ASoC: mchp-spdifrx: add runtime PM support and fixes

Merge series from Claudiu Beznea <claudiu.beznea@microchip.com>:

This series adds runtime PM support for Microchip SPDIFRX driver.
Along with it I added few fixes identified while going though the code
and playing with Microchip SPDIFRX controller.

sound/soc/atmel/mchp-spdifrx.c

@@ -9,6 +9,7 @@
 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/module.h>
+#include <linux/pm_runtime.h>
 #include <linux/regmap.h>
 #include <linux/spinlock.h>
 
@@ -192,6 +193,43 @@ static bool mchp_spdifrx_precious_reg(struct device *dev, unsigned int reg)
 	}
 }
 
+static bool mchp_spdifrx_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case SPDIFRX_IMR:
+	case SPDIFRX_ISR:
+	case SPDIFRX_RSR:
+	case SPDIFRX_CHSR(0, 0):
+	case SPDIFRX_CHSR(0, 1):
+	case SPDIFRX_CHSR(0, 2):
+	case SPDIFRX_CHSR(0, 3):
+	case SPDIFRX_CHSR(0, 4):
+	case SPDIFRX_CHSR(0, 5):
+	case SPDIFRX_CHUD(0, 0):
+	case SPDIFRX_CHUD(0, 1):
+	case SPDIFRX_CHUD(0, 2):
+	case SPDIFRX_CHUD(0, 3):
+	case SPDIFRX_CHUD(0, 4):
+	case SPDIFRX_CHUD(0, 5):
+	case SPDIFRX_CHSR(1, 0):
+	case SPDIFRX_CHSR(1, 1):
+	case SPDIFRX_CHSR(1, 2):
+	case SPDIFRX_CHSR(1, 3):
+	case SPDIFRX_CHSR(1, 4):
+	case SPDIFRX_CHSR(1, 5):
+	case SPDIFRX_CHUD(1, 0):
+	case SPDIFRX_CHUD(1, 1):
+	case SPDIFRX_CHUD(1, 2):
+	case SPDIFRX_CHUD(1, 3):
+	case SPDIFRX_CHUD(1, 4):
+	case SPDIFRX_CHUD(1, 5):
+	case SPDIFRX_VERSION:
+		return true;
+	default:
+		return false;
+	}
+}
+
 static const struct regmap_config mchp_spdifrx_regmap_config = {
 	.reg_bits = 32,
 	.reg_stride = 4,
@@ -200,6 +238,8 @@ static const struct regmap_config mchp_spdifrx_regmap_config = {
 	.readable_reg = mchp_spdifrx_readable_reg,
 	.writeable_reg = mchp_spdifrx_writeable_reg,
 	.precious_reg = mchp_spdifrx_precious_reg,
+	.volatile_reg = mchp_spdifrx_volatile_reg,
+	.cache_type = REGCACHE_FLAT,
 };
 
 #define SPDIFRX_GCLK_RATIO_MIN	(12 * 64)
@@ -209,17 +249,34 @@ static const struct regmap_config mchp_spdifrx_regmap_config = {
 
 #define SPDIFRX_CHANNELS	2
 
+/**
+ * struct mchp_spdifrx_ch_stat: MCHP SPDIFRX channel status
+ * @data: channel status bits
+ * @done: completion to signal channel status bits acquisition done
+ */
 struct mchp_spdifrx_ch_stat {
 	unsigned char data[SPDIFRX_CS_BITS / 8];
 	struct completion done;
 };
 
+/**
+ * struct mchp_spdifrx_user_data: MCHP SPDIFRX user data
+ * @data: user data bits
+ * @done: completion to signal user data bits acquisition done
+ */
 struct mchp_spdifrx_user_data {
 	unsigned char data[SPDIFRX_UD_BITS / 8];
 	struct completion done;
-	spinlock_t lock;	/* protect access to user data */
 };
 
+/**
+ * struct mchp_spdifrx_mixer_control: MCHP SPDIFRX mixer control data structure
+ * @ch_stat: array of channel statuses
+ * @user_data: array of user data
+ * @ulock: ulock bit status
+ * @badf: badf bit status
+ * @signal: signal bit status
+ */
 struct mchp_spdifrx_mixer_control {
 	struct mchp_spdifrx_ch_stat ch_stat[SPDIFRX_CHANNELS];
 	struct mchp_spdifrx_user_data user_data[SPDIFRX_CHANNELS];
@@ -228,17 +285,26 @@ struct mchp_spdifrx_mixer_control {
 	bool signal;
 };
 
