i2cHelper.py

#!/usr/bin/python

import smbus
import time
import os

RPI_REVISION_0 = ["900092"]
RPI_REVISION_1 = ["0002", "0003", "0004", "0005", "0006", "0007", "0008", "0009", "000d", "000e", "000f", "0010", "0011", "0012", "0013"]
RPI_REVISION_2 = ["a01041", "a21041"]
RPI_REVISION_3 = ["a02082", "a22082"]

CPU_Number = ''

def getPiRevision():
	global CPU_Number
	try:
		f = open('/proc/cpuinfo','r')
		for line in f:
			if line.startswith('Revision'):
				CPU_Number = line[11:-1]
				if CPU_Number in RPI_REVISION_0:
					return 0
				elif CPU_Number in RPI_REVISION_1:
					return 1
				elif CPU_Number in RPI_REVISION_2:
					return 2
				elif CPU_Number in RPI_REVISION_3:
					return 3
				else:
					return CPU_Number
	except:
		f.close()
		return 'open file error'
	finally:
		f.close()

def getPiI2CBusNumber():
	# get I2C bus number from /proc/cpuinfo*
	revision = getPiRevision()
	if revision in [2, 3]:
		return 1 
	elif revision in [0, 1]:
		return 0
	else:
		raise ValueError("Error occur while getting Pi Revision. Revision:{0}".format(revision))

def remove_line(tfile,sstr):
	i2c_list = []
	try:
		lines=open(tfile,'r').readlines()
		flen=len(lines)-1
		for i in range(flen):
			if sstr in lines[i]:
				i2c_list.append(i)
		for i in range(len(i2c_list)-1, 0, -1):
			lines.remove(lines[i2c_list[i]])
		open(tfile,'w').writelines(lines)
		
	except Exception,e:
		print 'remove_line:', e

def add_line(tfile,sstr):
	try:
		lines=open(tfile,'r').readlines()
		lines.append(sstr)
		open(tfile,'w').writelines(lines)
		
	except Exception,e:
		print 'add line:', e

def setting_i2c():
	remove_line('/boot/config.txt', 'dtparam=i2c_arm=')
	add_line('/boot/config.txt', '\ndtparam=i2c_arm=on\n')

def main():
	global CPU_Number
	print ''
	print '   ===================================='
	print '   ||                                ||'
	print '   ||     Raspberry Pi I2C check     ||'
	print '   ||                                ||'
	print '   ===================================='
	print ''
	time.sleep(2)
	print "   Checking your Pi's information."
	your_pi_revision = getPiRevision()
	you_i2c_bus_number = getPiI2CBusNumber()
	time.sleep(1)
	print '   Your cpu revision:', CPU_Number
	time.sleep(1)
	print '   Your Raspberry Pi is Revision', your_pi_revision
	time.sleep(1)
	print '   Your I2C bus number is:', you_i2c_bus_number
	time.sleep(1)
	print ''
	time.sleep(1)
	print '   Checking your device...'
	flag = False
	device = 'i2c-' + str(you_i2c_bus_number)
	for dev in os.listdir('/dev/'):
		if dev == device:
			flag = True
	time.sleep(1)
	if flag:
		print '   I2C setting is fine.'
		time.sleep(1)
		print '   Runing i2cdetect..'
		time.sleep(1)
		print ''
		command = 'i2cdetect -y ' + str(you_i2c_bus_number)
		os.system(command)
	else:
		print '   I2C has not been setup.'
		time.sleep(1)
		print ''
		time.sleep(1)
		print '   Backup...',
		os.system('cp /boot/config.txt /boot/config.bak')
		print 'done'
		time.sleep(1)
		print '   Setting i2c...',
		setting_i2c()
		print 'done'
		time.sleep(1)
		print '   I2C has set. It would change after reboot.'
		time.sleep(1)
		check = raw_input('   Do you want to reboot now?(y/n) ')
		flag = True
		while flag:
			if check in ['y', 'Y']:
				print '   Your Raspberry Pi will be reboot in 5 second.'
				for i in range(6):
					time.sleep(1)
					print '   ', 5-i
				print '   Rebooting...'
				flag = False
				os.system('reboot')
			elif check in ['n', 'N']:
				time.sleep(1)
				print '   Done.'
				flag = False
			else:
				print '   It should be "Y" or "N", in capital or not. Try again.'

if __name__ == '__main__':
	main()