[PATCH] I2C: i2c-vid.h: Support for VID to reg conversion

Adds conversion from VID (mV) to register value. Used by the atxp1 I2C module.
Removed uneeded switch case.
Signed-off-by: NSebastian Witt <se.witt@gmx.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

include/linux/i2c-vid.h

@@ -97,3 +97,15 @@ static inline int vid_from_reg(int val, int vrm)
 		                     2050 - (val) * 50);
 	}
 }
+
+static inline int vid_to_reg(int val, int vrm)
+{
+	switch (vrm) {
+	case 91:		/* VRM 9.1 */
+	case 90:		/* VRM 9.0 */
+		return ((val >= 1100) && (val <= 1850) ?
+			((18499 - val * 10) / 25 + 5) / 10 : -1);
+	default:
+		return -1;
+	}
+}