1 files changed, 46 insertions, 23 deletions

diff --git a/sound/soc/codecs/wm_hubs.c b/sound/soc/codecs/wm_hubs.c
index 2cb8153..31c2a57 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)