I think one may find that JJ Cale was very well known indeed, although the critically acclaimed Grammy Award winner was never overly fond of self glorification.
His 1972 album Naturally was truly amazing. The majority of tracks on this record alone would go on to be covered by many other famous artists, Clapton being just one.
The sixth track on his fourth album titled Troubadour, was a song called Cocaine, yep that's the one.
The last album I purchased of his, was done in joint collaboration with Eric Clapton, The Road to Escondido (2006). Its a ripper, if you like the Tulsa sound.
JJ Cale was, and still is a legend. Only unknown to those less educated in the genre. Like Gram Parsons or Towns Van Zandt, to name but two more.
Vale JJ Cale.