ASoC: da7219: Fix pole orientation detection on OMTP headsets when playing music

The OMTP pin define headsets can be mis-detected as line out
instead of OMTP, causing obvious issues with audio quality.
This patch is to put increased resistances within
the device at a suitable point.

To solve this issue better, the new mechanism setup
ground switches with conditional delay control
and these allow for more stabile detection process
to operate as intended. This conditional delay control
will not impact the hardware process
but use extra system resource.

This commit improves control of ground switches in the AAD logic.

Signed-off-by: David Rau <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

sound/soc/codecs/da7219-aad.c

···
 	struct snd_soc_dapm_context *dapm = snd_soc_component_get_dapm(component);
 	struct da7219_priv *da7219 = snd_soc_component_get_drvdata(component);
 	u8 events[DA7219_AAD_IRQ_REG_MAX];
-	u8 statusa;
+	u8 statusa, srm_st;
 	int i, report = 0, mask = 0;
+
+	srm_st = snd_soc_component_read(component, DA7219_PLL_SRM_STS) & DA7219_PLL_SRM_STS_MCLK;
+	msleep(da7219_aad->gnd_switch_delay * ((srm_st == 0x0) ? 2 : 1) - 4);
+	/* Enable ground switch */
+	snd_soc_component_update_bits(component, 0xFB, 0x01, 0x01);
 
 	/* Read current IRQ events */
 	regmap_bulk_read(da7219->regmap, DA7219_ACCDET_IRQ_EVENT_A,
···
 			snd_soc_dapm_disable_pin(dapm, "Mic Bias");
 			snd_soc_dapm_sync(dapm);
 
-			/* Enable ground switch */
-			snd_soc_component_update_bits(component, 0xFB, 0x01, 0x01);
+			/* Disable ground switch */
+			snd_soc_component_update_bits(component, 0xFB, 0x01, 0x00);
 		}
 	}
 
···
 	}
 }
 
+static void da7219_aad_handle_gnd_switch_time(struct snd_soc_component *component)
+{
+	struct da7219_priv *da7219 = snd_soc_component_get_drvdata(component);
+	struct da7219_aad_priv *da7219_aad = da7219->aad;
+	u8 jack_det;
+
+	jack_det = snd_soc_component_read(component, DA7219_ACCDET_CONFIG_2)
+		& DA7219_JACK_DETECT_RATE_MASK;
+	switch (jack_det) {
+	case 0x00:
+		da7219_aad->gnd_switch_delay = 32;
+		break;
+	case 0x10:
+		da7219_aad->gnd_switch_delay = 64;
+		break;
+	case 0x20:
+		da7219_aad->gnd_switch_delay = 128;
+		break;
+	case 0x30:
+		da7219_aad->gnd_switch_delay = 256;
+		break;
+	default:
+		da7219_aad->gnd_switch_delay = 32;
+		break;
+	}
+}
 
 /*
  * Suspend/Resume
···
 	snd_soc_component_update_bits(component, DA7219_ACCDET_CONFIG_1,
 			    DA7219_BUTTON_CONFIG_MASK, 0);
 
-	/* Enable ground switch */
-	snd_soc_component_update_bits(component, 0xFB, 0x01, 0x01);
-
 	INIT_WORK(&da7219_aad->btn_det_work, da7219_aad_btn_det_work);
 	INIT_WORK(&da7219_aad->hptest_work, da7219_aad_hptest_work);
 
···
 	memset(mask, 0, DA7219_AAD_IRQ_REG_MAX);
 	regmap_bulk_write(da7219->regmap, DA7219_ACCDET_IRQ_MASK_A,
 			  &mask, DA7219_AAD_IRQ_REG_MAX);
+
+	da7219_aad_handle_gnd_switch_time(component);
 
 	return 0;
 }

sound/soc/codecs/da7219-aad.h

···
 struct da7219_aad_priv {
 	struct snd_soc_component *component;
 	int irq;
+	int gnd_switch_delay;
 
 	u8 micbias_pulse_lvl;
 	u32 micbias_pulse_time;