Port of the Linux sun4i DRM drivers needed to scan out a framebuffer on
an A64 MIPI DSI panel: DE2 bus (SRAM handover), DE2 mixer (one UI layer,
XRGB8888), TCON0 in CPU/DSI mode, sun6i MIPI DSI controller (video mode,
DCS writes/reads) and the A31-generation MIPI D-PHY. A display-engine
glue driver follows the of-graph, allocates a framebuffer and exposes it
through fbd(4) for vt(4).
The framebuffer is rotated 90 degrees, so that the console in portrait mode
is facing the user that has plugged-in the keyboard sleeve that comes with
the PineTab.
Note that this is an adaptation of the Linux driver, unlike the 4 other patches.
I still need to check with the original authors that they give a permission to
relicence their code. So this revision is only here to help review the other 4
patches for now.
Tested on a PineTab early adopter.