hwmon: (dme1737) fix divide-by-0

This patch fixes a possible divide-by-0 and a minor bug in the
FAN_FROM_REG macro (in TPC mode).

Signed-off-by: Juerg Haefliger <juergh at gmail.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>

1 files changed, 11 insertions, 4 deletions

diff --git a/drivers/hwmon/dme1737.c b/drivers/hwmon/dme1737.c
index 85064fb0b7c2..307f48de051f 100644
--- a/drivers/hwmon/dme1737.c
+++ b/drivers/hwmon/dme1737.c
@@ -283,14 +283,21 @@ static inline int TEMP_HYST_TO_REG(int val, int ix, int reg)
 /* Fan input RPM */
 static inline int FAN_FROM_REG(int reg, int tpc)
 {
-        return (reg == 0 || reg == 0xffff) ? 0 :
-                (tpc == 0) ? 90000 * 60 / reg : tpc * reg;
+        if (tpc) {
+                return tpc * reg;
+        } else {
+                return (reg == 0 || reg == 0xffff) ? 0 : 90000 * 60 / reg;
+        }
 }
 
 static inline int FAN_TO_REG(int val, int tpc)
 {
-        return SENSORS_LIMIT((tpc == 0) ? 90000 * 60 / val : val / tpc,
-                             0, 0xffff);
+        if (tpc) {
+                return SENSORS_LIMIT(val / tpc, 0, 0xffff);
+        } else {
+                return (val <= 0) ? 0xffff :
+                        SENSORS_LIMIT(90000 * 60 / val, 0, 0xfffe);
+        }
 }
 
 /* Fan TPC (tach pulse count)