Status:
- = Planned.
X = In progress, some work done.
* = Done.
? = Not sure if worth the effort or useful at all.
N = Decided against.

Within 2.1.x
* Binary Semaphores on top of Counting Semaphores.
* Direct unbuffered UART driver.
  Requirements: low level, callbacks, DMA capable, state machines buildable
                on top, support data words greater than 8 bits, callback for
                "last byte transmitted (RS485)", simple implementation,
                verifiable.
* Rework STM32 drivers to use friendly IRQ names and centralized DMA macros.
* I-class functions for the ADC/PWM drivers.
* All the device driver structures must have a fields extension macro and
  initializer hook.
* All the device driver callbacks must have the driver pointer as first
  parameter.
* Change the SPI driver to be able to work asynchronously using callbacks,
  keep the synchronous APIs available as option.
* Add an optional spiPolledExchange() API to the SPI driver model.
* Update the STM32 SPI driver to the new model.
* Make the ADC driver have the same synchronous/asynchronous API of the
  new SPI driver model.
* General HAL improvements.
* Update the AT91SAM7 SPI driver (DMA and/or ISR).
  * Verify the FatFs demo on both the AT91SAM7X and AT91SAM7S.
* Update the LPC214x SPI driver (ISR).
  * Verify the LPC214x FatFs demo.
* Write a new SPI driver for LPC1xxx (ISR)(it should be very close to the
  LPC214x one).
N Evaluate if to add a synchronous API to the UART driver, eventually do so.
* Global documentation reorganization in order to allow both separate documents
  and the usual blob document.
* PDF generation from the documentation system (only separate documents, not
  the blob).
* Automatic compilation and upload of the various documents on the web site
  (doxygen + rsync).
* New STM8S/A SPI driver.
* Reorganization of the STM32 family port-level support.
* Remove preprocessor directives from the assembler files and restore the
  RIDE7 build files in the STM32 demo.
* Move dynamic APIs into a separate source file.
* Improved support in the STM32 HAL support for multiple sub-families. Do
  not check for the family in the various drivers but simply check for
  switch macros like STM32_HAS_USART3, STM32_HAS_SPI3. This what the
  drivers will not need changes when adding new sub-families.
* STM8L official HAL support, it will have to be separated from the STM8S/STM8A
  HAL because it is very different.
  * Shared ISR management.
  * STM8L-Discovery demo.
* Add the STM32F100 (Value Line) sub-family to the official STM32 HAL support.
  * STM32VL-Discovery demo.
* Remove the PAL default configuration from the various hal_lld.c and move
  them into board.c files, this will remove an ugly dependency.
* Realign the STM8 port to the new STM8L one as options, naming conventions
  and general solutions.
* Support for more compilers (IAR, Keil, ARMCMx only initially).
X Support for not just Makefiles (Ride7, Crossworks etc).
* IAR port for Cortex-Mx, add demos for all the supported families.
* Keil port for Cortex-Mx, add demos for all the supported families.
* Change the serial drivers to have a single event source instead of three.
  Add Rx and Tx to the existing flags mechanism. Move up the flags handling in
  the superclass.
X Except for the above, bug fixing only until the 2.2.0 release.

Within 2.3.x (hopefully)
- Resist doing more changes and optimizations to the kernel.
? Make thread functions return void.
- Introduce a "THREAD" function prefix in order to hide compiler-specific
  optimizations for thread functions.
X Add an USB abstract device driver class.
X USB driver implementation for STM32F103/STM32F102.
X Add a Serial over USB generic device driver implementing a USB Communication
  Device Class and offering a Serial-like interface to the applications.
- Add a switch to enable/disable the priority inheritance algorithm in mutexes.
X File System infrastructure.
  - Official FatFs wrapper using the new infrastructure, dedicated test suite.
X Transactional flash file system implementation.
X I2C device driver class support and at least one implementation.
- Serial over UART complex driver driver, evaluate from the performance
  results if to make obsolete the current dedicated Serial driver.
X Shared DMA channels support in the STM32/STM8L HALs.
X New device driver models: Clock, Systick, RTC, WDG, DAC, Power Monitor.
- MAC driver for STM32F107 (hardware missing).
- Device drivers for STM8/STM8L (ADC, PWM, bring them on par with STM32).
- Batch testing of the ARM7/ARMCMx port using OpenOCD, with reports.
- Debug-related features and tools.
- Add a *very simple* ADC API for single one shot sampling (implement it as
  an injected conversion on the STM32).
- Update C++ wrapper (Heap, Pools, Mailboxes and any new feature).
- Threads Pools manager in the library.

Later but within 2.x.x
- Dedicated TCP/IP stack.
? ISO7816 driver over UART driver, both reader and card side (hardware
  missing).
- Merge the Coldfire branch in mainline (hardware missing).
- Merge the H8S branch in mainline (hardware missing).
- MAC driver revision in order to support copy-less operations, this will
  require changes to lwIP or a new TCP/IP stack however.

Ideas for 3.x.x:
- MMU/MPU support.
- High resolution timers and tickless kernel.
- Multicore support.

Side projects:
X ChibiOS Wizard, UML modeling and ChibiOS applications code and
  documentation generator.
? File System
- Visual debugger/monitor interfaced through OpenOCD.