一.硬件原理图

耳机输出硬件原理图：

耳机实物图：

耳机插入硬件原理：

耳机插入后HP_DET_L会连接耳机的GND，从而实现HP_DET_L叫从高到低的状态。

耳机插入软件原理：

软件需要在驱动里面定时的读取gpio的状态，实现实时检测耳机插入拔出的热插拔功能。

二.设备树DTS修改

目前需求在功放驱动里面添加耳机的插入检测, 功放为ad82584.

插入检测HP_DET_L(GPIO1_D2).

设备树DTS配置：

ad82584f_stereo: ad82584f-stereo@31 {
	compatible = "ad82584f";
	#sound-dai-cells = <0>;
	reg = <0x31>;
	spk-con-gpio = <&gpio0 RK_PD5 GPIO_ACTIVE_HIGH>;
  + earphone-det-gpio = <&gpio1 RK_PD2 GPIO_ACTIVE_HIGH>;
	set_state_enable = <1>;
	pinctrl-names = "default";
	pinctrl-0 = <&earphone_det>;
	status = "okay";
};

三.代码修改

在probe函数里面读取gpio：

ad82584f_probe：

data->earphone_det_gpio = devm_gpiod_get_optional(&client->dev,
						     "earphone-det",
						     GPIOD_IN);
if (IS_ERR(data->earphone_det_gpio)) {
	dev_warn(dev, "get earphone_det_gpio failed\n");
	return PTR_ERR(data->earphone_det_gpio);
}

在ad82584f_codec_probe添加定时检测gpio状态函数：

检测函数为：ad82584f_earphone_check_work。

INIT_DELAYED_WORK(&ad82584f->earphone_check_work, ad82584f_earphone_check_work);
schedule_delayed_work(&ad82584f->earphone_check_work,msecs_to_jiffies(5000));

static void ad82584f_earphone_check_work(struct work_struct *work)
{
	struct ad82584f_data *ad82584f = container_of(work, struct ad82584f_data,
			earphone_check_work.work);
	if (ad82584f->earphone_det_gpio) {
		bool curEarphone_plug_in = (gpiod_get_value(ad82584f->earphone_det_gpio)  > 0) ? false:true; //检测耳机插入状态
		if(curEarphone_plug_in != ad82584f->preEarphone_plug_in){
			if(curEarphone_plug_in){
				dev_info(ad82584f->dev, "%s: earphone plug in\n", __func__);
				if(of_property_read_bool(ad82584f->dev->of_node, "set_state_enable")){  //使能耳机功能
					extcon_set_state_sync(ad82584f->extcon, EXTCON_JACK_HEADPHONE, true);  
					extcon_set_state_sync(ad82584f->extcon, EXTCON_JACK_MICROPHONE, true);
				}
				ad82584f_enable_spk(ad82584f,0);
				}else{
				dev_info(ad82584f->dev, "%s: earphone plug out\n", __func__);
				if(of_property_read_bool(ad82584f->dev->of_node, "set_state_enable")){
					extcon_set_state_sync(ad82584f->extcon, EXTCON_JACK_HEADPHONE, false);
					extcon_set_state_sync(ad82584f->extcon, EXTCON_JACK_MICROPHONE, false);
				}
				ad82584f_enable_spk(ad82584f,1);
			    //gpiod_set_value(ad82584f->spk_ctl_gpio, 0);
			}
			ad82584f->preEarphone_plug_in = curEarphone_plug_in;
		}
	}
	schedule_delayed_work(&ad82584f->earphone_check_work,
			      msecs_to_jiffies(1000));
}