記錄高通msm8909耳機檢測的機制，相關程式碼

kernel/arch/arm/boot/dts/qcom/msm8909-qrd-skuc.dtsi

	sound {
		compatible = "qcom,msm8x16-audio-codec";
		qcom,model = "msm8909-skuc-snd-card";
		qcom,msm-snd-card-id = <0>;
		qcom,msm-codec-type = "internal";
		qcom,msm-ext-pa = "primary";
		qcom,msm-mclk-freq = <9600000>;
		qcom,msm-mbhc-hphl-swh = <0>;
		qcom,msm-mbhc-gnd-swh = <0>;
		qcom,msm-hs-micbias-type = "internal";
		qcom,msm-micbias1-ext-cap;
		qcom,msm-micbias2-ext-cap;
		qcom,audio-routing =
			"RX_BIAS", "MCLK",
			"SPK_RX_BIAS", "MCLK",
			"INT_LDO_H", "MCLK",
			"MIC BIAS Internal1", "Handset Mic",
			"MIC BIAS Internal2", "Headset Mic",
			"MIC BIAS Internal3", "Secondary Mic",
			"AMIC1", "MIC BIAS Internal1",
			"AMIC2", "MIC BIAS Internal2",
			"AMIC3", "MIC BIAS Internal3";
		pinctrl-names = "cdc_lines_act",
				"cdc_lines_sus";
		pinctrl-0 = <&cdc_pdm_lines_act>;
		pinctrl-1 = <&cdc_pdm_lines_sus>;
		asoc-platform = <&pcm0>, <&pcm1>, <&voip>, <&voice>,
				<&loopback>, <&compress>, <&hostless>,
				<&afe>, <&lsm>, <&routing>, <&lpa>,
				<&voice_svc>;
		asoc-platform-names = "msm-pcm-dsp.0", "msm-pcm-dsp.1",
				"msm-voip-dsp", "msm-pcm-voice", "msm-pcm-loopback",
				"msm-compress-dsp", "msm-pcm-hostless", "msm-pcm-afe",
				"msm-lsm-client", "msm-pcm-routing", "msm-pcm-lpa",
				"msm-voice-svc";
		asoc-cpu = <&dai_pri_auxpcm>, <&dai_hdmi>,
				<&dai_mi2s0>, <&dai_mi2s1>, <&dai_mi2s2>, <&dai_mi2s3>,
				<&sb_0_rx>, <&sb_0_tx>, <&sb_1_rx>, <&sb_1_tx>,
				<&sb_3_rx>, <&sb_3_tx>, <&sb_4_rx>, <&sb_4_tx>,
				<&bt_sco_rx>, <&bt_sco_tx>, <&int_fm_rx>, <&int_fm_tx>,
				<&afe_pcm_rx>, <&afe_pcm_tx>, <&afe_proxy_rx>, <&afe_proxy_tx>,
				<&incall_record_rx>, <&incall_record_tx>, <&incall_music_rx>,
				<&incall_music_2_rx>;
		asoc-cpu-names = "msm-dai-q6-auxpcm.1", "msm-dai-q6-hdmi.8",
				"msm-dai-q6-mi2s.0", "msm-dai-q6-mi2s.1",
				"msm-dai-q6-mi2s.2", "msm-dai-q6-mi2s.3",
				"msm-dai-q6-dev.16384", "msm-dai-q6-dev.16385",
				"msm-dai-q6-dev.16386", "msm-dai-q6-dev.16387",
				"msm-dai-q6-dev.16390", "msm-dai-q6-dev.16391",
				"msm-dai-q6-dev.16392", "msm-dai-q6-dev.16393",
				"msm-dai-q6-dev.12288", "msm-dai-q6-dev.12289",
				"msm-dai-q6-dev.12292", "msm-dai-q6-dev.12293",
				"msm-dai-q6-dev.224", "msm-dai-q6-dev.225",
				"msm-dai-q6-dev.241", "msm-dai-q6-dev.240",
				"msm-dai-q6-dev.32771", "msm-dai-q6-dev.32772",
				"msm-dai-q6-dev.32773", "msm-dai-q6-dev.32770";
		asoc-codec = <&stub_codec>, <&pm8909_conga_dig>;
		asoc-codec-names = "msm-stub-codec.1", "tombak_codec";
	};
 

kernel/arch/arm/boot/dts/qcom/msm-pm8909.dtsi

	pm8909_conga_dig: [email protected] {
			compatible = "qcom,msm8x16_wcd_codec";
			reg = <0xf000 0x100>;
			interrupt-parent = <&spmi_bus>;
			interrupts = <0x1 0xf0 0x0>,
				     <0x1 0xf0 0x1>,
				     <0x1 0xf0 0x2>,
				     <0x1 0xf0 0x3>,
				     <0x1 0xf0 0x4>,
				     <0x1 0xf0 0x5>,
				     <0x1 0xf0 0x6>,
				     <0x1 0xf0 0x7>;
			interrupt-names = "spk_cnp_int",
					  "spk_clip_int",
					  "spk_ocp_int",
					  "ins_rem_det1",
					  "but_rel_det",
					  "but_press_det",
					  "ins_rem_det",
					  "mbhc_int";

			cdc-vdda-cp-supply = <&pm8909_s2>;
			qcom,cdc-vdda-cp-voltage = <1800000 2200000>;
			qcom,cdc-vdda-cp-current = <500000>;

			cdc-vdda-h-supply = <&pm8909_l5>;
			qcom,cdc-vdda-h-voltage = <1800000 1800000>;
			qcom,cdc-vdda-h-current = <10000>;

			cdc-vdd-px-supply = <&pm8909_l5>;
			qcom,cdc-vdd-px-voltage = <1800000 1800000>;
			qcom,cdc-vdd-px-current = <5000>;

			cdc-vdd-pa-supply = <&pm8909_s2>;
			qcom,cdc-vdd-pa-voltage = <1800000 2200000>;
			qcom,cdc-vdd-pa-current = <260000>;

			cdc-vdd-mic-bias-supply = <&pm8909_l13>;
			qcom,cdc-vdd-mic-bias-voltage = <3075000 3075000>;
			qcom,cdc-vdd-mic-bias-current = <5000>;

			qcom,cdc-mclk-clk-rate = <9600000>;

			qcom,cdc-static-supplies = "cdc-vdda-h",
						   "cdc-vdd-px",
						   "cdc-vdd-pa",
						   "cdc-vdda-cp";

			qcom,cdc-on-demand-supplies = "cdc-vdd-mic-bias";
		};

		pm8909_conga_analog: 
 
[email protected] {
			compatible = "qcom,msm8x16_wcd_codec";
			reg = <0xf100 0x100>;
			interrupt-parent = <&spmi_bus>;
			interrupts = <0x1 0xf1 0x0>,
				     <0x1 0xf1 0x1>,
				     <0x1 0xf1 0x2>,
				     <0x1 0xf1 0x3>,
				     <0x1 0xf1 0x4>,
				     <0x1 0xf1 0x5>;
			interrupt-names = "ear_ocp_int",
					  "hphr_ocp_int",
					  "hphl_ocp_det",
					  "ear_cnp_int",
					  "hphr_cnp_int",
					  "hphl_cnp_int";
		};
 

msm8909的耳機介面在pm8909上

HPH (耳機簡寫headphone)

MIC_BIAS (耳機麥克風偏置電壓)

MICx_IN(耳機的mic輸入口)

HPH_L(耳機左聲道)

HPH_R(耳機右聲道)

HS_DET(耳機檢測腳)  headset_detect

HPH_REF(耳機參考地)     一些接耳機通道的外接PA,如果耳機地不接這裡,接主機板的地,可能通話過中會電流聲

NC  常關耳機插座(hp_det和hph_l短路,插入耳機,hp_det和hph_l斷路)

NO 常開耳機插座(這種型別常見,hp_det和hph_l斷路,插入耳機,hph_l接了一個喇叭(小電阻)到地,相當有hp_det和hph_l短路)

