4 files changed, 54 insertions, 23 deletions

diff --git a/sound/soc/codecs/wm8993.c b/sound/soc/codecs/wm8993.c
index 589e3fa24734..67fe5ccc6082 100644
--- a/sound/soc/codecs/wm8993.c
+++ b/sound/soc/codecs/wm8993.c
@@ -735,6 +735,7 @@ static int class_w_put(struct snd_kcontrol *kcontrol,
 					    0);
 		}
 		wm8993->class_w_users++;
+		wm8993->hubs_data.class_w = true;
 	}
 
 	/* Implement the change */
@@ -751,6 +752,7 @@ static int class_w_put(struct snd_kcontrol *kcontrol,
 					    WM8993_CP_DYN_V);
 		}
 		wm8993->class_w_users--;
+		wm8993->hubs_data.class_w = false;
 	}
 
 	dev_dbg(codec->dev, "Indirect DAC use count now %d\n",
diff --git a/sound/soc/codecs/wm8994.c b/sound/soc/codecs/wm8994.c
index 0db59c3aa5d4..3f70dee048b0 100644
--- a/sound/soc/codecs/wm8994.c
+++ b/sound/soc/codecs/wm8994.c
@@ -2228,6 +2228,7 @@ static int clk_sys_event(struct snd_soc_dapm_widget *w,
 
 static void wm8994_update_class_w(struct snd_soc_codec *codec)
 {
+	struct wm8994_priv *wm8994 = snd_soc_codec_get_drvdata(codec);
 	int enable = 1;
 	int source = 0;  /* GCC flow analysis can't track enable */
 	int reg, reg_r;
@@ -2278,11 +2279,13 @@ static void wm8994_update_class_w(struct snd_soc_codec *codec)
 				    WM8994_CP_DYN_PWR |
 				    WM8994_CP_DYN_SRC_SEL_MASK,
 				    source | WM8994_CP_DYN_PWR);
+		wm8994->hubs.class_w = true;
 		
 	} else {
 		dev_dbg(codec->dev, "Class W disabled\n");
 		snd_soc_update_bits(codec, WM8994_CLASS_W_1,
 				    WM8994_CP_DYN_PWR, 0);
+		wm8994->hubs.class_w = false;
 	}
 }
 
diff --git a/sound/soc/codecs/wm_hubs.c b/sound/soc/codecs/wm_hubs.c
index 2cb81538cd91..31c2a5724d85 100644
--- a/sound/soc/codecs/wm_hubs.c
+++ b/sound/soc/codecs/wm_hubs.c
@@ -94,6 +94,18 @@ static void calibrate_dc_servo(struct snd_soc_codec *codec)
 	struct wm_hubs_data *hubs = snd_soc_codec_get_drvdata(codec);
 	u16 reg, reg_l, reg_r, dcs_cfg;
 
+	/* If we're using a digital only path and have a previously
+	 * callibrated DC servo offset stored then use that. */
+	if (hubs->class_w && hubs->class_w_dcs) {
+		dev_dbg(codec->dev, "Using cached DC servo offset %x\n",
+			hubs->class_w_dcs);
+		snd_soc_write(codec, WM8993_DC_SERVO_3, hubs->class_w_dcs);
+		wait_for_dc_servo(codec,
+				  WM8993_DCS_TRIG_DAC_WR_0 |
+				  WM8993_DCS_TRIG_DAC_WR_1);
+		return;
+	}
+
 	/* Set for 32 series updates */
 	snd_soc_update_bits(codec, WM8993_DC_SERVO_1,
 			    WM8993_DCS_SERIES_NO_01_MASK,
@@ -101,34 +113,34 @@ static void calibrate_dc_servo(struct snd_soc_codec *codec)
 	wait_for_dc_servo(codec,
 			  WM8993_DCS_TRIG_SERIES_0 | WM8993_DCS_TRIG_SERIES_1);
 
