[PATCH v2] mfd: cs42l43: Move cancel_work_sync() into remove

[PATCH v2] mfd: cs42l43: Move cancel_work_sync() into remove

[Charles Keepax]

The cs42l43 driver kicks off a work item waiting for the device
to appear on the SoundWire bus, once the device appears the
MFD children are added and the clean up is then done through
devres. As the work is synchronised in from the devres clean
up this could lead to new devres items being added after the
clean up has started, if the driver is removed before the work
has fully completed. The work should be synchronised before any
devres clean up is started.

Fixes: 0f35dc4bd50d ("mfd: cs42l43: Use devres for remove as well")
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---

Changes since v1:
 - Drop extra pm_runtime put for the case the boot work doesn't run and
   switch to flush_work such that we always know the boot work has run.

 drivers/mfd/cs42l43-i2c.c |  8 ++++++++
 drivers/mfd/cs42l43-sdw.c |  8 ++++++++
 drivers/mfd/cs42l43.c     | 12 ++++++++----
 drivers/mfd/cs42l43.h     |  1 +
 4 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/drivers/mfd/cs42l43-i2c.c b/drivers/mfd/cs42l43-i2c.c
index cbe05c3ea9100..36c5b03bae693 100644
--- a/drivers/mfd/cs42l43-i2c.c
+++ b/drivers/mfd/cs42l43-i2c.c
@@ -54,6 +54,13 @@ static int cs42l43_i2c_probe(struct i2c_client *i2c)
 	return cs42l43_dev_probe(cs42l43);
 }
 
+static void cs42l43_i2c_remove(struct i2c_client *i2c)
+{
+	struct cs42l43 *cs42l43 = dev_get_drvdata(&i2c->dev);
+
+	cs42l43_dev_remove(cs42l43);
+}
+
 #if IS_ENABLED(CONFIG_OF)
 static const struct of_device_id cs42l43_of_match[] = {
 	{ .compatible = "cirrus,cs42l43", .data = (void *)CS42L43_DEVID_VAL },
@@ -81,6 +88,7 @@ static struct i2c_driver cs42l43_i2c_driver = {
 	},
 
 	.probe		= cs42l43_i2c_probe,
+	.remove		= cs42l43_i2c_remove,
 };
 module_i2c_driver(cs42l43_i2c_driver);
 
diff --git a/drivers/mfd/cs42l43-sdw.c b/drivers/mfd/cs42l43-sdw.c
index 0a6999453f325..afed34d23af80 100644
--- a/drivers/mfd/cs42l43-sdw.c
+++ b/drivers/mfd/cs42l43-sdw.c
@@ -180,6 +180,13 @@ static int cs42l43_sdw_probe(struct sdw_slave *sdw, const struct sdw_device_id *
 	return cs42l43_dev_probe(cs42l43);
 }
 
+static void cs42l43_sdw_remove(struct sdw_slave *sdw)
+{
+	struct cs42l43 *cs42l43 = dev_get_drvdata(&sdw->dev);
+
+	cs42l43_dev_remove(cs42l43);
+}
+
 static const struct sdw_device_id cs42l43_sdw_id[] = {
 	SDW_SLAVE_ENTRY(0x01FA, 0x4243, (void *)CS42L43_DEVID_VAL),
 	SDW_SLAVE_ENTRY(0x01FA, 0x2A3B, (void *)CS42L43B_DEVID_VAL),
@@ -194,6 +201,7 @@ static struct sdw_driver cs42l43_sdw_driver = {
 	},
 
 	.probe		= cs42l43_sdw_probe,
+	.remove		= cs42l43_sdw_remove,
 	.id_table	= cs42l43_sdw_id,
 	.ops		= &cs42l43_sdw_ops,
 };
diff --git a/drivers/mfd/cs42l43.c b/drivers/mfd/cs42l43.c
index 4212ebcca60b5..3d26c33fee1d3 100644
--- a/drivers/mfd/cs42l43.c
+++ b/drivers/mfd/cs42l43.c
@@ -1099,15 +1099,19 @@ static int cs42l43_power_down(struct cs42l43 *cs42l43)
 	return 0;
 }
 
-static void cs42l43_dev_remove(void *data)
+static void cs42l43_dev_power_down(void *data)
 {
 	struct cs42l43 *cs42l43 = data;
 
-	cancel_work_sync(&cs42l43->boot_work);
-
 	cs42l43_power_down(cs42l43);
 }
 
+void cs42l43_dev_remove(struct cs42l43 *cs42l43)
+{
+	flush_work(&cs42l43->boot_work);
+}
+EXPORT_SYMBOL_NS_GPL(cs42l43_dev_remove, "MFD_CS42L43");
+
 int cs42l43_dev_probe(struct cs42l43 *cs42l43)
 {
 	int i, ret;
@@ -1153,7 +1157,7 @@ int cs42l43_dev_probe(struct cs42l43 *cs42l43)
 	if (ret)
 		return ret;
 
-	ret = devm_add_action_or_reset(cs42l43->dev, cs42l43_dev_remove, cs42l43);
+	ret = devm_add_action_or_reset(cs42l43->dev, cs42l43_dev_power_down, cs42l43);
 	if (ret)
 		return ret;
 
diff --git a/drivers/mfd/cs42l43.h b/drivers/mfd/cs42l43.h
index a0068f6572e2c..862bc6fb68cb7 100644
--- a/drivers/mfd/cs42l43.h
+++ b/drivers/mfd/cs42l43.h
@@ -25,5 +25,6 @@ bool cs42l43_precious_register(struct device *dev, unsigned int reg);
 bool cs42l43_volatile_register(struct device *dev, unsigned int reg);
 
 int cs42l43_dev_probe(struct cs42l43 *cs42l43);
+void cs42l43_dev_remove(struct cs42l43 *cs42l43);
 
 #endif /* CS42L43_CORE_INT_H */
-- 
2.47.3