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i2c: Move adapter locking helpers to i2c-core

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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>
This commit is contained in:
Jean Delvare 2010-08-11 18:20:58 +02:00
parent d44f19d586
commit fe61e07e9e
2 changed files with 37 additions and 22 deletions
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39
drivers/i2c/i2c-core.c
View File

@ -429,6 +429,35 @@ static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
__i2c_check_addr_busy);
}
/**
* 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
@ -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);

20
include/linux/i2c.h
View File

@ -382,23 +382,9 @@ static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data)
dev_set_drvdata(&dev->dev, data);
}
/**
* i2c_lock_adapter - Prevent access to an I2C bus segment
* @adapter: Target I2C bus segment
*/
static inline void i2c_lock_adapter(struct i2c_adapter *adapter)
{
rt_mutex_lock(&adapter->bus_lock);
}
/**
* i2c_unlock_adapter - Reauthorize access to an I2C bus segment
* @adapter: Target I2C bus segment
*/
static inline void i2c_unlock_adapter(struct i2c_adapter *adapter)
{
rt_mutex_unlock(&adapter->bus_lock);
}
/* Adapter locking functions, exported for shared pin cases */
void i2c_lock_adapter(struct i2c_adapter *);
void i2c_unlock_adapter(struct i2c_adapter *);
/*flags for the client struct: */
#define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */