1 files changed, 14 insertions, 8 deletions

diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
index 10fbd6d84..99b54be6b 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -634,7 +634,6 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 
 	dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
 
-	mutex_lock(&dev->lock);
 	pm_runtime_get_sync(dev->dev);
 
 	reinit_completion(&dev->cmd_complete);
@@ -673,11 +672,12 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 	}
 
 	/*
-	 * We must disable the adapter before unlocking the &dev->lock mutex
-	 * below. Otherwise the hardware might continue generating interrupts
-	 * which in turn causes a race condition with the following transfer.
-	 * Needs some more investigation if the additional interrupts are
-	 * a hardware bug or this driver doesn't handle them correctly yet.
+	 * We must disable the adapter before returning and signaling the end
+	 * of the current transfer. Otherwise the hardware might continue
+	 * generating interrupts which in turn causes a race condition with
+	 * the following transfer.  Needs some more investigation if the
+	 * additional interrupts are a hardware bug or this driver doesn't
+	 * handle them correctly yet.
 	 */
 	__i2c_dw_enable(dev, false);
 
@@ -706,7 +706,6 @@ done:
 done_nolock:
 	pm_runtime_mark_last_busy(dev->dev);
 	pm_runtime_put_autosuspend(dev->dev);
-	mutex_unlock(&dev->lock);
 
 	return ret;
 }
@@ -860,7 +859,6 @@ int i2c_dw_probe(struct dw_i2c_dev *dev)
 	int r;
 
 	init_completion(&dev->cmd_complete);
-	mutex_init(&dev->lock);
 
 	r = i2c_dw_init(dev);
 	if (r)
@@ -883,9 +881,17 @@ int i2c_dw_probe(struct dw_i2c_dev *dev)
 		return r;
 	}
 
+	/*
+	 * Increment PM usage count during adapter registration in order to
+	 * avoid possible spurious runtime suspend when adapter device is
+	 * registered to the device core and immediate resume in case bus has
+	 * registered I2C slaves that do I2C transfers in their probe.
+	 */
+	pm_runtime_get_noresume(dev->dev);
 	r = i2c_add_numbered_adapter(adap);
 	if (r)
 		dev_err(dev->dev, "failure adding adapter: %d\n", r);
+	pm_runtime_put_noidle(dev->dev);
 
 	return r;
 }