staging:iio: Add missing event code extract macros

Add macros for extracting whether the event is for a differential channel and
the second channel number from the event code. These were the only two fields
which did not have such an macro yet.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/iio/events.h

@@ -97,7 +97,9 @@ enum iio_event_direction {
 /* Event code number extraction depends on which type of event we have.
  * Perhaps review this function in the future*/
 #define IIO_EVENT_CODE_EXTRACT_CHAN(mask) ((__s16)(mask & 0xFFFF))
+#define IIO_EVENT_CODE_EXTRACT_CHAN2(mask) ((__s16)(((mask) >> 16) & 0xFFFF))
 
 #define IIO_EVENT_CODE_EXTRACT_MODIFIER(mask) ((mask >> 40) & 0xFF)
+#define IIO_EVENT_CODE_EXTRACT_DIFF(mask) (((mask) >> 55) & 0x1)
 
 #endif