec_clk ) )
  103. 	{
  104. 		ret = PTR_ERR ( data->codec_clk );
  105. 		dev_err ( &pdev->dev, "failed to get codec clk: %d\n", ret );
  106. 		goto fail;
  107. 	}
  108.  
  109. 	//使能时钟
  110. 	data->clk_frequency = clk_get_rate ( data->codec_clk );
  111. 	ret = clk_prepare_enable ( data->codec_clk );
  112. 	if ( ret )
  113. 	{
  114. 		dev_err ( &codec_dev->dev, "failed to enable codec clk: %d\n", ret );
  115. 		goto fail;
  116. 	}
  117.  
  118. 	data->dai.name = "HiFi";
  119. 	data->dai.stream_name = "HiFi";
  120. 	data->dai.codec_dai_name = "tas2505-hifi"; //此处名字需与codec中snd_soc_dai_driver结构中的name相同
  121. 	data->dai.cpu_dai_name = dev_name ( &cpu_pdev->dev ); //得到设备的名字 该名字是在设备树转化成platform device被赋予
  122. 	data->dai.codec_of_node = codec_np;
  123. 	data->dai.platform_of_node = cpu_np;
  124.  
  125. 	printk ( "cpu_dai_name = %s\n",data->dai.cpu_dai_name );
  126.  
  127. 	data->dai.init = &imx_tas2505_dai_init; //
  128. 	data->dai.ops = &imx_hifi_ops;
  129. 	
  130. 	//设置与codec的通信格式为I2S cpu为主 codec为从 	
  131. 	data->dai.dai_fmt = SND_SOC_DAIFMT_I2S | SND_SOC_DAIFMT_NB_NF |
  132. 	                    SND_SOC_DAIFMT_CBS_CFS;
  133.  
  134. 	data->card.dev = &pdev->dev;
  135. 	ret = snd_soc_of_parse_card_name ( &data->card, "model" );
  136. 	if ( ret )
  137. 	{
  138. 		goto fail;
  139. 	}
  140. 	
  141. 	//找到设备树名字为audio-routing的项 并取出sink和source
  142. 	ret = snd_soc_of_parse_audio_routing ( &data->card, "audio-routing" );
  143. 	
  144. 	if ( ret )
  145. 	{
  146. 		goto fail;
  147. 	}
  148. 	data->card.num_links = 1;
  149. 	data->card.owner = THIS_MODULE;
  150. 	data->card.dai_link = &data->dai;
  151. 	data->card.dapm_widgets = imx_tas2505_dapm_widgets; //注册不由codec寄存器控制的外部器件
  152. 	data->card.num_dapm_widgets = ARRAY_SIZE ( imx_tas2505_dapm_widgets );
  153.  
  154.     //设置私有数据
  155. 	platform_set_drvdata ( pdev, &data->card );
  156. 	snd_soc_card_set_drvdata ( &data->card, data );
  157.  
  158.     //注册声卡
  159. 	ret = devm_snd_soc_register_card ( &pdev->dev, &data->card );
  160. 	if ( ret )
  161. 	{
  162. 		dev_err ( &pdev->dev, "snd_soc_register_card failed (%d)\n", ret );
  163. 		goto fail;
  164. 	}
  165.  
  166. 	of_node_put ( cpu_np );
  167. 	of_node_put ( codec_np );
  168.  
  169. 	return 0;
  170.  
  171. fail:
  172. 	if ( data && !IS_ERR ( data->codec_clk ) )
  173. 	{
  174. 		clk_put ( data->codec_clk );
  175. 	}
  176. 	if ( cpu_np )
  177. 	{
  178. 		of_node_put ( cpu_np );
  179. 	}
  180. 	if ( codec_np )
  181. 	{
  182. 		of_node_put ( codec_np );
  183. 	}
  184.  
  185. 	return ret;
  186. }

 

