ASoC: codec: Disable surge protection before impedance detection

If surge protection is enabled, it interferes with HPHL
and does not give proper impedance for high impedance cable.
Disable surge protection before impedance detection and
enable it again after impedance detection on wcd937x and wcd938x.

Change-Id: I13840b0ba9fd9ce16b90f42dcd1a25ffb928b504
Signed-off-by: Vatsal Bucha <[email protected]>

asoc/codecs/wcd937x/wcd937x-mbhc.c

@@ -547,6 +547,12 @@ static void wcd937x_wcd_mbhc_calc_impedance(struct wcd_mbhc *mbhc, uint32_t *zl,
 	regmap_update_bits(wcd937x->regmap,
 			   WCD937X_ANA_MBHC_MECH, 0x01, 0x00);
 
+	/* Disable surge protection before impedance detection.
+	 * This is done to give correct value for high impedance.
+	 */
+	regmap_update_bits(wcd937x->regmap,
+			   WCD937X_HPH_SURGE_HPHLR_SURGE_EN, 0xC0, 0x00);
+
 	/* First get impedance on Left */
 	d1 = d1_a[1];
 	zdet_param_ptr = &zdet_param[1];
@@ -663,6 +669,9 @@ right_ch_impedance:
 		mbhc->hph_type = WCD_MBHC_HPH_MONO;
 	}
 
+	/* Enable surge protection again after impedance detection */
+	regmap_update_bits(wcd937x->regmap,
+			   WCD937X_HPH_SURGE_HPHLR_SURGE_EN, 0xC0, 0xC0);
 zdet_complete:
 	snd_soc_component_write(component, WCD937X_ANA_MBHC_BTN5, reg0);
 	snd_soc_component_write(component, WCD937X_ANA_MBHC_BTN6, reg1);

asoc/codecs/wcd938x/wcd938x-mbhc.c

@@ -547,6 +547,12 @@ static void wcd938x_wcd_mbhc_calc_impedance(struct wcd_mbhc *mbhc, uint32_t *zl,
 	regmap_update_bits(wcd938x->regmap,
 			   WCD938X_ANA_MBHC_MECH, 0x01, 0x00);
 
+	/* Disable surge protection before impedance detection.
+	 * This is done to give correct value for high impedance.
+	 */
+	regmap_update_bits(wcd938x->regmap,
+                          WCD938X_HPH_SURGE_HPHLR_SURGE_EN, 0xC0, 0x00);
+
 	/* First get impedance on Left */
 	d1 = d1_a[1];
 	zdet_param_ptr = &zdet_param[1];
@@ -656,6 +662,9 @@ right_ch_impedance:
 		mbhc->hph_type = WCD_MBHC_HPH_MONO;
 	}
 
+	/* Enable surge protection again after impedance detection */
+	regmap_update_bits(wcd938x->regmap,
+			   WCD938X_HPH_SURGE_HPHLR_SURGE_EN, 0xC0, 0xC0);
 zdet_complete:
 	snd_soc_component_write(component, WCD938X_ANA_MBHC_BTN5, reg0);
 	snd_soc_component_write(component, WCD938X_ANA_MBHC_BTN6, reg1);