ASoC: Improved wm_hubs headphone handling

Perform DC servo offset calibration using a series update sequence
rather than startup update sequence, tuning the configuration of the
WM8993 DC servo to make best use of this.

Also introduce currently unused data allowing us to correct for
any systematic errors in the DC servo calibration results and an
alternative startup path for the headphone output which performs
better with some chip revisions.  The alternative setup sequence is
enabled for WM8993.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>

sound/soc/codecs/wm8993.c

@@ -213,6 +213,7 @@ static struct {
 };
 
 struct wm8993_priv {
+	struct wm_hubs_data hubs_data;
 	u16 reg_cache[WM8993_REGISTER_COUNT];
 	struct wm8993_platform_data pdata;
 	struct snd_soc_codec codec;
@@ -997,6 +998,11 @@ static int wm8993_set_bias_level(struct snd_soc_codec *codec,
 
 	case SND_SOC_BIAS_STANDBY:
 		if (codec->bias_level == SND_SOC_BIAS_OFF) {
+			/* Tune DC servo configuration */
+			snd_soc_write(codec, 0x44, 3);
+			snd_soc_write(codec, 0x56, 3);
+			snd_soc_write(codec, 0x44, 0);
+
 			/* Bring up VMID with fast soft start */
 			snd_soc_update_bits(codec, WM8993_ANTIPOP2,
 					    WM8993_STARTUP_BIAS_ENA |
@@ -1591,6 +1597,8 @@ static int wm8993_i2c_probe(struct i2c_client *i2c,
 	codec->num_dai = 1;
 	codec->private_data = wm8993;
 
+	wm8993->hubs_data.hp_startup_mode = 1;
+
 	memcpy(wm8993->reg_cache, wm8993_reg_defaults,
 	       sizeof(wm8993->reg_cache));
 

sound/soc/codecs/wm_hubs.c

@@ -68,24 +68,77 @@ static void wait_for_dc_servo(struct snd_soc_codec *codec)
 	int count = 0;
 
 	dev_dbg(codec->dev, "Waiting for DC servo...\n");
+
 	do {
 		count++;
 		msleep(1);
 		reg = snd_soc_read(codec, WM8993_DC_SERVO_READBACK_0);
-		dev_dbg(codec->dev, "DC servo status: %x\n", reg);
-	} while ((reg & WM8993_DCS_CAL_COMPLETE_MASK)
-		 != WM8993_DCS_CAL_COMPLETE_MASK && count < 1000);
+		dev_dbg(codec->dev, "DC servo: %x\n", reg);
+	} while (reg & WM8993_DCS_DATAPATH_BUSY);
 
-	if ((reg & WM8993_DCS_CAL_COMPLETE_MASK)
-	    != WM8993_DCS_CAL_COMPLETE_MASK)
+	if (reg & WM8993_DCS_DATAPATH_BUSY)
 		dev_err(codec->dev, "Timed out waiting for DC Servo\n");
 }
 
