Rockchip RK3399 - Codec驱动（ Realtek ALC5651）
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开发板 ：NanoPC-T4开发板
eMMC ：16GB
LPDDR3 ：4GB
显示屏 ：15.6英寸HDMI接口显示屏
u-boot ：2023.04
linux ：6.3
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在Rockchip RK3399 - ASoC Codec驱动基础中我们介绍了codec驱动涉及到的数据结构以及核心API。并且已经了解到每个codec driver必须提供以下功能：
- codec dai和pcm的配置信息：通过struct snd_soc_dai_driver描述，包括dai的能力描述和操作接口；
- codec的控制接口：其控制接口一般是I2C或SPI。控制接口用于读写codec的寄存器。在struct snd_soc_component_driver结构体中，有大量字段描述codec的控制接口，比如read、write等；
- Mixer和其它音频控件；
- codec的音频操作：通过结构体struct snd_soc_dai_ops描述；
- DAPM描述信息；
- DAPM事件处理程序；
本节我们将会以rt5651驱动为例进行分析，驱动源码位于sound/soc/codecs/rt5651.c文件。
一、设备树配置
1.1 设备节点rt5651
我们在arch/arm64/boot/dts/rockchip/rk3399-evb.dts文件添加rt5651设备节点，该节点位于i2c1节点下：
&i2c1 { status = "okay"; i2c-scl-rising-time-ns = <300>; i2c-scl-falling-time-ns = <15>; rt5651: rt5651@1a { #sound-dai-cells = <0>; compatible = "rockchip,rt5651"; reg = <0x1a>; clocks = <&cru SCLK_I2S_8CH_OUT>; clock-names = "mclk"; status = "okay"; }; };
其中：
- status ：指定设备状态为“正常”，表示该设备状态为正常运行；
- i2c-scl-rising-time-ns：定义了SCL信号上升时间的最小值，单位是纳秒；
- i2c-scl-falling-time-ns：定义了SCL信号下降时间的最小值，单位是纳秒；
接着定义I2C从设备节点rt5651，即音频编解码器的设备节点，其名称为 rt5651，I2C从设备7位地址为0x1a；
- compatible：指定设备驱动程序的兼容性，即告诉内核该设备可以被哪些驱动程序所使用；
- reg：指定了rt5651设备在I2C控制器上的设备地址；
- clock-names：指定时钟名称，"mclk"表示MCLK时钟；
- clocks：mclk时钟来自SCLK_I2S_8CH_OUT；
- status ：指定设备状态为“正常”，表示该设备状态为正常运行；
关于rt5651设备节点更多属性可以参考文档:Documentation/devicetree/bindings/sound/rt5651.txt。
i2c1设备节点定义在arch/arm64/boot/dts/rockchip/rk3399.dtsi，内容如下：
i2c1: i2c@ff110000 { compatible = "rockchip,rk3399-i2c"; reg = <0x0 0xff110000 0x0 0x1000>; assigned-clocks = <&cru SCLK_I2C1>; assigned-clock-rates = <200000000>; clocks = <&cru SCLK_I2C1>, <&cru PCLK_I2C1>; clock-names = "i2c", "pclk"; interrupts = <GIC_SPI 59 IRQ_TYPE_LEVEL_HIGH 0>; pinctrl-names = "default"; pinctrl-0 = <&i2c1_xfer>; #address-cells = <1>; #size-cells = <0>; status = "disabled"; };
1.2 时钟频率
这里我们看看一下时钟频率配置：
clocks = <&cru SCLK_I2S_8CH_OUT>; clock-names = "mclk";
1.2.1 clk_i2sout
SCLK_I2S_8CH_OUT为平台为时钟分配的特定的id，定义在drivers/clk/rockchip/clk-rk3399.c：
COMPOSITE_NODIV(SCLK_I2S_8CH_OUT, "clk_i2sout", mux_i2sout_p, CLK_SET_RATE_PARENT, RK3399_CLKSEL_CON(31), 2, 1, MFLAGS, RK3399_CLKGATE_CON(8), 12, GFLAGS)
这是composite类型的时钟，其中COMPOSITE_NODIV宏定义在drivers/clk/rockchip/clk.h：
#define COMPOSITE_NODIV(_id, cname, pnames, f, mo, ms, mw, mf, \ go, gs, gf) \ { \ .id = _id, \ .branch_type = branch_composite, \ .name = cname, \ .parent_names = pnames, \ .num_parents = ARRAY_SIZE(pnames), \ .flags = f, \ .muxdiv_offset = mo, \ .mux_shift = ms, \ .mux_width = mw, \ .mux_flags = mf, \ .gate_offset = go, \ .gate_shift = gs, \ .gate_flags = gf, \ }
(1) 在RK3399 datasheet中，我们可以找到名字为clk_i2sout的时钟的信息，从下图可以看到它有两个父时钟，一个ID为62，可以在datasheet表中找到62代表的是clk_i2sout_src；另一个ID为64，可以在datasheet表中找到64代表的是clk_12m；
实际上mux_i2sout_p中存放的就是这两个父时钟的名称；
PNAME(mux_i2sout_p) = { "clk_i2sout_src", "xin12m" };
我们可以找到时钟clk_i2sout_src的定义，它是一个多路选择类型的时钟，如下所示；
MUX(0, "clk_i2sout_src", mux_i2sch_p, CLK_SET_RATE_PARENT, RK3399_CLKSEL_CON(31), 0, 2, MFLAGS),
而xin12m应该是一个fixed rate clock（有源晶振、无源晶振）。
(2) 宏RK3399_CLKGATE_CON定义在drivers/clk/rockchip/clk.h：
#define RK3399_CLKGATE_CON(x) ((x) * 0x4 + 0x300)
通过RK3399_CLKGATE_CON(8)可以得到寄存器偏移地址8*0x04+0x300=0x320，偏移0x320是CRU_CLKGATE_CON8寄存器。
接着我们看一下CRU_CLKGATE_CON8寄存器，CRU_CLKGATE_CON8为Internal clock gating register8，其中位[12]含义如下：
可以看到位12为clk_i2sout时钟使能位，低电平使能，高电平禁用。 那clk_i2sout到底是什么时钟呢？
RK3399平台有三路I2S(其中一路内部使用，可以不管)，但是MCLK只有一个，也就是说I2S0、I2S1只有一路能占用，因此我猜测clk_i2sout应该就是MCLK信号线的时钟。
(3) 宏RK3399_CLKSEL_CON定义在drivers/clk/rockchip/clk.h：
#define RK3399_CLKSEL_CON(x) ((x) * 0x4 + 0x100)
通过RK3399_CLKSEL_CON(31)可以得到寄存器偏移地址31*0x04+0x100=0x17C，偏移0x17C是CRU_CLKSEL_CON31寄存器。
接着我们看一下CRU_CLKSEL_CON31寄存器，CRU_CLKSEL_CON31为Internal clock select and divide register31，其中位[2]含义如下：
可以看到位2用于clk_i2sout时钟源选择，这里需要配置为clk_i2s。
1.2.2 时钟链路
经过上面的分析，我们不难推断出clk_i2sout的时钟链路如下所示：
其中clk_i2sout_src的时钟源由clk_i2s0、clk_i2s1、clk_i2s2，其定义在mux_i2sch_p：
PNAME(mux_i2sch_p) = { "clk_i2s0", "clk_i2s1","clk_i2s2" };
由CRU_CLKSEL_CON31寄存器的位[1:0]控制时钟源的选择：
关于时钟源clk_i2s0以及之前的时钟链路我们在Rockchip RK3399 - Platform驱动（DMA&i2s0）中介绍。
二、I2C控制器驱动
RK3399这款SOC的I2C结构，其内部有9个I2C控制器，这里我们以I2C1为例，其中I2C1_SCL连接GPIO4_A2引脚，I2C1_SDA连接GPIO4_A1引脚。
关于RK3399 I2C控制器驱动实现位于drivers/i2c/busses/i2c-rk3x.c文件，I2C控制器驱动是基于platform模型的，主要提供一个algorithm底层的I2C协议的收发函数。
在platform driver中probe函数中：
- 动态分配i2c_adapter，并进行成员初始化，包括设置algo；
- 初始化I2C总线所使用的的GPIO功能复用为I2C；
- 初始化I2C控制器相关的寄存器；
- 获取资源信息，并注册I2C中断处理函数；
- 最后调用i2c_add_adapter将i2c_adapter注册到i2c_bus_type总线，并且注册时会：
- 调用of_i2c_register_devices，解析I2C控制器设备节点的子设备节点，从而调用of_i2c_register_device完成I2C从设备的注册；
- 调用i2c_scan_board_info，扫描并使用i2c_new_device注册I2C从设备。
of_i2c_register_device内部通过调用of_i2c_get_board_info函数解析设备节点rt5651可以得到如下定义的I2C从设备：
struct i2c_board_info info = { // type的值是取自rt5651设备节点compatible属性值,之后的内容 ，compatible = "rockchip,rt5651"得到的就是rt5651 .type = "rt5651", // 会赋值给i2c_client的name字段 .addr = 0x1a, .of_node = rt5651设备节点, }；
然后将该I2C从设备注册到系统，更多的细节在这一节我们不去研究。有关I2C驱动的内容可以先参考linux驱动移植-I2C总线设备驱动、linux驱动移植-I2C适配器驱动移植、linux驱动移植-I2C驱动移植（OLED SSD1306），关于RK3399 I2C控制器驱动后面有时间再单独介绍。
三、Codec驱动
3.1 模块入口函数
我们定位到sound/soc/codecs/rt5651.c文件的最后：
module_i2c_driver(rt5651_i2c_driver);
3.1.1 module_i2c_driver
module_i2c_driver宏可以展开为相应驱动模块的init和exit接口，其定义在include/linux/i2c.h：
/** * module_i2c_driver() - Helper macro for registering a modular I2C driver * @__i2c_driver: i2c_driver struct * * Helper macro for I2C drivers which do not do anything special in module * init/exit. This eliminates a lot of boilerplate. Each module may only * use this macro once, and calling it replaces module_init() and module_exit() */ #define module_i2c_driver(__i2c_driver) \ module_driver(__i2c_driver, i2c_add_driver, \ i2c_del_driver)
3.1.2 module_driver
module_driver定义在include/linux/device/driver.h：
/** * module_driver() - Helper macro for drivers that don't do anything * special in module init/exit. This eliminates a lot of boilerplate. * Each module may only use this macro once, and calling it replaces * module_init() and module_exit(). * * @__driver: driver name * @__register: register function for this driver type * @__unregister: unregister function for this driver type * @...: Additional arguments to be passed to __register and __unregister. * * Use this macro to construct bus specific macros for registering * drivers, and do not use it on its own. */ #define module_driver(__driver, __register, __unregister, ...) \ static int __init __driver##_init(void) \ { \ return __register(&(__driver) , ##__VA_ARGS__); \ } \ module_init(__driver##_init); \ static void __exit __driver##_exit(void) \ { \ __unregister(&(__driver) , ##__VA_ARGS__); \ } \ module_exit(__driver##_exit);
3.1.3 展开后
因此如下定义：
module_i2c_driver(rt5651_i2c_driver);
经过上述宏的作用之后，就成为如下形式：
static int __init ov4689_i2c_driver_init(void) { return i2c_add_driver(&rt5651_i2c_driver); } static void __exit ov4689_i2c_driver_exit(void) { return i2c_del_driver(&rt5651_i2c_driver); }
其中i2c_add_driver函数用于注册I2C设备驱动。
3.2 rt5651_i2c_driver
这里我们需要关注一下i2c_driver结构体变量rt5651_i2c_driver ：
static struct i2c_driver rt5651_i2c_driver = { .driver = { .name = "rt5651", .acpi_match_table = ACPI_PTR(rt5651_acpi_match), .of_match_table = of_match_ptr(rt5651_of_match), // 用于设备树匹配 }, .probe_new = rt5651_i2c_probe, .id_table = rt5651_i2c_id, };
其成员：
- driver.of_match_table：用于设备树匹配；
- probe：当I2C驱动和I2C从设备信息匹配成功之后，就会调用probe函数；
- id_table：id列表，用于和I2C从设备名称进行匹配；
3.2.1 rt5651_of_match
如果使用了设备树，rt5651_of_match被定义为：
#if defined(CONFIG_OF) static const struct of_device_id rt5651_of_match[] = { { .compatible = "realtek,rt5651", }, // 用来匹配的I2C从设备，匹配设备节点rt5651 {}, /* 最后一个必须为空,表示结束 */ }; MODULE_DEVICE_TABLE(of, rt5651_of_match); #endif
由于在I2C控制器注册的时候为声卡设备注册了I2C从设备（对应数据结构struct i2c_client），其名称为rt5651，因此会与I2C从设备驱动中rt5651_of_match匹配失败。
3.2.2 rt5651_i2c_id
i2c_device_id中存放的是和I2C驱动匹配的I2C从设备的名称，以rt5651_i2c_id为例：
static const struct i2c_device_id rt5651_i2c_id[] = { { "rt5651", 0 }, // 用来匹配的I2C从设备 { } /* 最后一个必须为空,表示结束 */ };
由于在I2C控制器注册的时候为声卡设备注册了I2C从设备（对应数据结构struct i2c_client），其名称为rt5651，因此会与I2C从设备驱动中的rt5651_i2c_id匹配成功，从而进入执行probe探测函数；
3.2.3 rt5651_i2c_probe
probe探测函数rt5651_i2c_probe定义如下：
static int rt5651_i2c_probe(struct i2c_client *i2c) // 参数为I2C从设备 { struct rt5651_priv *rt5651; int ret; int err; rt5651 = devm_kzalloc(&i2c->dev, sizeof(*rt5651), // 动态申请内存，数据结构类型为struct rt5651_priv GFP_KERNEL); if (NULL == rt5651) return -ENOMEM; i2c_set_clientdata(i2c, rt5651); // i2c->dev.driver_data = rt5651 设置为驱动数据 rt5651->regmap = devm_regmap_init_i2c(i2c, &rt5651_regmap); // 注册regmap实例 if (IS_ERR(rt5651->regmap)) { ret = PTR_ERR(rt5651->regmap); dev_err(&i2c->dev, "Failed to allocate register map: %d\n", ret); return ret; }
// 读取RT5651_DEVICE_ID寄存器的值，RT5651_DEVICE_ID值为0xff，寄存器地址0xff存放的是设备ID，数据位宽为16位 err = regmap_read(rt5651->regmap, RT5651_DEVICE_ID, &ret);if (err) // 读取失败 return err; if (ret != RT5651_DEVICE_ID_VALUE) { // 0x6281 dev_err(&i2c->dev, "Device with ID register %#x is not rt5651\n", ret); return -ENODEV; } regmap_write(rt5651->regmap, RT5651_RESET, 0); // 寄存器地址0x00为软件复位寄存器，写入0x00将会复位所有寄存器的 ret = regmap_register_patch(rt5651->regmap, init_list, // 用于初始化rt5651，向一组寄存器中写入值 ARRAY_SIZE(init_list)); if (ret != 0) dev_warn(&i2c->dev, "Failed to apply regmap patch: %d\n", ret); rt5651->irq = i2c->irq; // I2C从设备所使用的的中断编号； 由于rt5651设备节点中并没有配置中断，所以i2c->irq默认值为0 rt5651->hp_mute = true; INIT_DELAYED_WORK(&rt5651->bp_work, rt5651_button_press_work); // 初始化延迟的工作rt5651->bp_work，设置工作函数为rt5651_button_press_work INIT_WORK(&rt5651->jack_detect_work, rt5651_jack_detect_work); // 初始化工作rt5651->jack_detect_work，设置工作函数为rt5651_jack_detect_work /* Make sure work is stopped on probe-error / remove */ ret = devm_add_action_or_reset(&i2c->dev, rt5651_cancel_work, rt5651); if (ret) return ret; ret = devm_request_irq(&i2c->dev, rt5651->irq, rt5651_irq, // 申请I2C中断，中断处理函数为rt5651_irq,；因为没有配置中断，所以这里中断会申请失败 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT | IRQF_NO_AUTOEN, "rt5651", rt5651); if (ret) { dev_warn(&i2c->dev, "Failed to reguest IRQ %d: %d\n", rt5651->irq, ret); rt5651->irq = -ENXIO; } ret = devm_snd_soc_register_component(&i2c->dev, // 注册component &soc_component_dev_rt5651, rt5651_dai, ARRAY_SIZE(rt5651_dai)); return ret; }
(1) 动态申请内存，数据结构类型为struct rt5651_priv，并调用i2c_set_clientdata将其设置为驱动数据；
