diff options
Diffstat (limited to 'drivers/i2c/i2c-core.c')
| -rw-r--r-- | drivers/i2c/i2c-core.c | 44 | 
1 files changed, 33 insertions, 11 deletions
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index feb7dc35918..ccc6445979c 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -1295,6 +1295,37 @@ module_exit(i2c_exit);   */  /** + * __i2c_transfer - unlocked flavor of i2c_transfer + * @adap: Handle to I2C bus + * @msgs: One or more messages to execute before STOP is issued to + *	terminate the operation; each message begins with a START. + * @num: Number of messages to be executed. + * + * Returns negative errno, else the number of messages executed. + * + * Adapter lock must be held when calling this function. No debug logging + * takes place. adap->algo->master_xfer existence isn't checked. + */ +int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) +{ +	unsigned long orig_jiffies; +	int ret, try; + +	/* Retry automatically on arbitration loss */ +	orig_jiffies = jiffies; +	for (ret = 0, try = 0; try <= adap->retries; try++) { +		ret = adap->algo->master_xfer(adap, msgs, num); +		if (ret != -EAGAIN) +			break; +		if (time_after(jiffies, orig_jiffies + adap->timeout)) +			break; +	} + +	return ret; +} +EXPORT_SYMBOL(__i2c_transfer); + +/**   * i2c_transfer - execute a single or combined I2C message   * @adap: Handle to I2C bus   * @msgs: One or more messages to execute before STOP is issued to @@ -1308,8 +1339,7 @@ module_exit(i2c_exit);   */  int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)  { -	unsigned long orig_jiffies; -	int ret, try; +	int ret;  	/* REVISIT the fault reporting model here is weak:  	 * @@ -1347,15 +1377,7 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)  			i2c_lock_adapter(adap);  		} -		/* Retry automatically on arbitration loss */ -		orig_jiffies = jiffies; -		for (ret = 0, try = 0; try <= adap->retries; try++) { -			ret = adap->algo->master_xfer(adap, msgs, num); -			if (ret != -EAGAIN) -				break; -			if (time_after(jiffies, orig_jiffies + adap->timeout)) -				break; -		} +		ret = __i2c_transfer(adap, msgs, num);  		i2c_unlock_adapter(adap);  		return ret;  |