import itertools, re
s = 'name1,value1,tag11=value11,tag12=value12,tag13=value13'
if re.match(r'[^,=]+,[^,=]+(?:,[^,=]+=[^,=]+)+$', s):
	l = re.split("[=,]", s)
	d = dict(itertools.izip_longest(*[iter(l)] * 2, fillvalue=""))
	print(d)
else:
	print("Not valid!")