(2) 调用devm_regmap_init_i2c注册regmap实例，这样i2c驱动驱动就可以正常调用regmap_write和regmap_read函数进行i2c数据传输了；
(3) 读取rt5651设备寄存器地址0xff的值，对于rt5651芯片寄存器地址0xff存放的是设备ID，因此读取到的为0x6281；
(4) 向rt5651软件复位寄存器地址0x00写入0，将所有寄存器的值复位；
(5) 调用regmap_register_patch向一组寄存器中写入值；其中init_list设置为：
static const struct reg_sequence init_list[] = { {RT5651_PR_BASE + 0x3d, 0x3e00}, };
regmap_register_patch定义在drivers/base/regmap/regmap.c：
/** * regmap_register_patch - Register and apply register updates to be applied * on device initialistion * * @map: Register map to apply updates to. * @regs: Values to update. * @num_regs: Number of entries in regs. * * Register a set of register updates to be applied to the device * whenever the device registers are synchronised with the cache and * apply them immediately. Typically this is used to apply * corrections to be applied to the device defaults on startup, such * as the updates some vendors provide to undocumented registers. * * The caller must ensure that this function cannot be called * concurrently with either itself or regcache_sync(). */ int regmap_register_patch(struct regmap *map, const struct reg_sequence *regs, int num_regs) { struct reg_sequence *p; int ret; bool bypass; if (WARN_ONCE(num_regs <= 0, "invalid registers number (%d)\n", num_regs)) return 0; p = krealloc(map->patch, sizeof(struct reg_sequence) * (map->patch_regs + num_regs), GFP_KERNEL); if (p) { memcpy(p + map->patch_regs, regs, num_regs * sizeof(*regs)); map->patch = p; map->patch_regs += num_regs; } else { return -ENOMEM; } map->lock(map->lock_arg); bypass = map->cache_bypass; map->cache_bypass = true; map->async = true; ret = _regmap_multi_reg_write(map, regs, num_regs); // 写入多个寄存器 map->async = false; map->cache_bypass = bypass; map->unlock(map->lock_arg); regmap_async_complete(map); return ret; }
(6) 初始化rt5651成员irq、hp_mute；初始化延迟的工作rt5651->bp_work，设置工作函数为rt5651_button_press_work；初始化工作rt5651->jack_detect_work，设置工作函数为rt5651_jack_detect_work；
(7) 调用devm_add_action_or_reset函数Make sure work is stopped on probe-error / remove；
static void rt5651_cancel_work(void *data) { struct rt5651_priv *rt5651 = data; cancel_work_sync(&rt5651->jack_detect_work); cancel_delayed_work_sync(&rt5651->bp_work); }
(8) 申请I2C中断，中断处理函数为rt5651_irq；
static irqreturn_t rt5651_irq(int irq, void *data) { struct rt5651_priv *rt5651 = data; queue_work(system_power_efficient_wq, &rt5651->jack_detect_work); return IRQ_HANDLED; }
由于我们设备节点rt5651中并没有配置中断，因此申请中断会失败，内核启动的时候也会输出相关错误信息；其中rt5651为模块的名称，1-001a为i2c_client->dev设备的名称；
[ 3.465917] rt5651 1-001a: Failed to reguest IRQ 0: -22
(9) 调用devm_snd_soc_register_component注册的component，该函数会动态申请一个component，并将其添加到全局链表component_list中，同时会建立dai_driver与component的关系。
注册component完成后，snd_soc_dai，snd_soc_dai_driver、snd_soc_component、snd_soc_component_driver之间的关系如下图：
其中：
- 新建的snd_soc_component的名称为i2c从设备对应的struct device_driver、struct device实例的名字拼接而成，即rt5651.1-001a；
- snd_soc_component的dai_list链表包含两个dai，第一个dai的名称为rt5651-aif1，第二个dai的名称为rt5651-aif2；
- 每个dai对应一个dai driver，第一个dai driver的名称为rt5651-aif1，第二个dai driver的名称为rt5651-aif2；
3.3 总结
我们在分析了platform驱动的源码之后，我们大致可以得到一个结论，codec驱动注册流程主要包含一下几个步骤：
(1) 构造一个struct snd_soc_component_driver实例，比如这里的soc_component_dev_rt5651，用于描述codec driver；需要初始化成员name、controls、dapm_widgets、dapm_routes等；
(2) 构造一个struct snd_soc_dai_driver，比如这里的rt5651_dai数组，用于描述dai和 pcm的能力和操作；需要初始化成员name、probe、playback、capture、ops等；
(3) 调用devm_snd_soc_register_component注册component；
四、soc_component_dev_rt5651
devm_snd_soc_register_component函数第二个参数为soc_component_dev_rt5651：
static const struct snd_soc_component_driver soc_component_dev_rt5651 = { .probe = rt5651_probe, .suspend = rt5651_suspend, .resume = rt5651_resume, .set_bias_level = rt5651_set_bias_level, .set_jack = rt5651_set_jack, .controls = rt5651_snd_controls, // kcontrol定义 .num_controls = ARRAY_SIZE(rt5651_snd_controls), .dapm_widgets = rt5651_dapm_widgets, // widget定义 .num_dapm_widgets = ARRAY_SIZE(rt5651_dapm_widgets), .dapm_routes = rt5651_dapm_routes, // route定义 .num_dapm_routes = ARRAY_SIZE(rt5651_dapm_routes), .use_pmdown_time = 1, .endianness = 1, };
其中controls、dapm_widgets、dapm_routes是与dapm相关的，可以用来表述codec内部的音频路径，具体参考Rockchip RK3399 - DAPM Widget&Route&Path。
这里我们简单提一下dapm：
(1) 当音频路径发生改变（比如上层使用tinymix工具设置音频通路）时，或发生数据流事件（比如启动或停止播放）时，都会触发dapm去遍历所有邻近的widget，检查是否存在完整的音频路径，如果存在完整的音频路径，则该路径上面的所有widget都是需要上电的，其他widget则下电；
(2) widget的上下电都是dapm根据策略自主控制的，外部无法干预，可以说dapm是一个专门为音频系统设计的自成体系的电源管理模块，独立于Linux电源管理之外。即使SoC休眠了，codec仍可以在正常工作，试想下这个情景：语音通话，modem dai连接到codec dai，语音数据不经过SoC，因此这种情形下SoC可以进入睡眠以降低功耗，只保持Codec正常工作就行了。
在Macine驱动中会进行ASoC声卡的注册，其中会执行soc_probe_component(card, component)，即进行component的探测工作，具体流程如下：
- 注册component->driver->dapm_widgets到声卡card的widgets链表中；
- 执行component->driver->probe(component)；
- 根据component->driver->controls数组创建并添加多个kcontrol到声卡card的controls链表；
- 遍历component->driver->dapm_routes数组，调用snd_soc_dapm_add_routes将snd_soc_dapm_route动态地生成所需要的snd_soc_dapm_path结构，然后将snd_soc_dapm_path注册到声卡card的paths链表；
- 将component添加到声卡component_dev_list链表；
4.1 DAPM描述
ALC5651功能框图如下所示，该图来自ALC5651 datasheet：
由于这种图只是一张框图，无法看到音频数据流具体路径细节，因此我们在datasheet中又找到了如下一张图：
上图中我们使用箭头标识了一条用于多媒体音频播放右声道的路径，音频通路是：
- AIF1 Playback（snd_soc_dapm_dai_in类型的playback dai widget） --> AIF1RX ：AIF表示音频数字接口；
- AIF1RX --> IF1 DAC；
- IF1 DAC --> IF1 DAC1 R;
- IF1 DAC1 R --> DAC MIXR：通过rt5651_dac_r_mix（名称为INF1 Switch）控制通断，由MX29寄存器位14来实现静音控制（0非静音，1静音）；
- DAC MIXR --> Audio DSP；
- Audio DSP --> Stereo DAC MIXR：通过rt5651_sto_dac_r_mix（名称DAC R1 Switch）控制通断，由MX2A寄存器位6来实现静音控制（0非静音，1静音）；
- Stereo DAC MIXR --> DAC R1；
- DAC R1 --> OUT MIXR ：通过rt5651_out_r_mix（名称为DAC R1 Switch）控制通断，由MX52寄存器位0来实现静音控制（0非静音，1静音）；
- OUT MIXR --> HPOVOL R：通过hpovol_r_control（名称为Switch）控制通断，由MX02寄存器位6来实现静音控制（0非静音，1静音）；
- HPOVOL R --> HPOR MIX：通过rt5651_hpo_mix（名称为HPO MIX HPVOL Switch）控制通断，由MX45寄存器位13来实现静音控制（0非静音，1静音）；
- HPOR MIX --> HP Amp；
- HP Amp -> HPO R Playback：通过hpo_r_mute_control（名称为Switch）控制通断，由MX02寄存器位7来实现静音控制（0非静音，1静音）；
- HPO R Playback --> HPOR ；
- HPOR --> Headphones（最后一个path定义在Machine驱动中）；
其中红色部分表示有相应的kcontrol，即需要switch打开，在该路径中 HPOL 为SND_SOC_DAPM_EP_SINK类型端点，但是路径中并没有SND_SOC_DAPM_EP_SOURCE类型端点。
此外对应的左声道音频路径：
- AIF1 Playback（snd_soc_dapm_dai_in类型的playback dai widget） --> AIF1RX ：AIF表示音频数字接口；
- AIF1RX --> IF1 DAC；
- IF1 DAC --> IF1 DAC1 L;
- IF1 DAC1 L --> DAC MIXL：通过rt5651_dac_l_mix（名称为INF1 Switch）控制通断，由MX29寄存器位6来实现静音控制（0非静音，1静音）；
- DAC MIXL --> Audio DSP；
- Audio DSP --> Stereo DAC MIXL：通过rt5651_sto_dac_l_mix（名称DAC L1 Switch）控制通断，由MX2A寄存器位14来实现静音控制（0非静音，1静音）；
- Stereo DAC MIXL --> DAC L1；
- DAC L1 --> OUT MIXL ：通过rt5651_out_l_mix（名称为DAC L1 Switch）控制通断，由MX4F寄存器位0来实现静音控制（0非静音，1静音）；
- OUT MIXL --> HPOVOL L：通过hpovol_l_control（名称为Switch）控制通断，由MX02寄存器位14来实现静音控制（0非静音，1静音）；
- HPOVOL L --> HPOL MIX：通过rt5651_hpo_mix（名称为HPO MIX HPVOL Switch）控制通断，由MX45寄存器位13来实现静音控制（0非静音，1静音）；
- HPOL MIX --> HP Amp；
- HP Amp -> HPO L Playback：通过hpo_l_mute_control（名称为Switch）控制通断，由MX02寄存器位15来实现静音控制（0非静音，1静音）；
- HPO L Playback --> HPOL ；
- HPOL --> Headphones（最后一个path定义在Machine驱动中）；
4.1.1 定义kcontrol
在sound/soc/codecs/rt5651.c定义了大量的kcontrol，包括普通kcontrol和dapm kcontrol：
static const DECLARE_TLV_DB_SCALE(out_vol_tlv, -4650, 150, 0); static const DECLARE_TLV_DB_MINMAX(dac_vol_tlv, -6562, 0); static const DECLARE_TLV_DB_SCALE(in_vol_tlv, -3450, 150, 0); static const DECLARE_TLV_DB_MINMAX(adc_vol_tlv, -1762, 3000); static const DECLARE_TLV_DB_SCALE(adc_bst_tlv, 0, 1200, 0); /* {0, +20, +24, +30, +35, +40, +44, +50, +52} dB */ static const DECLARE_TLV_DB_RANGE(bst_tlv, 0, 0, TLV_DB_SCALE_ITEM(0, 0, 0), 1, 1, TLV_DB_SCALE_ITEM(2000, 0, 0), 2, 2, TLV_DB_SCALE_ITEM(2400, 0, 0), 3, 5, TLV_DB_SCALE_ITEM(3000, 500, 0), 6, 6, TLV_DB_SCALE_ITEM(4400, 0, 0), 7, 7, TLV_DB_SCALE_ITEM(5000, 0, 0), 8, 8, TLV_DB_SCALE_ITEM(5200, 0, 0) ); /* Interface data select */ static const char * const rt5651_data_select[] = { "Normal", "Swap", "left copy to right", "right copy to left"}; static SOC_ENUM_SINGLE_DECL(rt5651_if2_dac_enum, RT5651_DIG_INF_DATA, RT5651_IF2_DAC_SEL_SFT, rt5651_data_select); static SOC_ENUM_SINGLE_DECL(rt5651_if2_adc_enum, RT5651_DIG_INF_DATA, RT5651_IF2_ADC_SEL_SFT, rt5651_data_select); static const struct snd_kcontrol_new rt5651_snd_controls[] = { /* Headphone Output Volume */ SOC_DOUBLE_TLV("HP Playback Volume", RT5651_HP_VOL, RT5651_L_VOL_SFT, RT5651_R_VOL_SFT, 39, 1, out_vol_tlv), /* OUTPUT Control */ SOC_DOUBLE_TLV("OUT Playback Volume", RT5651_LOUT_CTRL1, RT5651_L_VOL_SFT, RT5651_R_VOL_SFT, 39, 1, out_vol_tlv), /* DAC Digital Volume */ SOC_DOUBLE("DAC2 Playback Switch", RT5651_DAC2_CTRL, RT5651_M_DAC_L2_VOL_SFT, RT5651_M_DAC_R2_VOL_SFT, 1, 1), SOC_DOUBLE_TLV("DAC1 Playback Volume", RT5651_DAC1_DIG_VOL, RT5651_L_VOL_SFT, RT5651_R_VOL_SFT, 175, 0, dac_vol_tlv), SOC_DOUBLE_TLV("Mono DAC Playback Volume", RT5651_DAC2_DIG_VOL, RT5651_L_VOL_SFT, RT5651_R_VOL_SFT, 175, 0, dac_vol_tlv), /* IN1/IN2/IN3 Control */ SOC_SINGLE_TLV("IN1 Boost", RT5651_IN1_IN2, RT5651_BST_SFT1, 8, 0, bst_tlv), SOC_SINGLE_TLV("IN2 Boost", RT5651_IN1_IN2, RT5651_BST_SFT2, 8, 0, bst_tlv), SOC_SINGLE_TLV("IN3 Boost", RT5651_IN3, RT5651_BST_SFT1, 8, 0, bst_tlv), /* INL/INR Volume Control */ SOC_DOUBLE_TLV("IN Capture Volume", RT5651_INL1_INR1_VOL, RT5651_INL_VOL_SFT, RT5651_INR_VOL_SFT, 31, 1, in_vol_tlv), /* ADC Digital Volume Control */ SOC_DOUBLE("ADC Capture Switch", RT5651_ADC_DIG_VOL, RT5651_L_MUTE_SFT, RT5651_R_MUTE_SFT, 1, 1), SOC_DOUBLE_TLV("ADC Capture Volume", RT5651_ADC_DIG_VOL, RT5651_L_VOL_SFT, RT5651_R_VOL_SFT, 127, 0, adc_vol_tlv), SOC_DOUBLE_TLV("Mono ADC Capture Volume", RT5651_ADC_DATA, RT5651_L_VOL_SFT, RT5651_R_VOL_SFT, 127, 0, adc_vol_tlv), /* ADC Boost Volume Control */ SOC_DOUBLE_TLV("ADC Boost Gain", RT5651_ADC_BST_VOL, RT5651_ADC_L_BST_SFT, RT5651_ADC_R_BST_SFT, 3, 0, adc_bst_tlv), /* ASRC */ SOC_SINGLE("IF1 ASRC Switch", RT5651_PLL_MODE_1, RT5651_STO1_T_SFT, 1, 0), SOC_SINGLE("IF2 ASRC Switch", RT5651_PLL_MODE_1, RT5651_STO2_T_SFT, 1, 0), SOC_SINGLE("DMIC ASRC Switch", RT5651_PLL_MODE_1, RT5651_DMIC_1_M_SFT, 1, 0), SOC_ENUM("ADC IF2 Data Switch", rt5651_if2_adc_enum), SOC_ENUM("DAC IF2 Data Switch", rt5651_if2_dac_enum), }; /* Digital Mixer */ static const struct snd_kcontrol_new rt5651_sto1_adc_l_mix[] = { SOC_DAPM_SINGLE("ADC1 Switch", RT5651_STO1_ADC_MIXER, RT5651_M_STO1_ADC_L1_SFT, 1, 1), SOC_DAPM_SINGLE("ADC2 Switch", RT5651_STO1_ADC_MIXER, RT5651_M_STO1_ADC_L2_SFT, 