hwmon: (lm78) Fix overflow problems seen when writing large temperature limits

On platforms with sizeof(int) < sizeof(long), writing a temperature
limit larger than MAXINT will result in unpredictable limit values
written to the chip. Avoid auto-conversion from long to int to fix
the problem.

Cc: Axel Lin <axel.lin@ingics.com>
Cc: stable@vger.kernel.org
Reviewed-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/lm78.c b/drivers/hwmon/lm78.c
index 9efadfc851bc99e97451963705d738be33591885..c1eb464f0fd0c18b3c2cb6496b8a3774476890af 100644 (file)
--- a/drivers/hwmon/lm78.c
+++ b/drivers/hwmon/lm78.c
@@ -108,7 +108,7 @@ static inline int FAN_FROM_REG(u8 val, int div)
  * TEMP: mC (-128C to +127C)
  * REG: 1C/bit, two's complement
  */
-static inline s8 TEMP_TO_REG(int val)
+static inline s8 TEMP_TO_REG(long val)
 {
        int nval = clamp_val(val, -128000, 127000) ;
        return nval < 0 ? (nval - 500) / 1000 : (nval + 500) / 1000;