+/**
+ * struct mchp_spdifrx_dev: MCHP SPDIFRX device data structure
+ * @capture: DAI DMA configuration data
+ * @control: mixer controls
+ * @mlock: mutex to protect concurency b/w configuration and control APIs
+ * @dev: struct device
+ * @regmap: regmap for this device
+ * @pclk: peripheral clock
+ * @gclk: generic clock
+ * @trigger_enabled: true if enabled though trigger() ops
+ */
 struct mchp_spdifrx_dev {
 	struct snd_dmaengine_dai_dma_data	capture;
 	struct mchp_spdifrx_mixer_control	control;
-	spinlock_t				blockend_lock;	/* protect access to blockend_refcount */
-	int					blockend_refcount;
+	struct mutex				mlock;
 	struct device				*dev;
 	struct regmap				*regmap;
 	struct clk				*pclk;
 	struct clk				*gclk;
-	unsigned int				fmt;
-	unsigned int				gclk_enabled:1;
+	unsigned int				trigger_enabled;
 };
 
 static void mchp_spdifrx_channel_status_read(struct mchp_spdifrx_dev *dev,
@@ -275,37 +341,11 @@ static void mchp_spdifrx_channel_user_data_read(struct mchp_spdifrx_dev *dev,
 	}
 }
 
-/* called from non-atomic context only */
-static void mchp_spdifrx_isr_blockend_en(struct mchp_spdifrx_dev *dev)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&dev->blockend_lock, flags);
-	dev->blockend_refcount++;
-	/* don't enable BLOCKEND interrupt if it's already enabled */
-	if (dev->blockend_refcount == 1)
-		regmap_write(dev->regmap, SPDIFRX_IER, SPDIFRX_IR_BLOCKEND);
-	spin_unlock_irqrestore(&dev->blockend_lock, flags);
-}
-
-/* called from atomic/non-atomic context */
-static void mchp_spdifrx_isr_blockend_dis(struct mchp_spdifrx_dev *dev)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&dev->blockend_lock, flags);
-	dev->blockend_refcount--;
-	/* don't enable BLOCKEND interrupt if it's already enabled */
-	if (dev->blockend_refcount == 0)
-		regmap_write(dev->regmap, SPDIFRX_IDR, SPDIFRX_IR_BLOCKEND);
-	spin_unlock_irqrestore(&dev->blockend_lock, flags);
-}
-
 static irqreturn_t mchp_spdif_interrupt(int irq, void *dev_id)
 {
 	struct mchp_spdifrx_dev *dev = dev_id;
 	struct mchp_spdifrx_mixer_control *ctrl = &dev->control;
-	u32 sr, imr, pending, idr = 0;
+	u32 sr, imr, pending;
 	irqreturn_t ret = IRQ_NONE;
 	int ch;
 
@@ -320,13 +360,10 @@ static irqreturn_t mchp_spdif_interrupt(int irq, void *dev_id)
 
 	if (pending & SPDIFRX_IR_BLOCKEND) {
 		for (ch = 0; ch < SPDIFRX_CHANNELS; ch++) {
-			spin_lock(&ctrl->user_data[ch].lock);
 			mchp_spdifrx_channel_user_data_read(dev, ch);
-			spin_unlock(&ctrl->user_data[ch].lock);
-
 			complete(&ctrl->user_data[ch].done);
 		}
-		mchp_spdifrx_isr_blockend_dis(dev);
+		regmap_write(dev->regmap, SPDIFRX_IDR, SPDIFRX_IR_BLOCKEND);
 		ret = IRQ_HANDLED;
 	}
 
@@ -334,7 +371,7 @@ static irqreturn_t mchp_spdif_interrupt(int irq, void *dev_id)
 		if (pending & SPDIFRX_IR_CSC(ch)) {
 			mchp_spdifrx_channel_status_read(dev, ch);
 			complete(&ctrl->ch_stat[ch].done);
-			idr |= SPDIFRX_IR_CSC(ch);
+			regmap_write(dev->regmap, SPDIFRX_IDR, SPDIFRX_IR_CSC(ch));
 			ret = IRQ_HANDLED;
 		}
 	}
@@ -344,8 +381,6 @@ static irqreturn_t mchp_spdif_interrupt(int irq, void *dev_id)
 		ret = IRQ_HANDLED;
 	}
 
