i2c: muxes always lock the parent adapter

Instead of checking for i2c parent adapters for every lock/unlock, simply
override the locking for muxes to always lock/unlock the parent adapter
directly.
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/i2c-core.c

@@ -962,12 +962,7 @@ static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
 				 unsigned int flags)
 {
-	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
-
-	if (parent)
-		i2c_lock_adapter(parent);
-	else
-		rt_mutex_lock(&adapter->bus_lock);
+	rt_mutex_lock(&adapter->bus_lock);
 }
 
 /**
@@ -979,12 +974,7 @@ static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
 				   unsigned int flags)
 {
-	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
-
-	if (parent)
-		return parent->trylock_bus(parent, flags);
-	else
-		return rt_mutex_trylock(&adapter->bus_lock);
+	return rt_mutex_trylock(&adapter->bus_lock);
 }
 
 /**
@@ -996,12 +986,7 @@ static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
 				   unsigned int flags)
 {
-	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
-
-	if (parent)
-		i2c_unlock_adapter(parent);
-	else
-		rt_mutex_unlock(&adapter->bus_lock);
+	rt_mutex_unlock(&adapter->bus_lock);
 }
 
 static void i2c_dev_set_name(struct i2c_adapter *adap,

drivers/i2c/i2c-mux.c

@@ -98,6 +98,33 @@ static unsigned int i2c_mux_parent_classes(struct i2c_adapter *parent)
 	return class;
 }
 
+static void i2c_parent_lock_bus(struct i2c_adapter *adapter,
+				unsigned int flags)
+{
+	struct i2c_mux_priv *priv = adapter->algo_data;
+	struct i2c_adapter *parent = priv->muxc->parent;
+
+	parent->lock_bus(parent, flags);
+}
+
+static int i2c_parent_trylock_bus(struct i2c_adapter *adapter,
+				  unsigned int flags)
+{
+	struct i2c_mux_priv *priv = adapter->algo_data;
+	struct i2c_adapter *parent = priv->muxc->parent;
+
+	return parent->trylock_bus(parent, flags);
+}
+
+static void i2c_parent_unlock_bus(struct i2c_adapter *adapter,
+				  unsigned int flags)
+{
+	struct i2c_mux_priv *priv = adapter->algo_data;
+	struct i2c_adapter *parent = priv->muxc->parent;
+
+	parent->unlock_bus(parent, flags);
+}
+
 struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent,
 				   struct device *dev, int max_adapters,
 				   int sizeof_priv, u32 flags,
@@ -165,6 +192,9 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
 	priv->adap.retries = parent->retries;
 	priv->adap.timeout = parent->timeout;
 	priv->adap.quirks = parent->quirks;
+	priv->adap.lock_bus = i2c_parent_lock_bus;
+	priv->adap.trylock_bus = i2c_parent_trylock_bus;
+	priv->adap.unlock_bus = i2c_parent_unlock_bus;
 
 	/* Sanity check on class */
 	if (i2c_mux_parent_classes(parent) & class)