耳機的左/右聲道到地電阻大概10歐姆,mic到地大概1K歐姆

這裡是no的耳機插座,設定

qcom,msm-mbhc-hphl-swh = <0>;

kernel/sound/soc/codecs/msm8x16-wcd.c

static const struct wcd_mbhc_intr intr_ids = {
	.mbhc_sw_intr =  MSM8X16_WCD_IRQ_MBHC_HS_DET,
	.mbhc_btn_press_intr = MSM8X16_WCD_IRQ_MBHC_PRESS,
	.mbhc_btn_release_intr = MSM8X16_WCD_IRQ_MBHC_RELEASE,
	.mbhc_hs_ins_intr = MSM8X16_WCD_IRQ_MBHC_INSREM_DET1,
	.mbhc_hs_rem_intr = MSM8X16_WCD_IRQ_MBHC_INSREM_DET,
	.hph_left_ocp = MSM8X16_WCD_IRQ_HPHL_OCP,
	.hph_right_ocp = MSM8X16_WCD_IRQ_HPHR_OCP,
};

static int msm8x16_wcd_codec_probe(struct snd_soc_codec *codec)
{
	struct msm8x16_wcd_priv *msm8x16_wcd_priv;
	struct msm8x16_wcd *msm8x16_wcd;
	int i, ret;

	dev_dbg(codec->dev, "%s()\n", __func__);

	msm8x16_wcd_priv = kzalloc(sizeof(struct msm8x16_wcd_priv), GFP_KERNEL);
	if (!msm8x16_wcd_priv) {
		dev_err(codec->dev, "Failed to allocate private data\n");
		return -ENOMEM;
	}

	for (i = 0; i < NUM_DECIMATORS; i++) {
		tx_hpf_work[i].msm8x16_wcd = msm8x16_wcd_priv;
		tx_hpf_work[i].decimator = i + 1;
		INIT_DELAYED_WORK(&tx_hpf_work[i].dwork,
			tx_hpf_corner_freq_callback);
	}

	codec->control_data = dev_get_drvdata(codec->dev);
	snd_soc_codec_set_drvdata(codec, msm8x16_wcd_priv);
	msm8x16_wcd_priv->codec = codec;

	/* codec resmgr module init */
	msm8x16_wcd = codec->control_data;
	msm8x16_wcd->dig_base = ioremap(MSM8X16_DIGITAL_CODEC_BASE_ADDR,
				  MSM8X16_DIGITAL_CODEC_REG_SIZE);
	if (msm8x16_wcd->dig_base == NULL) {
		dev_err(codec->dev, "%s ioremap failed\n", __func__);
		kfree(msm8x16_wcd_priv);
		return -ENOMEM;
	}
	msm8x16_wcd_priv->spkdrv_reg =
		wcd8x16_wcd_codec_find_regulator(codec->control_data,
						MSM89XX_VDD_SPKDRV_NAME);
	msm8x16_wcd_priv->pmic_rev = snd_soc_read(codec,
					MSM8X16_WCD_A_DIGITAL_REVISION1);
	msm8x16_wcd_priv->codec_version = snd_soc_read(codec,
					MSM8X16_WCD_A_DIGITAL_PERPH_SUBTYPE);
	if (msm8x16_wcd_priv->codec_version == CONGA) {
		dev_dbg(codec->dev, "%s :Conga REV: %d\n", __func__,
					msm8x16_wcd_priv->codec_version);
		msm8x16_wcd_priv->ext_spk_boost_set = true;
	} else {
		dev_dbg(codec->dev, "%s :PMIC REV: %d\n", __func__,
					msm8x16_wcd_priv->pmic_rev);
	}
	/*
	 * set to default boost option BOOST_SWITCH, user mixer path can change
	 * it to BOOST_ALWAYS or BOOST_BYPASS based on solution chosen.
	 */
	msm8x16_wcd_priv->boost_option = BOOST_SWITCH;
	msm8x16_wcd_dt_parse_boost_info(codec);
	msm8x16_wcd_set_boost_v(codec);

	snd_soc_add_codec_controls(codec, impedance_detect_controls,
				   ARRAY_SIZE(impedance_detect_controls));

	msm8x16_wcd_bringup(codec);
	msm8x16_wcd_codec_init_reg(codec);
	msm8x16_wcd_update_reg_defaults(codec);

	wcd9xxx_spmi_set_codec(codec);

	msm8x16_wcd_priv->on_demand_list[ON_DEMAND_MICBIAS].supply =
				wcd8x16_wcd_codec_find_regulator(
				codec->control_data,
				on_demand_supply_name[ON_DEMAND_MICBIAS]);
	atomic_set(&msm8x16_wcd_priv->on_demand_list[ON_DEMAND_MICBIAS].ref, 0);