1, 1), }; static const struct snd_kcontrol_new rt5651_sto1_adc_r_mix[] = { SOC_DAPM_SINGLE("ADC1 Switch", RT5651_STO1_ADC_MIXER, RT5651_M_STO1_ADC_R1_SFT, 1, 1), SOC_DAPM_SINGLE("ADC2 Switch", RT5651_STO1_ADC_MIXER, RT5651_M_STO1_ADC_R2_SFT, 1, 1), }; static const struct snd_kcontrol_new rt5651_sto2_adc_l_mix[] = { SOC_DAPM_SINGLE("ADC1 Switch", RT5651_STO2_ADC_MIXER, RT5651_M_STO2_ADC_L1_SFT, 1, 1), SOC_DAPM_SINGLE("ADC2 Switch", RT5651_STO2_ADC_MIXER, RT5651_M_STO2_ADC_L2_SFT, 1, 1), }; static const struct snd_kcontrol_new rt5651_sto2_adc_r_mix[] = { SOC_DAPM_SINGLE("ADC1 Switch", RT5651_STO2_ADC_MIXER, RT5651_M_STO2_ADC_R1_SFT, 1, 1), SOC_DAPM_SINGLE("ADC2 Switch", RT5651_STO2_ADC_MIXER, RT5651_M_STO2_ADC_R2_SFT, 1, 1), }; static const struct snd_kcontrol_new rt5651_dac_l_mix[] = { SOC_DAPM_SINGLE("Stereo ADC Switch", RT5651_AD_DA_MIXER, RT5651_M_ADCMIX_L_SFT, 1, 1), SOC_DAPM_SINGLE("INF1 Switch", RT5651_AD_DA_MIXER, RT5651_M_IF1_DAC_L_SFT, 1, 1), }; static const struct snd_kcontrol_new rt5651_dac_r_mix[] = { SOC_DAPM_SINGLE("Stereo ADC Switch", RT5651_AD_DA_MIXER, RT5651_M_ADCMIX_R_SFT, 1, 1), SOC_DAPM_SINGLE("INF1 Switch", RT5651_AD_DA_MIXER, RT5651_M_IF1_DAC_R_SFT, 1, 1), }; static const struct snd_kcontrol_new rt5651_sto_dac_l_mix[] = { SOC_DAPM_SINGLE("DAC L1 Switch", RT5651_STO_DAC_MIXER, RT5651_M_DAC_L1_MIXL_SFT, 1, 1), SOC_DAPM_SINGLE("DAC L2 Switch", RT5651_STO_DAC_MIXER, RT5651_M_DAC_L2_MIXL_SFT, 1, 1), SOC_DAPM_SINGLE("DAC R1 Switch", RT5651_STO_DAC_MIXER, RT5651_M_DAC_R1_MIXL_SFT, 1, 1), }; static const struct snd_kcontrol_new rt5651_sto_dac_r_mix[] = { SOC_DAPM_SINGLE("DAC R1 Switch", RT5651_STO_DAC_MIXER, RT5651_M_DAC_R1_MIXR_SFT, 1, 1), SOC_DAPM_SINGLE("DAC R2 Switch", RT5651_STO_DAC_MIXER, RT5651_M_DAC_R2_MIXR_SFT, 1, 1), SOC_DAPM_SINGLE("DAC L1 Switch", RT5651_STO_DAC_MIXER, RT5651_M_DAC_L1_MIXR_SFT, 1, 1), }; static const struct snd_kcontrol_new rt5651_dd_dac_l_mix[] = { SOC_DAPM_SINGLE("DAC L1 Switch", RT5651_DD_MIXER, RT5651_M_STO_DD_L1_SFT, 1, 1), SOC_DAPM_SINGLE("DAC L2 Switch", RT5651_DD_MIXER, RT5651_M_STO_DD_L2_SFT, 1, 1), SOC_DAPM_SINGLE("DAC R2 Switch", RT5651_DD_MIXER, RT5651_M_STO_DD_R2_L_SFT, 1, 1), }; static const struct snd_kcontrol_new rt5651_dd_dac_r_mix[] = { SOC_DAPM_SINGLE("DAC R1 Switch", RT5651_DD_MIXER, RT5651_M_STO_DD_R1_SFT, 1, 1), SOC_DAPM_SINGLE("DAC R2 Switch", RT5651_DD_MIXER, RT5651_M_STO_DD_R2_SFT, 1, 1), SOC_DAPM_SINGLE("DAC L2 Switch", RT5651_DD_MIXER, RT5651_M_STO_DD_L2_R_SFT, 1, 1), }; /* Analog Input Mixer */ static const struct snd_kcontrol_new rt5651_rec_l_mix[] = { SOC_DAPM_SINGLE("INL1 Switch", RT5651_REC_L2_MIXER, RT5651_M_IN1_L_RM_L_SFT, 1, 1), SOC_DAPM_SINGLE("BST3 Switch", RT5651_REC_L2_MIXER, RT5651_M_BST3_RM_L_SFT, 1, 1), SOC_DAPM_SINGLE("BST2 Switch", RT5651_REC_L2_MIXER, RT5651_M_BST2_RM_L_SFT, 1, 1), SOC_DAPM_SINGLE("BST1 Switch", RT5651_REC_L2_MIXER, RT5651_M_BST1_RM_L_SFT, 1, 1), }; static const struct snd_kcontrol_new rt5651_rec_r_mix[] = { SOC_DAPM_SINGLE("INR1 Switch", RT5651_REC_R2_MIXER, RT5651_M_IN1_R_RM_R_SFT, 1, 1), SOC_DAPM_SINGLE("BST3 Switch", RT5651_REC_R2_MIXER, RT5651_M_BST3_RM_R_SFT, 1, 1), SOC_DAPM_SINGLE("BST2 Switch", RT5651_REC_R2_MIXER, RT5651_M_BST2_RM_R_SFT, 1, 1), SOC_DAPM_SINGLE("BST1 Switch", RT5651_REC_R2_MIXER, RT5651_M_BST1_RM_R_SFT, 1, 1), }; /* Analog Output Mixer */ static const struct snd_kcontrol_new rt5651_out_l_mix[] = { SOC_DAPM_SINGLE("BST1 Switch", RT5651_OUT_L3_MIXER, RT5651_M_BST1_OM_L_SFT, 1, 1), SOC_DAPM_SINGLE("BST2 Switch", RT5651_OUT_L3_MIXER, RT5651_M_BST2_OM_L_SFT, 1, 1), SOC_DAPM_SINGLE("INL1 Switch", RT5651_OUT_L3_MIXER, RT5651_M_IN1_L_OM_L_SFT, 1, 1), SOC_DAPM_SINGLE("REC MIXL Switch", RT5651_OUT_L3_MIXER, RT5651_M_RM_L_OM_L_SFT, 1, 1), SOC_DAPM_SINGLE("DAC L1 Switch", RT5651_OUT_L3_MIXER, RT5651_M_DAC_L1_OM_L_SFT, 1, 1), }; static const struct snd_kcontrol_new rt5651_out_r_mix[] = { SOC_DAPM_SINGLE("BST2 Switch", RT5651_OUT_R3_MIXER, RT5651_M_BST2_OM_R_SFT, 1, 1), SOC_DAPM_SINGLE("BST1 Switch", RT5651_OUT_R3_MIXER, RT5651_M_BST1_OM_R_SFT, 1, 1), SOC_DAPM_SINGLE("INR1 Switch", RT5651_OUT_R3_MIXER, RT5651_M_IN1_R_OM_R_SFT, 1, 1), SOC_DAPM_SINGLE("REC MIXR Switch", RT5651_OUT_R3_MIXER, RT5651_M_RM_R_OM_R_SFT, 1, 1), SOC_DAPM_SINGLE("DAC R1 Switch", RT5651_OUT_R3_MIXER, RT5651_M_DAC_R1_OM_R_SFT, 1, 1), }; static const struct snd_kcontrol_new rt5651_hpo_mix[] = { SOC_DAPM_SINGLE("HPO MIX DAC1 Switch", RT5651_HPO_MIXER, RT5651_M_DAC1_HM_SFT, 1, 1), SOC_DAPM_SINGLE("HPO MIX HPVOL Switch", RT5651_HPO_MIXER, RT5651_M_HPVOL_HM_SFT, 1, 1), }; static const struct snd_kcontrol_new rt5651_lout_mix[] = { SOC_DAPM_SINGLE("DAC L1 Switch", RT5651_LOUT_MIXER, RT5651_M_DAC_L1_LM_SFT, 1, 1), SOC_DAPM_SINGLE("DAC R1 Switch", RT5651_LOUT_MIXER, RT5651_M_DAC_R1_LM_SFT, 1, 1), SOC_DAPM_SINGLE("OUTVOL L Switch", RT5651_LOUT_MIXER, RT5651_M_OV_L_LM_SFT, 1, 1), SOC_DAPM_SINGLE("OUTVOL R Switch", RT5651_LOUT_MIXER, RT5651_M_OV_R_LM_SFT, 1, 1), }; static const struct snd_kcontrol_new outvol_l_control = SOC_DAPM_SINGLE("Switch", RT5651_LOUT_CTRL1, RT5651_VOL_L_SFT, 1, 1); static const struct snd_kcontrol_new outvol_r_control = SOC_DAPM_SINGLE("Switch", RT5651_LOUT_CTRL1, RT5651_VOL_R_SFT, 1, 1); static const struct snd_kcontrol_new lout_l_mute_control = SOC_DAPM_SINGLE_AUTODISABLE("Switch", RT5651_LOUT_CTRL1, RT5651_L_MUTE_SFT, 1, 1); static const struct snd_kcontrol_new lout_r_mute_control = SOC_DAPM_SINGLE_AUTODISABLE("Switch", RT5651_LOUT_CTRL1, RT5651_R_MUTE_SFT, 1, 1); static const struct snd_kcontrol_new hpovol_l_control = SOC_DAPM_SINGLE("Switch", RT5651_HP_VOL, RT5651_VOL_L_SFT, 1, 1); static const struct snd_kcontrol_new hpovol_r_control = SOC_DAPM_SINGLE("Switch", RT5651_HP_VOL, RT5651_VOL_R_SFT, 1, 1); static const struct snd_kcontrol_new hpo_l_mute_control = SOC_DAPM_SINGLE_AUTODISABLE("Switch", RT5651_HP_VOL, RT5651_L_MUTE_SFT, 1, 1); static const struct snd_kcontrol_new hpo_r_mute_control = SOC_DAPM_SINGLE_AUTODISABLE("Switch", RT5651_HP_VOL, RT5651_R_MUTE_SFT, 1, 1); /* Stereo ADC source */ static const char * const rt5651_stereo1_adc1_src[] = {"DD MIX", "ADC"}; static SOC_ENUM_SINGLE_DECL( rt5651_stereo1_adc1_enum, RT5651_STO1_ADC_MIXER, RT5651_STO1_ADC_1_SRC_SFT, rt5651_stereo1_adc1_src); static const struct snd_kcontrol_new rt5651_sto1_adc_l1_mux = SOC_DAPM_ENUM("Stereo1 ADC L1 source", rt5651_stereo1_adc1_enum); static const struct snd_kcontrol_new rt5651_sto1_adc_r1_mux = SOC_DAPM_ENUM("Stereo1 ADC R1 source", rt5651_stereo1_adc1_enum); static const char * const rt5651_stereo1_adc2_src[] = {"DMIC", "DD MIX"}; static SOC_ENUM_SINGLE_DECL( rt5651_stereo1_adc2_enum, RT5651_STO1_ADC_MIXER, RT5651_STO1_ADC_2_SRC_SFT, rt5651_stereo1_adc2_src); static const struct snd_kcontrol_new rt5651_sto1_adc_l2_mux = SOC_DAPM_ENUM("Stereo1 ADC L2 source", rt5651_stereo1_adc2_enum); static const struct snd_kcontrol_new rt5651_sto1_adc_r2_mux = SOC_DAPM_ENUM("Stereo1 ADC R2 source", rt5651_stereo1_adc2_enum); /* Mono ADC source */ static const char * const rt5651_sto2_adc_l1_src[] = {"DD MIXL", "ADCL"}; static SOC_ENUM_SINGLE_DECL( rt5651_sto2_adc_l1_enum, RT5651_STO1_ADC_MIXER, RT5651_STO2_ADC_L1_SRC_SFT, rt5651_sto2_adc_l1_src); static const struct snd_kcontrol_new rt5651_sto2_adc_l1_mux = SOC_DAPM_ENUM("Stereo2 ADC1 left source", rt5651_sto2_adc_l1_enum); static const char * const rt5651_sto2_adc_l2_src[] = {"DMIC L", "DD MIXL"}; static SOC_ENUM_SINGLE_DECL( rt5651_sto2_adc_l2_enum, RT5651_STO1_ADC_MIXER, RT5651_STO2_ADC_L2_SRC_SFT, rt5651_sto2_adc_l2_src); static const struct snd_kcontrol_new rt5651_sto2_adc_l2_mux = SOC_DAPM_ENUM("Stereo2 ADC2 left source", rt5651_sto2_adc_l2_enum); static const char * const rt5651_sto2_adc_r1_src[] = {"DD MIXR", "ADCR"}; static SOC_ENUM_SINGLE_DECL( rt5651_sto2_adc_r1_enum, RT5651_STO1_ADC_MIXER, RT5651_STO2_ADC_R1_SRC_SFT, rt5651_sto2_adc_r1_src); static const struct snd_kcontrol_new rt5651_sto2_adc_r1_mux = SOC_DAPM_ENUM("Stereo2 ADC1 right source", rt5651_sto2_adc_r1_enum); static const char * const rt5651_sto2_adc_r2_src[] = {"DMIC R", "DD MIXR"}; static SOC_ENUM_SINGLE_DECL( rt5651_sto2_adc_r2_enum, RT5651_STO1_ADC_MIXER, RT5651_STO2_ADC_R2_SRC_SFT, rt5651_sto2_adc_r2_src); static const struct snd_kcontrol_new rt5651_sto2_adc_r2_mux = SOC_DAPM_ENUM("Stereo2 ADC2 right source", rt5651_sto2_adc_r2_enum); /* DAC2 channel source */ static const char * const rt5651_dac_src[] = {"IF1", "IF2"}; static SOC_ENUM_SINGLE_DECL(rt5651_dac_l2_enum, RT5651_DAC2_CTRL, RT5651_SEL_DAC_L2_SFT, rt5651_dac_src); static const struct snd_kcontrol_new rt5651_dac_l2_mux = SOC_DAPM_ENUM("DAC2 left channel source", rt5651_dac_l2_enum); static SOC_ENUM_SINGLE_DECL( rt5651_dac_r2_enum, RT5651_DAC2_CTRL, RT5651_SEL_DAC_R2_SFT, rt5651_dac_src); static const struct snd_kcontrol_new rt5651_dac_r2_mux = SOC_DAPM_ENUM("DAC2 right channel source", rt5651_dac_r2_enum); /* IF2_ADC channel source */ static const char * const rt5651_adc_src[] = {"IF1 ADC1", "IF1 ADC2"}; static SOC_ENUM_SINGLE_DECL(rt5651_if2_adc_src_enum, RT5651_DIG_INF_DATA, RT5651_IF2_ADC_SRC_SFT, rt5651_adc_src); static const struct snd_kcontrol_new rt5651_if2_adc_src_mux = SOC_DAPM_ENUM("IF2 ADC channel source", rt5651_if2_adc_src_enum); /* PDM select */ static const char * const rt5651_pdm_sel[] = {"DD MIX", "Stereo DAC MIX"}; static SOC_ENUM_SINGLE_DECL( rt5651_pdm_l_sel_enum, RT5651_PDM_CTL, RT5651_PDM_L_SEL_SFT, rt5651_pdm_sel); static SOC_ENUM_SINGLE_DECL( rt5651_pdm_r_sel_enum, RT5651_PDM_CTL, RT5651_PDM_R_SEL_SFT, rt5651_pdm_sel); static const struct snd_kcontrol_new rt5651_pdm_l_mux = SOC_DAPM_ENUM("PDM L select", rt5651_pdm_l_sel_enum); static const struct snd_kcontrol_new rt5651_pdm_r_mux = SOC_DAPM_ENUM("PDM R select", rt5651_pdm_r_sel_enum);
有关kcontrol辅助定义宏我们在Rockchip RK3399 - ASoC 声卡之Control设备 kcontrol章节中已经介绍，比如：
- SOC_SINGLE：最简单的控件了，这种控件只有一个控制量，比如一个开关，或者是一个数值变量（比如Codec中某个频率，FIFO大小等等）；
- SOC_SINGLE_TLV：是SOC_SINGLE的一种扩展，主要用于定义那些有增益控制的控件，例如音量控制器，EQ均衡器等等；
- SOC_DOUBLE：与SOC_SINGLE相对应，区别是SOC_SINGLE只控制一个变量，而SOC_DOUBLE则可以同时在一个寄存器中控制两个相似的变量，最常用的就是用于一些立体声的控件；
- SOC_DOUBLE_TLV：与SOC_SINGLE_TLV对应的立体声版本，通常用于立体声音量控件的定义；
- SOC_ENUM：用于定义一个定义一个Mux控件；
有关dapm kcontrol辅助定义宏我们在Rockchip RK3399 - DAPM Widget&Route&Path kcontrol章节中已经介绍，相比普通的kcontrol控件，dapm的kcontrol只是把info，get，put回调函数换掉了，比如：SOC_DAPM_SINGLE：对应普通控件的SOC_SINGLE.
