Hello folks, here's an RFC for using compiled-in dtb's for initializing board devices that can't be probed via bus'es or firmware. Use cases are boards with non-oftree firmware (ACPI, etc) where certain platform devices can't be directly enumerated via firmware. Traditionally we had to write board specific drivers that check for board identification (DMI strings, etc), then initialize the actual devices and their links (eg. gpio<->leds/buttons, ...). Often this can be expressed just by DT. This patch queue does a bunch of preparations in oftree code, so we can support multiple fully independent DT's (not using DT overlays). And then adds a generic driver parses compiled-in fdt blobs, checks for mathing DMI strings and initializes the devices. As an example, the last patch adds an alternative implementation for the PC engines APU2/3/4 board family based on device tree. The approach can be easily be extended to other kinds of composite devices, eg. PCI cards or USB dongles. Yet some drawbacks of the current implementation: * individual FDT's can't be modularized yet (IMHO, we don't have DMI-based modprobing anyways) * can't reconfigure or attach to devices outside the individual DT's (eg. probed by PCI, etc) have fun, --mtx
