This commit on 5.4-2.3.x-imx introduces the use of EPDC that is (at least) undocumented in MCIMX28RM.pdf (i.MX28 Reference Manual). I don't believe it has an undocumented EPDC IP inside though.
Newer SoCs like i.MX6 and i.MX8 have EPDCs implemented and their LCDIF version is 4. LCDIF on i.MX28 is also version 4 and the comparison of IP version can accidentally cause access to non-existent registers.
Should I patch the lines to remove EPDC-related lines if I use 5.4-2.3.x-imx on i.MX28?