ASoC: wm8904: fix wrong outputs volume after power reactivation

Restore volume after charge pump and PGA activation to ensure
that volume settings are correctly applied when re-enabling codec
from SND_SOC_BIAS_OFF state.
CLASS_W, CHARGE_PUMP and POWER_MANAGEMENT_2 register configuration
affect how the volume register are applied and must be configured first.

Fixes: a91eb19 ("ASoC: Initial WM8904 CODEC driver")
Link: https://lore.kernel.org/all/c7864c35-738c-a867-a6a6-ddf9f98df7e7@gmail.com/
Signed-off-by: Emanuele Ghidoli <emanuele.ghidoli@toradex.com>
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>

Author: eghidoli

sound/soc/codecs/wm8904.c

@@ -697,6 +697,7 @@ static int out_pga_event(struct snd_soc_dapm_widget *w,
 	int dcs_mask;
 	int dcs_l, dcs_r;
 	int dcs_l_reg, dcs_r_reg;
+	int an_out_reg;
 	int timeout;
 	int pwr_reg;
 
@@ -712,6 +713,7 @@ static int out_pga_event(struct snd_soc_dapm_widget *w,
 		dcs_mask = WM8904_DCS_ENA_CHAN_0 | WM8904_DCS_ENA_CHAN_1;
 		dcs_r_reg = WM8904_DC_SERVO_8;
 		dcs_l_reg = WM8904_DC_SERVO_9;
+		an_out_reg = WM8904_ANALOGUE_OUT1_LEFT;
 		dcs_l = 0;
 		dcs_r = 1;
 		break;
@@ -720,6 +722,7 @@ static int out_pga_event(struct snd_soc_dapm_widget *w,
 		dcs_mask = WM8904_DCS_ENA_CHAN_2 | WM8904_DCS_ENA_CHAN_3;
 		dcs_r_reg = WM8904_DC_SERVO_6;
 		dcs_l_reg = WM8904_DC_SERVO_7;
+		an_out_reg = WM8904_ANALOGUE_OUT2_LEFT;
 		dcs_l = 2;
 		dcs_r = 3;
 		break;
@@ -792,6 +795,10 @@ static int out_pga_event(struct snd_soc_dapm_widget *w,
 		snd_soc_component_update_bits(component, reg,
 				    WM8904_HPL_ENA_OUTP | WM8904_HPR_ENA_OUTP,
 				    WM8904_HPL_ENA_OUTP | WM8904_HPR_ENA_OUTP);
+
+		/* Update volume, requires PGA to be powered */
+		val = snd_soc_component_read(component, an_out_reg);
+		snd_soc_component_write(component, an_out_reg, val);
 		break;
 
 	case SND_SOC_DAPM_POST_PMU: