[E3-hacking] [PATCH v4 4/5(7)] input: serio: add support for Amstrad Delta serial keyboard port

Dmitry Torokhov dmitry.torokhov at gmail.com
Tue May 4 21:58:00 BST 2010

On Tue, May 04, 2010 at 09:48:36PM +0100, Russell King - ARM Linux wrote:
> On Tue, May 04, 2010 at 01:40:41PM -0700, Tony Lindgren wrote:
> > * Janusz Krzysztofik <jkrzyszt at tis.icnet.pl> [100427 18:09]:
> > > The patch introduces a serio driver that supports a keyboard serial port found
> > > on the Amstrad Delta videophone board.
> > > 
> > > After initializing the hardware, the driver reads its input data from a buffer
> > > filled in by the board FIQ (Fast Interrupt Request) handler.
> > > 
> > > Standard AT keyboard driver (atkbd) will be used on top of the serio layer for 
> > > handling the E3 keyboard (called mailboard) connected to the port. Since the 
> > > device generated scancodes differ from what the atkbd expects, a custom key 
> > > code to scan code table must be loaded from userspace for the keyboard to be 
> > > useable.
> What's the rationale for this approach?  There's no requirement for the
> atkbd driver to be used for all keyboards.  It seems very obscure (and
> backward) way to do things.
> Why not implement the serio driver for the IO level, and a separate
> keyboard driver which can handle the protocol and interpret the
> scancodes?

Because it is AT-like keyboard with messed up scancodes, it responds to
our probes as a regular keyboard so we can't auto-select proper keymap.
If you were to connect a standard PS/2 keyboard to E3 port it would work
without any special keymap.


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