diff --git a/src/arch/avr/i2c.c b/src/arch/avr/i2c.c
index 2591336..e3255be 100644
--- a/src/arch/avr/i2c.c
+++ b/src/arch/avr/i2c.c
@@ -2,15 +2,12 @@
 #include <avr/io.h>
 #include <util/twi.h>
 
-#include <arch/i2c.h>
 #include <board/cpu.h>
+#include <common/i2c.h>
 
 #define TIMEOUT (F_CPU/1000)
 
-#define I2C_READ 0x01
-#define I2C_WRITE 0x00
-
-uint8_t i2c_start(uint8_t addr, uint8_t rw) {
+uint8_t i2c_start(uint8_t addr, bool read) {
 	uint32_t count;
 
 	// reset TWI control register
@@ -32,7 +29,7 @@ uint8_t i2c_start(uint8_t addr, uint8_t rw) {
 	}
 
 	// load slave addr into data register
-	TWDR = ((addr << 1) | rw);
+	TWDR = ((addr << 1) | read);
 	// start transmission of addr
 	TWCR = (1<<TWINT) | (1<<TWEN);
 	// wait for end of transmission
@@ -53,7 +50,7 @@ uint8_t i2c_start(uint8_t addr, uint8_t rw) {
 	return 0;
 }
 
-void i2c_stop() {
+void i2c_stop(void) {
 	// transmit STOP condition
 	TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
 }
@@ -81,83 +78,16 @@ uint8_t i2c_write(uint8_t data) {
 	return 0;
 }
 
-uint8_t i2c_read_ack() {
-	// start TWI module and acknowledge data after reception
-	TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA);
+uint8_t i2c_read(bool ack) {
+    if (ack) {
+    	// start TWI module and acknowledge data after reception
+    	TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA);
+    } else {
+        // start receiving without acknowledging reception
+    	TWCR = (1<<TWINT) | (1<<TWEN);
+    }
 	// wait for end of transmission
 	while( !(TWCR & (1<<TWINT)) );
 	// return received data from TWDR
 	return TWDR;
 }
-
-uint8_t i2c_read_nack() {
-	// start receiving without acknowledging reception
-	TWCR = (1<<TWINT) | (1<<TWEN);
-	// wait for end of transmission
-	while( !(TWCR & (1<<TWINT)) );
-	// return received data from TWDR
-	return TWDR;
-}
-
-uint8_t i2c_recv(uint8_t addr, uint8_t* data, uint16_t length) {
-	if (i2c_start(addr, I2C_READ)) return 1;
-
-	uint16_t i;
-	for (i = 0; i < (length-1); i++)
-	{
-		data[i] = i2c_read_ack();
-	}
-	data[(length-1)] = i2c_read_nack();
-
-	i2c_stop();
-
-	return 0;
-}
-
-uint8_t i2c_send(uint8_t addr, uint8_t* data, uint16_t length) {
-	if (i2c_start(addr, I2C_WRITE)) return 1;
-
-	uint16_t i;
-	for (i = 0; i < length; i++) {
-		if (i2c_write(data[i])) return 1;
-	}
-
-	i2c_stop();
-
-	return 0;
-}
-
-uint8_t i2c_get(uint8_t addr, uint8_t reg, uint8_t* data, uint16_t length) {
-	if (i2c_start(addr, I2C_WRITE)) return 1;
-
-	if (i2c_write(reg)) return 1;
-
-	if (i2c_start(addr, I2C_READ)) return 1;
-
-	uint16_t i;
-	for (i = 0; i < (length-1); i++)
-	{
-		data[i] = i2c_read_ack();
-	}
-	data[(length-1)] = i2c_read_nack();
-
-	i2c_stop();
-
-	return 0;
-}
-
-uint8_t i2c_set(uint8_t addr, uint8_t reg, uint8_t* data, uint16_t length) {
-	if (i2c_start(addr, I2C_WRITE)) return 1;
-
-	if(i2c_write(reg)) return 1;
-
-	uint16_t i;
-	for (i = 0; i < length; i++)
-	{
-		if (i2c_write(data[i])) return 1;
-	}
-
-	i2c_stop();
-
-	return 0;
-}
diff --git a/src/arch/avr/include/arch/i2c.h b/src/arch/avr/include/arch/i2c.h
deleted file mode 100644
index 4d62795..0000000
--- a/src/arch/avr/include/arch/i2c.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#ifndef _ARCH_I2C_H
-#define _ARCH_I2C_H
-
-uint8_t i2c_recv(uint8_t addr, uint8_t* data, uint16_t length);
-uint8_t i2c_send(uint8_t addr, uint8_t* data, uint16_t length);
-
-uint8_t i2c_get(uint8_t addr, uint8_t reg, uint8_t* data, uint16_t length);
-uint8_t i2c_set(uint8_t addr, uint8_t reg, uint8_t* data, uint16_t length);
-
-#endif // _ARCH_I2C_H
diff --git a/src/board/arduino/mega2560/include/board/i2c.h b/src/board/arduino/mega2560/include/board/i2c.h
index 0b68535..450ca6c 100644
--- a/src/board/arduino/mega2560/include/board/i2c.h
+++ b/src/board/arduino/mega2560/include/board/i2c.h
@@ -1,8 +1,6 @@
 #ifndef _BOARD_I2C_H
 #define _BOARD_I2C_H
 
