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- The U-Boot Driver Model Project
- ===============================
- Keyboard input analysis
- =======================
- Marek Vasut <marek.vasut@gmail.com>
- 2012-02-20
- I) Overview
- -----------
- The keyboard drivers are most often registered with STDIO subsystem. There are
- components of the keyboard drivers though, which operate in severe ad-hoc
- manner, often being related to interrupt-driven keypress reception. This
- components will require the most sanitization of all parts of keyboard input
- subsystem.
- Otherwise, the keyboard is no different from other standard input but with the
- necessity to decode scancodes. These are decoded using tables provided by
- keyboard drivers. These tables are often driver specific.
- II) Approach
- ------------
- The most problematic part is the interrupt driven keypress reception. For this,
- the buffers that are currently shared throughout the whole U-Boot would need to
- be converted into driver's private data.
- III) Analysis of in-tree drivers
- --------------------------------
- 1) board/mpl/common/kbd.c
- -------------------------
- This driver is a classic STDIO driver, no problem with conversion is expected.
- Only necessary change will be to move this driver to a proper location.
- 2) board/rbc823/kbd.c
- ---------------------
- This driver is a classic STDIO driver, no problem with conversion is expected.
- Only necessary change will be to move this driver to a proper location.
- 3) drivers/input/keyboard.c
- ---------------------------
- This driver is special in many ways. Firstly because this is a universal stub
- driver for converting scancodes from i8042 and the likes. Secondly because the
- buffer is filled by various other ad-hoc implementations of keyboard input by
- using this buffer as an extern. This will need to be fixed by allowing drivers
- to pass certain routines to this driver via platform data.
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