	BLOCKING_INIT_NOTIFIER_HEAD(&msm8x16_wcd_priv->notifier);

	msm8x16_wcd_priv->fw_data = kzalloc(sizeof(*(msm8x16_wcd_priv->fw_data))
			, GFP_KERNEL);
	if (!msm8x16_wcd_priv->fw_data) {
		dev_err(codec->dev, "Failed to allocate fw_data\n");
		iounmap(msm8x16_wcd->dig_base);
		kfree(msm8x16_wcd_priv);
		return -ENOMEM;
	}

	set_bit(WCD9XXX_MBHC_CAL, msm8x16_wcd_priv->fw_data->cal_bit);
	ret = wcd_cal_create_hwdep(msm8x16_wcd_priv->fw_data,
			WCD9XXX_CODEC_HWDEP_NODE, codec);
	if (ret < 0) {
		dev_err(codec->dev, "%s hwdep failed %d\n", __func__, ret);
		iounmap(msm8x16_wcd->dig_base);
		kfree(msm8x16_wcd_priv->fw_data);
		kfree(msm8x16_wcd_priv);
		return ret;
	}

	wcd_mbhc_init(&msm8x16_wcd_priv->mbhc, codec, &mbhc_cb, &intr_ids,
			true);

	msm8x16_wcd_priv->mclk_enabled = false;
	msm8x16_wcd_priv->clock_active = false;
	msm8x16_wcd_priv->config_mode_active = false;

	/* Set initial MICBIAS voltage level */
	msm8x16_wcd_set_micb_v(codec);

	/* Set initial cap mode */
	msm8x16_wcd_configure_cap(codec, false, false);
	registered_codec = codec;
	modem_state_notifier =
	    subsys_notif_register_notifier("modem",
					   &modem_state_notifier_block);
	if (!modem_state_notifier) {
		dev_err(codec->dev, "Failed to register modem state notifier\n"
			);
		iounmap(msm8x16_wcd->dig_base);
		kfree(msm8x16_wcd_priv->fw_data);
		kfree(msm8x16_wcd_priv);
		registered_codec = NULL;
		return -ENOMEM;
	}
	return 0;
}

kernel/sound/soc/codecs/wcd-mbhc-v2.c

int wcd_mbhc_init(struct wcd_mbhc *mbhc, struct snd_soc_codec *codec,
		      const struct wcd_mbhc_cb *mbhc_cb,
		      const struct wcd_mbhc_intr *mbhc_cdc_intr_ids,
		      bool impedance_det_en)
{
	int ret = 0;
	int hph_swh = 0;
	int gnd_swh = 0;
	struct snd_soc_card *card = codec->card;
	const char *hph_switch = "qcom,msm-mbhc-hphl-swh";
	const char *gnd_switch = "qcom,msm-mbhc-gnd-swh";

	fb_notifier.notifier_call = fb_notifierier_callback;
	ret = fb_register_client(&fb_notifier);
	if (ret)
		printk( KERN_CRIT"%s: micbias Unable to register fb_notifier: %d\n", __func__,ret);

	ret = of_property_read_u32(card->dev->of_node, hph_switch, &hph_swh);
	if (ret) {
		dev_err(card->dev,
			"%s: missing %s in dt node\n", __func__, hph_switch);
		goto err;
	}

	ret = of_property_read_u32(card->dev->of_node, gnd_switch, &gnd_swh);
	if (ret) {
		dev_err(card->dev,
			"%s: missing %s in dt node\n", __func__, gnd_switch);
		goto err;
	}

	mbhc->in_swch_irq_handler = false;
	mbhc->current_plug = MBHC_PLUG_TYPE_NONE;
	mbhc->is_btn_press = false;
	mbhc->codec = codec;
	mbhc->intr_ids = mbhc_cdc_intr_ids;
	mbhc->impedance_detect = impedance_det_en;
	mbhc->hphl_swh = hph_swh;
	mbhc->gnd_swh = gnd_swh;
	mbhc->micbias_enable = false;
	mbhc->mbhc_cb = mbhc_cb;
	mbhc->btn_press_intr = false;
	mbhc->is_hs_recording = false;
	mbhc->is_extn_cable = false;
	mbhc->skip_imped_detection = false;

	if (mbhc->intr_ids == NULL) {
		pr_err("%s: Interrupt mapping not provided\n", __func__);
		return -EINVAL;
	}

	if (mbhc->headset_jack.jack == NULL) {
		ret = snd_soc_jack_new(codec, "Headset Jack",
				WCD_MBHC_JACK_MASK, &mbhc->headset_jack);
		if (ret) {
			pr_err("%s: Failed to create new jack\n", __func__);
			return ret;
		}