-	regmap_write(dev->regmap, SPDIFRX_IDR, idr);
-
 	return ret;
 }
 
@@ -353,47 +388,40 @@ static int mchp_spdifrx_trigger(struct snd_pcm_substream *substream, int cmd,
 				struct snd_soc_dai *dai)
 {
 	struct mchp_spdifrx_dev *dev = snd_soc_dai_get_drvdata(dai);
-	u32 mr;
-	int running;
-	int ret;
-
-	regmap_read(dev->regmap, SPDIFRX_MR, &mr);
-	running = !!(mr & SPDIFRX_MR_RXEN_ENABLE);
+	int ret = 0;
 
 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 	case SNDRV_PCM_TRIGGER_RESUME:
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
-		if (!running) {
-			mr &= ~SPDIFRX_MR_RXEN_MASK;
-			mr |= SPDIFRX_MR_RXEN_ENABLE;
-			/* enable overrun interrupts */
-			regmap_write(dev->regmap, SPDIFRX_IER,
-				     SPDIFRX_IR_OVERRUN);
-		}
+		mutex_lock(&dev->mlock);
+		/* Enable overrun interrupts */
+		regmap_write(dev->regmap, SPDIFRX_IER, SPDIFRX_IR_OVERRUN);
+
+		/* Enable receiver. */
+		regmap_update_bits(dev->regmap, SPDIFRX_MR, SPDIFRX_MR_RXEN_MASK,
+				   SPDIFRX_MR_RXEN_ENABLE);
+		dev->trigger_enabled = true;
+		mutex_unlock(&dev->mlock);
 		break;
 	case SNDRV_PCM_TRIGGER_STOP:
 	case SNDRV_PCM_TRIGGER_SUSPEND:
 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
-		if (running) {
-			mr &= ~SPDIFRX_MR_RXEN_MASK;
-			mr |= SPDIFRX_MR_RXEN_DISABLE;
-			/* disable overrun interrupts */
-			regmap_write(dev->regmap, SPDIFRX_IDR,
-				     SPDIFRX_IR_OVERRUN);
-		}
+		mutex_lock(&dev->mlock);
+		/* Disable overrun interrupts */
+		regmap_write(dev->regmap, SPDIFRX_IDR, SPDIFRX_IR_OVERRUN);
+
+		/* Disable receiver. */
+		regmap_update_bits(dev->regmap, SPDIFRX_MR, SPDIFRX_MR_RXEN_MASK,
+				   SPDIFRX_MR_RXEN_DISABLE);
+		dev->trigger_enabled = false;
+		mutex_unlock(&dev->mlock);
 		break;
 	default:
-		return -EINVAL;
+		ret = -EINVAL;
 	}
 
-	ret = regmap_write(dev->regmap, SPDIFRX_MR, mr);
-	if (ret) {
-		dev_err(dev->dev, "unable to enable/disable RX: %d\n", ret);
-		return ret;
-	}
-
-	return 0;
+	return ret;
 }
 
 static int mchp_spdifrx_hw_params(struct snd_pcm_substream *substream,
@@ -413,13 +441,6 @@ static int mchp_spdifrx_hw_params(struct snd_pcm_substream *substream,
 		return -EINVAL;
 	}
 
-	regmap_read(dev->regmap, SPDIFRX_MR, &mr);
-
-	if (mr & SPDIFRX_MR_RXEN_ENABLE) {
-		dev_err(dev->dev, "PCM already running\n");
-		return -EBUSY;
-	}
-
 	if (params_channels(params) != SPDIFRX_CHANNELS) {
 		dev_err(dev->dev, "unsupported number of channels: %d\n",
 			params_channels(params));
@@ -445,47 +466,46 @@ static int mchp_spdifrx_hw_params(struct snd_pcm_substream *substream,
 		return -EINVAL;
 	}
 
