1 files changed, 163 insertions, 0 deletions
diff --git a/src/lm75.c b/src/lm75.c
new file mode 100644
index 0000000..fac61c2
--- /dev/null
+++ b/src/lm75.c
@@ -0,0 +1,163 @@
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+
+#include "lm75.h"
+
+extern int file;
+extern void bus_err(int ern);
+extern void print_help(void);
+unsigned char buf[5];
+
+
+void lm75_list_all(void)
+{
+    printf(
+        "00: Temperature data  [°C]     (reg: 0x00)\n"
+        "01: Configuration     [hex]    (reg: 0x01)\n"
+        "02: Tos (Overtemp)    [°C]     (reg: 0x03)\n"
+        "03: Thys (Hysteresis) [°C]     (reg: 0x04)\n"
+        "\n");
+}
+
+
+
+void lm75_get_data(void)
+{
+	if(write(file, buf, 1) != 1) 
+    {
+        bus_err(errno);
+    }
+
+    if(read(file, buf, 2) != 2) 
+    {
+        bus_err(errno);
+    } 
+}
+
+
+
+float lm75_read_temp(float offset)
+{
+    signed int rawtemp = 0;
+    float temp;
+
+    buf[0] = 0x00;
+    
+    lm75_get_data();
+     
+    rawtemp = (buf[0]*256 + buf[1]) >> 5;  //(buf[0] << 8), and (>> 5), 11bit device is also supported
+
+	if((rawtemp & 0x400) == 0x400)         //check if the msb(bit11) is 1 (1024 = 0x400),  2'complement negative number
+	{
+	    rawtemp = rawtemp - 2048;          //2^11 = 2048 
+	}
+
+	temp = rawtemp * 0.125 ;               //11bit->0.125°C  or  9bit->0.5°C	
+    return (temp + offset);    
+}
+
+
+
+float lm75_read_tos(void)          
+{                                           
+    int rawtemp = 0;                        
+                                            
+    buf[0] = 0x02;                          
+                                            
+    lm75_get_data();                                                         
+                                                           
+    rawtemp = buf[0]*256 + buf[1];                           
+    rawtemp = (rawtemp) >> 7;           //9bit data
+    
+    if((rawtemp & 256) == 256)          // check if the msb  2'complement negative number
+    {
+        rawtemp = rawtemp - 512 ;       // 2^9 = 512;
+    }
+    
+    return (rawtemp * 0.5);             //9bit -> 0.5 celsius                                                                                                                 
+}                       
+
+
+
+float lm75_read_thys(void)          
+{                                           
+    int rawtemp = 0;                        
+                                            
+    buf[0] = 0x03;                          
+                                            
+    lm75_get_data();                                                      
+                                                           
+    rawtemp = buf[0]*256 + buf[1];                           
+    rawtemp = (rawtemp) >> 7;           //9bit data
+    
+    if((rawtemp & 256) == 256)          // check if the msb  2'complement negative number
+    {
+        rawtemp = rawtemp - 512 ;       // 2^9 = 512;
+    }
+    
+    return (rawtemp * 0.5);             //9bit -> 0.5 celsius                                                                                                                 
+}                       
+     
+
+char lm75_read_conf(void)                                                                                                         
+{
+    
+    buf[0] = 0x01;                                                                                                                 
+    
+    lm75_get_data();
+    
+    return buf[0];                                                                                                                                   
+}
+
+
+
+void lm75_read_all(const char *opts)
+{
+    if(opts != NULL)
+    {
+        printf("00:%f\n", lm75_read_temp(strtof(opts, NULL)));
+    }
+    else
+    {
+        printf("00:%f\n", lm75_read_temp(0.0));
+    }     
+
+    printf("01:0x%x\n", lm75_read_conf()); 
+    printf("02:%f\n", lm75_read_tos()); 
+    printf("03:%f\n", lm75_read_thys()); 
+}
+
+
+
+void lm75_read_one(const char *opts)
+{
+    int id;
+    char *ptr;
+    
+    id = strtol (opts,&ptr,0); //all format allowed
+    ptr++;      //one separator allowed
+        
+    switch (id)
+    {
+        case 0x00:
+            printf("00:%f\n", lm75_read_temp(strtof(ptr, NULL)));
+            break;
+        case 0x01:
+            printf("01:0x%x\n", lm75_read_conf());
+            break;
+        case 0x02:
+            printf("02:%f\n", lm75_read_tos());
+            break;
+        case 0x03:
+            printf("03:%f\n", lm75_read_thys()); 
+            break;
+        default:
+            print_help();
+    } 
+}
+