regmap: Use different lockdep class for each regmap init call

Lockdep validator complains about recursive locking and deadlock
when two different regmap instances are called in a nested order.
That happens anytime a regmap read/write call needs to access
another regmap.

This is because, for performance reason, lockdep groups all locks
initialized by the same mutex_init() in the same lock class.
Therefore all regmap mutexes are in the same lock class, leading
to lockdep "nested locking" warnings if a regmap accesses another
regmap.

In general, it is impossible to establish in advance the hierarchy
of regmaps, so we make sure that each regmap init call initializes
its own static lock_class_key. This is done by wrapping all
regmap_init calls into macros.

This also allows us to give meaningful names to the lock_class_key.
For example, in rt5677 case, we have in /proc/lockdep_chains:
irq_context: 0
[ffffffc0018d2198] &dev->mutex
[ffffffc0018d2198] &dev->mutex
[ffffffc001bd7f60] rt5677:5104:(&rt5677_regmap)->_lock
[ffffffc001bd7f58] rt5677:5096:(&rt5677_regmap_physical)->_lock
[ffffffc001b95448] &(&base->lock)->rlock

The above would have resulted in a lockdep recursive warning
previously. This is not the case anymore as the lockdep validator
now clearly identifies the 2 regmaps as separate.

Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

6 files changed, 107 insertions, 61 deletions

diff --git a/drivers/base/regmap/regmap-ac97.c b/drivers/base/regmap/regmap-ac97.c
index 8d304e2a943d..aa631be8b821 100644
--- a/drivers/base/regmap/regmap-ac97.c
+++ b/drivers/base/regmap/regmap-ac97.c
@@ -87,12 +87,15 @@ static const struct regmap_bus ac97_regmap_bus = {
  * The return value will be an ERR_PTR() on error or a valid pointer to
  * a struct regmap.
  */
-struct regmap *regmap_init_ac97(struct snd_ac97 *ac97,
-				const struct regmap_config *config)
+struct regmap *__regmap_init_ac97(struct snd_ac97 *ac97,
+				  const struct regmap_config *config,
+				  struct lock_class_key *lock_key,
+				  const char *lock_name)
 {
-	return regmap_init(&ac97->dev, &ac97_regmap_bus, ac97, config);
+	return __regmap_init(&ac97->dev, &ac97_regmap_bus, ac97, config,
+			     lock_key, lock_name);
 }
-EXPORT_SYMBOL_GPL(regmap_init_ac97);
+EXPORT_SYMBOL_GPL(__regmap_init_ac97);
 
 /**
  * devm_regmap_init_ac97(): Initialise AC'97 register map
@@ -104,11 +107,14 @@ EXPORT_SYMBOL_GPL(regmap_init_ac97);
  * to a struct regmap.  The regmap will be automatically freed by the
  * device management code.
  */
-struct regmap *devm_regmap_init_ac97(struct snd_ac97 *ac97,
-				     const struct regmap_config *config)
+struct regmap *__devm_regmap_init_ac97(struct snd_ac97 *ac97,
+				       const struct regmap_config *config,
+				       struct lock_class_key *lock_key,
+				       const char *lock_name)
 {
-	return devm_regmap_init(&ac97->dev, &ac97_regmap_bus, ac97, config);
+	return __devm_regmap_init(&ac97->dev, &ac97_regmap_bus, ac97, config,
+				  lock_key, lock_name);
 }
-EXPORT_SYMBOL_GPL(devm_regmap_init_ac97);
+EXPORT_SYMBOL_GPL(__devm_regmap_init_ac97);
 
 MODULE_LICENSE("GPL v2");
diff --git a/drivers/base/regmap/regmap-i2c.c b/drivers/base/regmap/regmap-i2c.c
index 4b76e33110a2..3163b22e2baf 100644
--- a/drivers/base/regmap/regmap-i2c.c
+++ b/drivers/base/regmap/regmap-i2c.c
@@ -242,17 +242,20 @@ static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *i2c,
  * The return value will be an ERR_PTR() on error or a valid pointer to
  * a struct regmap.
  */
-struct regmap *regmap_init_i2c(struct i2c_client *i2c,
-			       const struct regmap_config *config)
+struct regmap *__regmap_init_i2c(struct i2c_client *i2c,
+				 const struct regmap_config *config,
+				 struct lock_class_key *lock_key,
+				 const char *lock_name)
 {
 	const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config);
 
 	if (IS_ERR(bus))
 		return ERR_CAST(bus);
 
-	return regmap_init(&i2c->dev, bus, &i2c->dev, config);
+	return __regmap_init(&i2c->dev, bus, &i2c->dev, config,
+			     lock_key, lock_name);
 }
-EXPORT_SYMBOL_GPL(regmap_init_i2c);
+EXPORT_SYMBOL_GPL(__regmap_init_i2c);
 
 /**
  * devm_regmap_init_i2c(): Initialise managed register map
@@ -264,16 +267,19 @@ EXPORT_SYMBOL_GPL(regmap_init_i2c);
  * to a struct regmap.  The regmap will be automatically freed by the
  * device management code.
  */
-struct regmap *devm_regmap_init_i2c(struct i2c_client *i2c,
-				    const struct regmap_config *config)
+struct regmap *__devm_regmap_init_i2c(struct i2c_client *i2c,
+				      const struct regmap_config *config,
+				      struct lock_class_key *lock_key,
+				      const char *lock_name)
 {
 	const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config);
 
 	if (IS_ERR(bus))
 		return ERR_CAST(bus);
 
-	return devm_regmap_init(&i2c->dev, bus, &i2c->dev, config);
+	return __devm_regmap_init(&i2c->dev, bus, &i2c->dev, config,
+				  lock_key, lock_name);
 }
-EXPORT_SYMBOL_GPL(devm_regmap_init_i2c);
+EXPORT_SYMBOL_GPL(__devm_regmap_init_i2c);
 
 MODULE_LICENSE("GPL");
diff --git a/drivers/base/regmap/regmap-mmio.c b/drivers/base/regmap/regmap-mmio.c
index 04a329a377e9..a1b2b270e4bc 100644
--- a/drivers/base/regmap/regmap-mmio.c
+++ b/drivers/base/regmap/regmap-mmio.c
@@ -307,9 +307,11 @@ err_free:
  * The return value will be an ERR_PTR() on error or a valid pointer to
  * a struct regmap.
  */
-struct regmap *regmap_init_mmio_clk(struct device *dev, const char *clk_id,
-				    void __iomem *regs,
-				    const struct regmap_config *config)
+struct regmap *__regmap_init_mmio_clk(struct device *dev, const char *clk_id,
+				      void __iomem *regs,
+				      const struct regmap_config *config,
+				      struct lock_class_key *lock_key,
+				      const char *lock_name)
 {
 	struct regmap_mmio_context *ctx;
 
@@ -317,9 +319,10 @@ struct regmap *regmap_init_mmio_clk(struct device *dev, const char *clk_id,
 	if (IS_ERR(ctx))
 		return ERR_CAST(ctx);
 
-	return regmap_init(dev, &regmap_mmio, ctx, config);
+	return __regmap_init(dev, &regmap_mmio, ctx, config,
+			     lock_key, lock_name);
 }
-EXPORT_SYMBOL_GPL(regmap_init_mmio_clk);
+EXPORT_SYMBOL_GPL(__regmap_init_mmio_clk);
 
 /**
  * devm_regmap_init_mmio_clk(): Initialise managed register map with clock
@@ -333,9 +336,12 @@ EXPORT_SYMBOL_GPL(regmap_init_mmio_clk);
  * to a struct regmap.  The regmap will be automatically freed by the
  * device management code.
  */
-struct regmap *devm_regmap_init_mmio_clk(struct device *dev, const char *clk_id,
-					 void __iomem *regs,
-					 const struct regmap_config *config)
+struct regmap *__devm_regmap_init_mmio_clk(struct device *dev,
+					   const char *clk_id,
+					   void __iomem *regs,
+					   const struct regmap_config *config,
+					   struct lock_class_key *lock_key,
+					   const char *lock_name)
 {
 	struct regmap_mmio_context *ctx;
 
@@ -343,8 +349,9 @@ struct regmap *devm_regmap_init_mmio_clk(struct device *dev, const char *clk_id,
 	if (IS_ERR(ctx))
 		return ERR_CAST(ctx);
 
-	return devm_regmap_init(dev, &regmap_mmio, ctx, config);
+	return __devm_regmap_init(dev, &regmap_mmio, ctx, config,
+				  lock_key, lock_name);
 }
-EXPORT_SYMBOL_GPL(devm_regmap_init_mmio_clk);
+EXPORT_SYMBOL_GPL(__devm_regmap_init_mmio_clk);
 
 MODULE_LICENSE("GPL v2");
diff --git a/drivers/base/regmap/regmap-spi.c b/drivers/base/regmap/regmap-spi.c
index 53d1148e80a0..4c7850d660d1 100644
--- a/drivers/base/regmap/regmap-spi.c
+++ b/drivers/base/regmap/regmap-spi.c
@@ -122,12 +122,15 @@ static struct regmap_bus regmap_spi = {
  * The return value will be an ERR_PTR() on error or a valid pointer to
  * a struct regmap.
  */
-struct regmap *regmap_init_spi(struct spi_device *spi,
-			       const struct regmap_config *config)
+struct regmap *__regmap_init_spi(struct spi_device *spi,
+				 const struct regmap_config *config,
+				 struct lock_class_key *lock_key,
+				 const char *lock_name)
 {
-	return regmap_init(&spi->dev, &regmap_spi, &spi->dev, config);
+	return __regmap_init(&spi->dev, &regmap_spi, &spi->dev, config,
+			     lock_key, lock_name);
 }
-EXPORT_SYMBOL_GPL(regmap_init_spi);
+EXPORT_SYMBOL_GPL(__regmap_init_spi);
 
 /**
  * devm_regmap_init_spi(): Initialise register map
@@ -139,11 +142,14 @@ EXPORT_SYMBOL_GPL(regmap_init_spi);
  * to a struct regmap.  The map will be automatically freed by the
  * device management code.
  */
-struct regmap *devm_regmap_init_spi(struct spi_device *spi,
-				    const struct regmap_config *config)
+struct regmap *__devm_regmap_init_spi(struct spi_device *spi,
+				      const struct regmap_config *config,
+				      struct lock_class_key *lock_key,
+				      const char *lock_name)
 {
-	return devm_regmap_init(&spi->dev, &regmap_spi, &spi->dev, config);
+	return __devm_regmap_init(&spi->dev, &regmap_spi, &spi->dev, config,
+				  lock_key, lock_name);
 }
-EXPORT_SYMBOL_GPL(devm_regmap_init_spi);
+EXPORT_SYMBOL_GPL(__devm_regmap_init_spi);
 
 MODULE_LICENSE("GPL");
diff --git a/drivers/base/regmap/regmap-spmi.c b/drivers/base/regmap/regmap-spmi.c
index d7026dc33388..7f50f5862d39 100644
--- a/drivers/base/regmap/regmap-spmi.c
+++ b/drivers/base/regmap/regmap-spmi.c
@@ -99,12 +99,15 @@ static struct regmap_bus regmap_spmi_base = {
  * The return value will be an ERR_PTR() on error or a valid pointer to
  * a struct regmap.
  */
-struct regmap *regmap_init_spmi_base(struct spmi_device *sdev,
-				     const struct regmap_config *config)
+struct regmap *__regmap_init_spmi_base(struct spmi_device *sdev,
+				       const struct regmap_config *config,
+				       struct lock_class_key *lock_key,
+				       const char *lock_name)
 {
-	return regmap_init(&sdev->dev, &regmap_spmi_base, sdev, config);
+	return __regmap_init(&sdev->dev, &regmap_spmi_base, sdev, config,
+			     lock_key, lock_name);
 }
-EXPORT_SYMBOL_GPL(regmap_init_spmi_base);
+EXPORT_SYMBOL_GPL(__regmap_init_spmi_base);
 
 /**
  * devm_regmap_init_spmi_base(): Create managed regmap for Base register space
@@ -115,12 +118,15 @@ EXPORT_SYMBOL_GPL(regmap_init_spmi_base);
  * to a struct regmap.  The regmap will be automatically freed by the
  * device management code.
  */
-struct regmap *devm_regmap_init_spmi_base(struct spmi_device *sdev,
-					  const struct regmap_config *config)
+struct regmap *__devm_regmap_init_spmi_base(struct spmi_device *sdev,
+					    const struct regmap_config *config,
+					    struct lock_class_key *lock_key,
+					    const char *lock_name)
 {
-	return devm_regmap_init(&sdev->dev, &regmap_spmi_base, sdev, config);
+	return __devm_regmap_init(&sdev->dev, &regmap_spmi_base, sdev, config,
+				  lock_key, lock_name);
 }
-EXPORT_SYMBOL_GPL(devm_regmap_init_spmi_base);
+EXPORT_SYMBOL_GPL(__devm_regmap_init_spmi_base);
 
 static int regmap_spmi_ext_read(void *context,
 				const void *reg, size_t reg_size,
@@ -230,12 +236,15 @@ static struct regmap_bus regmap_spmi_ext = {
  * The return value will be an ERR_PTR() on error or a valid pointer to
  * a struct regmap.
  */
-struct regmap *regmap_init_spmi_ext(struct spmi_device *sdev,
-				    const struct regmap_config *config)
+struct regmap *__regmap_init_spmi_ext(struct spmi_device *sdev,
+				      const struct regmap_config *config,
+				      struct lock_class_key *lock_key,
+				      const char *lock_name)
 {
-	return regmap_init(&sdev->dev, &regmap_spmi_ext, sdev, config);
+	return __regmap_init(&sdev->dev, &regmap_spmi_ext, sdev, config,
+			     lock_key, lock_name);
 }
-EXPORT_SYMBOL_GPL(regmap_init_spmi_ext);
+EXPORT_SYMBOL_GPL(__regmap_init_spmi_ext);
 
