First recorded (as “Keep A-Knockin’ An You Can’t Get In”) by James “Boodle It” Wiggins (February 1928), and (as “You Can’t Come In”) Bert Mays (October 1928).
Other versions by Lil Johnson (as “Keep on Knocking” 1935), Milton Brown & His Musical Brownies (as “Keep a Knockin'” 1936), Bob Wills & His Texas Playboys (as “Keep Knockin’ (But You Can’t Come In)” 1938), Louis Jordan & His Tympany Five (as “Keep A-Knockin'” 1939).
Hit version by Little Richard (US #8/R&B #2/UK #21 1957).
From the wiki: “‘Keep A-Knockin” has one of those confounding origin pedigrees more common than not in the early days of recorded music. Several recordings used similar lyrics and similar melody, with a baffling merry-go-round of credits … or non-credits.
“In 1928, a few months apart, James ‘Boodle It’ Wiggins and Bert Mays, each independent of the other, recorded the similarly-titled and similarly-sounding songs ‘Keep a-Knockin’ An You Can’t Get It’ and ‘You Can’t Come In’ – but neither recording listed a writer’s credit. This was followed by recordings in the 1930s by Lil Johnson, Milton Brown, and Bob Wills, respectively titled ‘Keep on Knocking’ (credited to Wiggins), ‘Keep a Knockin” (uncredited), and ‘Keep Knockin’ (But You Can’t Come In) (uncredited)’.