Two bug fixes for tas5805m codec driver

Merge series from Daniel Beer <daniel.beer@igorinstitute.com>:

This pair of patches fixes two issues which crept in while revising the
original submission, at a time when I no longer had access to test
hardware.

The fixes here have been tested and verified on hardware.

sound/soc/codecs/tas5805m.c

@@ -154,6 +154,7 @@ static const uint32_t tas5805m_volume[] = {
 #define TAS5805M_VOLUME_MIN	0
 
 struct tas5805m_priv {
+	struct i2c_client		*i2c;
 	struct regulator		*pvdd;
 	struct gpio_desc		*gpio_pdn_n;
 
@@ -165,6 +166,9 @@ struct tas5805m_priv {
 	int				vol[2];
 	bool				is_powered;
 	bool				is_muted;
+
+	struct work_struct		work;
+	struct mutex			lock;
 };
 
 static void set_dsp_scale(struct regmap *rm, int offset, int vol)
@@ -181,13 +185,11 @@ static void set_dsp_scale(struct regmap *rm, int offset, int vol)
 	regmap_bulk_write(rm, offset, v, ARRAY_SIZE(v));
 }
 
-static void tas5805m_refresh(struct snd_soc_component *component)
+static void tas5805m_refresh(struct tas5805m_priv *tas5805m)
 {
-	struct tas5805m_priv *tas5805m =
-		snd_soc_component_get_drvdata(component);
 	struct regmap *rm = tas5805m->regmap;
 
-	dev_dbg(component->dev, "refresh: is_muted=%d, vol=%d/%d\n",
+	dev_dbg(&tas5805m->i2c->dev, "refresh: is_muted=%d, vol=%d/%d\n",
 		tas5805m->is_muted, tas5805m->vol[0], tas5805m->vol[1]);
 
 	regmap_write(rm, REG_PAGE, 0x00);
@@ -201,6 +203,9 @@ static void tas5805m_refresh(struct snd_soc_component *component)
 	set_dsp_scale(rm, 0x24, tas5805m->vol[0]);
 	set_dsp_scale(rm, 0x28, tas5805m->vol[1]);
 
+	regmap_write(rm, REG_PAGE, 0x00);
+	regmap_write(rm, REG_BOOK, 0x00);
+
 	/* Set/clear digital soft-mute */
 	regmap_write(rm, REG_DEVICE_CTRL_2,
 		(tas5805m->is_muted ? DCTRL2_MUTE : 0) |
@@ -226,8 +231,11 @@ static int tas5805m_vol_get(struct snd_kcontrol *kcontrol,
 	struct tas5805m_priv *tas5805m =
 		snd_soc_component_get_drvdata(component);
 
+	mutex_lock(&tas5805m->lock);
 	ucontrol->value.integer.value[0] = tas5805m->vol[0];
 	ucontrol->value.integer.value[1] = tas5805m->vol[1];
+	mutex_unlock(&tas5805m->lock);
+
 	return 0;
 }
 
@@ -243,11 +251,13 @@ static int tas5805m_vol_put(struct snd_kcontrol *kcontrol,
 		snd_soc_kcontrol_component(kcontrol);
 	struct tas5805m_priv *tas5805m =
 		snd_soc_component_get_drvdata(component);
+	int ret = 0;
 
 	if (!(volume_is_valid(ucontrol->value.integer.value[0]) &&
 	      volume_is_valid(ucontrol->value.integer.value[1])))
 		return -EINVAL;
 
+	mutex_lock(&tas5805m->lock);
 	if (tas5805m->vol[0] != ucontrol->value.integer.value[0] ||
 	    tas5805m->vol[1] != ucontrol->value.integer.value[1]) {
 		tas5805m->vol[0] = ucontrol->value.integer.value[0];
@@ -256,11 +266,12 @@ static int tas5805m_vol_put(struct snd_kcontrol *kcontrol,
 			tas5805m->vol[0], tas5805m->vol[1],
 			tas5805m->is_powered);
 		if (tas5805m->is_powered)
-			tas5805m_refresh(component);
-		return 1;
+			tas5805m_refresh(tas5805m);
+		ret = 1;
 	}
+	mutex_unlock(&tas5805m->lock);
 
-	return 0;
+	return ret;
 }
 
 static const struct snd_kcontrol_new tas5805m_snd_controls[] = {
@@ -294,54 +305,83 @@ static int tas5805m_trigger(struct snd_pcm_substream *substream, int cmd,
 	struct snd_soc_component *component = dai->component;
 	struct tas5805m_priv *tas5805m =
 		snd_soc_component_get_drvdata(component);
-	struct regmap *rm = tas5805m->regmap;
-	unsigned int chan, global1, global2;
 
 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 	case SNDRV_PCM_TRIGGER_RESUME:
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
-		dev_dbg(component->dev, "DSP startup\n");
-
-		/* We mustn't issue any I2C transactions until the I2S
-		 * clock is stable. Furthermore, we must allow a 5ms
-		 * delay after the first set of register writes to
-		 * allow the DSP to boot before configuring it.
-		 */
-		usleep_range(5000, 10000);
-		send_cfg(rm, dsp_cfg_preboot,
-			ARRAY_SIZE(dsp_cfg_preboot));
-		usleep_range(5000, 15000);
-		send_cfg(rm, tas5805m->dsp_cfg_data,
-			tas5805m->dsp_cfg_len);
-
-		tas5805m->is_powered = true;
-		tas5805m_refresh(component);
+		dev_dbg(component->dev, "clock start\n");
+		schedule_work(&tas5805m->work);
 		break;
 
 	case SNDRV_PCM_TRIGGER_STOP:
 	case SNDRV_PCM_TRIGGER_SUSPEND:
 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
-		dev_dbg(component->dev, "DSP shutdown\n");
+		break;
 
-		tas5805m->is_powered = false;
+	default:
+		return -EINVAL;
+	}
 
-		regmap_write(rm, REG_PAGE, 0x00);
-		regmap_write(rm, REG_BOOK, 0x00);
+	return 0;
+}
 
-		regmap_read(rm, REG_CHAN_FAULT, &chan);
-		regmap_read(rm, REG_GLOBAL_FAULT1, &global1);
-		regmap_read(rm, REG_GLOBAL_FAULT2, &global2);
+static void do_work(struct work_struct *work)
+{
+	struct tas5805m_priv *tas5805m =
+	       container_of(work, struct tas5805m_priv, work);
+	struct regmap *rm = tas5805m->regmap;
 
-		dev_dbg(component->dev,
-			"fault regs: CHAN=%02x, GLOBAL1=%02x, GLOBAL2=%02x\n",
-			chan, global1, global2);
+	dev_dbg(&tas5805m->i2c->dev, "DSP startup\n");
 
-		regmap_write(rm, REG_DEVICE_CTRL_2, DCTRL2_MODE_HIZ);
-		break;
+	mutex_lock(&tas5805m->lock);
+	/* We mustn't issue any I2C transactions until the I2S
+	 * clock is stable. Furthermore, we must allow a 5ms
+	 * delay after the first set of register writes to
+	 * allow the DSP to boot before configuring it.
+	 */
+	usleep_range(5000, 10000);
+	send_cfg(rm, dsp_cfg_preboot, ARRAY_SIZE(dsp_cfg_preboot));
+	usleep_range(5000, 15000);
+	send_cfg(rm, tas5805m->dsp_cfg_data, tas5805m->dsp_cfg_len);
+
+	tas5805m->is_powered = true;
+	tas5805m_refresh(tas5805m);
+	mutex_unlock(&tas5805m->lock);
+}
 