+	/* Different chips in the family support different readback
+	 * methods.
+	 */
+	switch (hubs->dcs_readback_mode) {
+	case 0:
+		reg_l = snd_soc_read(codec, WM8993_DC_SERVO_READBACK_1)
+			& WM8993_DCS_INTEG_CHAN_0_MASK;;
+		reg_r = snd_soc_read(codec, WM8993_DC_SERVO_READBACK_2)
+			& WM8993_DCS_INTEG_CHAN_1_MASK;
+		break;
+	case 1:
+		reg = snd_soc_read(codec, WM8993_DC_SERVO_3);
+		reg_l = (reg & WM8993_DCS_DAC_WR_VAL_1_MASK)
+			>> WM8993_DCS_DAC_WR_VAL_1_SHIFT;
+		reg_r = reg & WM8993_DCS_DAC_WR_VAL_0_MASK;
+		break;
+	default:
+		WARN(1, "Unknown DCS readback method");
+		break;
+	}
+
+	dev_dbg(codec->dev, "DCS input: %x %x\n", reg_l, reg_r);
+
 	/* Apply correction to DC servo result */
 	if (hubs->dcs_codes) {
 		dev_dbg(codec->dev, "Applying %d code DC servo correction\n",
 			hubs->dcs_codes);
 
-		/* Different chips in the family support different
-		 * readback methods.
-		 */
-		switch (hubs->dcs_readback_mode) {
-		case 0:
-			reg_l = snd_soc_read(codec, WM8993_DC_SERVO_READBACK_1)
-				& WM8993_DCS_INTEG_CHAN_0_MASK;;
-			reg_r = snd_soc_read(codec, WM8993_DC_SERVO_READBACK_2)
-				& WM8993_DCS_INTEG_CHAN_1_MASK;
-			break;
-		case 1:
-			reg = snd_soc_read(codec, WM8993_DC_SERVO_3);
-			reg_l = (reg & WM8993_DCS_DAC_WR_VAL_1_MASK)
-				>> WM8993_DCS_DAC_WR_VAL_1_SHIFT;
-			reg_r = reg & WM8993_DCS_DAC_WR_VAL_0_MASK;
-			break;
-		default:
-			WARN(1, "Unknown DCS readback method");
-			break;
-		}
-
-		dev_dbg(codec->dev, "DCS input: %x %x\n", reg_l, reg_r);
-
 		/* HPOUT1L */
 		if (reg_l + hubs->dcs_codes > 0 &&
 		    reg_l + hubs->dcs_codes < 0xff)
@@ -148,7 +160,15 @@ static void calibrate_dc_servo(struct snd_soc_codec *codec)
 		wait_for_dc_servo(codec,
 				  WM8993_DCS_TRIG_DAC_WR_0 |
 				  WM8993_DCS_TRIG_DAC_WR_1);
+	} else {
+		dcs_cfg = reg_l << WM8993_DCS_DAC_WR_VAL_1_SHIFT;
+		dcs_cfg |= reg_r;
 	}
+
+	/* Save the callibrated offset if we're in class W mode and
+	 * therefore don't have any analogue signal mixed in. */
+	if (hubs->class_w)
+		hubs->class_w_dcs = dcs_cfg;
 }
 
 /*
@@ -163,6 +183,9 @@ static int wm8993_put_dc_servo(struct snd_kcontrol *kcontrol,
 
 	ret = snd_soc_put_volsw_2r(kcontrol, ucontrol);
 
+	/* Updating the analogue gains invalidates the DC servo cache */
+	hubs->class_w_dcs = 0;
+
 	/* If we're applying an offset correction then updating the
 	 * callibration would be likely to introduce further offsets. */
 	if (hubs->dcs_codes)
diff --git a/sound/soc/codecs/wm_hubs.h b/sound/soc/codecs/wm_hubs.h
index e51c16683589..f8a5e976b5e6 100644
--- a/sound/soc/codecs/wm_hubs.h
+++ b/sound/soc/codecs/wm_hubs.h
@@ -23,6 +23,9 @@ struct wm_hubs_data {
 	int dcs_codes;
 	int dcs_readback_mode;
 	int hp_startup_mode;
+
+	bool class_w;
+	u16 class_w_dcs;
 };
 
 extern int wm_hubs_add_analogue_controls(struct snd_soc_codec *);