+/*
+ * Startup calibration of the DC servo
+ */
+static void calibrate_dc_servo(struct snd_soc_codec *codec)
+{
+	struct wm_hubs_data *hubs = codec->private_data;
+	u16 reg, dcs_cfg;
+
+	/* Set for 32 series updates */
+	snd_soc_update_bits(codec, WM8993_DC_SERVO_1,
+			    WM8993_DCS_SERIES_NO_01_MASK,
+			    32 << WM8993_DCS_SERIES_NO_01_SHIFT);
+
+	/* Enable the DC servo.  Write all bits to avoid triggering startup
+	 * or write calibration.
+	 */
+	snd_soc_update_bits(codec, WM8993_DC_SERVO_0,
+			    0xFFFF,
+			    WM8993_DCS_ENA_CHAN_0 |
+			    WM8993_DCS_ENA_CHAN_1 |
+			    WM8993_DCS_TRIG_SERIES_1 |
+			    WM8993_DCS_TRIG_SERIES_0);
+
+	wait_for_dc_servo(codec);
+
+	/* Apply correction to DC servo result */
+	if (hubs->dcs_codes) {
+		dev_dbg(codec->dev, "Applying %d code DC servo correction\n",
+			hubs->dcs_codes);
+
+		/* HPOUT1L */
+		reg = snd_soc_read(codec, WM8993_DC_SERVO_READBACK_1) &
+			WM8993_DCS_INTEG_CHAN_0_MASK;;
+		reg += hubs->dcs_codes;
+		dcs_cfg = reg << WM8993_DCS_DAC_WR_VAL_1_SHIFT;
+
+		/* HPOUT1R */
+		reg = snd_soc_read(codec, WM8993_DC_SERVO_READBACK_2) &
+			WM8993_DCS_INTEG_CHAN_1_MASK;
+		reg += hubs->dcs_codes;
+		dcs_cfg |= reg;
+
+		/* Do it */
+		snd_soc_write(codec, WM8993_DC_SERVO_3, dcs_cfg);
+		snd_soc_update_bits(codec, WM8993_DC_SERVO_0,
+				    WM8993_DCS_TRIG_DAC_WR_0 |
+				    WM8993_DCS_TRIG_DAC_WR_1,
+				    WM8993_DCS_TRIG_DAC_WR_0 |
+				    WM8993_DCS_TRIG_DAC_WR_1);
+
+		wait_for_dc_servo(codec);
+	}
+}
+
 /*
  * Update the DC servo calibration on gain changes
  */
 static int wm8993_put_dc_servo(struct snd_kcontrol *kcontrol,
-			      struct snd_ctl_elem_value *ucontrol)
+			       struct snd_ctl_elem_value *ucontrol)
 {
 	struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);
 	int ret;
@@ -251,6 +304,47 @@ SOC_SINGLE_TLV("LINEOUT2 Volume", WM8993_LINE_OUTPUTS_VOLUME, 0, 1, 1,
 	       line_tlv),
 };
 
+static int hp_supply_event(struct snd_soc_dapm_widget *w,
+			   struct snd_kcontrol *kcontrol, int event)
+{
+	struct snd_soc_codec *codec = w->codec;
+	struct wm_hubs_data *hubs = codec->private_data;
+
+	switch (event) {
+	case SND_SOC_DAPM_PRE_PMU:
+		switch (hubs->hp_startup_mode) {
+		case 0:
+			break;
+		case 1:
+			/* Enable the headphone amp */
+			snd_soc_update_bits(codec, WM8993_POWER_MANAGEMENT_1,
+					    WM8993_HPOUT1L_ENA |
+					    WM8993_HPOUT1R_ENA,
+					    WM8993_HPOUT1L_ENA |
+					    WM8993_HPOUT1R_ENA);
+
+			/* Enable the second stage */
+			snd_soc_update_bits(codec, WM8993_ANALOGUE_HP_0,
+					    WM8993_HPOUT1L_DLY |
+					    WM8993_HPOUT1R_DLY,
+					    WM8993_HPOUT1L_DLY |
+					    WM8993_HPOUT1R_DLY);
+			break;
+		default:
+			dev_err(codec->dev, "Unknown HP startup mode %d\n",
+				hubs->hp_startup_mode);
+			break;
+		}
+
+	case SND_SOC_DAPM_PRE_PMD:
+		snd_soc_update_bits(codec, WM8993_CHARGE_PUMP_1,
+				    WM8993_CP_ENA, 0);
+		break;
+	}
+
+	return 0;
+}
+
 static int hp_event(struct snd_soc_dapm_widget *w,
 		    struct snd_kcontrol *kcontrol, int event)
 {
@@ -271,14 +365,11 @@ static int hp_event(struct snd_soc_dapm_widget *w,
 		reg |= WM8993_HPOUT1L_DLY | WM8993_HPOUT1R_DLY;
 		snd_soc_write(codec, WM8993_ANALOGUE_HP_0, reg);
 
