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Commit 4c57e379 authored by Henrik Rydberg's avatar Henrik Rydberg Committed by Dmitry Torokhov
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Input: bcm5974 - add documentation for the driver 



This patch adds documentation for the bcm5974 to Documentation/input/.

Signed-off-by: default avatarHenrik Rydberg <rydberg@euromail.se>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent 53402193

Documentation/input/bcm5974.txt

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BCM5974 Driver (bcm5974)

------------------------

	Copyright (C) 2008-2009	Henrik Rydberg <rydberg@euromail.se>



The USB initialization and package decoding was made by Scott Shawcroft as

part of the touchd user-space driver project:

	Copyright (C) 2008	Scott Shawcroft (scott.shawcroft@gmail.com)



The BCM5974 driver is based on the appletouch driver:

	Copyright (C) 2001-2004	Greg Kroah-Hartman (greg@kroah.com)

	Copyright (C) 2005	Johannes Berg (johannes@sipsolutions.net)

	Copyright (C) 2005	Stelian Pop (stelian@popies.net)

	Copyright (C) 2005	Frank Arnold (frank@scirocco-5v-turbo.de)

	Copyright (C) 2005	Peter Osterlund (petero2@telia.com)

	Copyright (C) 2005	Michael Hanselmann (linux-kernel@hansmi.ch)

	Copyright (C) 2006	Nicolas Boichat (nicolas@boichat.ch)



This driver adds support for the multi-touch trackpad on the new Apple

Macbook Air and Macbook Pro laptops. It replaces the appletouch driver on

those computers, and integrates well with the synaptics driver of the Xorg

system.



Known to work on Macbook Air, Macbook Pro Penryn and the new unibody

Macbook 5 and Macbook Pro 5.



Usage

-----



The driver loads automatically for the supported usb device ids, and

becomes available both as an event device (/dev/input/event*) and as a

mouse via the mousedev driver (/dev/input/mice).



USB Race

--------



The Apple multi-touch trackpads report both mouse and keyboard events via

different interfaces of the same usb device. This creates a race condition

with the HID driver, which, if not told otherwise, will find the standard

HID mouse and keyboard, and claim the whole device. To remedy, the usb

product id must be listed in the mouse_ignore list of the hid driver.



Debug output

------------



To ease the development for new hardware version, verbose packet output can

be switched on with the debug kernel module parameter. The range [1-9]

yields different levels of verbosity. Example (as root):



echo -n 9 > /sys/module/bcm5974/parameters/debug



tail -f /var/log/debug



echo -n 0 > /sys/module/bcm5974/parameters/debug



Trivia

------



The driver was developed at the ubuntu forums in June 2008 [1], and now has

a more permanent home at bitmath.org [2].



Links

-----



[1] http://ubuntuforums.org/showthread.php?t=840040

[2] http://http://bitmath.org/code/