在这些定义中我们可以找到位于多媒体音频播放右声道路径上的dapm kcontrol；
static const struct snd_kcontrol_new rt5651_dac_r_mix[] = { SOC_DAPM_SINGLE("Stereo ADC Switch", RT5651_AD_DA_MIXER, // 寄存器配置为RT5651_AD_DA_MIXER=0x29，偏移位配置为7 RT5651_M_ADCMIX_R_SFT, 1, 1), SOC_DAPM_SINGLE("INF1 Switch", RT5651_AD_DA_MIXER, // 寄存器配置为RT5651_AD_DA_MIXER=0x29，偏移位配置为6 RT5651_M_IF1_DAC_R_SFT, 1, 1), }; static const struct snd_kcontrol_new rt5651_sto_dac_r_mix[] = { SOC_DAPM_SINGLE("DAC R1 Switch", RT5651_STO_DAC_MIXER, // 寄存器配置为RT5651_STO_DAC_MIXER=0x2a，偏移位配置为6 RT5651_M_DAC_R1_MIXR_SFT, 1, 1), SOC_DAPM_SINGLE("DAC R2 Switch", RT5651_STO_DAC_MIXER, // 寄存器配置为RT5651_STO_DAC_MIXER=0x2a，偏移位配置为4 RT5651_M_DAC_R2_MIXR_SFT, 1, 1), SOC_DAPM_SINGLE("DAC L1 Switch", RT5651_STO_DAC_MIXER, // 寄存器配置为RT5651_STO_DAC_MIXER=0x2a，偏移位配置为1 RT5651_M_DAC_L1_MIXR_SFT, 1, 1), }; static const struct snd_kcontrol_new rt5651_out_r_mix[] = { SOC_DAPM_SINGLE("BST2 Switch", RT5651_OUT_R3_MIXER, // 寄存器配置为RT5651_OUT_R3_MIXER=0x52，偏移位配置为5 RT5651_M_BST2_OM_R_SFT, 1, 1), SOC_DAPM_SINGLE("BST1 Switch", RT5651_OUT_R3_MIXER, // 寄存器配置为RT5651_OUT_R3_MIXER=0x52，偏移位配置为6 RT5651_M_BST1_OM_R_SFT, 1, 1), SOC_DAPM_SINGLE("INR1 Switch", RT5651_OUT_R3_MIXER, // 寄存器配置为RRT5651_OUT_R3_MIXER=0x52，偏移位配置为4 RT5651_M_IN1_R_OM_R_SFT, 1, 1), SOC_DAPM_SINGLE("REC MIXR Switch", RT5651_OUT_R3_MIXER, // 寄存器配置为RT5651_OUT_R3_MIXER=0x4f，偏移位配置为3 RT5651_M_RM_R_OM_R_SFT, 1, 1), SOC_DAPM_SINGLE("DAC R1 Switch", RT5651_OUT_R3_MIXER, // 寄存器配置为RT5651_OUT_R3_MIXER，偏移位配置为0 RT5651_M_DAC_R1_OM_R_SFT, 1, 1), }; static const struct snd_kcontrol_new hpovol_r_control = SOC_DAPM_SINGLE("Switch", RT5651_HP_VOL, // 寄存器配置为RT5651_HP_VOL=0x02，偏移位配置为6 RT5651_VOL_R_SFT, 1, 1); static const struct snd_kcontrol_new rt5651_hpo_mix[] = { SOC_DAPM_SINGLE("HPO MIX DAC1 Switch", RT5651_HPO_MIXER, // 寄存器配置为RT5651_HPO_MIXER=0x45，偏移位配置为14 RT5651_M_DAC1_HM_SFT, 1, 1), SOC_DAPM_SINGLE("HPO MIX HPVOL Switch", RT5651_HPO_MIXER, // 寄存器配置为RT5651_HPO_MIXER=0x45，偏移位配置为13 RT5651_M_HPVOL_HM_SFT, 1, 1), }; static const struct snd_kcontrol_new hpo_r_mute_control = SOC_DAPM_SINGLE_AUTODISABLE("Switch", RT5651_HP_VOL, // 寄存器配置为RT5651_HP_VOL=0x02，偏移位配置为7 RT5651_R_MUTE_SFT, 1, 1);
左声道：
static const struct snd_kcontrol_new rt5651_dac_l_mix[] = { SOC_DAPM_SINGLE("Stereo ADC Switch", RT5651_AD_DA_MIXER, // 寄存器配置为RT5651_AD_DA_MIXER=0x29，偏移位配置为15 RT5651_M_ADCMIX_L_SFT, 1, 1), SOC_DAPM_SINGLE("INF1 Switch", RT5651_AD_DA_MIXER, // 寄存器配置为RT5651_AD_DA_MIXER=0x29，偏移位配置为14 RT5651_M_IF1_DAC_L_SFT, 1, 1), }; static const struct snd_kcontrol_new rt5651_sto_dac_l_mix[] = { SOC_DAPM_SINGLE("DAC L1 Switch", RT5651_STO_DAC_MIXER, // 寄存器配置为RT5651_STO_DAC_MIXER=0x2a，偏移位配置为14 RT5651_M_DAC_L1_MIXL_SFT, 1, 1), SOC_DAPM_SINGLE("DAC L2 Switch", RT5651_STO_DAC_MIXER, // 寄存器配置为RT5651_STO_DAC_MIXER=0x2a，偏移位配置为12 RT5651_M_DAC_L2_MIXL_SFT, 1, 1), SOC_DAPM_SINGLE("DAC R1 Switch", RT5651_STO_DAC_MIXER, // 寄存器配置为RT5651_STO_DAC_MIXER=0x2a，偏移位配置为9 RT5651_M_DAC_R1_MIXL_SFT, 1, 1), }; static const struct snd_kcontrol_new rt5651_out_l_mix[] = { SOC_DAPM_SINGLE("BST1 Switch", RT5651_OUT_L3_MIXER, // 寄存器配置为RT5651_OUT_L3_MIXER=0x4f，偏移位配置为5 RT5651_M_BST1_OM_L_SFT, 1, 1), SOC_DAPM_SINGLE("BST2 Switch", RT5651_OUT_L3_MIXER, // 寄存器配置为RT5651_OUT_L3_MIXER=0x4f，偏移位配置为6 RT5651_M_BST2_OM_L_SFT, 1, 1), SOC_DAPM_SINGLE("INL1 Switch", RT5651_OUT_L3_MIXER, // 寄存器配置为RT5651_OUT_L3_MIXER=0x4f，偏移位配置为4 RT5651_M_IN1_L_OM_L_SFT, 1, 1), SOC_DAPM_SINGLE("REC MIXL Switch", RT5651_OUT_L3_MIXER, // 寄存器配置为RT5651_OUT_L3_MIXER=0x4f，偏移位配置为3 RT5651_M_RM_L_OM_L_SFT, 1, 1), SOC_DAPM_SINGLE("DAC L1 Switch", RT5651_OUT_L3_MIXER, // 寄存器配置为RT5651_OUT_L3_MIXER=0x4f，偏移位配置为0 RT5651_M_DAC_L1_OM_L_SFT, 1, 1), }; static const struct snd_kcontrol_new hpovol_l_control = SOC_DAPM_SINGLE("Switch", RT5651_HP_VOL, // 寄存器配置为RT5651_HP_VOL=0x02，偏移位配置为14 RT5651_VOL_L_SFT, 1, 1); static const struct snd_kcontrol_new rt5651_hpo_mix[] = { SOC_DAPM_SINGLE("HPO MIX DAC1 Switch", RT5651_HPO_MIXER, // 寄存器配置为RT5651_HPO_MIXER=0x45，偏移位配置为14 RT5651_M_DAC1_HM_SFT, 1, 1), SOC_DAPM_SINGLE("HPO MIX HPVOL Switch", RT5651_HPO_MIXER, // 寄存器配置为RT5651_HPO_MIXER=0x45，偏移位配置为13 RT5651_M_HPVOL_HM_SFT, 1, 1), }; static const struct snd_kcontrol_new hpo_l_mute_control = SOC_DAPM_SINGLE_AUTODISABLE("Switch", RT5651_HP_VOL, // 寄存器配置为RT5651_HP_VOL=0x02，偏移位配置为15 RT5651_L_MUTE_SFT, 1, 1);
4.1.2 定义widget
在sound/soc/codecs/rt5651.c定义了大量的widget：
static const struct snd_soc_dapm_widget rt5651_dapm_widgets[] = { /* ASRC */ SND_SOC_DAPM_SUPPLY_S("I2S1 ASRC", 1, RT5651_PLL_MODE_2, 15, 0, NULL, 0), SND_SOC_DAPM_SUPPLY_S("I2S2 ASRC", 1, RT5651_PLL_MODE_2, 14, 0, NULL, 0), SND_SOC_DAPM_SUPPLY_S("STO1 DAC ASRC", 1, RT5651_PLL_MODE_2, 13, 0, NULL, 0), SND_SOC_DAPM_SUPPLY_S("STO2 DAC ASRC", 1, RT5651_PLL_MODE_2, 12, 0, NULL, 0), SND_SOC_DAPM_SUPPLY_S("ADC ASRC", 1, RT5651_PLL_MODE_2, 11, 0, NULL, 0), /* micbias */ SND_SOC_DAPM_SUPPLY("LDO", RT5651_PWR_ANLG1, RT5651_PWR_LDO_BIT, 0, NULL, 0), SND_SOC_DAPM_SUPPLY("micbias1", RT5651_PWR_ANLG2, RT5651_PWR_MB1_BIT, 0, NULL, 0), /* Input Lines */ SND_SOC_DAPM_INPUT("MIC1"), SND_SOC_DAPM_INPUT("MIC2"), SND_SOC_DAPM_INPUT("MIC3"), SND_SOC_DAPM_INPUT("IN1P"), SND_SOC_DAPM_INPUT("IN2P"), SND_SOC_DAPM_INPUT("IN2N"), SND_SOC_DAPM_INPUT("IN3P"), SND_SOC_DAPM_INPUT("DMIC L1"), SND_SOC_DAPM_INPUT("DMIC R1"), SND_SOC_DAPM_SUPPLY("DMIC CLK", RT5651_DMIC, RT5651_DMIC_1_EN_SFT, 0, set_dmic_clk, SND_SOC_DAPM_PRE_PMU), /* Boost */ SND_SOC_DAPM_PGA_E("BST1", RT5651_PWR_ANLG2, RT5651_PWR_BST1_BIT, 0, NULL, 0, rt5651_bst1_event, SND_SOC_DAPM_PRE_PMD | SND_SOC_DAPM_POST_PMU), SND_SOC_DAPM_PGA_E("BST2", RT5651_PWR_ANLG2, RT5651_PWR_BST2_BIT, 0, NULL, 0, rt5651_bst2_event, SND_SOC_DAPM_PRE_PMD | SND_SOC_DAPM_POST_PMU), SND_SOC_DAPM_PGA_E("BST3", RT5651_PWR_ANLG2, RT5651_PWR_BST3_BIT, 0, NULL, 0, rt5651_bst3_event, SND_SOC_DAPM_PRE_PMD | SND_SOC_DAPM_POST_PMU), /* Input Volume */ SND_SOC_DAPM_PGA("INL1 VOL", RT5651_PWR_VOL, RT5651_PWR_IN1_L_BIT, 0, NULL, 0), SND_SOC_DAPM_PGA("INR1 VOL", RT5651_PWR_VOL, RT5651_PWR_IN1_R_BIT, 0, NULL, 0), SND_SOC_DAPM_PGA("INL2 VOL", RT5651_PWR_VOL, RT5651_PWR_IN2_L_BIT, 0, NULL, 0), SND_SOC_DAPM_PGA("INR2 VOL", RT5651_PWR_VOL, RT5651_PWR_IN2_R_BIT, 0, NULL, 0), /* REC Mixer */ SND_SOC_DAPM_MIXER("RECMIXL", RT5651_PWR_MIXER, RT5651_PWR_RM_L_BIT, 0, rt5651_rec_l_mix, ARRAY_SIZE(rt5651_rec_l_mix)), SND_SOC_DAPM_MIXER("RECMIXR", RT5651_PWR_MIXER, RT5651_PWR_RM_R_BIT, 0, rt5651_rec_r_mix, ARRAY_SIZE(rt5651_rec_r_mix)), /* ADCs */ SND_SOC_DAPM_ADC("ADC L", NULL, SND_SOC_NOPM, 0, 0), SND_SOC_DAPM_ADC("ADC R", NULL, SND_SOC_NOPM, 0, 0), SND_SOC_DAPM_SUPPLY("ADC L Power", RT5651_PWR_DIG1, RT5651_PWR_ADC_L_BIT, 0, NULL, 0), SND_SOC_DAPM_SUPPLY("ADC R Power", RT5651_PWR_DIG1, RT5651_PWR_ADC_R_BIT, 0, NULL, 0), /* ADC Mux */ SND_SOC_DAPM_MUX("Stereo1 ADC L2 Mux", SND_SOC_NOPM, 0, 0, &rt5651_sto1_adc_l2_mux), SND_SOC_DAPM_MUX("Stereo1 ADC R2 Mux", SND_SOC_NOPM, 0, 0, &rt5651_sto1_adc_r2_mux), SND_SOC_DAPM_MUX("Stereo1 ADC L1 Mux", SND_SOC_NOPM, 0, 0, &rt5651_sto1_adc_l1_mux), SND_SOC_DAPM_MUX("Stereo1 ADC R1 Mux", SND_SOC_NOPM, 0, 0, &rt5651_sto1_adc_r1_mux), SND_SOC_DAPM_MUX("Stereo2 ADC L2 Mux", SND_SOC_NOPM, 0, 0, &rt5651_sto2_adc_l2_mux), SND_SOC_DAPM_MUX("Stereo2 ADC L1 Mux", SND_SOC_NOPM, 0, 0, &rt5651_sto2_adc_l1_mux), SND_SOC_DAPM_MUX("Stereo2 ADC R1 Mux", SND_SOC_NOPM, 0, 0, &rt5651_sto2_adc_r1_mux), SND_SOC_DAPM_MUX("Stereo2 ADC R2 Mux", SND_SOC_NOPM, 0, 0, &rt5651_sto2_adc_r2_mux), /* ADC Mixer */ SND_SOC_DAPM_SUPPLY("Stereo1 Filter", RT5651_PWR_DIG2, RT5651_PWR_ADC_STO1_F_BIT, 0, NULL, 0), SND_SOC_DAPM_SUPPLY("Stereo2 Filter", RT5651_PWR_DIG2, RT5651_PWR_ADC_STO2_F_BIT, 0, NULL, 0), SND_SOC_DAPM_MIXER("Stereo1 ADC MIXL", SND_SOC_NOPM, 0, 0, rt5651_sto1_adc_l_mix, ARRAY_SIZE(rt5651_sto1_adc_l_mix)), SND_SOC_DAPM_MIXER("Stereo1 ADC MIXR", SND_SOC_NOPM, 0, 0, rt5651_sto1_adc_r_mix, ARRAY_SIZE(rt5651_sto1_adc_r_mix)), SND_SOC_DAPM_MIXER("Stereo2 ADC MIXL", SND_SOC_NOPM, 0, 0, rt5651_sto2_adc_l_mix, ARRAY_SIZE(rt5651_sto2_adc_l_mix)), SND_SOC_DAPM_MIXER("Stereo2 ADC MIXR", SND_SOC_NOPM, 0, 0, rt5651_sto2_adc_r_mix, ARRAY_SIZE(rt5651_sto2_adc_r_mix)), /* Digital Interface */ SND_SOC_DAPM_SUPPLY("I2S1", RT5651_PWR_DIG1, RT5651_PWR_I2S1_BIT, 0, NULL, 0), SND_SOC_DAPM_PGA("IF1 DAC", SND_SOC_NOPM, 0, 0, NULL, 0), SND_SOC_DAPM_PGA("IF1 DAC1 L", SND_SOC_NOPM, 0, 0, NULL, 0), SND_SOC_DAPM_PGA("IF1 DAC1 R", SND_SOC_NOPM, 0, 0, NULL, 0), SND_SOC_DAPM_PGA("IF1 ADC1", SND_SOC_NOPM, 0, 0, NULL, 0), SND_SOC_DAPM_PGA("IF1 DAC2 L", SND_SOC_NOPM, 0, 0, NULL, 0), SND_SOC_DAPM_PGA("IF1 DAC2 R", SND_SOC_NOPM, 0, 0, NULL, 0), SND_SOC_DAPM_PGA("IF1 ADC2", SND_SOC_NOPM, 0, 0, NULL, 0), SND_SOC_DAPM_SUPPLY("I2S2", RT5651_PWR_DIG1, RT5651_PWR_I2S2_BIT, 0, NULL, 0), SND_SOC_DAPM_PGA("IF2 DAC", SND_SOC_NOPM, 0, 0, NULL, 0), SND_SOC_DAPM_PGA("IF2 DAC L", SND_SOC_NOPM, 0, 0, NULL, 0), SND_SOC_DAPM_PGA("IF2 DAC R", SND_SOC_NOPM, 0, 0, NULL, 0), SND_SOC_DAPM_MUX("IF2 ADC", SND_SOC_NOPM, 0, 0, &rt5651_if2_adc_src_mux), /* Digital Interface Select */ SND_SOC_DAPM_MUX("PDM L Mux", RT5651_PDM_CTL, RT5651_M_PDM_L_SFT, 1, &rt5651_pdm_l_mux), SND_SOC_DAPM_MUX("PDM R Mux", RT5651_PDM_CTL, RT5651_M_PDM_R_SFT, 1, &rt5651_pdm_r_mux), /* Audio Interface */ SND_SOC_DAPM_AIF_IN("AIF1RX", "AIF1 Playback", 0, SND_SOC_NOPM, 0, 0), SND_SOC_DAPM_AIF_OUT("AIF1TX", "AIF1 Capture", 0, SND_SOC_NOPM, 0, 0), SND_SOC_DAPM_AIF_IN("AIF2RX", "AIF2 Playback", 0, SND_SOC_NOPM, 0, 0), SND_SOC_DAPM_AIF_OUT("AIF2TX", "AIF2 Capture", 0, SND_SOC_NOPM, 0, 0), /* Audio DSP */ SND_SOC_DAPM_PGA("Audio DSP", SND_SOC_NOPM, 0, 0, NULL, 0), /* Output Side */ /* DAC mixer before sound effect */ SND_SOC_DAPM_MIXER("DAC MIXL", SND_SOC_NOPM, 0, 0, rt5651_dac_l_mix, ARRAY_SIZE(rt5651_dac_l_mix)), SND_SOC_DAPM_MIXER("DAC MIXR", SND_SOC_NOPM, 0, 0, rt5651_dac_r_mix, ARRAY_SIZE(rt5651_dac_r_mix)), /* DAC2 channel Mux */ SND_SOC_DAPM_MUX("DAC L2 Mux", SND_SOC_NOPM, 0, 0, &rt5651_dac_l2_mux), SND_SOC_DAPM_MUX("DAC R2 Mux", SND_SOC_NOPM, 0, 0, &rt5651_dac_r2_mux), SND_SOC_DAPM_PGA("DAC L2 Volume", SND_SOC_NOPM, 0, 0, NULL, 0), SND_SOC_DAPM_PGA("DAC R2 Volume", SND_SOC_NOPM, 0, 0, NULL, 0), SND_SOC_DAPM_SUPPLY("Stero1 DAC Power", RT5651_PWR_DIG2, RT5651_PWR_DAC_STO1_F_BIT, 0, NULL, 0), SND_SOC_DAPM_SUPPLY("Stero2 DAC Power", RT5651_PWR_DIG2, RT5651_PWR_DAC_STO2_F_BIT, 0, NULL, 0), /* DAC Mixer */ SND_SOC_DAPM_MIXER("Stereo DAC MIXL", SND_SOC_NOPM, 0, 0, rt5651_sto_dac_l_mix, ARRAY_SIZE(rt5651_sto_dac_l_mix)), SND_SOC_DAPM_MIXER("Stereo DAC MIXR", SND_SOC_NOPM, 0, 0, rt5651_sto_dac_r_mix, ARRAY_SIZE(rt5651_sto_dac_r_mix)), SND_SOC_DAPM_MIXER("DD MIXL", SND_SOC_NOPM, 0, 0, rt5651_dd_dac_l_mix, ARRAY_SIZE(rt5651_dd_dac_l_mix)), SND_SOC_DAPM_MIXER("DD