-	if (dev->gclk_enabled) {
-		clk_disable_unprepare(dev->gclk);
-		dev->gclk_enabled = 0;
+	mutex_lock(&dev->mlock);
+	if (dev->trigger_enabled) {
+		dev_err(dev->dev, "PCM already running\n");
+		ret = -EBUSY;
+		goto unlock;
 	}
+
+	/* GCLK is enabled by runtime PM. */
+	clk_disable_unprepare(dev->gclk);
+
 	ret = clk_set_min_rate(dev->gclk, params_rate(params) *
 					  SPDIFRX_GCLK_RATIO_MIN + 1);
 	if (ret) {
 		dev_err(dev->dev,
 			"unable to set gclk min rate: rate %u * ratio %u + 1\n",
 			params_rate(params), SPDIFRX_GCLK_RATIO_MIN);
-		return ret;
+		/* Restore runtime PM state. */
+		clk_prepare_enable(dev->gclk);
+		goto unlock;
 	}
 	ret = clk_prepare_enable(dev->gclk);
 	if (ret) {
 		dev_err(dev->dev, "unable to enable gclk: %d\n", ret);
-		return ret;
+		goto unlock;
 	}
-	dev->gclk_enabled = 1;
 
 	dev_dbg(dev->dev, "GCLK range min set to %d\n",
 		params_rate(params) * SPDIFRX_GCLK_RATIO_MIN + 1);
 
-	return regmap_write(dev->regmap, SPDIFRX_MR, mr);
-}
+	ret = regmap_write(dev->regmap, SPDIFRX_MR, mr);
 
-static int mchp_spdifrx_hw_free(struct snd_pcm_substream *substream,
-				struct snd_soc_dai *dai)
-{
-	struct mchp_spdifrx_dev *dev = snd_soc_dai_get_drvdata(dai);
+unlock:
+	mutex_unlock(&dev->mlock);
 
-	if (dev->gclk_enabled) {
-		clk_disable_unprepare(dev->gclk);
-		dev->gclk_enabled = 0;
-	}
-	return 0;
+	return ret;
 }
 
 static const struct snd_soc_dai_ops mchp_spdifrx_dai_ops = {
 	.trigger	= mchp_spdifrx_trigger,
 	.hw_params	= mchp_spdifrx_hw_params,
-	.hw_free	= mchp_spdifrx_hw_free,
 };
 
 #define MCHP_SPDIF_RATES	SNDRV_PCM_RATE_8000_192000
@@ -515,22 +535,58 @@ static int mchp_spdifrx_cs_get(struct mchp_spdifrx_dev *dev,
 {
 	struct mchp_spdifrx_mixer_control *ctrl = &dev->control;
 	struct mchp_spdifrx_ch_stat *ch_stat = &ctrl->ch_stat[channel];
-	int ret;
+	int ret = 0;
 
-	regmap_write(dev->regmap, SPDIFRX_IER, SPDIFRX_IR_CSC(channel));
-	/* check for new data available */
-	ret = wait_for_completion_interruptible_timeout(&ch_stat->done,
-							msecs_to_jiffies(100));
-	/* IP might not be started or valid stream might not be present */
-	if (ret < 0) {
-		dev_dbg(dev->dev, "channel status for channel %d timeout\n",
-			channel);
+	mutex_lock(&dev->mlock);
+
+	ret = pm_runtime_resume_and_get(dev->dev);
+	if (ret < 0)
+		goto unlock;
+
+	/*
+	 * We may reach this point with both clocks enabled but the receiver
+	 * still disabled. To void waiting for completion and return with
+	 * timeout check the dev->trigger_enabled.
+	 *
+	 * To retrieve data:
+	 * - if the receiver is enabled CSC IRQ will update the data in software
+	 *   caches (ch_stat->data)
+	 * - otherwise we just update it here the software caches with latest
+	 *   available information and return it; in this case we don't need
+	 *   spin locking as the IRQ is disabled and will not be raised from
+	 *   anywhere else.
+	 */
+
+	if (dev->trigger_enabled) {
+		reinit_completion(&ch_stat->done);
+		regmap_write(dev->regmap, SPDIFRX_IER, SPDIFRX_IR_CSC(channel));
+		/* Check for new data available */
+		ret = wait_for_completion_interruptible_timeout(&ch_stat->done,
+								msecs_to_jiffies(100));
+		/* Valid stream might not be present */
+		if (ret <= 0) {
+			dev_dbg(dev->dev, "channel status for channel %d timeout\n",
+				channel);
+			regmap_write(dev->regmap, SPDIFRX_IDR, SPDIFRX_IR_CSC(channel));
+			ret = ret ? : -ETIMEDOUT;
+			goto pm_runtime_put;
+		} else {
+			ret = 0;
+		}
+	} else {
+		/* Update software cache with latest channel status. */
+		mchp_spdifrx_channel_status_read(dev, channel);
 	}
 
 	memcpy(uvalue->value.iec958.status, ch_stat->data,
 	       sizeof(ch_stat->data));
 
