Janis Joplin & the Big Brother and the holding company.

Riff I :
(1st time)

E|-3--1--3-------------------------------------------------------5-3---0-3-0-
A|-----------2--3--4?5-4-5-------5--------5---3--2---2-2----------------
D|--------------------------------2------2--2----------------------------------
G|------------------------------------------------------------------------------

(2nd time)

E|--3--1--3------------------------------------------------------
A|------------2--3-----5-4-5----------2-3-2-------------------
D|-----------------------------------------------2-3-4-5---------
G|-----------------------------------------------------------------

Riff II:
(1st time)

E|----------------------------------------------
A|--3-----3------3-----5-----5------5-------
D|----1-1---1-1---1-----3-3---3-3---3-5--
G|---------------------------------------------

(2nd time)

E|----------------------------------------------
A|--3-----3------3-----5-----5------5-------
D|----1-1---1-1---1-----3-3---3-3---3-5--
G|---------------------------------------------

E|-----------------------------
A|--4-5----4-5---4-5--------
D|-------3------5------3-4-5-
G|-----------------------------

Riff I and repeat on and on the 1st time.

Riff II

Bridge:  

G  /  D  /  C  / G

Repeat riff I on and on.

Bridge II:

G  /  C  / G  /  C
 
Riff II ends like this:

E|--------------------------------------------------------3---
A|-3-----3------3-----5------5------4-5---4-5---4-5---5--
D|---1-1---1-1---1-----3-3----3-3------3-----5----------5
G|-------------------------------------------------------------3-