add library support for logarithms and exponents (!) to support

vt1211 / vt8235 thermistor calculations. Add such calculations to
      vt1211/vt8235 section in sensors.conf; bump library version to 1.4.0.


git-svn-id: http://lm-sensors.org/svn/lm-sensors/trunk@1667 7894878c-1315-0410-8ee3-d5d059ff63e0

etc/sensors.conf.eg

@@ -93,6 +93,10 @@
 # translated to a /proc value. '@' is the value to operate on. You may
 # refer to other readable features (like '2 * vid').
 #
+# The following operators are valid: + - * / ( ) ^ `
+# ^ is e**x and ` is ln(x) (valid in library version 1.4.0 /
+# lm_sensors 2.7.1 or higher)
+#
 # Like for the label statement, there are logical groups here. They are
 # sometimes a bit different, though. For example, fan1_div is in the
 # logical label group of fan1 (it gets the same label if none is declared
@@ -1374,7 +1378,6 @@ chip "adm1021-*" "adm1023-*" "max1617-*" "max1617a-*" "thmc10-*" "lm84-*" "gl523
 chip "vt1211-*" "vt8231-*"
 #
 # temp1 and in6 are not implemented in vt1211 / vt8231
-# temp4-7 (thermistor) cacluations unimplemented here - requires logarithms :(
 #
 #							1 for temp, 0 for volt.
 #	Sensor		Voltage Mode	Temp Mode	config bit
@@ -1451,15 +1454,33 @@ chip "vt1211-*" "vt8231-*"
 
 #   compute temp1  (@ - 65) / 0.9686,  (@ * 0.9686) + 65
     compute temp3  (@ - 65) / 0.9686,  (@ * 0.9686) + 65
+#
+# thermistor calculations.
+# 3435 is the thermistor beta.
+# '^' is the e**x operator; '`' is the ln(x) operator
+# (valid in library version 1.4.0 / lm_sensors 2.7.1 or higher)
+# This assumes that the thermistor forms a resistor divider with a resistor
+# equal to its nominal value @ 25C. If not, the math gets even harder.
+#
+    compute temp2  (1 / (((1 / 3435) * (` ((253 - @) / (@ - 43)))) + (1 / 298.15)))  - 273.15, \
+                   253 - (210 / (1 + (1 / (^ (((3435 * (25 - @)) / ((@ + 273.15) * 298.15)))))))
+    compute temp4  (1 / (((1 / 3435) * (` ((253 - @) / (@ - 43)))) + (1 / 298.15)))  - 273.15, \
+                   253 - (210 / (1 + (1 / (^ (((3435 * (25 - @)) / ((@ + 273.15) * 298.15)))))))
+    compute temp5  (1 / (((1 / 3435) * (` ((253 - @) / (@ - 43)))) + (1 / 298.15)))  - 273.15, \
+                   253 - (210 / (1 + (1 / (^ (((3435 * (25 - @)) / ((@ + 273.15) * 298.15)))))))
+    compute temp6  (1 / (((1 / 3435) * (` ((253 - @) / (@ - 43)))) + (1 / 298.15)))  - 273.15, \
+                   253 - (210 / (1 + (1 / (^ (((3435 * (25 - @)) / ((@ + 273.15) * 298.15)))))))
+    compute temp7  (1 / (((1 / 3435) * (` ((253 - @) / (@ - 43)))) + (1 / 298.15)))  - 273.15, \
+                   253 - (210 / (1 + (1 / (^ (((3435 * (25 - @)) / ((@ + 273.15) * 298.15)))))))
 
 #   set temp1_hyst 40
 #   set temp1_over 45
-    set temp2_hyst 55
-    set temp2_over 60
+    set temp2_hyst 40
+    set temp2_over 45
     set temp3_hyst 60
     set temp3_over 65
-    set temp4_hyst 60
-    set temp4_over 65
+    set temp4_hyst 40
+    set temp4_over 45
 
     set fan1_min 3000
     set fan2_min 3000

lib/Module.mk

@@ -29,7 +29,7 @@ LIBMAN5FILES := $(MODULE_DIR)/sensors.conf.5
 
 # The main and minor version of the library
 LIBMAINVER := 1
-LIBMINORVER := 3.0
+LIBMINORVER := 4.0
 LIBVER := $(LIBMAINVER).$(LIBMINORVER)
 
 # The static lib name, the shared lib name, and the internal ('so') name of

lib/access.c

@@ -19,6 +19,7 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include <math.h>
 #include "access.h"
 #include "sensors.h"
 #include "data.h"
@@ -395,6 +396,14 @@ int sensors_eval_expr(sensors_chip_name chipname, const sensors_expr *expr,
   case sensors_negate:
     *result = -res1;
     return 0;
+  case sensors_exp:
+    *result = exp(res1);
+    return 0;
+  case sensors_log:
+    if (res1 < 0.0)
+      return -SENSORS_ERR_DIV_ZERO;
+    *result = log(res1);
+    return 0;
   }
   return 0;
 }

lib/conf-lex.l

@@ -178,6 +178,12 @@ OCTESC		(1[0-7]{0,2})|([2-7][0-7]?)|(0[1-7][0-7]?)|(00[1-7])
 <MIDDLE>"@"	{
 		  return '@';
 		}
+<MIDDLE>"^"	{
+		  return '^';
+		}
+<MIDDLE>"`"	{
+		  return '`';
+		}
 
  /* Quoted string */
 <MIDDLE>\"	{

lib/conf-parse.y

@@ -102,6 +102,7 @@ static sensors_chip *current_chip = NULL;
 %left <nothing> '-' '+'
 %left <nothing> '*' '/'
 %left <nothing> NEG
+%right <nothing> '^' '`'
 
 %token <nothing> ','
 %token <nothing> EOL
@@ -272,6 +273,20 @@ expression:	  FLOAT
 		  }
 		| '(' expression ')'
 		  { $$ = $2; }
+		| '^' expression
+		  { $$ = malloc_expr(); 
+		    $$->kind = sensors_kind_sub;
+		    $$->data.subexpr.op = sensors_exp;
+		    $$->data.subexpr.sub1 = $2;
+		    $$->data.subexpr.sub2 = NULL;
+		  }
+		| '`' expression
+		  { $$ = malloc_expr(); 
+		    $$->kind = sensors_kind_sub;
+		    $$->data.subexpr.op = sensors_log;
+		    $$->data.subexpr.sub1 = $2;
+		    $$->data.subexpr.sub2 = NULL;
+		  }
 ;
 
 i2cbus_name:	  NAME

lib/data.h

@@ -29,7 +29,7 @@
 /* Kinds of expression operators recognized */
 typedef enum sensors_operation { 
   sensors_add, sensors_sub, sensors_multiply, sensors_divide, 
-  sensors_negate } sensors_operation;
+  sensors_negate, sensors_exp, sensors_log } sensors_operation;
 
 /* An expression can have several forms */
 typedef enum sensors_expr_kind {