i2c: Move adapter locking helpers to i2c-core

Uninline i2c adapter locking helper functions, move them to i2c-core,
and use them in i2c-core itself. The functions are still exported for
external users. This makes future updates to the locking model (which
will be needed for multiplexing support) possible and transparent.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Michael Lawnick <ml.lawnick@gmx.de>

1 files changed, 34 insertions, 5 deletions

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 6e1c2f54d9cf..e09e143379b1 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -430,6 +430,35 @@ static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 }
 
 /**
+ * i2c_lock_adapter - Get exclusive access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ */
+void i2c_lock_adapter(struct i2c_adapter *adapter)
+{
+        rt_mutex_lock(&adapter->bus_lock);
+}
+EXPORT_SYMBOL_GPL(i2c_lock_adapter);
+
+/**
+ * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ */
+static int i2c_trylock_adapter(struct i2c_adapter *adapter)
+{
+        return rt_mutex_trylock(&adapter->bus_lock);
+}
+
+/**
+ * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ */
+void i2c_unlock_adapter(struct i2c_adapter *adapter)
+{
+        rt_mutex_unlock(&adapter->bus_lock);
+}
+EXPORT_SYMBOL_GPL(i2c_unlock_adapter);
+
+/**
  * i2c_new_device - instantiate an i2c device
  * @adap: the adapter managing the device
  * @info: describes one I2C device; bus_num is ignored
@@ -1238,12 +1267,12 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 #endif
 
                 if (in_atomic() || irqs_disabled()) {
-                        ret = rt_mutex_trylock(&adap->bus_lock);
+                        ret = i2c_trylock_adapter(adap);
                         if (!ret)
                                 /* I2C activity is ongoing. */
                                 return -EAGAIN;
                 } else {
-                        rt_mutex_lock(&adap->bus_lock);
+                        i2c_lock_adapter(adap);
                 }
 
                 /* Retry automatically on arbitration loss */
@@ -1255,7 +1284,7 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
                         if (time_after(jiffies, orig_jiffies + adap->timeout))
                                 break;
                 }
-                rt_mutex_unlock(&adap->bus_lock);
+                i2c_unlock_adapter(adap);
 
                 return ret;
         } else {
@@ -2013,7 +2042,7 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
         flags &= I2C_M_TEN | I2C_CLIENT_PEC;
 
         if (adapter->algo->smbus_xfer) {
-                rt_mutex_lock(&adapter->bus_lock);
+                i2c_lock_adapter(adapter);
 
                 /* Retry automatically on arbitration loss */
                 orig_jiffies = jiffies;
@@ -2027,7 +2056,7 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
                                        orig_jiffies + adapter->timeout))
                                 break;
                 }
-                rt_mutex_unlock(&adapter->bus_lock);
+                i2c_unlock_adapter(adapter);
         } else
                 res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
                                               command, protocol, data);