		ret = snd_soc_jack_new(codec, "Button Jack",
				       WCD_MBHC_JACK_BUTTON_MASK,
				       &mbhc->button_jack);
		if (ret) {
			pr_err("Failed to create new jack\n");
			return ret;
		}

		ret = snd_jack_set_key(mbhc->button_jack.jack,
				       SND_JACK_BTN_0,
				       KEY_MEDIA);
		if (ret) {
			pr_err("%s: Failed to set code for btn-0\n",
				__func__);
			return ret;
		}
		ret = snd_jack_set_key(mbhc->button_jack.jack,
				       SND_JACK_BTN_1,
				       KEY_VOICECOMMAND);
		if (ret) {
			pr_err("%s: Failed to set code for btn-1:%d\n",
					__func__, ret);
			return ret;
		}
		ret = snd_jack_set_key(mbhc->button_jack.jack,
				       SND_JACK_BTN_2,
				       KEY_VOLUMEUP);
		if (ret) {
			pr_err("%s: Failed to set code for btn-2:%d\n",
				__func__, ret);
			return ret;
		}
		ret = snd_jack_set_key(mbhc->button_jack.jack,
				       SND_JACK_BTN_3,
				       KEY_VOLUMEDOWN);
		if (ret) {
			pr_err("%s: Failed to set code for btn-3:%d\n",
				__func__, ret);
			return ret;
		}

		INIT_DELAYED_WORK(&mbhc->mbhc_firmware_dwork,
				  wcd_mbhc_fw_read);
		INIT_DELAYED_WORK(&mbhc->mbhc_btn_dwork, wcd_btn_lpress_fn);
	}

	/* Register event notifier */
	mbhc->nblock.notifier_call = wcd_event_notify;
	ret = msm8x16_register_notifier(codec, &mbhc->nblock);
	if (ret) {
		pr_err("%s: Failed to register notifier %d\n", __func__, ret);
		return ret;
	}

	init_waitqueue_head(&mbhc->wait_btn_press);
	mutex_init(&mbhc->codec_resource_lock);

	ret = wcd9xxx_spmi_request_irq(mbhc->intr_ids->mbhc_sw_intr,
				  wcd_mbhc_mech_plug_detect_irq,
				  "mbhc sw intr", mbhc);
	if (ret) {
		pr_err("%s: Failed to request irq %d, ret = %d\n", __func__,
		       mbhc->intr_ids->mbhc_sw_intr, ret);
		goto err_mbhc_sw_irq;
	}

	ret = wcd9xxx_spmi_request_irq(mbhc->intr_ids->mbhc_btn_press_intr,
				  wcd_mbhc_btn_press_handler,
				  "Button Press detect",
				  mbhc);
	if (ret) {
		pr_err("%s: Failed to request irq %d\n", __func__,
		       mbhc->intr_ids->mbhc_btn_press_intr);
		goto err_btn_press_irq;
	}

	ret = wcd9xxx_spmi_request_irq(mbhc->intr_ids->mbhc_btn_release_intr,
				  wcd_mbhc_release_handler,
				  "Button Release detect", mbhc);
	if (ret) {
		pr_err("%s: Failed to request irq %d\n", __func__,
			mbhc->intr_ids->mbhc_btn_release_intr);
		goto err_btn_release_irq;
	}

	ret = wcd9xxx_spmi_request_irq(mbhc->intr_ids->mbhc_hs_ins_intr,
				  wcd_mbhc_hs_ins_irq,
				  "Elect Insert", mbhc);
	if (ret) {
		pr_err("%s: Failed to request irq %d\n", __func__,
		       mbhc->intr_ids->mbhc_hs_ins_intr);
		goto err_mbhc_hs_ins_irq;
	}
	wcd9xxx_spmi_disable_irq(mbhc->intr_ids->mbhc_hs_ins_intr);

	ret = wcd9xxx_spmi_request_irq(mbhc->intr_ids->mbhc_hs_rem_intr,
				  wcd_mbhc_hs_rem_irq,
				  "Elect Remove", mbhc);
	if (ret) {
		pr_err("%s: Failed to request irq %d\n", __func__,
		       mbhc->intr_ids->mbhc_hs_rem_intr);
		goto err_mbhc_hs_rem_irq;
	}
	wcd9xxx_spmi_disable_irq(mbhc->intr_ids->mbhc_hs_rem_intr);

