[PATCH] ASoC: cs42l43: Move shutter IRQ handling into a worker thread

[Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx>]

The microphone/speaker privacy shutter ALSA control handlers need to
call pm_runtime_resume, since the hardware needs to be powered up to
check the hardware state of the shutter. The IRQ handler for the
shutters also needs to notify the ALSA control to inform user-space
the shutters updated. However this leads to a mutex inversion, between
the sdw_dev_lock and the controls_rwsem.

To avoid this mutex inversion add a work item for handling the shutter
IRQ and move the notifies into that.

Signed-off-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx>
---
 sound/soc/codecs/cs42l43.c | 43 +++++++++++++++++++++++++++-----------
 sound/soc/codecs/cs42l43.h |  3 +++
 2 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/sound/soc/codecs/cs42l43.c b/sound/soc/codecs/cs42l43.c
index 92674314227c4..74cb396ec0576 100644
--- a/sound/soc/codecs/cs42l43.c
+++ b/sound/soc/codecs/cs42l43.c
@@ -249,9 +249,10 @@ CS42L43_IRQ_COMPLETE(spkr_startup)
 CS42L43_IRQ_COMPLETE(spkl_startup)
 CS42L43_IRQ_COMPLETE(load_detect)
 
-static irqreturn_t cs42l43_mic_shutter(int irq, void *data)
+static void cs42l43_mic_shutter_work(struct work_struct *work)
 {
-	struct cs42l43_codec *priv = data;
+	struct cs42l43_codec *priv = container_of(work, struct cs42l43_codec,
+						  mic_shutter_work);
 	static const char * const controls[] = {
 		"Decimator 1 Switch",
 		"Decimator 2 Switch",
@@ -263,32 +264,47 @@ static irqreturn_t cs42l43_mic_shutter(int irq, void *data)
 	dev_dbg(priv->dev, "Microphone shutter changed\n");
 
 	if (!priv->component)
-		return IRQ_NONE;
+		return;
 
 	for (i = 0; i < ARRAY_SIZE(controls); i++) {
-		ret = snd_soc_component_notify_control(priv->component,
-						       controls[i]);
+		ret = snd_soc_component_notify_control(priv->component, controls[i]);
 		if (ret)
-			return IRQ_NONE;
+			dev_err(priv->dev, "Failed to notify control %s: %d\n",
+				controls[i], ret);
 	}
+}
+
+static irqreturn_t cs42l43_mic_shutter(int irq, void *data)
+{
+	struct cs42l43_codec *priv = data;
+
+	queue_work(system_wq, &priv->mic_shutter_work);
 
 	return IRQ_HANDLED;
 }
 
-static irqreturn_t cs42l43_spk_shutter(int irq, void *data)
+static void cs42l43_spk_shutter_work(struct work_struct *work)
 {
-	struct cs42l43_codec *priv = data;
+	struct cs42l43_codec *priv = container_of(work, struct cs42l43_codec,
+						  mic_shutter_work);
+	const char * const control = "Speaker Digital Switch";
 	int ret;
 
 	dev_dbg(priv->dev, "Speaker shutter changed\n");
 
 	if (!priv->component)
-		return IRQ_NONE;
+		return;
 
-	ret = snd_soc_component_notify_control(priv->component,
-					       "Speaker Digital Switch");
+	ret = snd_soc_component_notify_control(priv->component, control);
 	if (ret)
-		return IRQ_NONE;
+		dev_err(priv->dev, "Failed to notify control %s: %d\n", control, ret);
+}
+
+static irqreturn_t cs42l43_spk_shutter(int irq, void *data)
+{
+	struct cs42l43_codec *priv = data;
+
+	queue_work(system_wq, &priv->spk_shutter_work);
 
 	return IRQ_HANDLED;
 }
@@ -2280,6 +2296,9 @@ static int cs42l43_codec_probe(struct platform_device *pdev)
 	INIT_WORK(&priv->button_release_work, cs42l43_button_release_work);
 	INIT_WORK(&priv->hp_ilimit_work, cs42l43_hp_ilimit_work);
 
+	INIT_WORK(&priv->mic_shutter_work, cs42l43_mic_shutter_work);
+	INIT_WORK(&priv->spk_shutter_work, cs42l43_spk_shutter_work);
+
 	pm_runtime_set_autosuspend_delay(priv->dev, 100);
 	pm_runtime_use_autosuspend(priv->dev);
 	pm_runtime_set_active(priv->dev);
diff --git a/sound/soc/codecs/cs42l43.h b/sound/soc/codecs/cs42l43.h
index 9924c13e1eb53..5592aab5c8042 100644
--- a/sound/soc/codecs/cs42l43.h
+++ b/sound/soc/codecs/cs42l43.h
@@ -100,6 +100,9 @@ struct cs42l43_codec {
 	struct delayed_work hp_ilimit_clear_work;
 	bool hp_ilimited;
 	int hp_ilimit_count;
+
+	struct work_struct mic_shutter_work;
+	struct work_struct spk_shutter_work;
 };
 
 #if IS_REACHABLE(CONFIG_SND_SOC_CS42L43_SDW)
-- 
2.39.2