[ltp] RFC : a hotkey, backlight, and bluetooth driver for SL series thinkpads

[Alexandre Rostovtsev]

(I apologize if you are receiving this for the second time, but since
my original email hasn't appeared on the archive page after an hour, I
am guessing it was filtered as spam because I was not subscribed to
the mailing list.)

Hi.

I have gotten tired of the lack of support for the SL series
ThinkPads, and decided to write a driver. You can see the results at
http://terpconnect.umd.edu/~rostovts/lenovo-sl-laptop/0.02/lenovo-sl-laptop.c

It adds support for the SL series hotkeys and adds a bluetooth rfkill
(enabling bluetooth via btusb).

In addition, the "control_backlight=1" module parameter makes the
module control the backlight brightness too. This is useful because
the SL series use the ACPI backlight brightness interface in a
completely non-standard manner, causing bugs (see
http://bugzilla.kernel.org/show_bug.cgi?id=12249) and it's likely that
future versions of the ACPI video driver will simply disable
brightness support for the SL series.

It does not support the hdaps accelerometer (which the SL series
machines theoretically come with), and frankly, I have no idea where
to start on that particular feature. Also, it does not check for BIOS
DMI strings (I have an SL300 and don't know what DMI strings other SL
ThinkPads use).

This is my first time writing kernel code, so I would appreciate any
advice and criticism.

Mostly, I am posting this because I am not sure where to go with the
driver in the future. Should it be integrated into the thinkpad_acpi
driver? While the bluetooth support is basically copypasta from
thinkpad_acpi, the hotkey and screen brightness interfaces seem to
have nothing in common with the rest of the ThinkPad series.

-Alexandre Rostovtsev.