2、codec驱动

  1. pinctrl_i2c2: i2c2grp {
  2. 			fsl,pins = <
  3. 				MX6QDL_PAD_KEY_COL3__I2C2_SCL		0x4001b8b1
  4. 				MX6QDL_PAD_KEY_ROW3__I2C2_SDA		0x4001b8b1
  5. 				MX6QDL_PAD_NANDF_D2__GPIO2_IO02     0x80000000 //reset pin
  6. 			>;
  7. 		};
  8.  
  9.  
  10. &iomuxc {
  11. 	pinctrl-names = "default";
  12. 	pinctrl-0 = <&pinctrl_hog>;
  13.         ......
  14.         pinctrl_hog: hoggrp {
  15.               fsl,pins = <
  16.                     ......
  17.                     /*CCM_CLKO1 为codec的时钟提供脚*/
  18.                     MX6QDL_PAD_GPIO_0__CCM_CLKO1    0x130b0
  19.                     ......
  20. 	           >;
  21. 	    };
  22.         ......
  23. };
  24.  
  25. &i2c2 {
  26. 	clock-frequency = <100000>;
  27. 	pinctrl-names = "default";
  28. 	pinctrl-0 = <&pinctrl_i2c2>;
  29. 	status = "okay";
  30.  
  31. 	codec: tas2505@18{
  32. 		compatible = "ti,tas2505"; 
  33. 		reg = <0x18>;
  34. 		clocks = <&clks IMX6QDL_CLK_CKO>;
  35. 		reset-gpio = <&gpio2 2 1>;		
  36. 		clock-names = "mclk";
  37. 	};
  38. 	
  39. };

reg：i2c设备地址，注意设备树中需要的是高7位地址。

clocks：时钟源，IMX6QDL_CLK_CKO定义的时钟源是MCLK，默认频率为24MHz。此时钟实际上也是可以修改的，参照How to change audio clock from 24M to 24.576M。

IMX6QDL_CLK_CKO 定义在include/dt-bindings/clock/imx6qdl-clock.h

设备树中也需要定义codec的时钟提供脚。

reset-gpio：设备的复位引脚

 

codec驱动中的probe函数如下：

  1. static int tas2505_i2c_probe ( struct i2c_client* client,
  2.                                const struct i2c_device_id* id )
  3. {
  4. 	struct device* dev = &client->dev;
  5. 	struct device_node* np =  dev->of_node;
  6. 	struct tas2505_data* tas2505;
  7. 	int ret;
  8.  
  9. 	tas2505 = devm_kzalloc ( &client->dev, sizeof ( *tas2505 ), GFP_KERNEL );
  10. 	if ( tas2505 == NULL )
  11. 	{
  12. 		return -ENOMEM;
  13. 	}
  14.  
  15.     //获取设备树的中reset-gpio脚
  16. 	tas2505->reset_gpio = of_get_named_gpio ( np, "reset-gpio", 0 );
  17.  
  18. 	if ( gpio_is_valid ( tas2505->reset_gpio ) )
  19. 	{
  20. 	    //设置成输出高
  21. 		ret = devm_gpio_request_one ( dev, tas2505->reset_gpio,
  22. 		                              GPIOF_OUT_INIT_HIGH,
  23. 		                              "reset" );
  24. 		if ( ret )
  25. 		{
  26. 			dev_err ( dev, "unable to get reset pin \n" );
  27. 			return ret;
  28. 		}
  29. 	}
  30.   
  31. 	tas2505->regmap = devm_regmap_init_i2c ( client, &tas2505_regmap_config ); //注册i2c regmap
  32. 	if ( IS_ERR ( tas2505->regmap ) )
  33. 	{
  34. 		ret = PTR_ERR ( tas2505->regmap );
  35. 		dev_err ( dev, "Failed to allocate register map: %d\n",
  36. 		          ret );
  37. 		return ret;
  38. 	}
  39.  
  40. 	tas2505->dev = dev;
  41.  
  42. 	//设置私有数据 sound核心层需要读取regmap 之后可以使用snd_soc_write等相关函数直接操作寄存器
  43. 	dev_set_drvdata ( tas2505->dev, tas2505 );
  44.  
  45.     //注册codec
  46. 	ret = snd_soc_register_codec ( dev,
  47. 	                               &soc_codec_dev_tas2505,
  48. 	                               tas2505_dai, ARRAY_SIZE ( tas2505_dai ) );
  49. 	if ( ret < 0 )
  50. 	{
  51. 		dev_err ( dev, "Failed to register codec: %d\n", ret );
  52. 	}
  53.  
  54. 	return ret;
  55. }

 

platform驱动基本不需要更改，我也没细看，所以就不分析了。

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