hwmon: (smsc47m192) Fix overflows seen when writing into limit attributes

Module test reports overflows when writing into temperature and voltage
limit attributes

temp1_min: Suspected overflow: [127000 vs. 0]
temp1_max: Suspected overflow: [127000 vs. 0]
temp1_offset: Suspected overflow: [127000 vs. 0]
temp2_min: Suspected overflow: [127000 vs. 0]
temp2_max: Suspected overflow: [127000 vs. 0]
temp2_offset: Suspected overflow: [127000 vs. 0]
temp3_min: Suspected overflow: [127000 vs. 0]
temp3_max: Suspected overflow: [127000 vs. 0]
temp3_offset: Suspected overflow: [127000 vs. 0]
in0_min: Suspected overflow: [3320 vs. 0]
in0_max: Suspected overflow: [3320 vs. 0]
in4_min: Suspected overflow: [15938 vs. 0]
in4_max: Suspected overflow: [15938 vs. 0]
in6_min: Suspected overflow: [1992 vs. 0]
in6_max: Suspected overflow: [1992 vs. 0]
in7_min: Suspected overflow: [2391 vs. 0]
in7_max: Suspected overflow: [2391 vs. 0]

The problem is caused by conversions from unsigned long to long and
from long to int.
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/smsc47m192.c

@@ -77,14 +77,15 @@ static inline unsigned int IN_FROM_REG(u8 reg, int n)
 
 static inline u8 IN_TO_REG(unsigned long val, int n)
 {
-	return clamp_val(SCALE(val, 192, nom_mv[n]), 0, 255);
+	val = clamp_val(val, 0, nom_mv[n] * 255 / 192);
+	return SCALE(val, 192, nom_mv[n]);
 }
 
 /*
  * TEMP: 0.001 degC units (-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)
 {
 	return SCALE(clamp_val(val, -128000, 127000), 1, 1000);
 }