Add ROADMAP.md for planned work

README.md

@@ -146,3 +146,5 @@ The JPEG decoder, `jpegio`, moved to micropython-pydevices'
 - [docs/ports/esp32.md](docs/ports/esp32.md) — Qualia DotClock + P4 mipidsi behavioral notes
 - [PyDevices/pydevices](https://github.com/PyDevices/pydevices) — canonical drivers and board configs
 - [PyDevices/pydevices-examples](https://github.com/PyDevices/pydevices-examples) — examples and gallery
+
+What's planned next is in [ROADMAP.md](ROADMAP.md).

ROADMAP.md

@@ -0,0 +1,22 @@
+# Roadmap
+
+displayif is heading toward faster, tear-free refreshes on big panels, by
+letting a drawing layer work with the panel's own memory rather than around it.
+
+## Refresh
+
+- A documented way to draw straight into a panel's own framebuffer: ask the
+  display for a writable surface, its stride and pixel order, and learn when
+  it stops being valid. That saves a full-frame copy on every present.
+- A shared dirty-region contract, so a drawing layer that knows which rows
+  changed can tell the display, instead of each blit working it out again.
+
+## Ports
+
+- Hardware runs still to do: RK043 (mimxrt eLCDIF), RT1170 DSI, and a long
+  Pico DVI soak on a full panel.
+- mimxrt `i80bus`: a board config in pydevices, and an optional DMA path for
+  bulk transfers.
+
+Bugs, and things you need that don't work yet, go to
+[issues](https://github.com/PyDevices/displayif/issues).

docs/roadmap-notes.md

@@ -4,6 +4,9 @@ Working checklist tracking displayif's build-out, moved out of
 [port-matrix.md](port-matrix.md) (a reference page, not a task list). Status
 verified against the tree on 2026-08-29.
 
+What's still ahead is in the repository's [ROADMAP.md](../ROADMAP.md); this page
+keeps the record of how the build-out went.
+
 1. Scaffold — done
 2. pydevices board configs on `dotclockframebuffer.DotClockFramebuffer` + `FBDisplay` — done
 3. `spibus` + smoke tests — done