MIXR", SND_SOC_NOPM, 0, 0, rt5651_dd_dac_r_mix, ARRAY_SIZE(rt5651_dd_dac_r_mix)), /* DACs */ SND_SOC_DAPM_DAC("DAC L1", NULL, SND_SOC_NOPM, 0, 0), SND_SOC_DAPM_DAC("DAC R1", NULL, SND_SOC_NOPM, 0, 0), SND_SOC_DAPM_SUPPLY("DAC L1 Power", RT5651_PWR_DIG1, RT5651_PWR_DAC_L1_BIT, 0, NULL, 0), SND_SOC_DAPM_SUPPLY("DAC R1 Power", RT5651_PWR_DIG1, RT5651_PWR_DAC_R1_BIT, 0, NULL, 0), /* OUT Mixer */ SND_SOC_DAPM_MIXER("OUT MIXL", RT5651_PWR_MIXER, RT5651_PWR_OM_L_BIT, 0, rt5651_out_l_mix, ARRAY_SIZE(rt5651_out_l_mix)), SND_SOC_DAPM_MIXER("OUT MIXR", RT5651_PWR_MIXER, RT5651_PWR_OM_R_BIT, 0, rt5651_out_r_mix, ARRAY_SIZE(rt5651_out_r_mix)), /* Ouput Volume */ SND_SOC_DAPM_SWITCH("OUTVOL L", RT5651_PWR_VOL, RT5651_PWR_OV_L_BIT, 0, &outvol_l_control), SND_SOC_DAPM_SWITCH("OUTVOL R", RT5651_PWR_VOL, RT5651_PWR_OV_R_BIT, 0, &outvol_r_control), SND_SOC_DAPM_SWITCH("HPOVOL L", RT5651_PWR_VOL, RT5651_PWR_HV_L_BIT, 0, &hpovol_l_control), SND_SOC_DAPM_SWITCH("HPOVOL R", RT5651_PWR_VOL, RT5651_PWR_HV_R_BIT, 0, &hpovol_r_control), SND_SOC_DAPM_PGA("INL1", RT5651_PWR_VOL, RT5651_PWR_IN1_L_BIT, 0, NULL, 0), SND_SOC_DAPM_PGA("INR1", RT5651_PWR_VOL, RT5651_PWR_IN1_R_BIT, 0, NULL, 0), SND_SOC_DAPM_PGA("INL2", RT5651_PWR_VOL, RT5651_PWR_IN2_L_BIT, 0, NULL, 0), SND_SOC_DAPM_PGA("INR2", RT5651_PWR_VOL, RT5651_PWR_IN2_R_BIT, 0, NULL, 0), /* HPO/LOUT/Mono Mixer */ SND_SOC_DAPM_MIXER("HPOL MIX", SND_SOC_NOPM, 0, 0, rt5651_hpo_mix, ARRAY_SIZE(rt5651_hpo_mix)), SND_SOC_DAPM_MIXER("HPOR MIX", SND_SOC_NOPM, 0, 0, rt5651_hpo_mix, ARRAY_SIZE(rt5651_hpo_mix)), SND_SOC_DAPM_SUPPLY("HP L Amp", RT5651_PWR_ANLG1, RT5651_PWR_HP_L_BIT, 0, NULL, 0), SND_SOC_DAPM_SUPPLY("HP R Amp", RT5651_PWR_ANLG1, RT5651_PWR_HP_R_BIT, 0, NULL, 0), SND_SOC_DAPM_MIXER("LOUT MIX", RT5651_PWR_ANLG1, RT5651_PWR_LM_BIT, 0, rt5651_lout_mix, ARRAY_SIZE(rt5651_lout_mix)), SND_SOC_DAPM_SUPPLY("Amp Power", RT5651_PWR_ANLG1, RT5651_PWR_HA_BIT, 0, rt5651_amp_power_event, SND_SOC_DAPM_POST_PMU), SND_SOC_DAPM_PGA_S("HP Amp", 1, SND_SOC_NOPM, 0, 0, rt5651_hp_event, SND_SOC_DAPM_PRE_PMD | SND_SOC_DAPM_POST_PMU), SND_SOC_DAPM_SWITCH("HPO L Playback", SND_SOC_NOPM, 0, 0, &hpo_l_mute_control), SND_SOC_DAPM_SWITCH("HPO R Playback", SND_SOC_NOPM, 0, 0, &hpo_r_mute_control), SND_SOC_DAPM_SWITCH("LOUT L Playback", SND_SOC_NOPM, 0, 0, &lout_l_mute_control), SND_SOC_DAPM_SWITCH("LOUT R Playback", SND_SOC_NOPM, 0, 0, &lout_r_mute_control), SND_SOC_DAPM_POST("HP Post", rt5651_hp_post_event), /* Output Lines */ SND_SOC_DAPM_OUTPUT("HPOL"), SND_SOC_DAPM_OUTPUT("HPOR"), SND_SOC_DAPM_OUTPUT("LOUTL"), SND_SOC_DAPM_OUTPUT("LOUTR"), SND_SOC_DAPM_OUTPUT("PDML"), SND_SOC_DAPM_OUTPUT("PDMR"), };
在rt5651_dapm_widgets中我们可以找到位于多媒体音频播放右声道路径上的widget；
/* Audio Interface */ SND_SOC_DAPM_AIF_IN("AIF1RX", "AIF1 Playback", 0, SND_SOC_NOPM, 0, 0), // 无寄存器 /* Digital Interface */ SND_SOC_DAPM_PGA("IF1 DAC", SND_SOC_NOPM, 0, 0, NULL, 0), // 虚拟widget SND_SOC_DAPM_PGA("IF1 DAC1 R", SND_SOC_NOPM, 0, 0, NULL, 0), // 虚拟widget /* Output Side */ /* DAC mixer before sound effect */ SND_SOC_DAPM_MIXER("DAC MIXR", SND_SOC_NOPM, 0, 0, //Right DAC Mixer包含2个kcontrol，每个kcontrol控制着Mixer的一个输入端的开启和关闭 rt5651_dac_r_mix, ARRAY_SIZE(rt5651_dac_r_mix)), /* Audio DSP */ SND_SOC_DAPM_PGA("Audio DSP", SND_SOC_NOPM, 0, 0, NULL, 0), /* DAC Mixer */ SND_SOC_DAPM_MIXER("Stereo DAC MIXR", SND_SOC_NOPM, 0, 0, // Right Stereo DAC Mixer包含3个kcontrol，每个kcontrol控制着Mixer的一个输入端的开启和关闭 rt5651_sto_dac_r_mix, ARRAY_SIZE(rt5651_sto_dac_r_mix)), /* DACs */ SND_SOC_DAPM_DAC("DAC R1", NULL, SND_SOC_NOPM, 0, 0), /* OUT Mixer */ SND_SOC_DAPM_MIXER("OUT MIXR", RT5651_PWR_MIXER, RT5651_PWR_OM_R_BIT, // Right Output Mixer包含5个kcontrol，每个kcontrol控制着Mixer的一个输入端的开启和关闭 0, rt5651_out_r_mix, ARRAY_SIZE(rt5651_out_r_mix)), /* Ouput Volume */ SND_SOC_DAPM_SWITCH("HPOVOL R", RT5651_PWR_VOL, // Right HPO Volume包含1个kcontrol，用于控制开关的通断 RT5651_PWR_HV_R_BIT, 0, &hpovol_r_control), /* HPO/LOUT/Mono Mixer */ SND_SOC_DAPM_MIXER("HPOR MIX", SND_SOC_NOPM, 0, 0, // Right HPO Mixer包含2个kcontrol,每个kcontrol控制着Mixer的一个输入端的开启和关闭 rt5651_hpo_mix, ARRAY_SIZE(rt5651_hpo_mix)), SND_SOC_DAPM_PGA_S("HP Amp", 1, SND_SOC_NOPM, 0, 0, rt5651_hp_event, SND_SOC_DAPM_PRE_PMD | SND_SOC_DAPM_POST_PMU), SND_SOC_DAPM_SWITCH("HPO R Playback", SND_SOC_NOPM, 0, 0, // Right HPO Playback包含1个kcontrol，用于控制开关的通断 &hpo_r_mute_control), /* Output Lines */ SND_SOC_DAPM_OUTPUT("HPOR"), // HPOR为ALC5651的Right HPO Output引脚，可以用来外耳机
左声道：
/* Audio Interface */ SND_SOC_DAPM_AIF_IN("AIF1RX", "AIF1 Playback", 0, SND_SOC_NOPM, 0, 0), // 无寄存器 /* Digital Interface */ SND_SOC_DAPM_PGA("IF1 DAC", SND_SOC_NOPM, 0, 0, NULL, 0), // 虚拟widget SND_SOC_DAPM_PGA("IF1 DAC1 L", SND_SOC_NOPM, 0, 0, NULL, 0), // 虚拟widget /* Output Side */ /* DAC mixer before sound effect */ SND_SOC_DAPM_MIXER("DAC MIXL", SND_SOC_NOPM, 0, 0, // Left DAC Mixer包含2个kcontrol，每个kcontrol控制着Mixer的一个输入端的开启和关闭 rt5651_dac_l_mix, ARRAY_SIZE(rt5651_dac_l_mix)), /* Audio DSP */ SND_SOC_DAPM_PGA("Audio DSP", SND_SOC_NOPM, 0, 0, NULL, 0), /* DAC Mixer */ SND_SOC_DAPM_MIXER("Stereo DAC MIXL", SND_SOC_NOPM, 0, 0, // Left Stereo DAC Mixer包含3个kcontrol，每个kcontrol控制着Mixer的一个输入端的开启和关闭 rt5651_sto_dac_l_mix, ARRAY_SIZE(rt5651_sto_dac_l_mix)), /* DACs */ SND_SOC_DAPM_DAC("DAC L1", NULL, SND_SOC_NOPM, 0, 0), /* OUT Mixer */ SND_SOC_DAPM_MIXER("OUT MIXL", RT5651_PWR_MIXER, RT5651_PWR_OM_L_BIT, // Left Output Mixer包含5个kcontrol，每个kcontrol控制着Mixer的一个输入端的开启和关闭 0, rt5651_out_l_mix, ARRAY_SIZE(rt5651_out_l_mix)), /* Ouput Volume */ SND_SOC_DAPM_SWITCH("HPOVOL L", RT5651_PWR_VOL, // Left HPO Volume包含1个kcontrol，用于控制开关的通断 RT5651_PWR_HV_L_BIT, 0, &hpovol_l_control), /* HPO/LOUT/Mono Mixer */ SND_SOC_DAPM_MIXER("HPOL MIX", SND_SOC_NOPM, 0, 0, // Left HPO Mixer包含2个kcontrol,每个kcontrol控制着Mixer的一个输入端的开启和关闭 rt5651_hpo_mix, ARRAY_SIZE(rt5651_hpo_mix)), SND_SOC_DAPM_PGA_S("HP Amp", 1, SND_SOC_NOPM, 0, 0, rt5651_hp_event, SND_SOC_DAPM_PRE_PMD | SND_SOC_DAPM_POST_PMU), SND_SOC_DAPM_SWITCH("HPO L Playback", SND_SOC_NOPM, 0, 0, // Left HPO Playback包含1个kcontrol，用于控制开关的通断 &hpo_l_mute_control), /* Output Lines */ SND_SOC_DAPM_OUTPUT("HPOL"), // HPOL为ALC5651的Left HPO Output引脚，可以用来外耳机
不知道你有没有注意到，上面定义的这些widget都没有设置相应的电源控制寄存器。
4.1.3 定义route
在sound/soc/codecs/rt5651.c定义了widget的链接路径：
static const struct snd_soc_dapm_route rt5651_dapm_routes[] = { {"Stero1 DAC Power", NULL, "STO1 DAC ASRC"}, {"Stero2 DAC Power", NULL, "STO2 DAC ASRC"}, {"I2S1", NULL, "I2S1 ASRC"}, {"I2S2", NULL, "I2S2 ASRC"}, {"IN1P", NULL, "LDO"}, {"IN2P", NULL, "LDO"}, {"IN3P", NULL, "LDO"}, {"IN1P", NULL, "MIC1"}, {"IN2P", NULL, "MIC2"}, {"IN2N", NULL, "MIC2"}, {"IN3P", NULL, "MIC3"}, {"BST1", NULL, "IN1P"}, {"BST2", NULL, "IN2P"}, {"BST2", NULL, "IN2N"}, {"BST3", NULL, "IN3P"}, {"INL1 VOL", NULL, "IN2P"}, {"INR1 VOL", NULL, "IN2N"}, {"RECMIXL", "INL1 Switch", "INL1 VOL"}, {"RECMIXL", "BST3 Switch", "BST3"}, {"RECMIXL", "BST2 Switch", "BST2"}, {"RECMIXL", "BST1 Switch", "BST1"}, {"RECMIXR", "INR1 Switch", "INR1 VOL"}, {"RECMIXR", "BST3 Switch", "BST3"}, {"RECMIXR", "BST2 Switch", "BST2"}, {"RECMIXR", "BST1 Switch", "BST1"}, {"ADC L", NULL, "RECMIXL"}, {"ADC L", NULL, "ADC L Power"}, {"ADC R", NULL, "RECMIXR"}, {"ADC R", NULL, "ADC R Power"}, {"DMIC L1", NULL, "DMIC CLK"}, {"DMIC R1", NULL, "DMIC CLK"}, {"Stereo1 ADC L2 Mux", "DMIC", "DMIC L1"}, {"Stereo1 ADC L2 Mux", "DD MIX", "DD MIXL"}, {"Stereo1 ADC L1 Mux", "ADC", "ADC L"}, {"Stereo1 ADC L1 Mux", "DD MIX", "DD MIXL"}, {"Stereo1 ADC R1 Mux", "ADC", "ADC R"}, {"Stereo1 ADC R1 Mux", "DD MIX", "DD MIXR"}, {"Stereo1 ADC R2 Mux", "DMIC", "DMIC R1"}, {"Stereo1 ADC R2 Mux", "DD MIX", "DD MIXR"}, {"Stereo2 ADC L2 Mux", "DMIC L", "DMIC L1"}, {"Stereo2 ADC L2 Mux", "DD MIXL", "DD MIXL"}, {"Stereo2 ADC L1 Mux", "DD MIXL", "DD MIXL"}, {"Stereo2 ADC L1 Mux", "ADCL", "ADC L"}, {"Stereo2 ADC R1 Mux", "DD MIXR", "DD MIXR"}, {"Stereo2 ADC R1 Mux", "ADCR", "ADC R"}, {"Stereo2 ADC R2 Mux", "DMIC R", "DMIC R1"}, {"Stereo2 ADC R2 Mux", "DD MIXR", "DD MIXR"}, {"Stereo1 ADC MIXL", "ADC1 Switch", "Stereo1 ADC L1 Mux"}, {"Stereo1 ADC MIXL", "ADC2 Switch", "Stereo1 ADC L2 Mux"}, {"Stereo1 ADC MIXL", NULL, "Stereo1 Filter"}, {"Stereo1 Filter", NULL, "ADC ASRC"}, {"Stereo1 ADC MIXR", "ADC1 Switch", "Stereo1 ADC R1 Mux"}, {"Stereo1 ADC MIXR", "ADC2 Switch", "Stereo1 ADC R2 Mux"}, {"Stereo1 ADC MIXR", NULL, "Stereo1 Filter"}, {"Stereo2 ADC MIXL", "ADC1 Switch", "Stereo2 ADC L1 Mux"}, {"Stereo2 ADC MIXL", "ADC2 Switch", "Stereo2 ADC L2 Mux"}, {"Stereo2 ADC MIXL", NULL, "Stereo2 Filter"}, {"Stereo2 Filter", NULL, "ADC ASRC"}, {"Stereo2 ADC MIXR", "ADC1 Switch", "Stereo2 ADC R1 Mux"}, {"Stereo2 ADC MIXR", "ADC2 Switch", "Stereo2 ADC R2 Mux"}, {"Stereo2 ADC MIXR", NULL, "Stereo2 Filter"}, {"IF1 ADC2", NULL, "Stereo2 ADC MIXL"}, {"IF1 ADC2", NULL, "Stereo2 ADC MIXR"}, {"IF1 ADC1", NULL, "Stereo1 ADC MIXL"}, {"IF1 ADC1", NULL, "Stereo1 ADC MIXR"}, {"IF1 ADC1", NULL, "I2S1"}, {"IF2 ADC", "IF1 ADC1", "IF1 ADC1"}, {"IF2 ADC", "IF1 ADC2", "IF1 ADC2"}, {"IF2 ADC", NULL, "I2S2"}, {"AIF1TX", NULL, "IF1 ADC1"}, {"AIF1TX", NULL, "IF1 ADC2"}, {"AIF2TX", NULL, "IF2 ADC"}, {"IF1 DAC", NULL, "AIF1RX"}, {"IF1 DAC", NULL, "I2S1"}, {"IF2 DAC", NULL, "AIF2RX"}, {"IF2 DAC", NULL, "I2S2"}, {"IF1 DAC1 L", NULL, "IF1 DAC"}, {"IF1 DAC1 R", NULL, "IF1 DAC"}, {"IF1 DAC2 L", NULL, "IF1 DAC"}, {"IF1 DAC2 R", NULL, "IF1 DAC"}, {"IF2 DAC L", NULL, "IF2 DAC"}, {"IF2 DAC R", NULL, "IF2 DAC"}, {"DAC MIXL", "Stereo ADC Switch", "Stereo1 ADC MIXL"}, {"DAC MIXL", "INF1 Switch", "IF1 DAC1 L"}, {"DAC MIXR", "Stereo ADC Switch", "Stereo1 ADC MIXR"}, {"DAC MIXR", "INF1 Switch", "IF1 DAC1 R"}, {"Audio DSP", NULL, "DAC MIXL"}, {"Audio DSP", NULL, "DAC MIXR"}, {"DAC L2 Mux", "IF1", "IF1 DAC2 L"}, {"DAC L2 Mux", "IF2", "IF2 DAC L"}, {"DAC L2 Volume", NULL, "DAC L2 Mux"}, {"DAC R2 Mux", "IF1", "IF1 DAC2 R"}, {"DAC R2 Mux", "IF2", "IF2 DAC R"}, {"DAC R2 Volume", NULL, "DAC R2 Mux"}, {"Stereo DAC MIXL", "DAC L1 Switch", "Audio DSP"}, {"Stereo DAC MIXL", "DAC L2 Switch", "DAC L2 Volume"}, {"Stereo DAC MIXL", "DAC R1 Switch", "DAC MIXR"}, {"Stereo DAC MIXL", NULL, "Stero1 DAC Power"}, {"Stereo DAC MIXL", NULL, "Stero2 DAC Power"}, {"Stereo DAC MIXR", "DAC R1 Switch", "Audio DSP"}, {"Stereo DAC MIXR", "DAC R2 Switch", "DAC R2 Volume"}, {"Stereo DAC MIXR", "DAC L1 Switch", "DAC MIXL"}, {"Stereo DAC MIXR", NULL, "Stero1 DAC Power"}, {"Stereo DAC MIXR", NULL, "Stero2 DAC Power"}, {"PDM L Mux", "Stereo DAC MIX", "Stereo DAC MIXL"}, {"PDM L Mux", "DD MIX", "DAC MIXL"}, {"PDM R Mux", "Stereo DAC MIX", "Stereo DAC MIXR"}, {"PDM R Mux", "DD MIX", "DAC MIXR"}, {"DAC L1", NULL, "Stereo DAC MIXL"}, {"DAC L1", NULL, "DAC L1 Power"}, {"DAC R1", NULL, "Stereo DAC MIXR"}, {"DAC