Change API of the eeprom_24aa64 module.

    * read and write byte functions.
    * page write function with size and page boundary check.
    * sequencial read function.

Apply changes made by Richard to the eeprom_24aa64 module.

    Changes made by Richard Carrillo (7solutions) for the fmcdio5chttla.
        * Proper exception raising and handling.
        * Avoiding infinite loop by adding timeouts.

Some cleanup in the comments and commented debug messages.

common/eeprom_24aa64.py

 #!/usr/bin/python
 
+# Copyright CERN, 2011
+# Author: Matthieu Cattin (CERN)
+# Author (modifications): Richard Carrillo <rcarrillo(AT)sevensols.com>
+# Licence: GPL v2 or later.
+# Website: http://www.ohwr.org
+# Website: http://www.sevensols.com
+# Last modifications: 26/4/2012
+
+# Import standard modules
 import sys
-import rr
 import time
+
+# Import specific modules
+import rr
 import i2c
 
+# Class to access the 24AA64 (64K EEPROM) chip.
+# It uses the I2C class.
 
 class C24AA64:
+
+        PAGE_SIZE = 32 # in bytes
+        PAGE_BOUNDARY_MASK = 0xFFFF - (PAGE_SIZE - 1)
+
 	def __init__(self, i2c, i2c_addr):
 		self.i2c = i2c
 		self.i2c_addr = i2c_addr
 
-	def wr_data(self, mem_addr, data):
-                if len(data) > 32:
-                        print "Maximum sequence write size is 32 byte!"
-                        return -1;
+        def wr_byte(self, mem_addr, byte):
 		self.i2c.start(self.i2c_addr, True)
                 self.i2c.write((mem_addr >> 8), False)
                 self.i2c.write((mem_addr & 0xFF), False)
-                #print('24AA64:write: data lenght=%d')%(len(data))
+                self.i2c.write(byte,True)
+
+        def rd_byte(self, mem_addr):
+		self.i2c.start(self.i2c_addr, True)
+		self.i2c.write((mem_addr >> 8), False)
+                self.i2c.write((mem_addr & 0xFF), False)
+		self.i2c.start(self.i2c_addr, False)
+                return self.i2c.read(True)
+
+        def wr_page(self, mem_addr, data):
+                #print '[24AA64] write data lenght=%d' % (len(data))
+                #print '[24AA64] write addr=%04X' % (mem_addr)
+                if(len(data) == 0):
+                        raise i2c.I2CDeviceOperationError("Nothing to transmit, data size is 0!")
+                if(len(data) > self.PAGE_SIZE):
+                        raise i2c.I2CDeviceOperationError("Maximum write size is " + str(self.PAGE_SIZE)+" byte!")
+                if((mem_addr | self.PAGE_BOUNDARY_MASK) ^ self.PAGE_BOUNDARY_MASK):
+                        raise i2c.I2CDeviceOperationError("Start write address is not aligned to a page boundary!")
+		self.i2c.start(self.i2c_addr, True)
+                self.i2c.write((mem_addr >> 8), False)
+                self.i2c.write((mem_addr & 0xFF), False)
+                #print '[24AA64] write data lenght=%d' % (len(data))
+                i = 0
 		for i in range(len(data)-1):
-                        #print('24AA64:write: i=%d')%(i)
+                        #print '[24AA64] write i=%d' % (i)
                         self.i2c.write(data[i],False)
                 if len(data) > 1:
                         i += 1
-                else:
-                        i = 0
-                #print('24AA64:write:last i=%d')%(i)
+                #print '[24AA64] write last i=%d' % (i)
                 self.i2c.write(data[i],True)
-		return 0;
 
-	def rd_data(self, mem_addr, size):
+	def rd_seq(self, mem_addr, size):
 		self.i2c.start(self.i2c_addr, True)
 		self.i2c.write((mem_addr >> 8), False)
                 self.i2c.write((mem_addr & 0xFF), False)
 		self.i2c.start(self.i2c_addr, False)
                 data = []
-                #print('24AA64:read: data lenght=%d')%(size)
+                #print '[24AA64] read data lenght=%d' % (size)
+                i=0
 		for i in range(size-1):
                         data.append(self.i2c.read(False))
-                        #print('24AA64:read: i=%d')%(i)
-                #print('24AA64:read:last i=%d')%(i)
+                        #print '[24AA64] read i=%d' % (i)
+                if len(data) > 1:
+                        i += 1
+                #print '[24AA64] read last i=%d' % (i)
                 data.append(self.i2c.read(True))
-		return data;
+		return data