-		/* Start the DC servo */
-		snd_soc_update_bits(codec, WM8993_DC_SERVO_0,
-				    0xFFFF,
-				    WM8993_DCS_ENA_CHAN_0 |
-				    WM8993_DCS_ENA_CHAN_1 |
-				    WM8993_DCS_TRIG_STARTUP_1 |
-				    WM8993_DCS_TRIG_STARTUP_0);
-		wait_for_dc_servo(codec);
+		/* Smallest supported update interval */
+		snd_soc_update_bits(codec, WM8993_DC_SERVO_1,
+				    WM8993_DCS_TIMER_PERIOD_01_MASK, 1);
+
+		calibrate_dc_servo(codec);
 
 		reg |= WM8993_HPOUT1R_OUTP | WM8993_HPOUT1R_RMV_SHORT |
 			WM8993_HPOUT1L_OUTP | WM8993_HPOUT1L_RMV_SHORT;
@@ -286,23 +377,19 @@ static int hp_event(struct snd_soc_dapm_widget *w,
 		break;
 
 	case SND_SOC_DAPM_PRE_PMD:
-		reg &= ~(WM8993_HPOUT1L_RMV_SHORT |
-			 WM8993_HPOUT1L_DLY |
-			 WM8993_HPOUT1L_OUTP |
-			 WM8993_HPOUT1R_RMV_SHORT |
-			 WM8993_HPOUT1R_DLY |
-			 WM8993_HPOUT1R_OUTP);
+		snd_soc_update_bits(codec, WM8993_ANALOGUE_HP_0,
+				    WM8993_HPOUT1L_DLY |
+				    WM8993_HPOUT1R_DLY |
+				    WM8993_HPOUT1L_RMV_SHORT |
+				    WM8993_HPOUT1R_RMV_SHORT, 0);
 
-		snd_soc_update_bits(codec, WM8993_DC_SERVO_0,
-				    0xffff, 0);
+		snd_soc_update_bits(codec, WM8993_ANALOGUE_HP_0,
+				    WM8993_HPOUT1L_OUTP |
+				    WM8993_HPOUT1R_OUTP, 0);
 
-		snd_soc_write(codec, WM8993_ANALOGUE_HP_0, reg);
 		snd_soc_update_bits(codec, WM8993_POWER_MANAGEMENT_1,
 				    WM8993_HPOUT1L_ENA | WM8993_HPOUT1R_ENA,
 				    0);
-
-		snd_soc_update_bits(codec, WM8993_CHARGE_PUMP_1,
-				    WM8993_CP_ENA, 0);
 		break;
 	}
 
@@ -473,6 +560,8 @@ SND_SOC_DAPM_MIXER("Right Output Mixer", WM8993_POWER_MANAGEMENT_3, 4, 0,
 SND_SOC_DAPM_PGA("Left Output PGA", WM8993_POWER_MANAGEMENT_3, 7, 0, NULL, 0),
 SND_SOC_DAPM_PGA("Right Output PGA", WM8993_POWER_MANAGEMENT_3, 6, 0, NULL, 0),
 
+SND_SOC_DAPM_SUPPLY("Headphone Supply", SND_SOC_NOPM, 0, 0, hp_supply_event, 
+		    SND_SOC_DAPM_PRE_PMU | SND_SOC_DAPM_PRE_PMD),
 SND_SOC_DAPM_PGA_E("Headphone PGA", SND_SOC_NOPM, 0, 0,
 		   NULL, 0,
 		   hp_event, SND_SOC_DAPM_POST_PMU | SND_SOC_DAPM_PRE_PMD),
@@ -626,6 +715,7 @@ static const struct snd_soc_dapm_route analogue_routes[] = {
 	{ "Headphone PGA", NULL, "Left Headphone Mux" },
 	{ "Headphone PGA", NULL, "Right Headphone Mux" },
 	{ "Headphone PGA", NULL, "CLK_SYS" },
+	{ "Headphone PGA", NULL, "Headphone Supply" },
 
 	{ "HPOUT1L", NULL, "Headphone PGA" },
 	{ "HPOUT1R", NULL, "Headphone PGA" },

sound/soc/codecs/wm_hubs.h

@@ -18,6 +18,12 @@ struct snd_soc_codec;
 
 extern const unsigned int wm_hubs_spkmix_tlv[];
 
+/* This *must* be the first element of the codec->private_data struct */
+struct wm_hubs_data {
+	int dcs_codes;
+	int hp_startup_mode;
+};
+
 extern int wm_hubs_add_analogue_controls(struct snd_soc_codec *);
 extern int wm_hubs_add_analogue_routes(struct snd_soc_codec *, int, int);
 extern int wm_hubs_handle_analogue_pdata(struct snd_soc_codec *,