-	return 0;
+pm_runtime_put:
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
+unlock:
+	mutex_unlock(&dev->mlock);
+	return ret;
 }
 
 static int mchp_spdifrx_cs1_get(struct snd_kcontrol *kcontrol,
@@ -564,29 +620,56 @@ static int mchp_spdifrx_subcode_ch_get(struct mchp_spdifrx_dev *dev,
 				       int channel,
 				       struct snd_ctl_elem_value *uvalue)
 {
-	unsigned long flags;
 	struct mchp_spdifrx_mixer_control *ctrl = &dev->control;
 	struct mchp_spdifrx_user_data *user_data = &ctrl->user_data[channel];
-	int ret;
+	int ret = 0;
 
-	reinit_completion(&user_data->done);
-	mchp_spdifrx_isr_blockend_en(dev);
-	ret = wait_for_completion_interruptible_timeout(&user_data->done,
-							msecs_to_jiffies(100));
-	/* IP might not be started or valid stream might not be present */
-	if (ret <= 0) {
-		dev_dbg(dev->dev, "user data for channel %d timeout\n",
-			channel);
-		mchp_spdifrx_isr_blockend_dis(dev);
-		return ret;
+	mutex_lock(&dev->mlock);
+
+	ret = pm_runtime_resume_and_get(dev->dev);
+	if (ret < 0)
+		goto unlock;
+
+	/*
+	 * We may reach this point with both clocks enabled but the receiver
+	 * still disabled. To void waiting for completion to just timeout we
+	 * check here the dev->trigger_enabled flag.
+	 *
+	 * To retrieve data:
+	 * - if the receiver is enabled we need to wait for blockend IRQ to read
+	 *   data to and update it for us in software caches
+	 * - otherwise reading the SPDIFRX_CHUD() registers is enough.
+	 */
+
+	if (dev->trigger_enabled) {
+		reinit_completion(&user_data->done);
+		regmap_write(dev->regmap, SPDIFRX_IER, SPDIFRX_IR_BLOCKEND);
+		ret = wait_for_completion_interruptible_timeout(&user_data->done,
+								msecs_to_jiffies(100));
+		/* Valid stream might not be present. */
+		if (ret <= 0) {
+			dev_dbg(dev->dev, "user data for channel %d timeout\n",
+				channel);
+			regmap_write(dev->regmap, SPDIFRX_IDR, SPDIFRX_IR_BLOCKEND);
+			ret = ret ? : -ETIMEDOUT;
+			goto pm_runtime_put;
+		} else {
+			ret = 0;
+		}
+	} else {
+		/* Update software cache with last available data. */
+		mchp_spdifrx_channel_user_data_read(dev, channel);
 	}
 
-	spin_lock_irqsave(&user_data->lock, flags);
 	memcpy(uvalue->value.iec958.subcode, user_data->data,
 	       sizeof(user_data->data));
-	spin_unlock_irqrestore(&user_data->lock, flags);
 
-	return 0;
+pm_runtime_put:
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
+unlock:
+	mutex_unlock(&dev->mlock);
+	return ret;
 }
 
 static int mchp_spdifrx_subcode_ch1_get(struct snd_kcontrol *kcontrol,
@@ -625,12 +708,34 @@ static int mchp_spdifrx_ulock_get(struct snd_kcontrol *kcontrol,
 	struct mchp_spdifrx_dev *dev = snd_soc_dai_get_drvdata(dai);
 	struct mchp_spdifrx_mixer_control *ctrl = &dev->control;
 	u32 val;
+	int ret;
 	bool ulock_old = ctrl->ulock;
 
-	regmap_read(dev->regmap, SPDIFRX_RSR, &val);
-	ctrl->ulock = !(val & SPDIFRX_RSR_ULOCK);
+	mutex_lock(&dev->mlock);
+
+	ret = pm_runtime_resume_and_get(dev->dev);
+	if (ret < 0)
+		goto unlock;
+
+	/*
+	 * The RSR.ULOCK has wrong value if both pclk and gclk are enabled
+	 * and the receiver is disabled. Thus we take into account the
+	 * dev->trigger_enabled here to return a real status.
+	 */
+	if (dev->trigger_enabled) {
+		regmap_read(dev->regmap, SPDIFRX_RSR, &val);
+		ctrl->ulock = !(val & SPDIFRX_RSR_ULOCK);
+	} else {
+		ctrl->ulock = 0;
+	}
+
 	uvalue->value.integer.value[0] = ctrl->ulock;
 