-#include <arch/i2c.h>
-
 void i2c_init(unsigned long baud);
 
 #endif // _BOARD_I2C_H
diff --git a/src/board/system76/galp3-c/smbus.c b/src/board/system76/galp3-c/smbus.c
index fff4ca8..8c23765 100644
--- a/src/board/system76/galp3-c/smbus.c
+++ b/src/board/system76/galp3-c/smbus.c
@@ -1,4 +1,5 @@
 #include <board/smbus.h>
+#include <ec/i2c.h>
 
 void smbus_init(void) {
     // 9.2 MHz * 4.7 us = 43.24
@@ -17,4 +18,7 @@ void smbus_init(void) {
 
     // Clock set to 50 Hz
     SCLKTSA = 1;
+
+    // Set up for i2c usage
+    i2c_reset(true);
 }
diff --git a/src/board/system76/galp3-c/stdio.c b/src/board/system76/galp3-c/stdio.c
index 8dbeec7..3a57dbf 100644
--- a/src/board/system76/galp3-c/stdio.c
+++ b/src/board/system76/galp3-c/stdio.c
@@ -1,9 +1,9 @@
 #include <stdio.h>
 
-#include <ec/i2c.h>
+#include <common/i2c.h>
 
 int putchar(int c) {
     unsigned char byte = (unsigned char)c;
-    i2c_write(0x76, &byte, 1);
+    i2c_send(0x76, &byte, 1);
     return (int)byte;
 }
diff --git a/src/common/i2c.c b/src/common/i2c.c
new file mode 100644
index 0000000..b3c4d9f
--- /dev/null
+++ b/src/common/i2c.c
@@ -0,0 +1,53 @@
+#include <common/i2c.h>
+
+int i2c_recv(uint8_t addr, uint8_t* data, int length) {
+    int res = 0;
+
+    res = i2c_start(addr, true);
+    if (res < 0) return res;
+
+    res = i2c_read(data, length);
+    if (res < 0) return res;
+
+	i2c_stop();
+
+	return res;
+}
+
+int i2c_send(uint8_t addr, uint8_t* data, int length) {
+    int res = 0;
+
+    res = i2c_start(addr, false);
+    if (res < 0) return res;
+
+    res = i2c_write(data, length);
+    if (res < 0) return res;
+
+	i2c_stop();
+
+	return res;
+}
+
+int i2c_get(uint8_t addr, uint8_t reg, uint8_t* data, int length) {
+    int res = 0;
+
+    res = i2c_start(addr, false);
+    if (res < 0) return res;
+
+    res = i2c_write(&reg, 1);
+    if (res < 0) return res;
+
+    return i2c_recv(addr, data, length);
+}
+
+int i2c_set(uint8_t addr, uint8_t reg, uint8_t* data, int length) {
+    int res = 0;
+
+    res = i2c_start(addr, false);
+    if (res < 0) return res;
+
+	res = i2c_write(&reg, 1);
+    if (res < 0) return res;
+
+    return i2c_send(addr, data, length);
+}
diff --git a/src/common/include/common/i2c.h b/src/common/include/common/i2c.h
new file mode 100644
index 0000000..8f79820
--- /dev/null
+++ b/src/common/include/common/i2c.h
@@ -0,0 +1,35 @@
+#ifndef _COMMON_I2C_H
+#define _COMMON_I2C_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+// Start i2c transaction
