[PATCH 7/7] ASoC: SDCA: Add lock to serialise the Function initialisation

[Charles Keepax <ckeepax@opensource.cirrus.com>]

To avoid issues on some devices serialise the boot of each SDCA Function
from the others.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---
 sound/soc/sdca/sdca_class.c          | 1 +
 sound/soc/sdca/sdca_class.h          | 2 ++
 sound/soc/sdca/sdca_class_function.c | 5 +++++
 3 files changed, 8 insertions(+)

diff --git a/sound/soc/sdca/sdca_class.c b/sound/soc/sdca/sdca_class.c
index 438695291257e..1b83aad1d9d3b 100644
--- a/sound/soc/sdca/sdca_class.c
+++ b/sound/soc/sdca/sdca_class.c
@@ -205,6 +205,7 @@ static int class_sdw_probe(struct sdw_slave *sdw, const struct sdw_device_id *id
 	drv->dev = dev;
 	drv->sdw = sdw;
 	mutex_init(&drv->regmap_lock);
+	mutex_init(&drv->init_lock);
 
 	dev_set_drvdata(drv->dev, drv);
 
diff --git a/sound/soc/sdca/sdca_class.h b/sound/soc/sdca/sdca_class.h
index bb4c9dd124296..6f24ea2bbd381 100644
--- a/sound/soc/sdca/sdca_class.h
+++ b/sound/soc/sdca/sdca_class.h
@@ -28,6 +28,8 @@ struct sdca_class_drv {
 	struct sdca_interrupt_info *irq_info;
 
 	struct mutex regmap_lock;
+	/* Serialise function initialisations */
+	struct mutex init_lock;
 	struct work_struct boot_work;
 	struct completion device_attach;
 
diff --git a/sound/soc/sdca/sdca_class_function.c b/sound/soc/sdca/sdca_class_function.c
index aed325087c1dd..5af13ced9ceff 100644
--- a/sound/soc/sdca/sdca_class_function.c
+++ b/sound/soc/sdca/sdca_class_function.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/auxiliary_bus.h>
+#include <linux/cleanup.h>
 #include <linux/minmax.h>
 #include <linux/module.h>
 #include <linux/pm.h>
@@ -244,6 +245,8 @@ static int class_function_boot(struct class_function_drv *drv)
 	unsigned int val;
 	int ret;
 
+	guard(mutex)(&drv->core->init_lock);
+
 	ret = regmap_read(drv->regmap, reg, &val);
 	if (ret < 0) {
 		dev_err(drv->dev, "failed to read function status: %d\n", ret);
@@ -418,6 +421,8 @@ static int class_function_runtime_resume(struct device *dev)
 	struct class_function_drv *drv = auxiliary_get_drvdata(auxdev);
 	int ret;
 
+	guard(mutex)(&drv->core->init_lock);
+
 	regcache_mark_dirty(drv->regmap);
 	regcache_cache_only(drv->regmap, false);
 
-- 
2.47.3