linux-kernel - [PATCH v2 2/3] ASoC: cs42l42: Change jack_detect

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Date:   Fri, 21 Jan 2022 12:04:11 +0000
From:   Richard Fitzgerald <rf@...nsource.cirrus.com>
To:     <broonie@...nel.org>
CC:     <alsa-devel@...a-project.org>, <linux-kernel@...r.kernel.org>,
        <patches@...nsource.cirrus.com>,
        Richard Fitzgerald <rf@...nsource.cirrus.com>
Subject: [PATCH v2 2/3] ASoC: cs42l42: Change jack_detect_mutex to a lock of all IRQ handling

Rename jack_detect_mutex to irq_lock and make it lock the entire IRQ
handling.

The jack_detect_mutex was introduced to synchronize registering an
ALSA jack handler, via cs42l42_set_jack(), with the jack state
processing in the IRQ handler, and was taken only around the
relevant part of the IRQ handling code.

System suspend will need to synchronize with the IRQ handler thread
so will need a similar mutex that surrounds all of the IRQ handling.
Repurposing the existing jack_detect_mutex is the simplest option.
It does no harm for a call to cs42l42_set_jack() to additionally
block the first few lines of IRQ handling, and the only interrupts
used by the driver are all for jack handling.

Signed-off-by: Richard Fitzgerald <rf@...nsource.cirrus.com>
---
 sound/soc/codecs/cs42l42.c | 11 +++++------
 sound/soc/codecs/cs42l42.h |  2 +-
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/sound/soc/codecs/cs42l42.c b/sound/soc/codecs/cs42l42.c
index 2c294868008e..f1b95d45af4a 100644
--- a/sound/soc/codecs/cs42l42.c
+++ b/sound/soc/codecs/cs42l42.c
@@ -550,7 +550,7 @@ static int cs42l42_set_jack(struct snd_soc_component *component, struct snd_soc_
 	struct cs42l42_private *cs42l42 = snd_soc_component_get_drvdata(component);
 
 	/* Prevent race with interrupt handler */
-	mutex_lock(&cs42l42->jack_detect_mutex);
+	mutex_lock(&cs42l42->irq_lock);
 	cs42l42->jack = jk;
 
 	if (jk) {
@@ -566,7 +566,7 @@ static int cs42l42_set_jack(struct snd_soc_component *component, struct snd_soc_
 			break;
 		}
 	}
-	mutex_unlock(&cs42l42->jack_detect_mutex);
+	mutex_unlock(&cs42l42->irq_lock);
 
 	return 0;
 }
@@ -1613,6 +1613,7 @@ static irqreturn_t cs42l42_irq_thread(int irq, void *data)
 	unsigned int i;
 	int report = 0;
 
+	mutex_lock(&cs42l42->irq_lock);
 
 	/* Read sticky registers to clear interurpt */
 	for (i = 0; i < ARRAY_SIZE(stickies); i++) {
@@ -1635,8 +1636,6 @@ static irqreturn_t cs42l42_irq_thread(int irq, void *data)
 		CS42L42_M_DETECT_FT_MASK |
 		CS42L42_M_HSBIAS_HIZ_MASK);
 
-	mutex_lock(&cs42l42->jack_detect_mutex);
-
 	/*
 	 * Check auto-detect status. Don't assume a previous unplug event has
 	 * cleared the flags. If the jack is unplugged and plugged during
@@ -1713,7 +1712,7 @@ static irqreturn_t cs42l42_irq_thread(int irq, void *data)
 		}
 	}
 
-	mutex_unlock(&cs42l42->jack_detect_mutex);
+	mutex_unlock(&cs42l42->irq_lock);
 
 	return IRQ_HANDLED;
 }
@@ -2062,7 +2061,7 @@ static int cs42l42_i2c_probe(struct i2c_client *i2c_client,
 
 	cs42l42->dev = &i2c_client->dev;
 	i2c_set_clientdata(i2c_client, cs42l42);
-	mutex_init(&cs42l42->jack_detect_mutex);
+	mutex_init(&cs42l42->irq_lock);
 
 	cs42l42->regmap = devm_regmap_init_i2c(i2c_client, &cs42l42_regmap);
 	if (IS_ERR(cs42l42->regmap)) {
diff --git a/sound/soc/codecs/cs42l42.h b/sound/soc/codecs/cs42l42.h
index 9fff183dce8e..53d96287abba 100644
--- a/sound/soc/codecs/cs42l42.h
+++ b/sound/soc/codecs/cs42l42.h
@@ -842,7 +842,7 @@ struct  cs42l42_private {
 	struct gpio_desc *reset_gpio;
 	struct completion pdn_done;
 	struct snd_soc_jack *jack;
-	struct mutex jack_detect_mutex;
+	struct mutex irq_lock;
 	int pll_config;
 	int bclk;
 	u32 sclk;
-- 
2.11.0