Changeset 2458 for lm-sensors/trunk/kernel/chips/via686a.c

Timestamp:

04/20/04 19:12:55 (9 years ago)

Author:

khali

Message:

Fix voltage roundings.

Files:

• lm-sensors/trunk/kernel/chips/via686a.c (modified) (1 diff)

lm-sensors/trunk/kernel/chips/via686a.c

@@ -126 +126 @@
 // (These conversions were contributed by Jonathan Teh Soon Yew 
 // <j.teh@iname.com>)
-// 
-// These get us close, but they don't completely agree with what my BIOS 
-// says- they are all a bit low.  But, it all we have to go on...
 static inline u8 IN_TO_REG(long val, int inNum)
 {
-        // to avoid floating point, we multiply everything by 100.
-        // val is guaranteed to be positive, so we can achieve the effect of 
-        // rounding by (...*10+5)/10.  Note that the *10 is hidden in the 
-        // /250 (which should really be /2500).
-        // At the end, we need to /100 because we *100 everything and we need
-        // to /10 because of the rounding thing, so we /1000.  
+        /* To avoid floating point, we multiply constants by 10 (100 for +12V).
+           Rounding is done (1205000 is actually 1330000 - 125000).
+           Remember that val is expressed in 0.01V/bit, which is why we divide
+           by an additional 1000 (10000 for +12V): 100 for val and 10 (100)
+           for the constants. */
         if (inNum <= 1)
                 return (u8)
-                    SENSORS_LIMIT(((val * 210240 - 13300) / 250 + 5) / 1000, 
-                                  0, 255);
+                    SENSORS_LIMIT((val * 21024 - 1205000) / 250000, 0, 255);
         else if (inNum == 2)
                 return (u8)
-                    SENSORS_LIMIT(((val * 157370 - 13300) / 250 + 5) / 1000, 
-                                  0, 255);
+                    SENSORS_LIMIT((val * 15737 - 1205000) / 250000, 0, 255);
         else if (inNum == 3)
                 return (u8)
-                    SENSORS_LIMIT(((val * 101080 - 13300) / 250 + 5) / 1000, 
-                                  0, 255);
+                    SENSORS_LIMIT((val * 10108 - 1205000) / 250000, 0, 255);
         else
-                return (u8) SENSORS_LIMIT(((val * 41714 - 13300) / 250 + 5)
-                                          / 1000, 0, 255);
+                return (u8)
+                    SENSORS_LIMIT((val * 41714 - 12050000) / 2500000, 0, 255);
 }
 
 static inline long IN_FROM_REG(u8 val, int inNum)
 {
-        // to avoid floating point, we multiply everything by 100.
-        // val is guaranteed to be positive, so we can achieve the effect of
-        // rounding by adding 0.5.  Or, to avoid fp math, we do (...*10+5)/10.
-        // We need to scale with *100 anyway, so no need to /100 at the end.
+        /* To avoid floating point, we multiply constants by 10 (100 for +12V).
+           We also multiply them by 100 because we want 0.01V/bit for the
+           output value. Rounding is done. */
         if (inNum <= 1)
-                return (long) (((250000 * val + 13300) / 210240 * 10 + 5) /10);
+                return (long) ((25000 * val + 133000 + 21024 / 2) / 21024);
         else if (inNum == 2)
-                return (long) (((250000 * val + 13300) / 157370 * 10 + 5) /10);
+                return (long) ((25000 * val + 133000 + 15737 / 2) / 15737);
         else if (inNum == 3)
-                return (long) (((250000 * val + 13300) / 101080 * 10 + 5) /10);
+                return (long) ((25000 * val + 133000 + 10108 / 2) / 10108);
         else
-                return (long) (((250000 * val + 13300) / 41714 * 10 + 5) /10);
+                return (long) ((250000 * val + 1330000 + 41714 / 2) / 41714);
 }