aboutsummaryrefslogtreecommitdiff
path: root/drivers/i2c/i2c-core.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/i2c/i2c-core.c')
-rw-r--r--drivers/i2c/i2c-core.c44
1 files changed, 33 insertions, 11 deletions
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 26488aa893d..2efa56c5ff2 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1312,6 +1312,37 @@ 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
@@ -1325,8 +1356,7 @@ 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:
*
@@ -1364,15 +1394,7 @@ 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;