i2c: Functions for byte-swapped smbus_write/read_word_data

Reimplemented at least 17 times discounting error mangling cases
where it could be used.

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index a6c652e..38a21c3 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -34,6 +34,7 @@
 #include <linux/sched.h>	/* for completion */
 #include <linux/mutex.h>
 #include <linux/of.h>		/* for struct device_node */
+#include <linux/swab.h>		/* for swab16 */
 
 extern struct bus_type i2c_bus_type;
 extern struct device_type i2c_adapter_type;
@@ -88,6 +89,22 @@
 				    u8 command);
 extern s32 i2c_smbus_write_word_data(const struct i2c_client *client,
 				     u8 command, u16 value);
+
+static inline s32
+i2c_smbus_read_word_swapped(const struct i2c_client *client, u8 command)
+{
+	s32 value = i2c_smbus_read_word_data(client, command);
+
+	return (value < 0) ? value : swab16(value);
+}
+
+static inline s32
+i2c_smbus_write_word_swapped(const struct i2c_client *client,
+			     u8 command, u16 value)
+{
+	return i2c_smbus_write_word_data(client, command, swab16(value));
+}
+
 /* Returns the number of read bytes */
 extern s32 i2c_smbus_read_block_data(const struct i2c_client *client,
 				     u8 command, u8 *values);