	ret = wcd9xxx_spmi_request_irq(mbhc->intr_ids->hph_left_ocp,
				  wcd_mbhc_hphl_ocp_irq, "HPH_L OCP detect",
				  mbhc);
	if (ret) {
		pr_err("%s: Failed to request irq %d\n", __func__,
		       mbhc->intr_ids->hph_left_ocp);
		goto err_hphl_ocp_irq;
	}

	ret = wcd9xxx_spmi_request_irq(mbhc->intr_ids->hph_right_ocp,
				  wcd_mbhc_hphr_ocp_irq, "HPH_R OCP detect",
				  mbhc);
	if (ret) {
		pr_err("%s: Failed to request irq %d\n", __func__,
		       mbhc->intr_ids->hph_right_ocp);
		goto err_hphr_ocp_irq;
	}

	pr_debug("%s: leave ret %d\n", __func__, ret);
	return ret;

err_hphr_ocp_irq:
	wcd9xxx_spmi_free_irq(mbhc->intr_ids->hph_left_ocp, mbhc);
err_hphl_ocp_irq:
	wcd9xxx_spmi_free_irq(mbhc->intr_ids->mbhc_hs_rem_intr, mbhc);
err_mbhc_hs_rem_irq:
	wcd9xxx_spmi_free_irq(mbhc->intr_ids->mbhc_hs_ins_intr, mbhc);
err_mbhc_hs_ins_irq:
	wcd9xxx_spmi_free_irq(mbhc->intr_ids->mbhc_btn_release_intr, mbhc);
err_btn_release_irq:
	wcd9xxx_spmi_free_irq(mbhc->intr_ids->mbhc_btn_press_intr, mbhc);
err_btn_press_irq:
	wcd9xxx_spmi_free_irq(mbhc->intr_ids->mbhc_sw_intr, mbhc);
err_mbhc_sw_irq:
	msm8x16_unregister_notifier(codec, &mbhc->nblock);
	mutex_destroy(&mbhc->codec_resource_lock);
err:
	pr_debug("%s: leave ret %d\n", __func__, ret);
	return ret;
}
EXPORT_SYMBOL(wcd_mbhc_init);

耳機檢測中斷函式

static void wcd_mbhc_swch_irq_handler(struct wcd_mbhc *mbhc)
{
	bool detection_type;
	bool micbias1;
	struct snd_soc_codec *codec = mbhc->codec;
	pr_debug("%s: enter\n", __func__);

	WCD_MBHC_RSC_LOCK(mbhc);

	mbhc->in_swch_irq_handler = true;

	/* cancel pending button press */
	if (wcd_cancel_btn_work(mbhc))
		pr_debug("%s: button press is canceled\n", __func__);

	detection_type = (snd_soc_read(codec,
				MSM8X16_WCD_A_ANALOG_MBHC_DET_CTL_1)) & 0x20;

	/* Set the detection type appropriately */
	snd_soc_update_bits(codec, MSM8X16_WCD_A_ANALOG_MBHC_DET_CTL_1,
			0x20, (!detection_type << 5));

	pr_debug("%s: mbhc->current_plug: %d detection_type: %d\n", __func__,
			mbhc->current_plug, detection_type);
	wcd_cancel_hs_detect_plug(mbhc, &mbhc->correct_plug_swch);