 /**
  * devm_regmap_init_spmi_ext(): Create managed regmap for Ext register space
@@ -246,11 +255,14 @@ EXPORT_SYMBOL_GPL(regmap_init_spmi_ext);
  * to a struct regmap.  The regmap will be automatically freed by the
  * device management code.
  */
-struct regmap *devm_regmap_init_spmi_ext(struct spmi_device *sdev,
-				     const struct regmap_config *config)
+struct regmap *__devm_regmap_init_spmi_ext(struct spmi_device *sdev,
+					   const struct regmap_config *config,
+					   struct lock_class_key *lock_key,
+					   const char *lock_name)
 {
-	return devm_regmap_init(&sdev->dev, &regmap_spmi_ext, sdev, config);
+	return __devm_regmap_init(&sdev->dev, &regmap_spmi_ext, sdev, config,
+				  lock_key, lock_name);
 }
-EXPORT_SYMBOL_GPL(devm_regmap_init_spmi_ext);
+EXPORT_SYMBOL_GPL(__devm_regmap_init_spmi_ext);
 
 MODULE_LICENSE("GPL");
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 7111d04f2621..b9fddccd6e06 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -527,10 +527,12 @@ EXPORT_SYMBOL_GPL(regmap_get_val_endian);
  * a struct regmap.  This function should generally not be called
  * directly, it should be called by bus-specific init functions.
  */
-struct regmap *regmap_init(struct device *dev,
-			   const struct regmap_bus *bus,
-			   void *bus_context,
-			   const struct regmap_config *config)
+struct regmap *__regmap_init(struct device *dev,
+			     const struct regmap_bus *bus,
+			     void *bus_context,
+			     const struct regmap_config *config,
+			     struct lock_class_key *lock_key,
+			     const char *lock_name)
 {
 	struct regmap *map;
 	int ret = -EINVAL;
@@ -556,10 +558,14 @@ struct regmap *regmap_init(struct device *dev,
 			spin_lock_init(&map->spinlock);
 			map->lock = regmap_lock_spinlock;
 			map->unlock = regmap_unlock_spinlock;
+			lockdep_set_class_and_name(&map->spinlock,
+						   lock_key, lock_name);
 		} else {
 			mutex_init(&map->mutex);
 			map->lock = regmap_lock_mutex;
 			map->unlock = regmap_unlock_mutex;
+			lockdep_set_class_and_name(&map->mutex,
+						   lock_key, lock_name);
 		}
 		map->lock_arg = map;
 	}
@@ -899,7 +905,7 @@ err_map:
 err:
 	return ERR_PTR(ret);
 }
-EXPORT_SYMBOL_GPL(regmap_init);
+EXPORT_SYMBOL_GPL(__regmap_init);
 
 static void devm_regmap_release(struct device *dev, void *res)
 {
@@ -919,10 +925,12 @@ static void devm_regmap_release(struct device *dev, void *res)
  * directly, it should be called by bus-specific init functions.  The
  * map will be automatically freed by the device management code.
  */
-struct regmap *devm_regmap_init(struct device *dev,
-				const struct regmap_bus *bus,
-				void *bus_context,
-				const struct regmap_config *config)
+struct regmap *__devm_regmap_init(struct device *dev,
+				  const struct regmap_bus *bus,
+				  void *bus_context,
+				  const struct regmap_config *config,
+				  struct lock_class_key *lock_key,
+				  const char *lock_name)
 {
 	struct regmap **ptr, *regmap;
 
@@ -930,7 +938,8 @@ struct regmap *devm_regmap_init(struct device *dev,
 	if (!ptr)
 		return ERR_PTR(-ENOMEM);
 
-	regmap = regmap_init(dev, bus, bus_context, config);
+	regmap = __regmap_init(dev, bus, bus_context, config,
+			       lock_key, lock_name);
 	if (!IS_ERR(regmap)) {
 		*ptr = regmap;
 		devres_add(dev, ptr);
@@ -940,7 +949,7 @@ struct regmap *devm_regmap_init(struct device *dev,
 
 	return regmap;
 }
-EXPORT_SYMBOL_GPL(devm_regmap_init);
+EXPORT_SYMBOL_GPL(__devm_regmap_init);
 
 static void regmap_field_init(struct regmap_field *rm_field,
 	struct regmap *regmap, struct reg_field reg_field)