[PATCH v2] ASoC: codecs: MBHC: Add support for special headset

[Srinivasa Rao Mandadapu]

Update MBHC driver to support special headset such as apple
and huwawei headsets.

Changes Since V1:
    -- Fix typo errors.

Signed-off-by: Srinivasa Rao Mandadapu <srivasam at codeaurora.org>
Co-developed-by: Venkata Prasad Potturu <potturu at codeaurora.org>
Signed-off-by: Venkata Prasad Potturu <potturu at codeaurora.org>
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla at linaro.org>
---
 sound/soc/codecs/wcd-mbhc-v2.c | 75 +++++++++++++++++++++++++++++++++++++++---
 1 file changed, 71 insertions(+), 4 deletions(-)

diff --git a/sound/soc/codecs/wcd-mbhc-v2.c b/sound/soc/codecs/wcd-mbhc-v2.c
index 405128c..d6545e4 100644
--- a/sound/soc/codecs/wcd-mbhc-v2.c
+++ b/sound/soc/codecs/wcd-mbhc-v2.c
@@ -1022,6 +1022,56 @@ static int wcd_mbhc_get_plug_from_adc(struct wcd_mbhc *mbhc, int adc_result)
 	return plug_type;
 }
 
+static int wcd_mbhc_get_spl_hs_thres(struct wcd_mbhc *mbhc)
+{
+	int hs_threshold, micbias_mv;
+
+	micbias_mv = wcd_mbhc_get_micbias(mbhc);
+	if (mbhc->cfg->hs_thr && mbhc->cfg->micb_mv != WCD_MBHC_ADC_MICBIAS_MV) {
+		if (mbhc->cfg->micb_mv == micbias_mv)
+			hs_threshold = mbhc->cfg->hs_thr;
+		else
+			hs_threshold = (mbhc->cfg->hs_thr * micbias_mv) / mbhc->cfg->micb_mv;
+	} else {
+		hs_threshold = ((WCD_MBHC_ADC_HS_THRESHOLD_MV * micbias_mv) /
+							WCD_MBHC_ADC_MICBIAS_MV);
+	}
+	return hs_threshold;
+}
+
+static bool wcd_mbhc_check_for_spl_headset(struct wcd_mbhc *mbhc)
+{
+	bool is_spl_hs = false;
+	int output_mv, hs_threshold, hph_threshold;
+
+	if (!mbhc->mbhc_cb->mbhc_micb_ctrl_thr_mic)
+		return false;
+
+	/* Bump up MIC_BIAS2 to 2.7V */
+	mbhc->mbhc_cb->mbhc_micb_ctrl_thr_mic(mbhc->component, MIC_BIAS_2, true);
+	usleep_range(10000, 10100);
+
+	output_mv = wcd_measure_adc_once(mbhc, MUX_CTL_IN2P);
+	hs_threshold = wcd_mbhc_get_spl_hs_thres(mbhc);
+	hph_threshold = wcd_mbhc_adc_get_hph_thres(mbhc);
+
+	if (output_mv > hs_threshold || output_mv < hph_threshold) {
+		if (mbhc->force_linein == true)
+			is_spl_hs = false;
+	} else {
+		is_spl_hs = true;
+	}
+
+	/* Back MIC_BIAS2 to 1.8v if the type is not special headset */
+	if (!is_spl_hs) {
+		mbhc->mbhc_cb->mbhc_micb_ctrl_thr_mic(mbhc->component, MIC_BIAS_2, false);
+		/* Add 10ms delay for micbias to settle */
+		usleep_range(10000, 10100);
+	}
+
+	return is_spl_hs;
+}
+
 static void wcd_correct_swch_plug(struct work_struct *work)
 {
 	struct wcd_mbhc *mbhc;
@@ -1029,12 +1079,14 @@ static void wcd_correct_swch_plug(struct work_struct *work)
 	enum wcd_mbhc_plug_type plug_type = MBHC_PLUG_TYPE_INVALID;
 	unsigned long timeout;
 	int pt_gnd_mic_swap_cnt = 0;
-	int output_mv, cross_conn, hs_threshold, try = 0;
+	int output_mv, cross_conn, hs_threshold, try = 0, micbias_mv;
+	bool is_spl_hs = false;
 	bool is_pa_on;
 
 	mbhc = container_of(work, struct wcd_mbhc, correct_plug_swch);
 	component = mbhc->component;
 
+	micbias_mv = wcd_mbhc_get_micbias(mbhc);
 	hs_threshold = wcd_mbhc_adc_get_hs_thres(mbhc);
 
 	/* Mask ADC COMPLETE interrupt */
@@ -1097,6 +1149,16 @@ static void wcd_correct_swch_plug(struct work_struct *work)
 		plug_type = wcd_mbhc_get_plug_from_adc(mbhc, output_mv);
 		is_pa_on = wcd_mbhc_read_field(mbhc, WCD_MBHC_HPH_PA_EN);
 
+		if ((output_mv > hs_threshold) && (!is_spl_hs)) {
+			is_spl_hs = wcd_mbhc_check_for_spl_headset(mbhc);
+			output_mv = wcd_measure_adc_once(mbhc, MUX_CTL_IN2P);
+
+			if (is_spl_hs) {
+				hs_threshold = (hs_threshold * wcd_mbhc_get_micbias(mbhc)) /
+									micbias_mv;
+			}
+		}
+
 		if ((output_mv <= hs_threshold) && !is_pa_on) {
 			/* Check for cross connection*/
 			cross_conn = wcd_check_cross_conn(mbhc);
@@ -1122,14 +1184,19 @@ static void wcd_correct_swch_plug(struct work_struct *work)
 			}
 		}
 
-		if (output_mv > hs_threshold) /* cable is extension cable */
+		/* cable is extension cable */
+		if (output_mv > hs_threshold || mbhc->force_linein == true)
 			plug_type = MBHC_PLUG_TYPE_HIGH_HPH;
 	}
 
 	wcd_mbhc_bcs_enable(mbhc, plug_type, true);
 
-	if (plug_type == MBHC_PLUG_TYPE_HIGH_HPH)
-		wcd_mbhc_write_field(mbhc, WCD_MBHC_ELECT_ISRC_EN, 1);
+	if (plug_type == MBHC_PLUG_TYPE_HIGH_HPH) {
+		if (is_spl_hs)
+			plug_type = MBHC_PLUG_TYPE_HEADSET;
+		else
+			wcd_mbhc_write_field(mbhc, WCD_MBHC_ELECT_ISRC_EN, 1);
+	}
 
 	wcd_mbhc_write_field(mbhc, WCD_MBHC_ADC_MODE, 0);
 	wcd_mbhc_write_field(mbhc, WCD_MBHC_ADC_EN, 0);
-- 
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