	micbias1 = (snd_soc_read(codec, MSM8X16_WCD_A_ANALOG_MICB_1_EN) & 0x80);
	if ((mbhc->current_plug == MBHC_PLUG_TYPE_NONE) &&
	    detection_type) {
		/* Make sure MASTER_BIAS_CTL is enabled */
		snd_soc_update_bits(codec,
				    MSM8X16_WCD_A_ANALOG_MASTER_BIAS_CTL,
				    0x30, 0x30);
		snd_soc_update_bits(codec,
				MSM8X16_WCD_A_ANALOG_MICB_1_EN,
				0x04, 0x04);
		if (!mbhc->mbhc_cfg->hs_ext_micbias)
			/* Enable Tx2 RBias if the headset
			 * is using internal micbias*/
			snd_soc_update_bits(codec,
					MSM8X16_WCD_A_ANALOG_MICB_1_INT_RBIAS,
					0x10, 0x10);
		/* Remove pull down on MIC BIAS2 */
		snd_soc_update_bits(codec,
				 MSM8X16_WCD_A_ANALOG_MICB_2_EN,
				0x20, 0x00);
		/* Enable HW FSM */
		snd_soc_update_bits(codec,
				MSM8X16_WCD_A_ANALOG_MBHC_FSM_CTL,
				0x80, 0x80);
		/* Apply trim if needed on the device */
		if (mbhc->mbhc_cb && mbhc->mbhc_cb->trim_btn_reg)
			mbhc->mbhc_cb->trim_btn_reg(codec);
		/* Enable external voltage source to micbias if present */
		if (mbhc->mbhc_cb && mbhc->mbhc_cb->enable_mb_source)
			mbhc->mbhc_cb->enable_mb_source(codec, true);
		mbhc->btn_press_intr = false;
		wcd_mbhc_detect_plug_type(mbhc);
	} else if ((mbhc->current_plug != MBHC_PLUG_TYPE_NONE)
			&& !detection_type) {
		/* Disable external voltage source to micbias if present */
		if (mbhc->mbhc_cb && mbhc->mbhc_cb->enable_mb_source)
			mbhc->mbhc_cb->enable_mb_source(codec, false);
		/* Disable HW FSM */
		snd_soc_update_bits(codec,
				MSM8X16_WCD_A_ANALOG_MBHC_FSM_CTL,
				0xB0, 0x00);
		snd_soc_update_bits(codec,
				MSM8X16_WCD_A_ANALOG_MICB_1_EN,
				0x04, 0x00);
		if (mbhc->mbhc_cb && mbhc->mbhc_cb->set_cap_mode)
			mbhc->mbhc_cb->set_cap_mode(codec, micbias1, false);
		mbhc->btn_press_intr = false;
		if (mbhc->current_plug == MBHC_PLUG_TYPE_HEADPHONE) {
			wcd_mbhc_report_plug(mbhc, 0, SND_JACK_HEADPHONE);
		} else if (mbhc->current_plug == MBHC_PLUG_TYPE_GND_MIC_SWAP) {
			wcd_mbhc_report_plug(mbhc, 0, SND_JACK_UNSUPPORTED);
		} else if (mbhc->current_plug == MBHC_PLUG_TYPE_HEADSET) {
			/* make sure to turn off Rbias */
			snd_soc_update_bits(codec,
					MSM8X16_WCD_A_ANALOG_MICB_1_INT_RBIAS,
					0x18, 0x08);
			snd_soc_update_bits(codec,
					MSM8X16_WCD_A_ANALOG_MICB_2_EN,
					0x20, 0x20);
			wcd9xxx_spmi_disable_irq(
					mbhc->intr_ids->mbhc_hs_rem_intr);
			wcd9xxx_spmi_disable_irq(
					mbhc->intr_ids->mbhc_hs_ins_intr);
			snd_soc_update_bits(codec,
					MSM8X16_WCD_A_ANALOG_MBHC_DET_CTL_1,
					0x01, 0x01);
			snd_soc_update_bits(codec,
					MSM8X16_WCD_A_ANALOG_MBHC_DET_CTL_2,
					0x06, 0x00);
			wcd_mbhc_report_plug(mbhc, 0, SND_JACK_HEADSET);
		} else if (mbhc->current_plug == MBHC_PLUG_TYPE_HIGH_HPH) {
			mbhc->is_extn_cable = false;
			wcd9xxx_spmi_disable_irq(
					mbhc->intr_ids->mbhc_hs_rem_intr);
			wcd9xxx_spmi_disable_irq(
					mbhc->intr_ids->mbhc_hs_ins_intr);
			snd_soc_update_bits(codec,
					MSM8X16_WCD_A_ANALOG_MBHC_DET_CTL_1,
					0x01, 0x01);
			snd_soc_update_bits(codec,
					MSM8X16_WCD_A_ANALOG_MBHC_DET_CTL_2,
					0x06, 0x00);
			wcd_mbhc_report_plug(mbhc, 0, SND_JACK_LINEOUT);
		}
	} else if (!detection_type) {
		/* Disable external voltage source to micbias if present */
		if (mbhc->mbhc_cb && mbhc->mbhc_cb->enable_mb_source)
			mbhc->mbhc_cb->enable_mb_source(codec, false);
		/* Disable HW FSM */
		snd_soc_update_bits(codec,
				MSM8X16_WCD_A_ANALOG_MBHC_FSM_CTL,
				0xB0, 0x00);
	}

