Merge branch 'i2c/for-current-fixed' into i2c/for-4.18

drivers/i2c/busses/i2c-designware-master.c

@@ -209,7 +209,10 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
 	i2c_dw_disable_int(dev);
 
 	/* Enable the adapter */
-	__i2c_dw_enable_and_wait(dev, true);
+	__i2c_dw_enable(dev, true);
+
+	/* Dummy read to avoid the register getting stuck on Bay Trail */
+	dw_readl(dev, DW_IC_ENABLE_STATUS);
 
 	/* Clear and enable interrupts */
 	dw_readl(dev, DW_IC_CLR_INTR);

drivers/i2c/busses/i2c-pmcmsp.c

@@ -564,10 +564,10 @@ static int pmcmsptwi_master_xfer(struct i2c_adapter *adap,
 		 * TODO: We could potentially loop and retry in the case
 		 * of MSP_TWI_XFER_TIMEOUT.
 		 */
-		return -1;
+		return -EIO;
 	}
 
-	return 0;
+	return num;
 }
 
 static u32 pmcmsptwi_i2c_func(struct i2c_adapter *adapter)

drivers/i2c/busses/i2c-viperboard.c

@@ -337,7 +337,7 @@ static int vprbrd_i2c_xfer(struct i2c_adapter *i2c, struct i2c_msg *msgs,
 		}
 		mutex_unlock(&vb->lock);
 	}
-	return 0;
+	return num;
 error:
 	mutex_unlock(&vb->lock);
 	return error;

drivers/i2c/i2c-core-acpi.c

@@ -445,10 +445,17 @@ static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
 	msgs[1].buf = buffer;
 
 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
-	if (ret < 0)
-		dev_err(&client->adapter->dev, "i2c read failed\n");
-	else
+	if (ret < 0) {
+		/* Getting a NACK is unfortunately normal with some DSTDs */
+		if (ret == -EREMOTEIO)
+			dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
+				data_len, client->addr, cmd, ret);
+		else
+			dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
+				data_len, client->addr, cmd, ret);
+	} else {
 		memcpy(data, buffer, data_len);
+	}
 
 	kfree(buffer);
 	return ret;