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
+unlock:
+	mutex_unlock(&dev->mlock);
+
 	return ulock_old != ctrl->ulock;
 }
 
@@ -641,10 +746,32 @@ static int mchp_spdifrx_badf_get(struct snd_kcontrol *kcontrol,
 	struct mchp_spdifrx_dev *dev = snd_soc_dai_get_drvdata(dai);
 	struct mchp_spdifrx_mixer_control *ctrl = &dev->control;
 	u32 val;
+	int ret;
 	bool badf_old = ctrl->badf;
 
-	regmap_read(dev->regmap, SPDIFRX_RSR, &val);
-	ctrl->badf = !!(val & SPDIFRX_RSR_BADF);
+	mutex_lock(&dev->mlock);
+
+	ret = pm_runtime_resume_and_get(dev->dev);
+	if (ret < 0)
+		goto unlock;
+
+	/*
+	 * The RSR.ULOCK has wrong value if both pclk and gclk are enabled
+	 * and the receiver is disabled. Thus we take into account the
+	 * dev->trigger_enabled here to return a real status.
+	 */
+	if (dev->trigger_enabled) {
+		regmap_read(dev->regmap, SPDIFRX_RSR, &val);
+		ctrl->badf = !!(val & SPDIFRX_RSR_BADF);
+	} else {
+		ctrl->badf = 0;
+	}
+
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
+unlock:
+	mutex_unlock(&dev->mlock);
+
 	uvalue->value.integer.value[0] = ctrl->badf;
 
 	return badf_old != ctrl->badf;
@@ -656,11 +783,49 @@ static int mchp_spdifrx_signal_get(struct snd_kcontrol *kcontrol,
 	struct snd_soc_dai *dai = snd_kcontrol_chip(kcontrol);
 	struct mchp_spdifrx_dev *dev = snd_soc_dai_get_drvdata(dai);
 	struct mchp_spdifrx_mixer_control *ctrl = &dev->control;
-	u32 val;
+	u32 val = ~0U, loops = 10;
+	int ret;
 	bool signal_old = ctrl->signal;
 
-	regmap_read(dev->regmap, SPDIFRX_RSR, &val);
-	ctrl->signal = !(val & SPDIFRX_RSR_NOSIGNAL);
+	mutex_lock(&dev->mlock);
+
+	ret = pm_runtime_resume_and_get(dev->dev);
+	if (ret < 0)
+		goto unlock;
+
+	/*
+	 * To get the signal we need to have receiver enabled. This
+	 * could be enabled also from trigger() function thus we need to
+	 * take care of not disabling the receiver when it runs.
+	 */
+	if (!dev->trigger_enabled) {
+		regmap_update_bits(dev->regmap, SPDIFRX_MR, SPDIFRX_MR_RXEN_MASK,
+				   SPDIFRX_MR_RXEN_ENABLE);
+
+		/* Wait for RSR.ULOCK bit. */
+		while (--loops) {
+			regmap_read(dev->regmap, SPDIFRX_RSR, &val);
+			if (!(val & SPDIFRX_RSR_ULOCK))
+				break;
+			usleep_range(100, 150);
+		}
+
+		regmap_update_bits(dev->regmap, SPDIFRX_MR, SPDIFRX_MR_RXEN_MASK,
+				   SPDIFRX_MR_RXEN_DISABLE);
+	} else {
+		regmap_read(dev->regmap, SPDIFRX_RSR, &val);
+	}
+
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
+
+unlock:
+	mutex_unlock(&dev->mlock);
+
+	if (!(val & SPDIFRX_RSR_ULOCK))
+		ctrl->signal = !(val & SPDIFRX_RSR_NOSIGNAL);
+	else
+		ctrl->signal = 0;
 	uvalue->value.integer.value[0] = ctrl->signal;
 
 	return signal_old != ctrl->signal;
@@ -682,22 +847,44 @@ static int mchp_spdifrx_rate_get(struct snd_kcontrol *kcontrol,
 {
 	struct snd_soc_dai *dai = snd_kcontrol_chip(kcontrol);
 	struct mchp_spdifrx_dev *dev = snd_soc_dai_get_drvdata(dai);
+	unsigned long rate;
 	u32 val;
-	int rate;
+	int ret;
 
