Fixup mod io

See merge request !40

coupler/mod_io_i2c.h

-// global relay state
+// global relay state - XXX: use a list rather than individual variables
 uint8_t I2C_0_RELAYS_STATE = 0; // state of 4 relays at I2C slave 0
 uint8_t I2C_1_RELAYS_STATE = 0; // state of 4 relays at I2C slave 1
 
@@ -8,8 +8,11 @@ static char *DEFAULT_I2C_0_ADDR = "0x58";
 // the list of attached I2C slaves
 const int DEFAULT_I2C_SLAVE_ADDR = 0x58;
 
-// XXX:code assumes only 8 I2C slaves but it can be up to 127
-int I2C_SLAVE_ADDR_LIST[] = {0, 0, 0, 0, 0, 0, 0, 0};
+// the current architecture of LIME2 supports up to 127 MOD-IO I2C slaves
+int I2C_SLAVE_ADDR_LIST[127] = {0};
+
+// the number of physical relays
+int DEFAULT_RELAY_COUNT = 4;
 
 // the block device at host machine
 static char *DEFAULT_I2C_BLOCK_DEVICE_NAME = "/dev/i2c-1";
@@ -173,7 +176,6 @@ static int getAnalogInputStateAIN(int i2c_addr, int **analog_input, uint8_t read
     }
 
     // step 3: write command over I2c
-    //__u8 read_reg = 0x30; /* Device register to access */
     char read_buf[10];
     read_buf[0] = read_reg;
     if (write(file, read_buf, 1) != 1)