	mbhc->in_swch_irq_handler = false;
	WCD_MBHC_RSC_UNLOCK(mbhc);
	pr_debug("%s: leave\n", __func__);
}

static irqreturn_t wcd_mbhc_mech_plug_detect_irq(int irq, void *data)
{
	int r = IRQ_HANDLED;
	struct wcd_mbhc *mbhc = data;

	pr_debug("%s: enter\n", __func__);
	if (unlikely(wcd9xxx_spmi_lock_sleep() == false)) {
		pr_warn("%s: failed to hold suspend\n", __func__);
		r = IRQ_NONE;
	} else {
		/* Call handler */
		wcd_mbhc_swch_irq_handler(mbhc);
		wcd9xxx_spmi_unlock_sleep();
	}
	pr_debug("%s: leave %d\n", __func__, r);
	return r;
}

經過一系列的檢測，判斷是headset,headphones等，如果是headphones，最終通過wcd_mbhc_jack_report將資料彙報上去。

static void wcd_mbhc_jack_report(struct wcd_mbhc *mbhc,
				struct snd_soc_jack *jack, int status, int mask)
{
	snd_soc_jack_report_no_dapm(jack, status, mask);
}

核心通用的耳機彙報函式

void snd_soc_jack_report_no_dapm(struct snd_soc_jack *jack, int status,
				 int mask)
{
	jack->status &= ~mask;
	jack->status |= status & mask;

	snd_jack_report(jack->jack, jack->status);
}
EXPORT_SYMBOL_GPL(snd_soc_jack_report_no_dapm);

void snd_jack_report(struct snd_jack *jack, int status)
{
	int i;

	if (!jack)
		return;

	for (i = 0; i < ARRAY_SIZE(jack->key); i++) {
		int testbit = SND_JACK_BTN_0 >> i;

		if (jack->type & testbit)
			input_report_key(jack->input_dev, jack->key[i],
					 status & testbit);
	}

	for (i = 0; i < ARRAY_SIZE(jack_switch_types); i++) {
		int testbit = 1 << i;
		if (jack->type & testbit)
			input_report_switch(jack->input_dev,
					    jack_switch_types[i],
					    status & testbit);
	}//分別判斷具體的位,有沒有相應的事件

	input_sync(jack->input_dev);
}
EXPORT_SYMBOL(snd_jack_report);

static inline void input_report_switch(struct input_dev *dev, unsigned int code, int value)
{
	input_event(dev, EV_SW, code, !!value);
}
#define EV_SW			0x05

三段耳機最終彙報上去的有效資料是

                                        5 　 2 　 1　(插頭型別　耳機訊號　插入/拔出)

                                        0  　0  　0（同步）

static int jack_switch_types[] = {
	SW_HEADPHONE_INSERT,
	SW_MICROPHONE_INSERT,
	SW_LINEOUT_INSERT,
	SW_JACK_PHYSICAL_INSERT,
	SW_VIDEOOUT_INSERT,
	SW_LINEIN_INSERT,
	SW_HPHL_OVERCURRENT,
	SW_HPHR_OVERCURRENT,
	SW_UNSUPPORT_INSERT,
	SW_MICROPHONE2_INSERT,
};

enum wcd_mbhc_plug_type {
	MBHC_PLUG_TYPE_INVALID = -1,//無效裝置
	MBHC_PLUG_TYPE_NONE,//未接入裝置
	MBHC_PLUG_TYPE_HEADSET,//四段耳機
	MBHC_PLUG_TYPE_HEADPHONE,//三段耳機
	MBHC_PLUG_TYPE_HIGH_HPH,//高阻抗耳機
	MBHC_PLUG_TYPE_GND_MIC_SWAP,//歐美標標誌位
};

當然也可以手工通過sendevent 傳送事件，systemui就能顯示耳機接入的圖示

getevent -i獲取Headset Jack對應的input,假設是/dev/input/event2,

則可以通過如下方法模擬耳機接入和拔出(getevent -i找到具體的eventn)

sendevent /dev/input/event2 5 2 1
sendevent /dev/input/event2 0 0 0

或者撥出耳機

sendevent /dev/input/event2 5 2 0
sendevent /dev/input/event2 0 0 0