-	regmap_read(dev->regmap, SPDIFRX_RSR, &val);
+	mutex_lock(&dev->mlock);
 
-	/* if the receiver is not locked, ISF data is invalid */
-	if (val & SPDIFRX_RSR_ULOCK || !(val & SPDIFRX_RSR_IFS_MASK)) {
+	ret = pm_runtime_resume_and_get(dev->dev);
+	if (ret < 0)
+		goto unlock;
+
+	/*
+	 * The RSR.ULOCK has wrong value if both pclk and gclk are enabled
+	 * and the receiver is disabled. Thus we take into account the
+	 * dev->trigger_enabled here to return a real status.
+	 */
+	if (dev->trigger_enabled) {
+		regmap_read(dev->regmap, SPDIFRX_RSR, &val);
+		/* If the receiver is not locked, ISF data is invalid. */
+		if (val & SPDIFRX_RSR_ULOCK || !(val & SPDIFRX_RSR_IFS_MASK)) {
+			ucontrol->value.integer.value[0] = 0;
+			goto pm_runtime_put;
+		}
+	} else {
+		/* Reveicer is not locked, IFS data is invalid. */
 		ucontrol->value.integer.value[0] = 0;
-		return 0;
+		goto pm_runtime_put;
 	}
 
 	rate = clk_get_rate(dev->gclk);
 
 	ucontrol->value.integer.value[0] = rate / (32 * SPDIFRX_RSR_IFS(val));
 
-	return 0;
+pm_runtime_put:
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
+unlock:
+	mutex_unlock(&dev->mlock);
+	return ret;
 }
 
 static struct snd_kcontrol_new mchp_spdifrx_ctrls[] = {
@@ -787,14 +974,6 @@ static int mchp_spdifrx_dai_probe(struct snd_soc_dai *dai)
 	struct mchp_spdifrx_dev *dev = snd_soc_dai_get_drvdata(dai);
 	struct mchp_spdifrx_mixer_control *ctrl = &dev->control;
 	int ch;
-	int err;
-
-	err = clk_prepare_enable(dev->pclk);
-	if (err) {
-		dev_err(dev->dev,
-			"failed to enable the peripheral clock: %d\n", err);
-		return err;
-	}
 
 	snd_soc_dai_init_dma_data(dai, NULL, &dev->capture);
 
@@ -808,11 +987,9 @@ static int mchp_spdifrx_dai_probe(struct snd_soc_dai *dai)
 		     SPDIFRX_MR_AUTORST_NOACTION |
 		     SPDIFRX_MR_PACK_DISABLED);
 
-	dev->blockend_refcount = 0;
 	for (ch = 0; ch < SPDIFRX_CHANNELS; ch++) {
 		init_completion(&ctrl->ch_stat[ch].done);
 		init_completion(&ctrl->user_data[ch].done);
-		spin_lock_init(&ctrl->user_data[ch].lock);
 	}
 
 	/* Add controls */
@@ -827,9 +1004,7 @@ static int mchp_spdifrx_dai_remove(struct snd_soc_dai *dai)
 	struct mchp_spdifrx_dev *dev = snd_soc_dai_get_drvdata(dai);
 
 	/* Disable interrupts */
-	regmap_write(dev->regmap, SPDIFRX_IDR, 0xFF);
-
-	clk_disable_unprepare(dev->pclk);
+	regmap_write(dev->regmap, SPDIFRX_IDR, GENMASK(14, 0));
 
 	return 0;
 }
@@ -861,6 +1036,48 @@ static const struct of_device_id mchp_spdifrx_dt_ids[] = {
 };
 MODULE_DEVICE_TABLE(of, mchp_spdifrx_dt_ids);
 
