w1: ds1wm: fix register offset (bus shift) calculation

Replace incorrect register offsett calculation by
direct configuration of bus_shift in mfd-cell.

Indirect definition of address-shift by resource size
was unobvious and was wrong (should have used a binary log).

Signed-off-by: Johannes Poehlmann <johannes.poehlmann@izt-labs.de>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/mfd/ds1wm.h b/include/linux/mfd/ds1wm.h
index 38a372a..79a01e8 100644
--- a/include/linux/mfd/ds1wm.h
+++ b/include/linux/mfd/ds1wm.h
@@ -1,13 +1,23 @@
-/* MFD cell driver data for the DS1WM driver */
+/* MFD cell driver data for the DS1WM driver
+ *
+ * to be defined in the MFD device that is
+ * using this driver for one of his sub devices
+ */
 
 struct ds1wm_driver_data {
 	int active_high;
 	int clock_rate;
-	/* in milliseconds, the amount of time to */
-	/* sleep following a reset pulse. Zero    */
-	/* should work if your bus devices recover*/
-	/* time respects the 1-wire spec since the*/
-	/* ds1wm implements the precise timings of*/
-	/* a reset pulse/presence detect sequence.*/
+	/* in milliseconds, the amount of time to
+	 * sleep following a reset pulse. Zero
+	 * should work if your bus devices recover
+	 * time respects the 1-wire spec since the
+	 * ds1wm implements the precise timings of
+	 * a reset pulse/presence detect sequence.
+	 */
 	unsigned int reset_recover_delay;
+
+	/* left shift of register number to get register address offsett.
+	 * Only 0,1,2 allowed for 8,16 or 32 bit bus width respectively
+	 */
+	unsigned int bus_shift;
 };