[PATCH 3.10 18/55] hwmon: (lm78) Fix overflow problems seen when writing large temperature limits

Greg Kroah-Hartman
2014-09-03T23:48:28Z

From: Guenter Roeck <linux@roeck-us.net>

commit 1074d683a51f1aded3562add9ef313e75d557327 upstream.

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>
Reviewed-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/hwmon/lm78.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/hwmon/lm78.c
+++ b/drivers/hwmon/lm78.c
@@ -108,7 +108,7 @@ static inline int FAN_FROM_REG(u8 val, i
* 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;