R1", NULL, "DAC R1 Power"}, {"DD MIXL", "DAC L1 Switch", "DAC MIXL"}, {"DD MIXL", "DAC L2 Switch", "DAC L2 Volume"}, {"DD MIXL", "DAC R2 Switch", "DAC R2 Volume"}, {"DD MIXL", NULL, "Stero2 DAC Power"}, {"DD MIXR", "DAC R1 Switch", "DAC MIXR"}, {"DD MIXR", "DAC R2 Switch", "DAC R2 Volume"}, {"DD MIXR", "DAC L2 Switch", "DAC L2 Volume"}, {"DD MIXR", NULL, "Stero2 DAC Power"}, {"OUT MIXL", "BST1 Switch", "BST1"}, {"OUT MIXL", "BST2 Switch", "BST2"}, {"OUT MIXL", "INL1 Switch", "INL1 VOL"}, {"OUT MIXL", "REC MIXL Switch", "RECMIXL"}, {"OUT MIXL", "DAC L1 Switch", "DAC L1"}, {"OUT MIXR", "BST2 Switch", "BST2"}, {"OUT MIXR", "BST1 Switch", "BST1"}, {"OUT MIXR", "INR1 Switch", "INR1 VOL"}, {"OUT MIXR", "REC MIXR Switch", "RECMIXR"}, {"OUT MIXR", "DAC R1 Switch", "DAC R1"}, {"HPOVOL L", "Switch", "OUT MIXL"}, {"HPOVOL R", "Switch", "OUT MIXR"}, {"OUTVOL L", "Switch", "OUT MIXL"}, {"OUTVOL R", "Switch", "OUT MIXR"}, {"HPOL MIX", "HPO MIX DAC1 Switch", "DAC L1"}, {"HPOL MIX", "HPO MIX HPVOL Switch", "HPOVOL L"}, {"HPOL MIX", NULL, "HP L Amp"}, {"HPOR MIX", "HPO MIX DAC1 Switch", "DAC R1"}, {"HPOR MIX", "HPO MIX HPVOL Switch", "HPOVOL R"}, {"HPOR MIX", NULL, "HP R Amp"}, {"LOUT MIX", "DAC L1 Switch", "DAC L1"}, {"LOUT MIX", "DAC R1 Switch", "DAC R1"}, {"LOUT MIX", "OUTVOL L Switch", "OUTVOL L"}, {"LOUT MIX", "OUTVOL R Switch", "OUTVOL R"}, {"HP Amp", NULL, "HPOL MIX"}, {"HP Amp", NULL, "HPOR MIX"}, {"HP Amp", NULL, "Amp Power"}, {"HPO L Playback", "Switch", "HP Amp"}, {"HPO R Playback", "Switch", "HP Amp"}, {"HPOL", NULL, "HPO L Playback"}, {"HPOR", NULL, "HPO R Playback"}, {"LOUT L Playback", "Switch", "LOUT MIX"}, {"LOUT R Playback", "Switch", "LOUT MIX"}, {"LOUTL", NULL, "LOUT L Playback"}, {"LOUTL", NULL, "Amp Power"}, {"LOUTR", NULL, "LOUT R Playback"}, {"LOUTR", NULL, "Amp Power"}, {"PDML", NULL, "PDM L Mux"}, {"PDMR", NULL, "PDM R Mux"}, };
在rt5651_dapm_widgets中我们可以找到位于多媒体音频播放右声道路径上的route；
{"IF1 DAC", NULL, "AIF1RX"},
{"IF1 DAC1 R", NULL, "IF1 DAC"},
{"DAC MIXR", "INF1 Switch", "IF1 DAC1 R"},
{"Audio DSP", NULL, "DAC MIXR"},
{"Stereo DAC MIXR", "DAC R1 Switch", "Audio DSP"},
{"DAC R1", NULL, "Stereo DAC MIXR"},
{"OUT MIXR", "DAC R1 Switch", "DAC R1"}
{"HPOVOL R", "Switch", "OUT MIXR"},
{"HPOR MIX", "HPO MIX HPVOL Switch", "HPOVOL R"},
{"HP Amp", NULL, "HPOR MIX"},
{"HPO R Playback", "Switch", "HP Amp"},
{"HPOR", NULL, "HPO R Playback"},
左声道：
{"IF1 DAC", NULL, "AIF1RX"},
{"IF1 DAC1 L", NULL, "IF1 DAC"},
{"DAC MIXL", "INF1 Switch", "IF1 DAC1 L"},
{"Audio DSP", NULL, "DAC MIXL"},
{"Stereo DAC MIXL", "DAC L1 Switch", "Audio DSP"},
{"DAC L1", NULL, "Stereo DAC MIXL"},
{"OUT MIXL", "DAC L1 Switch", "DAC L1"}
{"HPOVOL L", "Switch", "OUT MIXL"},
{"HPOL MIX", "HPO MIX HPVOL Switch", "HPOVOL L"},
{"HP Amp", NULL, "HPOL MIX"},
{"HPO L Playback", "Switch", "HP Amp"},
{"HPOL", NULL, "HPO L Playback"},
三个参数分别为sink、control、source，比如：
{"DAC MIXL", "INF1 Switch", "IF1 DAC1 L"}
输入端的widget名称为IF1 DAC1 L，输出端的widget名称为DAC MIXL，名称为INF1 Switch的kcontrol用于控制这两个widget之间连接的通断（需要注意的是该kcontrol位于输出端的kcontrol中）；
// 输入端widget SND_SOC_DAPM_PGA("IF1 DAC1 L", SND_SOC_NOPM, 0, 0, NULL, 0); // 寄存器设置为SND_SOC_NOPM，表示没有寄存器可以控制该widget的上下电 // 输出端widget SND_SOC_DAPM_MIXER("DAC MIXL", SND_SOC_NOPM, 0, 0, // 寄存器设置为SND_SOC_NOPM，表示没有寄存器可以控制该widget的上下电 rt5651_dac_l_mix, ARRAY_SIZE(rt5651_dac_l_mix)); // Left DAC Mixer包含2个kcontrol，每个kcontrol控制着Mixer的一个输入端的开启和关闭 // 输出端widget关联的kcontrol static const struct snd_kcontrol_new rt5651_dac_l_mix[] = { SOC_DAPM_SINGLE("Stereo ADC Switch", RT5651_AD_DA_MIXER, // 寄存器配置为RT5651_AD_DA_MIXER=0x29，偏移位配置为15 RT5651_M_ADCMIX_L_SFT, 1, 1), SOC_DAPM_SINGLE("INF1 Switch", RT5651_AD_DA_MIXER, // 寄存器配置为RT5651_AD_DA_MIXER=0x29，偏移位配置为14 RT5651_M_IF1_DAC_L_SFT, 1, 1), };
4.2 rt5651_probe
rt5651_probe函数在sound/soc/codecs/rt5651.c中定义：
static int rt5651_probe(struct snd_soc_component *component) { struct rt5651_priv *rt5651 = snd_soc_component_get_drvdata(component); // 取出component->dev设备的driver_data，就是上面介绍的rt5651结构变量 rt5651->component = component; // 设置cpmponent snd_soc_component_update_bits(component, RT5651_PWR_ANLG1, // 向寄存器写入值，RT5651_PWR_ANLG1的值为0x63，寄存器地址0x63用于电源控制寄存器3 RT5651_PWR_LDO_DVO_MASK, RT5651_PWR_LDO_DVO_1_2V); // RT5651_PWR_LDO_DVO_MASK值为0x03 RT5651_PWR_LDO_DVO_1_2V值为2 因此这里向位[1:0]写入10'b // 即配置LDO output电压为1.2V snd_soc_component_force_bias_level(component, SND_SOC_BIAS_OFF); // Set the COMPONENT DAPM bias level，即dapm->bias_level=0 rt5651_apply_properties(component); return 0; }
snd_soc_component_update_bits函数定义在sound/soc/soc-component.c， 用于进行i2c控制传输，向i2c从设备指定寄存器地址写入值；
static int snd_soc_component_update_bits_legacy( struct snd_soc_component *component, unsigned int reg, unsigned int mask, unsigned int val, bool *change) // mask描述的是需要更改的位 { unsigned int old, new; int ret = 0; mutex_lock(&component->io_mutex); old = soc_component_read_no_lock(component, reg); // 读取寄存器的值 new = (old & ~mask) | (val & mask); // 计算新的值 *change = old != new; // 判断旧值和新值是否一样 if (*change) // 如果发生改变，则写入新的值 ret = soc_component_write_no_lock(component, reg, new); mutex_unlock(&component->io_mutex); return soc_component_ret_reg_rw(component, ret, reg); } /** * snd_soc_component_update_bits() - Perform read/modify/write cycle * @component: Component to update * @reg: Register to update * @mask: Mask that specifies which bits to update * @val: New value for the bits specified by mask * * Return: 1 if the operation was successful and the value of the register * changed, 0 if the operation was successful, but the value did not change. * Returns a negative error code otherwise. */ int snd_soc_component_update_bits(struct snd_soc_component *component, unsigned int reg, unsigned int mask, unsigned int val) { bool change; int ret; if (component->regmap) // 走这里 // 当前使用regmap，调用regmap接口，其中component->regmap是regmap私有数据 ret = regmap_update_bits_check(component->regmap, reg, mask, val, &change); else ret = snd_soc_component_update_bits_legacy(component, reg, mask, val, &change); if (ret < 0) return soc_component_ret_reg_rw(component, ret, reg); return change; }
4.3 set_bias_level
set_bias_level用于设置codec域的偏置电压，那什么是偏置电压呢？在电容式麦克风中，为了使麦克风的工作点稳定，需要加一个直流电压，这个直流电压就是偏置电压，偏置电压的作用主要有以下几个方面：
- 稳定麦克风的工作点；在没有偏置电压的情况下，麦克风的输出信号会受到温度、湿度等环境因素的影响，导致输出信号的偏移，而偏置电压可以保持麦克风的工作不变，保证输出信号的稳定性；
- 提高麦克风的灵敏度，偏置电压可以使麦克风的灵敏度增加，从而提高声音的捕获能力；
- 降低麦克风的噪声；偏移电压可以降低麦克风的噪声水平，使得麦克风的输出信号更清晰；
对于ALC5651芯片MICBIAS1引脚会输出一个偏置电压，提供给外置麦克风；
set_bias_level函数会被dapm_power_widgets函数调用，这里被设置为了rt5651_set_bias_level。set_bias_level函数在sound/soc/codecs/rt5651.c中定义：
static int rt5651_set_bias_level(struct snd_soc_component *component, enum snd_soc_bias_level level) { switch (level) { case SND_SOC_BIAS_PREPARE: // 准备状态 // 获取dapm->bias_level，待机->准备 if (SND_SOC_BIAS_STANDBY == snd_soc_component_get_bias_level(component)) { // RT5651_PLL_MODE_1的值为0x83，寄存器0x83为ASRC控制寄存器，这里是判断位[15]、[12]、[9]是否为1 // 其中位[15]为I2S1模式选择控制 0：正常模式 1：ASRC模式 // 位[12]为I2S2模式选择控制 0：正常模式 1：ASRC模式 // 位[9] Select Control for ASRC Mode in DMIC1 Function 0：正常模式 1：ASRC模式 if (snd_soc_component_read(component, RT5651_PLL_MODE_1) & 0x9200) // RT5651_D_MISC的值为0xFA，寄存器地址0xFA为基本控制寄存器 snd_soc_component_update_bits(component, RT5651_D_MISC, 0xc00, 0xc00); // 这里向位[11:10]写入11'b，芯片手册中并没有描述这两位有什么作用 } break; case SND_SOC_BIAS_STANDBY: // 待机状态 // 获取dapm->bias_level，关闭状态->待机状态 if (SND_SOC_BIAS_OFF == snd_soc_component_get_bias_level(component)) { // RT5651_PWR_ANLG1的值为0x63，寄存器地址0x63用于电源控制寄存器3 snd_soc_component_update_bits(component, RT5651_PWR_ANLG1, // RT5651_PWR_VREF1位[15]，VREF1 Power Control：0下电、1上电 // RT5651_PWR_MB位[13]，MBIAS Power Control：0下电、1上电 // RT5651_PWR_BG位[11]，MBIAS Bandgap Power Control：0下电、1上电 // RT5651_PWR_VREF2位[4]，VREF2 Power Control：0下电、1上电 RT5651_PWR_VREF1 | RT5651_PWR_MB | RT5651_PWR_BG | RT5651_PWR_VREF2, RT5651_PWR_VREF1 | RT5651_PWR_MB | RT5651_PWR_BG | RT5651_PWR_VREF2); usleep_range(10000, 15000); // RT5651_PWR_FV1位[14]，VREF1 Fast Mode Control：0 Fast VREF、1 Slow VREF, (For good analog performance) // RT5651_PWR_FV2位[0]，VREF2 Fast Mode Control：0 Fast VREF、1 Slow VREF, (For good analog performance) snd_soc_component_update_bits(component, RT5651_PWR_ANLG1, RT5651_PWR_FV1 | RT5651_PWR_FV2, RT5651_PWR_FV1 | RT5651_PWR_FV2); // RT5651_D_MISC的值为0xFA，寄存器地址0xFA为基本控制寄存器,芯片手册中并没有描述位[1]有什么作用 snd_soc_component_update_bits(component, RT5651_D_MISC, 0x1, 0x1); } break; case SND_SOC_BIAS_OFF: // 关闭状态 snd_soc_component_write(component, RT5651_D_MISC, 0x0010); snd_soc_component_write(component, RT5651_PWR_DIG1, 0x0000); snd_soc_component_write(component, RT5651_PWR_DIG2, 0x0000); snd_soc_component_write(component, RT5651_PWR_VOL, 0x0000); snd_soc_component_write(component, RT5651_PWR_MIXER, 0x0000); /* Do not touch the LDO voltage select bits on bias-off */ snd_soc_component_update_bits(component, RT5651_PWR_ANLG1, ~RT5651_PWR_LDO_DVO_MASK, 0); /* Leave PLL1 and jack-detect power as is, all others off */ snd_soc_component_update_bits(component, RT5651_PWR_ANLG2, ~(RT5651_PWR_PLL | RT5651_PWR_JD_M), 0); break; default: break; } return 0; }
这里寄存器配置有点看不懂，在datasheet中有些寄存器的位描述并没有找到，有兴趣自行研究吧。
4.4 set_jack
set_jack用于设置ACL5651的jack，这里被设置为了rt5651_set_jack，函数在sound/soc/codecs/rt5651.c中定义：
static int rt5651_set_jack(struct snd_soc_component *component, struct snd_soc_jack *jack, void *data) { if (jack) rt5651_enable_jack_detect(component, jack, data); else rt5651_disable_jack_detect(component); return 0; }
在ASoC中使用struct snd_soc_jack来描述jack，并提供了对其状态、引脚等进行管理和通知的功能。这里如何定义了jack，将会调用rt5651_enable_jack_detect，用于实现麦克风插入/拔出的检测。
4.4.1 麦克风检测
我大概说一下ALC5651麦克风插入/拔出的检测原理，ACL5651支持对sta_gpio_jd、、sta_jd1_1、sta_jd1_2、sta_jd2、sta_micbias1_ovcd的的检测（JD英文为jack dection），具体如下：
这里以sta_jd1_1、sta_jd1_2、sta_jd2为例，分别连接ALC5651的JD1、JD2引脚，用于三路麦克风1的检测；
一般情况下，IRQ输出需要与JD功能结合使用。当 JD被触发时，IRQ会向主机输出一个标志，通知软件驱动程序。软件驱动程序将根据系统设计执行相应的操作。以下是流程图：
Jack dection功能可用于打开或关闭相关的输出端口。当插孔检测引脚被触发时，选择的输出端口将打开或关闭。例如，在HP（耳机）和LOUT（扬声器）自动切换功能中，当JD被触发时会进行自动切换。
设置步骤如下：
- 选择JD触发源：将sta_jd1_1作为JD状态。MX-BC[11:9] = 001’b；
- 000’b: From sta_gpio_jd；
- 001’b: From sta_jd1_1；
- 010’b: From sta_jd1_2；
- 011’b: From sta_jd2；
- Others: Reserved；
- 根据JD的激活状态设置目标行为：当JD被触发时，进行HP和LOUT的自动切换。 MX-BB[11:10] = 11’b & MX-BB[3:2] = 10’b；
- 位[11]：Enable Jack Detect Trigger HPOUT，0：禁止，1：使能；
- 位[10]：Select Jack Detect Polarity Trigger HPOUT，0：低电平触发，1：高平触发；
- 位[3]：Enable Jack Detect Trigger LOUT，0：禁止，1：使能；
- 位[2]：Select Jack Detect Polarity Trigger LOUT：0：低电平触发，1：高平触发；
- 当JD状态为低电平时，HP_OUT（耳机输出）将静音，LOUT（扬声器输出）将恢复正常声音。 当JD状态由低电平变为高电平时，HP将恢复正常声音，LOUT将静音。
注意：对于HP和SPK插孔切换功能，驱动程序需要先打开DAC通往HP路径的通路和DAC通往LOUT路径的通路。MX-BB的寄存器控制仅用于对HP和SPK进行静音/取消静音功能。
当我们移植完了声卡驱动，并通过开发板ubuntu系统进行音频播放的时候，我特意查看了一下0xBB、0xBC寄存器的值：
- 0xBB：Jack Dection控制寄存器1，值为0x00；
- 0xBC：Jack Dection控制寄存器2，值为0x00.
