Tuning is down 1/2 step

C
Call on meeeee
Em      F
Call on me

if you wanted to play it in regular tuning, the chords are

B
Call on meeee
Ebm     E
Call on me

For this configuration, I find higher chords to be best, such as these:

B:
7
7
8
x
x
x
Ebm: 
6
7
8
x
x
x
or you can use this Ebm for variation:
11
11
11
x
x
x
E:
7
9
9
x
x
x

Easy song. just repeat the three chords throughout.