[U-Boot] unified keyboard queuing?

[Simon Glass]

Hi Michal,

On 9 January 2015 at 09:33, Michal Suchanek <hramrach at gmail.com> wrote:
> Hello,
>
> I was looking at adding another keyboard driver.
>
> So far there is USB keyboard and AT keyboard both with its own queuing
> code and different incomplete translation table.
>
> For one, USB keyboard has some fake arrow key hack which is *not*
> included in the AT keyboard code afaict.
>
> I managed to read a button state on my tablet and send KEY_ENTER which
> produces some weird character because I was supposed to send '\r' to
> stdin instead.
>
> With 3 ~ 7 buttons it is obviously desirable that users can configure
> what the buttons  send. Both because the number of buttons is limited
> and because the logical button to physical button mapping may be
> different on some devices. So far I only saw Vol+ and Vol- swapped,
> though.
>
> I see a few options here
>
> 1) hard code the 3 keys commonly used on tablets to do something
> useful so that people can use Vol+/Vol-/power to browse a menu and
> select an item. Tablets that have Vol+ and Vol- swapped will just be
> slightly annoying
>
> 2) make this configurable with some sort of options in Kconfig (7
> options total for all supported keys). This should result in compiled
> code the size of (1)
>
> 3) make some central keyboard translation so that USB keyboard, AT
> keyboard and any other keyboard can send same keycodes which are
> translated to characters sent to stdin the same way. Use keycodes in
> Kconfig options or possibly read a dtb which specifies the key layout
> for Linux. Will result in much larger code for small 7-key keyboard
> but will possibly make keyboards more predictable overall.

See input.c which aims to do this. I forgot to move i8042.c over to
use that framework, but a few other drivers use it. Also see
key_matrix.c which implements the device tree binding, making the
keyboard scan codes configurable.

Regards,
Simon