-	default:
-		return -EINVAL;
+static int tas5805m_dac_event(struct snd_soc_dapm_widget *w,
+			      struct snd_kcontrol *kcontrol, int event)
+{
+	struct snd_soc_component *component = snd_soc_dapm_to_component(w->dapm);
+	struct tas5805m_priv *tas5805m =
+		snd_soc_component_get_drvdata(component);
+	struct regmap *rm = tas5805m->regmap;
+
+	if (event & SND_SOC_DAPM_PRE_PMD) {
+		unsigned int chan, global1, global2;
+
+		dev_dbg(component->dev, "DSP shutdown\n");
+		cancel_work_sync(&tas5805m->work);
+
+		mutex_lock(&tas5805m->lock);
+		if (tas5805m->is_powered) {
+			tas5805m->is_powered = false;
+
+			regmap_write(rm, REG_PAGE, 0x00);
+			regmap_write(rm, REG_BOOK, 0x00);
+
+			regmap_read(rm, REG_CHAN_FAULT, &chan);
+			regmap_read(rm, REG_GLOBAL_FAULT1, &global1);
+			regmap_read(rm, REG_GLOBAL_FAULT2, &global2);
+
+			dev_dbg(component->dev, "fault regs: CHAN=%02x, "
+				"GLOBAL1=%02x, GLOBAL2=%02x\n",
+				chan, global1, global2);
+
+			regmap_write(rm, REG_DEVICE_CTRL_2, DCTRL2_MODE_HIZ);
+		}
+		mutex_unlock(&tas5805m->lock);
 	}
 
 	return 0;
@@ -354,7 +394,8 @@ static const struct snd_soc_dapm_route tas5805m_audio_map[] = {
 
 static const struct snd_soc_dapm_widget tas5805m_dapm_widgets[] = {
 	SND_SOC_DAPM_AIF_IN("DAC IN", "Playback", 0, SND_SOC_NOPM, 0, 0),
-	SND_SOC_DAPM_DAC("DAC", NULL, SND_SOC_NOPM, 0, 0),
+	SND_SOC_DAPM_DAC_E("DAC", NULL, SND_SOC_NOPM, 0, 0,
+		tas5805m_dac_event, SND_SOC_DAPM_PRE_PMD),
 	SND_SOC_DAPM_OUTPUT("OUT")
 };
 
@@ -375,11 +416,14 @@ static int tas5805m_mute(struct snd_soc_dai *dai, int mute, int direction)
 	struct tas5805m_priv *tas5805m =
 		snd_soc_component_get_drvdata(component);
 
+	mutex_lock(&tas5805m->lock);
 	dev_dbg(component->dev, "set mute=%d (is_powered=%d)\n",
 		mute, tas5805m->is_powered);
+
 	tas5805m->is_muted = mute;
 	if (tas5805m->is_powered)
-		tas5805m_refresh(component);
+		tas5805m_refresh(tas5805m);
+	mutex_unlock(&tas5805m->lock);
 
 	return 0;
 }
@@ -434,6 +478,7 @@ static int tas5805m_i2c_probe(struct i2c_client *i2c)
 	if (!tas5805m)
 		return -ENOMEM;
 
+	tas5805m->i2c = i2c;
 	tas5805m->pvdd = devm_regulator_get(dev, "pvdd");
 	if (IS_ERR(tas5805m->pvdd)) {
 		dev_err(dev, "failed to get pvdd supply: %ld\n",
@@ -507,6 +552,9 @@ static int tas5805m_i2c_probe(struct i2c_client *i2c)
 	gpiod_set_value(tas5805m->gpio_pdn_n, 1);
 	usleep_range(10000, 15000);
 
+	INIT_WORK(&tas5805m->work, do_work);
+	mutex_init(&tas5805m->lock);
+
 	/* Don't register through devm. We need to be able to unregister
 	 * the component prior to deasserting PDN#
 	 */
@@ -527,6 +575,7 @@ static void tas5805m_i2c_remove(struct i2c_client *i2c)
 	struct device *dev = &i2c->dev;
 	struct tas5805m_priv *tas5805m = dev_get_drvdata(dev);
 
+	cancel_work_sync(&tas5805m->work);
 	snd_soc_unregister_component(dev);
 	gpiod_set_value(tas5805m->gpio_pdn_n, 0);
 	usleep_range(10000, 15000);