+// Must be defined by arch, board, or ec
+int i2c_start(uint8_t addr, bool read);
+
+// Stop i2c transaction
+// Must be defined by arch, board, or ec
+void i2c_stop(void);
+
+// Send a byte on i2c bus
+// Must be defined by arch, board, or ec
+int i2c_write(uint8_t * data, int length);
+
+// Read bytes from bus
+// Must be defined by arch, board, or ec
+int i2c_read(uint8_t * data, int length);
+
+// Read multiple bytes from address in one transaction
+int i2c_recv(uint8_t addr, uint8_t* data, int length);
+
+// Write multiple bytes to address in one transaction
+int i2c_send(uint8_t addr, uint8_t* data, int length);
+
+// Read multiple bytes from a register in one transaction
+int i2c_get(uint8_t addr, uint8_t reg, uint8_t* data, int length);
+
+// Write multiple bytes to a register in one transaction
+int i2c_set(uint8_t addr, uint8_t reg, uint8_t* data, int length);
+
+#endif // _COMMON_I2C_H
diff --git a/src/ec/it8587e/i2c.c b/src/ec/it8587e/i2c.c
index 9eb7edd..943cd70 100644
--- a/src/ec/it8587e/i2c.c
+++ b/src/ec/it8587e/i2c.c
@@ -1,7 +1,10 @@
+#include <stdbool.h>
+
 #include <board/cpu.h>
-#include <ec/i2c.h>
+#include <common/i2c.h>
 #include <ec/smbus.h>
 
+//TODO: find best value
 #define TIMEOUT (F_CPU/1000)
 
 #define HOSTA_BYTE_DONE (1 << 7)
@@ -14,66 +17,118 @@
 #define HOSTA_BUSY (1 << 0)
 #define HOSTA_ERR (HOSTA_TIMEOUT | HOSTA_NACK | HOSTA_FAIL | HOSTA_BUS_ERR | HOSTA_DEV_ERR)
 
-static void i2c_kill(void) {
-    if (HOSTAA & HOSTA_BUSY) {
-        HOCTLA = (1 << 1);
-        // TODO: is timeout needed?
-        while (HOSTAA & HOSTA_BUSY) {}
-    }
+void i2c_reset(bool kill) {
+    // Set kill bit
+    if (kill) HOCTLA |= (1 << 1);
+    // Wait for host to finish
+    while (HOSTAA & HOSTA_BUSY) {}
+    // Clear status register
     HOSTAA = HOSTAA;
+    // Clear current command
     HOCTLA = 0;
+    // Disable host interface
     HOCTL2A = 0;
 }
 
-uint8_t i2c_transaction(uint8_t addr_rw, uint8_t *data, uint16_t length) {
-    // End any current transaction
-    i2c_kill();
+int i2c_start(uint8_t addr, bool read) {
+    // If we are already in a transaction
+    if (HOSTAA & HOSTA_BYTE_DONE) {
+        // If we are switching direction
+        if ((TRASLAA & 1) != read) {
+            // If we are switching to read mode
+            if (read) {
+                // Enable direction switch
+                HOCTL2A |= (1 << 3) | (1 << 2);
 
-    // Enable host controller with i2c compatibility
-    HOCTL2A = (1 << 1) | 1;
-	// Set slave address
-	TRASLAA = addr_rw;
-
-    static uint8_t __pdata status;
-    static uint32_t __pdata timeout;
-    static uint16_t __pdata i;
-	for (i = 0; i < length; i++) {
-        if ((addr_rw & 1) && ((i + 1) == length)) {
-            // Set last byte
-            HOCTLA |= (1 << 5);
-        }
-        // Clear status
-        HOSTAA = HOSTAA;
-        if (!(addr_rw & 1)) {
-            // Set data byte
-            HOBDBA = data[i];
-        }
-        if (i == 0) {
-            // Start transaction
-            HOCTLA = (1 << 6) | (0b111 << 2);
-        }
-        for(timeout = TIMEOUT; timeout > 0; timeout++) {
-            status = HOSTAA;
-            HOSTAA = status;
-            if (status & HOSTA_ERR) {
-                timeout = 0;
-                break;
-            }
-            if (status & HOSTA_BYTE_DONE) {
-                break;
+                // Clear status to start switch process
+                HOSTAA = HOSTAA;
+            } else {
+                // Unsupported!
+                i2c_reset(true);
+                return -1;
             }
         }
-        if (timeout == 0) {
-            i2c_kill();
-            return 1;
-        }
-        if (addr_rw & 1) {
-            // Get data byte
-            data[i] = HOBDBA;
-        }
-	}
+    } else {
+        // Enable host controller with i2c compatibility
+        HOCTL2A = (1 << 1) | 1;
 
-    HOCTL2A = 0;
+        // Set address
+        TRASLAA = (addr << 1) | read;
+    }
 
 	return 0;
 }
+
+void i2c_stop(void) {
+    // Disable i2c compatibility
+    HOCTL2A &= ~(1 << 1);
+    // Clear status
+    HOSTAA = HOSTAA;
+
+    i2c_reset(false);
+}
+
+static int i2c_transaction(uint8_t * data, int length, bool read) {
+    int i;
+    for (i = 0; i < length; i++) {
+        if (read) {
+            // If last byte
+            if ((i + 1) == length) {
+                // Set last byte bit
+                HOCTLA |= (1 << 5);
+            }
+        } else {
+            // Write byte
+            HOBDBA = data[i];
+        }
+
+        // If we are already in a transaction
+        if (HOSTAA & HOSTA_BYTE_DONE) {
+            // Clear status to process next byte
+            HOSTAA = HOSTAA;
+        } else
+        // If we are waiting on direction switch
+        if (HOCTLA & (1 << 2)) {
+            // Complete direction switch
+            HOCTLA &= ~(1 << 2);
+        } else {
+            // Start new transaction
+            HOCTLA = (1 << 6) | (0b111 << 2);
+        }
+
+        // Wait for byte done, timeout, or error
+        // uint32_t timeout;
+        // for(timeout = TIMEOUT; timeout > 0; timeout--) {
+        for(;;) {
+            uint8_t status = HOSTAA;
+            if (status & HOSTA_BYTE_DONE) {
+                // If byte is finished, break
+                break;
+            } else if (status & HOSTA_ERR) {
+                // If error occured, kill transaction and return error
+                i2c_reset(true);
+                return -(int)(status & HOSTA_ERR);
+            }
+        }
+        // if (timeout == 0) {
+        //     // If timeout occured, kill transaction and return error
+        //     i2c_reset(true);
+        //     return -1;
+        // }
+
+        if (read) {
+            // Read byte
+            data[i] = HOBDBA;
+        }
+    }
+
+    return i;
+}
+
+int i2c_read(uint8_t * data, int length) {
+    return i2c_transaction(data, length, true);
+}
+
+int i2c_write(uint8_t * data, int length) {
+    return i2c_transaction(data, length, false);
+}
diff --git a/src/ec/it8587e/include/ec/i2c.h b/src/ec/it8587e/include/ec/i2c.h
index 60afcbd..7b1af45 100644
--- a/src/ec/it8587e/include/ec/i2c.h
+++ b/src/ec/it8587e/include/ec/i2c.h
@@ -1,10 +1,8 @@
 #ifndef _EC_I2C_H
 #define _EC_I2C_H
 
-#include <stdint.h>
+#include <common/i2c.h>
 
-uint8_t i2c_transaction(uint8_t addr_rw, uint8_t * data, uint16_t length);
-#define i2c_read(addr, data, length) i2c_transaction(((uint8_t)addr << 1) | 1, data, length)
-#define i2c_write(addr, data, length) i2c_transaction(((uint8_t)addr << 1), data, length)
+void i2c_reset(bool kill);
 
 #endif // _EC_I2C_H