+static int mchp_spdifrx_runtime_suspend(struct device *dev)
+{
+	struct mchp_spdifrx_dev *spdifrx = dev_get_drvdata(dev);
+
+	regcache_cache_only(spdifrx->regmap, true);
+	clk_disable_unprepare(spdifrx->gclk);
+	clk_disable_unprepare(spdifrx->pclk);
+
+	return 0;
+}
+
+static int mchp_spdifrx_runtime_resume(struct device *dev)
+{
+	struct mchp_spdifrx_dev *spdifrx = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_prepare_enable(spdifrx->pclk);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(spdifrx->gclk);
+	if (ret)
+		goto disable_pclk;
+
+	regcache_cache_only(spdifrx->regmap, false);
+	regcache_mark_dirty(spdifrx->regmap);
+	ret = regcache_sync(spdifrx->regmap);
+	if (ret) {
+		regcache_cache_only(spdifrx->regmap, true);
+		clk_disable_unprepare(spdifrx->gclk);
+disable_pclk:
+		clk_disable_unprepare(spdifrx->pclk);
+	}
+
+	return ret;
+}
+
+static const struct dev_pm_ops mchp_spdifrx_pm_ops = {
+	RUNTIME_PM_OPS(mchp_spdifrx_runtime_suspend, mchp_spdifrx_runtime_resume,
+		       NULL)
+};
+
 static int mchp_spdifrx_probe(struct platform_device *pdev)
 {
 	struct mchp_spdifrx_dev *dev;
@@ -913,19 +1130,36 @@ static int mchp_spdifrx_probe(struct platform_device *pdev)
 			"failed to get the PMC generated clock: %d\n", err);
 		return err;
 	}
-	spin_lock_init(&dev->blockend_lock);
+
+	/*
+	 * Signal control need a valid rate on gclk. hw_params() configures
+	 * it propertly but requesting signal before any hw_params() has been
+	 * called lead to invalid value returned for signal. Thus, configure
+	 * gclk at a valid rate, here, in initialization, to simplify the
+	 * control path.
+	 */
+	clk_set_min_rate(dev->gclk, 48000 * SPDIFRX_GCLK_RATIO_MIN + 1);
+
+	mutex_init(&dev->mlock);
 
 	dev->dev = &pdev->dev;
 	dev->regmap = regmap;
 	platform_set_drvdata(pdev, dev);
 
+	pm_runtime_enable(dev->dev);
+	if (!pm_runtime_enabled(dev->dev)) {
+		err = mchp_spdifrx_runtime_resume(dev->dev);
+		if (err)
+			goto pm_runtime_disable;
+	}
+
 	dev->capture.addr	= (dma_addr_t)mem->start + SPDIFRX_RHR;
 	dev->capture.maxburst	= 1;
 
 	err = devm_snd_dmaengine_pcm_register(&pdev->dev, NULL, 0);
 	if (err) {
 		dev_err(&pdev->dev, "failed to register PCM: %d\n", err);
-		return err;
+		goto pm_runtime_suspend;
 	}
 
 	err = devm_snd_soc_register_component(&pdev->dev,
@@ -933,20 +1167,40 @@ static int mchp_spdifrx_probe(struct platform_device *pdev)
 					      &mchp_spdifrx_dai, 1);
 	if (err) {
 		dev_err(&pdev->dev, "fail to register dai\n");
-		return err;
+		goto pm_runtime_suspend;
 	}
 
 	regmap_read(regmap, SPDIFRX_VERSION, &vers);
 	dev_info(&pdev->dev, "hw version: %#lx\n", vers & SPDIFRX_VERSION_MASK);
 
 	return 0;
+
+pm_runtime_suspend:
+	if (!pm_runtime_status_suspended(dev->dev))
+		mchp_spdifrx_runtime_suspend(dev->dev);
+pm_runtime_disable:
+	pm_runtime_disable(dev->dev);
+	return err;
+}
+
+static int mchp_spdifrx_remove(struct platform_device *pdev)
+{
+	struct mchp_spdifrx_dev *dev = platform_get_drvdata(pdev);
+
+	pm_runtime_disable(dev->dev);
+	if (!pm_runtime_status_suspended(dev->dev))
+		mchp_spdifrx_runtime_suspend(dev->dev);
+
+	return 0;
 }
 
 static struct platform_driver mchp_spdifrx_driver = {
 	.probe	= mchp_spdifrx_probe,
+	.remove = mchp_spdifrx_remove,
 	.driver	= {
 		.name	= "mchp_spdifrx",
 		.of_match_table = of_match_ptr(mchp_spdifrx_dt_ids),
+		.pm	= pm_ptr(&mchp_spdifrx_pm_ops),
 	},
 };