Commit fe61e07e authored by Jean Delvare's avatar Jean Delvare
Browse files

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: default avatarJean Delvare <khali@linux-fr.org>
Cc: Michael Lawnick <ml.lawnick@gmx.de>
parent d44f19d5

drivers/i2c/i2c-core.c

+34 −5
Original line number Diff line number Diff line
@@ -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);

include/linux/i2c.h

+3 −17
Original line number Diff line number Diff line
@@ -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 */

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