4.4.2 rt5651_enable_jack_detect
函数rt5651_enable_jack_detect定义如下，这里我们就不分析了：
static void rt5651_enable_jack_detect(struct snd_soc_component *component, struct snd_soc_jack *hp_jack, struct gpio_desc *gpiod_hp_det) { struct rt5651_priv *rt5651 = snd_soc_component_get_drvdata(component); bool using_internal_jack_detect = true; /* Select jack detect source */ switch (rt5651->jd_src) { case RT5651_JD_NULL: rt5651->gpiod_hp_det = gpiod_hp_det; if (!rt5651->gpiod_hp_det) return; /* No jack detect */ using_internal_jack_detect = false; break; case RT5651_JD1_1: snd_soc_component_update_bits(component, RT5651_JD_CTRL2, // RT5651_JD_CTRL2值为0xBC RT5651_JD_TRG_SEL_MASK, RT5651_JD_TRG_SEL_JD1_1); /* active-low is normal, set inv flag for active-high */ if (rt5651->jd_active_high) snd_soc_component_update_bits(component, RT5651_IRQ_CTRL1, // RT5651_JD_CTRL1值为0xBB RT5651_JD1_1_IRQ_EN | RT5651_JD1_1_INV, RT5651_JD1_1_IRQ_EN | RT5651_JD1_1_INV); else snd_soc_component_update_bits(component, RT5651_IRQ_CTRL1, RT5651_JD1_1_IRQ_EN | RT5651_JD1_1_INV, RT5651_JD1_1_IRQ_EN); break; case RT5651_JD1_2: snd_soc_component_update_bits(component, RT5651_JD_CTRL2, RT5651_JD_TRG_SEL_MASK, RT5651_JD_TRG_SEL_JD1_2); /* active-low is normal, set inv flag for active-high */ if (rt5651->jd_active_high) snd_soc_component_update_bits(component, RT5651_IRQ_CTRL1, RT5651_JD1_2_IRQ_EN | RT5651_JD1_2_INV, RT5651_JD1_2_IRQ_EN | RT5651_JD1_2_INV); else snd_soc_component_update_bits(component, RT5651_IRQ_CTRL1, RT5651_JD1_2_IRQ_EN | RT5651_JD1_2_INV, RT5651_JD1_2_IRQ_EN); break; case RT5651_JD2: snd_soc_component_update_bits(component, RT5651_JD_CTRL2, RT5651_JD_TRG_SEL_MASK, RT5651_JD_TRG_SEL_JD2); /* active-low is normal, set inv flag for active-high */ if (rt5651->jd_active_high) snd_soc_component_update_bits(component, RT5651_IRQ_CTRL1, RT5651_JD2_IRQ_EN | RT5651_JD2_INV, RT5651_JD2_IRQ_EN | RT5651_JD2_INV); else snd_soc_component_update_bits(component, RT5651_IRQ_CTRL1, RT5651_JD2_IRQ_EN | RT5651_JD2_INV, RT5651_JD2_IRQ_EN); break; default: dev_err(component->dev, "Currently only JD1_1 / JD1_2 / JD2 are supported\n"); return; } if (using_internal_jack_detect) { /* IRQ output on GPIO1 */ snd_soc_component_update_bits(component, RT5651_GPIO_CTRL1, RT5651_GP1_PIN_MASK, RT5651_GP1_PIN_IRQ); /* Enable jack detect power */ snd_soc_component_update_bits(component, RT5651_PWR_ANLG2, RT5651_PWR_JD_M, RT5651_PWR_JD_M); } /* Set OVCD threshold current and scale-factor */ snd_soc_component_write(component, RT5651_PR_BASE + RT5651_BIAS_CUR4, 0xa800 | rt5651->ovcd_sf); snd_soc_component_update_bits(component, RT5651_MICBIAS, RT5651_MIC1_OVCD_MASK | RT5651_MIC1_OVTH_MASK | RT5651_PWR_CLK12M_MASK | RT5651_PWR_MB_MASK, RT5651_MIC1_OVCD_EN | rt5651->ovcd_th | RT5651_PWR_MB_PU | RT5651_PWR_CLK12M_PU); /* * The over-current-detect is only reliable in detecting the absence * of over-current, when the mic-contact in the jack is short-circuited, * the hardware periodically retries if it can apply the bias-current * leading to the ovcd status flip-flopping 1-0-1 with it being 0 about * 10% of the time, as we poll the ovcd status bit we might hit that * 10%, so we enable sticky mode and when checking OVCD we clear the * status, msleep() a bit and then check to get a reliable reading. */ snd_soc_component_update_bits(component, RT5651_IRQ_CTRL2, RT5651_MB1_OC_STKY_MASK, RT5651_MB1_OC_STKY_EN); rt5651->hp_jack = hp_jack; if (rt5651_support_button_press(rt5651)) { rt5651_enable_micbias1_for_ovcd(component); rt5651_enable_micbias1_ovcd_irq(component); } enable_irq(rt5651->irq); // 使能中断，在设备树中我们并没有配置该项，如果配置了可以用来检测检测麦克风的插入/拔出 /* sync initial jack state */ queue_work(system_power_efficient_wq, &rt5651->jack_detect_work); }
五、rt5651_dai
由于ALC5651有两组I2S接口，可以同时用于耳机输出以及Line output；RK3399与ALC5651连线如下：
**************** ***********
* * * <------ * <---- MIC
RAM <--------PCM-> * <----------> * <-I2S------------I2S1-> * *
* * | * ------> * ----> Line output
**************** | * *
RK3399 | * *
-----I2S2-> * ------> * ----> HEADPHONE
***********
ALC5651
codec dai和pcm配置信息通过结构体snd_soc_dai_driver描述，包括了dai的能力描述和操作接口；devm_snd_soc_register_component函数第三个参数为rt5651_dai，数组中长度为2，分别与ALC5651的两组I2S接口一一对应；
static struct snd_soc_dai_driver rt5651_dai[] = { { .name = "rt5651-aif1", // dai的名称，会赋值给与其关联的snd_soc_dai的name成员
// 音频数据链路是通过dai_name到ALC5651的component的dai_list链表中来查找dai的
.id = RT5651_AIF1, // 0，dai的id .playback = { // 声卡注册的时候会为其创建一个类型为snd_soc_dapm_dai_in的playback dai widget，其name以及sname均设置为"AIF1 Playback" .stream_name = "AIF1 Playback", .channels_min = 1, // 最小通道数 .channels_max = 2, // 最大通道数 .rates = RT5651_STEREO_RATES, .formats = RT5651_FORMATS, }, .capture = { // 声卡注册的时候会为其创建一个类型为snd_soc_dapm_dai_out的capture dai widget，其name以及sname均设置为"AIF1 Capture" .stream_name = "AIF1 Capture", .channels_min = 1, .channels_max = 2, .rates = RT5651_STEREO_RATES, // 支持的采样率 SNDRV_PCM_RATE_8000_96000 999~96000之间 .formats = RT5651_FORMATS, // 支持的位深度 (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S20_3LE | SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S8) }, .ops = &rt5651_aif_dai_ops, }, { .name = "rt5651-aif2", .id = RT5651_AIF2, // 1，dai的id .playback = { .stream_name = "AIF2 Playback", .channels_min = 1, .channels_max = 2, .rates = RT5651_STEREO_RATES, .formats = RT5651_FORMATS, }, .capture = { .stream_name = "AIF2 Capture", .channels_min = 1, .channels_max = 2, .rates = RT5651_STEREO_RATES, .formats = RT5651_FORMATS, }, .ops = &rt5651_aif_dai_ops, }, };
其中：
- name：codec dai的名称标识，dai_link通过配置codec dai_name来找到对应的codec dai；
- capture：描述capture的能力；如回放设备所支持的声道数、采样率、音频格式；非常重要的字段；
- playback：描述playback的能力；如录制设备所支持声道数、采样率、音频格式；非常重要的字段；
- ops：codec dai的操作函数集，这些函数集非常重要，用于dai的时钟配置、格式配置、硬件参数配置。
在注册ASoC声卡的时候，会调用soc_probe_link_components，每一个dai创建两个音频数据流的widget，以名字为 rt5651-aif1的dai为例：
- 一个是类型为snd_soc_dapm_dai_in名称为AIF1 Playback的播放流widget；
- 另一个是类型为snd_soc_dapm_dai_out名称为AIF1 Capture的录音流widget；
同时也会为构造以播放流widget作为输入端的路径，其连接sname为"AIF1 Playback"的widget；在rt5651_dapm_widgets数组中可以定位名字为AIF1RX的widge其sname与之匹配；
SND_SOC_DAPM_AIF_IN("AIF1RX", "AIF1 Playback", 0, SND_SOC_NOPM, 0, 0)
同时也会构造以录音流widget作为输出端的路径，其输入端连接sname为"AIF1 Capture"的widget；在rt5651_dapm_widgets数组中可以定位名字为AIF1RX的widge其sname与之匹配；
SND_SOC_DAPM_AIF_OUT("AIF1TX", "AIF1 Capture", 0, SND_SOC_NOPM, 0, 0)
此时我们就可以得到一个从dai widget作为输入端的路径：AIF1 Playback --> AIF1RX --> IF1 DAC --> IF1 DAC1 L .... -->HPO L Playback --> HPOL --> Headphones 。
5.1 rt5651_aif_dai_ops
音频操作接口通过结构体struct snd_soc_dai_ops描述：
static const struct snd_soc_dai_ops rt5651_aif_dai_ops = { .hw_params = rt5651_hw_params, .set_fmt = rt5651_set_dai_fmt, .set_sysclk = rt5651_set_dai_sysclk, .set_pll = rt5651_set_dai_pll, };
其中：
- set_sysclk：用于设置系统时钟，对于codec dai来说系统时钟指的是ALC5651 i2s1接口的MCLK信号线输入的时钟，同时也是RK3399 i2s0接口的MCLK信号线输出的时钟（对应的时钟名称为clk_i2sout）；当上层打开pcm设备时，需要回调该接口设置ALC5651的系统时钟，ALC5651才能正常工作；
- set_pll：用于设置ALC5651的PLL的分频系数，ALC5651一般接了一个MCLK作为ALC5651的PLL输入时钟源，回调该函数基于MCLK来产生ALC5651 PLL时钟；
- set_fmt：设置数字音频接口格式，具体见 include/sound/soc-dai.h；
- SND_SOC_DAIFMT_I2S：数字音频接口是I2S格式，常用于多媒体音频；
- SND_SOC_DAIFMT_RIGHT_J：数字音频接口是I2S右对齐格式；
- SND_SOC_DAIFMT_LEFT_J：数字音频接口是I2S左对齐格式；
- SND_SOC_DAIFMT_DSP_A：数字音频接口是PCM格式，常用于语音通话；
- SND_SOC_DAIFMT_DSP_B：数字音频接口是PCM格式，常用于语音通话；
- SND_SOC_DAIFMT_CBM_CFM：ALC5651作为主机，BCLK 和 LRCLK由ALC5651提供；
- SND_SOC_DAIFMT_CBS_CFS：ALC5651作为从机，BCLK和LRCLK由SoC/CPU提供；
- .......
- hw_params：codec dai硬件参数设置，根据上层设定的声道数、采样率、数据格式，来配置codec dai相关寄存器；
5.2 时钟
ALC5651的系统时钟（指的是下图MX80[15:14]寄存器控制的Mux的输出时钟）可以从MCLK和PLL中选择，MCLK时钟由外部时钟源提供，而PLL的参考时钟可以从MCLK、BCLK1/2。
5.2.1 set_sysclk
ALC5651音频操作接口set_sysclk函数用于设置系统时钟，set_sysclk被设置为rt5651_set_dai_sysclk，定义在sound/soc/codecs/rt5651.c：
static int rt5651_set_dai_sysclk(struct snd_soc_dai *dai, int clk_id, unsigned int freq, int dir) // clk_id传入的0，dir也是传入的0，freq传入的是系统时钟频率 { struct snd_soc_component *component = dai->component; // 取出component->dev设备的driver_data，就是上面介绍的rt5651结构变量 struct rt5651_priv *rt5651 = snd_soc_component_get_drvdata(component); unsigned int reg_val = 0; unsigned int pll_bit = 0; if (freq == rt5651->sysclk && clk_id == rt5651->sysclk_src) // 如果已经配置，直接返回 return 0; switch (clk_id) { // 系统时钟时钟源 MCLK、PLL case RT5651_SCLK_S_MCLK: // 0 走这里 reg_val |= RT5651_SCLK_SRC_MCLK; // 0<<14 break; case RT5651_SCLK_S_PLL1: // 1 reg_val |= RT5651_SCLK_SRC_PLL1; // 1<<14 pll_bit |= RT5651_PWR_PLL; // 1<<9 break; case RT5651_SCLK_S_RCCLK: // 2 reg_val |= RT5651_SCLK_SRC_RCCLK; // 2<<14 break; default: dev_err(component->dev, "Invalid clock id (%d)\n", clk_id); return -EINVAL; } // 向寄存器写入值，RT5651_PWR_ANLG2的值为0x64，寄存器地址0x64用于电源控制寄存器4; // RT5651_PWR_LDO_DVO_MASK值为1<<9，因此这里向位[9]写入0/1，即PLL下电/上电 snd_soc_component_update_bits(component, RT5651_PWR_ANLG2, RT5651_PWR_PLL, pll_bit); // 向寄存器写入值，RT5651_GLB_CLK的值为0x80，寄存器地址0x84全局时钟控制 // RT5651_SCLK_SRC_MASK值为3<<14，因此这里向位[15:14]写入reg_val snd_soc_component_update_bits(component, RT5651_GLB_CLK, RT5651_SCLK_SRC_MASK, reg_val); rt5651->sysclk = freq; // 设置系统时钟频率 rt5651->sysclk_src = clk_id; // 设置系统时钟时钟源 dev_dbg(dai->dev, "Sysclk is %dHz and clock id is %d\n", freq, clk_id); return 0; }
该函数主要是用来配置ALC5651系统时钟，通过配置ALC5651相关寄存器来实现：
- RT5651_PWR_ANLG2：电源控制寄存器4，寄存器地址为0x64，位[9]用来进行PLL Power Control（0：PLL Power Down、1：PLL Power Up）；
- RT5651_GLB_CLK：全局时钟控制寄存器，寄存器地址为0x80，位[15:14]用来进行System Clock Source MUX Control（00'b：MCLK、01'b：PLL、10'b：保留、11'b：保留）；
因此我们可以得出结论：
- 如果配置系统时钟时钟源rt5651->sysclk_src为MCLK，则配置PLL下电；此时PLL禁用，系统时钟频率则为外部输入的MCLK的时钟频率；
- 如果配置系统时钟时钟源rt5651->sysclk_src为PLL，则配置PLL上电；此时PLL使能，因此可以根据系统时钟频率动态计算PLL分频系数，并通过set_pll设置PLL分频系数；
当我们移植完了声卡驱动，并通过开发板ubuntu系统进行音频播放的时候，我特意查看了一下0x64、0x80寄存器的值：
- 0x64：寄存器值为0x00，表明PLL处于禁用状态；
- 0x80：寄存器值为0x00，表明ALC5651系统时钟时钟源选择为MCLK；
5.2.2 set_pll
如果我们在set_sysclk中设置了系统时钟类型rt5651->sysclk_src为PLL，则需要通过ALC5651音频操作接口set_pll函数设置PLL分频系数，set_pll被设置为rt5651_set_dai_pll，定义在sound/soc/codecs/rt5651.c：
函数由若干个参数，其中：
- source：PLL的输入时钟源类型，可以是MCLK、BCLK1、BLCK2中任意一个；一般设置为MCLK；
- freq_in：为PLL输入时钟源的频率；
- freq_out：经过PLL分频后的输出频率；
函数源代码如下：
static int rt5651_set_dai_pll(struct snd_soc_dai *dai, int pll_id, int source, unsigned int freq_in, unsigned int freq_out) // 输入频率 -> 输出频率 { struct snd_soc_component *component = dai->component;
// 取出component->dev设备的driver_data，就是上面介绍的rt5651结构变量 struct rt5651_priv *rt5651 = snd_soc_component_get_drvdata(component); struct rl6231_pll_code pll_code; int ret; if (source == rt5651->pll_src && freq_in == rt5651->pll_in && // 如果已经配置，直接返回 freq_out == rt5651->pll_out) return 0; if (!freq_in || !freq_out) { // 如果PLL输入、或者输出时钟频率为0 dev_dbg(component->dev, "PLL disabled\n"); rt5651->pll_in = 0; rt5651->pll_out = 0; snd_soc_component_update_bits(component, RT5651_GLB_CLK, RT5651_SCLK_SRC_MASK, RT5651_SCLK_SRC_MCLK); return 0; } switch (source) { // 时钟类型 case RT5651_PLL1_S_MCLK: // 0 MCLK作为PLL的输入时钟源 snd_soc_component_update_bits(component, RT5651_GLB_CLK, // 配置MX80寄存器位[13:12]为00'b，PLL时钟源选择为MCLK RT5651_PLL1_SRC_MASK, RT5651_PLL1_SRC_MCLK); break; case RT5651_PLL1_S_BCLK1: // 1 snd_soc_component_update_bits(component, RT5651_GLB_CLK, // 配置MX80寄存器位[13:12]为01'b，PLL时钟源选择为BLCK1 RT5651_PLL1_SRC_MASK, RT5651_PLL1_SRC_BCLK1); break; case RT5651_PLL1_S_BCLK2: // 2 snd_soc_component_update_bits(component, RT5651_GLB_CLK, // 配置MX80寄存器位[13:12]为10'b，PLL时钟源选择为MCLK2 RT5651_PLL1_SRC_MASK, RT5651_PLL1_SRC_BCLK2); break; default: dev_err(component->dev, "Unknown PLL source %d\n", source); return -EINVAL; } ret = rl6231_pll_calc(freq_in, freq_out, &pll_code); // 根据输入、输出频率 计算pll_code if (ret < 0) { dev_err(component->dev, "Unsupported input clock %d\n", freq_in); return ret; } dev_dbg(component->dev, "bypass=%d m=%d n=%d k=%d\n", pll_code.m_bp, (pll_code.m_bp ? 0 : pll_code.m_code), pll_code.n_code, pll_code.k_code); snd_soc_component_write(component, RT5651_PLL_CTRL1, pll_code.n_code << RT5651_PLL_N_SFT | pll_code.k_code); // 配置N RT5651_PLL_N_SFT=7 snd_soc_component_write(component, RT5651_PLL_CTRL2, ((pll_code.m_bp ? 0 : pll_code.m_code) << RT5651_PLL_M_SFT) | // 配置M RT5651_PLL_M_SFT=12 (pll_code.m_bp << RT5651_PLL_M_BP_SFT)); // RT5651_PLL_M_BP_SFT=11 rt5651->pll_in = freq_in; // 保存配置 rt5651->pll_out = freq_out; rt5651->pll_src = source; return 0; }
AL5651 PLL控制寄存器有两个MX81：PLL控制寄存器1，MX82：PLL控制寄存器2；
PLL的输出频率计算公式如下：
$$$F_{OUT}=\frac{MCLK*(N+2)}{(M+2)*(K+2)} {典型的K=2} $
当输出时钟频率为44.1kHz：
rl6231_pll_calc函数是根据输入时钟频率、和输出时钟频率来计算N和M的，函数定义在sound/soc/codecs/rl6231.c，由于计算过程比较复杂，咱们就不研究了。
当我们移植完了声卡驱动，并通过开发板ubuntu系统进行音频播放的时候，我特意查看了一下0x81、0x82寄存器的值：
- 0x81：0x00，由于PLL被禁用了，因此配置PLL控制寄存器没啥意义了；
- 0x82：0x00，由于PLL被禁用了，因此配置PLL控制寄存器没啥意义了；
5.3 set_fmt
set_fmt用于设置ALC565数字音频接口格式，set_fmt被设置为rt5651_set_dai_fmt，定义在sound/soc/codecs/rt5651.c：
static int rt5651_set_dai_fmt(struct snd_soc_dai *dai, unsigned int fmt) { struct snd_soc_component *component = dai->component;
// 取出component->dev设备的driver_data，就是上面介绍的rt5651结构变量 struct rt5651_priv *rt5651 = snd_soc_component_get_drvdata(component); unsigned int reg_val = 0; switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) { // 0xf000 case SND_SOC_DAIFMT_CBM_CFM: // ALC5651作为主机 1<<12 rt5651->master[dai->id] = 1; break; case SND_SOC_DAIFMT_CBS_CFS: // ALC5651作为从机 4<<12 reg_val |= RT5651_I2S_MS_S; rt5651->master[dai->id] = 0; break; default: return -EINVAL; } switch (fmt & SND_SOC_DAIFMT_INV_MASK) { // BCLK极性配置 case SND_SOC_DAIFMT_NB_NF: break; case SND_SOC_DAIFMT_IB_NF: reg_val |= RT5651_I2S_BP_INV; break; default: return -EINVAL; } switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) { // 音频数据接口格式，0x000f case SND_SOC_DAIFMT_I2S: // 标准I2S模式 break; case SND_SOC_DAIFMT_LEFT_J: // I2S左对齐模式 reg_val |= RT5651_I2S_DF_LEFT; break; case SND_SOC_DAIFMT_DSP_A: reg_val |= RT5651_I2S_DF_PCM_A; //PCM模式A break; case SND_SOC_DAIFMT_DSP_B: reg_val |= RT5651_I2S_DF_PCM_B; // PCM模式B break; default: return -EINVAL; } switch (dai->id) { // I2S1 或者 I2S2 case RT5651_AIF1: // I2S1 snd_soc_component_update_bits(component, RT5651_I2S1_SDP, // MX70 RT5651_I2S_MS_MASK | RT5651_I2S_BP_MASK | // 1<<15 1<<7 RT5651_I2S_DF_MASK, reg_val); // 3 break; case RT5651_AIF2: // I2S2 snd_soc_component_update_bits(component, RT5651_I2S2_SDP, RT5651_I2S_MS_MASK | RT5651_I2S_BP_MASK | RT5651_I2S_DF_MASK, reg_val); break; default: dev_err(component->dev, "Wrong dai->id: %d\n", dai->id); return -EINVAL; } return 0; }
该函数主要是用来配置ALC5651数字音频接口格式，通过配置ALC5651 数字音频接口控制寄存器来实现，针对I2S1、I2S2接口各有一个配置寄存器。咱们以RT5651_I2S1_SDP为例介绍，I2S1数字音频接口控制寄存器，寄存器地址为0x70；
- 位[15]：I2S1 Digital Interface Mode Control，0’b: Master Mode（主机模式，即ALC5651作为主设备），1’b: Slave Mode（从机模式，即ALC5651作为从设备）；
- 位[7]：I2S1 BCLK Polarity Control，0’b: Normal，1’b: Invert（BLCK极性控制）；
- 位[1:0]：I2S1 PCM Data Format Selection；
- 00’b: I2S format（I2S标准模式）；
- 01’b: Left justified（I2S左对齐模式）；
- 10’b: PCM Mode A (LRCK One Plus at Master Mode)（PCM模式A）；
- 11’b: PCM Mode B (LRCK One Plus at Master Mode)（PCM模式B）；
当我们移植完了声卡驱动，并通过开发板ubuntu系统进行音频播放的时候，我特意查看了一下0x70寄存器的值：
- 0x70：值为0x8000，第15位被设置为1，表明ALC5651设备作为丛机模式；第7位被设置为0，BLCK Polarity正常；位[1:0]被设置为00'b，I2S标准模式；
5.4 hw_params
hw_params被设置为rt5651_hw_params，用于codec dai硬件参数设置，根据上层设定的声道数、采样率、数据格式，来配置codec dai相关寄存器；
static int rt5651_hw_params(struct snd_pcm_substream *substream, struct snd_pcm_hw_params *params, struct snd_soc_dai *dai) { struct snd_soc_component *component = dai->component; struct rt5651_priv *rt5651 = snd_soc_component_get_drvdata(component); // 取出component->dev设备的driver_data，就是上面介绍的rt5651结构变量 unsigned int val_len = 0, val_clk, mask_clk; int pre_div, bclk_ms, frame_size; rt5651->lrck[dai->id] = params_rate(params); // LRCK，声道选择信号，其频率等于采样频率 pre_div = rl6231_get_clk_info(rt5651->sysclk, rt5651->lrck[dai->id]); // 计算预分频值，用于DIV_F1(参考ALC5651是时钟模块架构) if (pre_div < 0) { dev_err(component->dev, "Unsupported clock setting\n"); return -EINVAL; } frame_size = snd_soc_params_to_frame_size(params); // 获取帧大小，即每帧所占用的位数；那什么是帧呢，以双声道为例，一帧指的就是包含左、右声道采样点的数据，可以理解为通道数*采样位数 if (frame_size < 0) { dev_err(component->dev, "Unsupported frame size: %d\n", frame_size); return -EINVAL; } bclk_ms = frame_size > 32 ? 1 : 0; rt5651->bclk[dai->id] = rt5651->lrck[dai->id] * (32 << bclk_ms); // 计算位时钟，BCLK=通道数×采样率×采样位数 dev_dbg(dai->dev, "bclk is %dHz and lrck is %dHz\n", rt5651->bclk[dai->id], rt5651->lrck[dai->id]); dev_dbg(dai->dev, "bclk_ms is %d and pre_div is %d for iis %d\n", bclk_ms, pre_div, dai->id); switch (params_width(params)) { // 设置位深度 case 16: break; case 20: val_len |= RT5651_I2S_DL_20; break; case 24: val_len |= RT5651_I2S_DL_24; break; case 8: val_len |= RT5651_I2S_DL_8; break; default: return -EINVAL; } switch (dai->id) { case RT5651_AIF1: // I2S1接口 mask_clk = RT5651_I2S_PD1_MASK; // 7<<12 val_clk = pre_div << RT5651_I2S_PD1_SFT; // RT5651_I2S_PD1_SFT=12 snd_soc_component_update_bits(component, RT5651_I2S1_SDP, // 0x70寄存器，更新位[3:2] RT5651_I2S_DL_MASK, val_len); // 3<<2 snd_soc_component_update_bits(component, RT5651_ADDA_CLK1, mask_clk, val_clk); // 0x73寄存器，更新位[14:12] break; case RT5651_AIF2: // I2S2接口 mask_clk = RT5651_I2S_BCLK_MS2_MASK | RT5651_I2S_PD2_MASK; val_clk = pre_div << RT5651_I2S_PD2_SFT; snd_soc_component_update_bits(component, RT5651_I2S2_SDP, RT5651_I2S_DL_MASK, val_len); snd_soc_component_update_bits(component, RT5651_ADDA_CLK1, mask_clk, val_clk); break; default: dev_err(component->dev, "Wrong dai->id: %d\n", dai->id); return -EINVAL; } return 0; }
这段代码是一个 RT5651音频芯片的硬件参数配置函数。它被用于设置数字音频接口的参数，包括采样率、帧大小等。
- 函数首先从传入的参数中获取采样率，并通过一个特定的函数（rl6231_get_clk_info）计算出相应的预分频值（pre_div）；
- 接下来，函数使用snd_soc_params_to_frame_size函数将参数转换成帧大小；
- 根据帧大小的值，函数计算位时钟（bit clock，即BCLK）的频率。这里使用了一个简单的公式：BCLK = 采样率 × 帧大小。同时，也计算了 BCLK 模式（bclk_ms）的值，该值取决于帧大小是否大于 32。函数会打印 BCLK和 LRCK 的频率以及bclk_ms和pre_div的值；
- 之后，计算I2S的位深度；
- 最后，根据不同的音频接口（dai->id），函数设置相应的寄存器位；
这里硬件寄存器操作涉及到0x70、以及0x73寄存器：
- RT5651_I2S1_SDP：I2S1数字音频接口控制寄存器，寄存器地址为0x70；位[3:2]表示I2S1位深度选择；
- 00'b：16位；
- 01'b：20位；
- 10‘b：24位；
- 11'b：8位；
- RT5651_ADDA_CLK1：ADC/DAC时钟控制寄存器，寄存器地址位0x73，位[14:12]用于控制I2S Clock Pre-Divider 1：
- 000'b：+1；
- 001'b：+2；
- 010'b：+3；
- 011'b：+4；
- 100'b：+6；
- 101'b：+8；
- 110'b：+12；
- 111'b：+16；
当我们移植完了声卡驱动，并通过开发板ubuntu系统进行音频播放的时候，我特意查看了一下0x70、0x73寄存器的值：
- 0x70：值为0x8000，位[3:2]被设置为0，表示位深度为16位；
- 0x73：值位0x0104，位[14:12]被设置为0，表示分频系数位1，则Clk_sys_i2s1 = MCLK=256*FS（采样频率）；
播放音频时，硬件参数配置具体如下（不同音乐文件，看到的数据format、rate可能不一样）：
root@rk3399:/proc/asound/card0/pcm0p/sub0# cat hw_params access: RW_INTERLEAVED format: S16_LE subformat: STD channels: 2 rate: 44100 (44100/1) period_size: 5513 buffer_size: 22052
5.4.1 params_rate
params_rate用于计算采样频率，函数定义在include/sound/pcm.h：
/** * params_rate - Get the sample rate from the hw params * @p: hw params * * Return: the sample rate */ static inline unsigned int params_rate(const struct snd_pcm_hw_params *p) { return hw_param_interval_c(p, SNDRV_PCM_HW_PARAM_RATE)->min; // 宏SNDRV_PCM_HW_PARAM_RATE的值为11 }
函数内部又调用了hw_param_interval_c：
static inline const struct snd_interval *hw_param_interval_c(const struct snd_pcm_hw_params *params, snd_pcm_hw_param_t var) { return ¶ms->intervals[var - SNDRV_PCM_HW_PARAM_FIRST_INTERVAL]; // 宏SNDRV_PCM_HW_PARAM_SAMPLE_BITS的值为8 }
这里实际上就是获取的params->intervals[3]->min的值，intervals数组第三个元素存放的就是近似采样率的信息。
5.4.2 snd_soc_params_to_frame_size
snd_soc_params_to_frame_size用于计算获取帧大小，函数定义在sound/soc/soc-utils.c：
int snd_soc_params_to_frame_size(struct snd_pcm_hw_params *params) { int sample_size; sample_size = snd_pcm_format_width(params_format(params)); if (sample_size < 0) return sample_size; return snd_soc_calc_frame_size(sample_size, params_channels(params), 1); }
其中params_format定义在include/sound/pcm_params.h：
/** * params_format - get the sample format from the hw params * @p: hw params */ static inline snd_pcm_format_t params_format(const struct snd_pcm_hw_params *p) { return (__force snd_pcm_format_t)snd_mask_min(hw_param_mask_c(p, SNDRV_PCM_HW_PARAM_FORMAT)); }
这里就不继续深究了，没啥意义。
5.4.3 params_width
函数params_width用于获取位深度，函数定义在include/sound/pcm_params.h：
/** * params_width - get the number of bits of the sample format from the hw params * @p: hw params * * This function returns the number of bits per sample that the selected sample * format of the hw params has. */ static inline int params_width(const struct snd_pcm_hw_params *p) { return snd_pcm_format_width(params_format(p)); }
参考文章
[2] 08.音频系统:第003课_LINUX音频驱动程序:第002节_ASOC音频驱动框架
[4] Linux ALSA声卡驱动之七：ASoC架构中的Codec
[6] 08.音频系统:第003课_Linux音频驱动程序:第005节_DAPM_widget_route_path
[7] [RK3399][Android7.1] 调试笔记 --- I2S1工作输出是12MHz问题
[8] RK3399平台适配TI-tlv320aic3111音频芯片
[9] Rockchip RK3399 - ALC5651 & I2S基础
[10] RK3399平台适配TI-tlv320aic3111音频芯片
[11] 基于RK3399分析Linux系统下的CPU时钟管理 - 第1篇
