mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-30 09:56:40 +07:00
d1659fcc59
This patch removes CVS keywords that weren't updated for a long time from comments. Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
291 lines
11 KiB
Plaintext
291 lines
11 KiB
Plaintext
Linux Input drivers v1.0
|
|
(c) 1999-2001 Vojtech Pavlik <vojtech@ucw.cz>
|
|
Sponsored by SuSE
|
|
----------------------------------------------------------------------------
|
|
|
|
0. Disclaimer
|
|
~~~~~~~~~~~~~
|
|
This program is free software; you can redistribute it and/or modify it
|
|
under the terms of the GNU General Public License as published by the Free
|
|
Software Foundation; either version 2 of the License, or (at your option)
|
|
any later version.
|
|
|
|
This program is distributed in the hope that it will be useful, but
|
|
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
|
|
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
|
|
more details.
|
|
|
|
You should have received a copy of the GNU General Public License along
|
|
with this program; if not, write to the Free Software Foundation, Inc., 59
|
|
Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
|
|
Should you need to contact me, the author, you can do so either by e-mail
|
|
- mail your message to <vojtech@ucw.cz>, or by paper mail: Vojtech Pavlik,
|
|
Simunkova 1594, Prague 8, 182 00 Czech Republic
|
|
|
|
For your convenience, the GNU General Public License version 2 is included
|
|
in the package: See the file COPYING.
|
|
|
|
1. Introduction
|
|
~~~~~~~~~~~~~~~
|
|
This is a collection of drivers that is designed to support all input
|
|
devices under Linux. While it is currently used only on for USB input
|
|
devices, future use (say 2.5/2.6) is expected to expand to replace
|
|
most of the existing input system, which is why it lives in
|
|
drivers/input/ instead of drivers/usb/.
|
|
|
|
The centre of the input drivers is the input module, which must be
|
|
loaded before any other of the input modules - it serves as a way of
|
|
communication between two groups of modules:
|
|
|
|
1.1 Device drivers
|
|
~~~~~~~~~~~~~~~~~~
|
|
These modules talk to the hardware (for example via USB), and provide
|
|
events (keystrokes, mouse movements) to the input module.
|
|
|
|
1.2 Event handlers
|
|
~~~~~~~~~~~~~~~~~~
|
|
These modules get events from input and pass them where needed via
|
|
various interfaces - keystrokes to the kernel, mouse movements via a
|
|
simulated PS/2 interface to GPM and X and so on.
|
|
|
|
2. Simple Usage
|
|
~~~~~~~~~~~~~~~
|
|
For the most usual configuration, with one USB mouse and one USB keyboard,
|
|
you'll have to load the following modules (or have them built in to the
|
|
kernel):
|
|
|
|
input
|
|
mousedev
|
|
keybdev
|
|
usbcore
|
|
uhci_hcd or ohci_hcd or ehci_hcd
|
|
usbhid
|
|
|
|
After this, the USB keyboard will work straight away, and the USB mouse
|
|
will be available as a character device on major 13, minor 63:
|
|
|
|
crw-r--r-- 1 root root 13, 63 Mar 28 22:45 mice
|
|
|
|
This device has to be created.
|
|
The commands to create it by hand are:
|
|
|
|
cd /dev
|
|
mkdir input
|
|
mknod input/mice c 13 63
|
|
|
|
After that you have to point GPM (the textmode mouse cut&paste tool) and
|
|
XFree to this device to use it - GPM should be called like:
|
|
|
|
gpm -t ps2 -m /dev/input/mice
|
|
|
|
And in X:
|
|
|
|
Section "Pointer"
|
|
Protocol "ImPS/2"
|
|
Device "/dev/input/mice"
|
|
ZAxisMapping 4 5
|
|
EndSection
|
|
|
|
When you do all of the above, you can use your USB mouse and keyboard.
|
|
|
|
3. Detailed Description
|
|
~~~~~~~~~~~~~~~~~~~~~~~
|
|
3.1 Device drivers
|
|
~~~~~~~~~~~~~~~~~~
|
|
Device drivers are the modules that generate events. The events are
|
|
however not useful without being handled, so you also will need to use some
|
|
of the modules from section 3.2.
|
|
|
|
3.1.1 usbhid
|
|
~~~~~~~~~~~~
|
|
usbhid is the largest and most complex driver of the whole suite. It
|
|
handles all HID devices, and because there is a very wide variety of them,
|
|
and because the USB HID specification isn't simple, it needs to be this big.
|
|
|
|
Currently, it handles USB mice, joysticks, gamepads, steering wheels
|
|
keyboards, trackballs and digitizers.
|
|
|
|
However, USB uses HID also for monitor controls, speaker controls, UPSs,
|
|
LCDs and many other purposes.
|
|
|
|
The monitor and speaker controls should be easy to add to the hid/input
|
|
interface, but for the UPSs and LCDs it doesn't make much sense. For this,
|
|
the hiddev interface was designed. See Documentation/usb/hiddev.txt
|
|
for more information about it.
|
|
|
|
The usage of the usbhid module is very simple, it takes no parameters,
|
|
detects everything automatically and when a HID device is inserted, it
|
|
detects it appropriately.
|
|
|
|
However, because the devices vary wildly, you might happen to have a
|
|
device that doesn't work well. In that case #define DEBUG at the beginning
|
|
of hid-core.c and send me the syslog traces.
|
|
|
|
3.1.2 usbmouse
|
|
~~~~~~~~~~~~~~
|
|
For embedded systems, for mice with broken HID descriptors and just any
|
|
other use when the big usbhid wouldn't be a good choice, there is the
|
|
usbmouse driver. It handles USB mice only. It uses a simpler HIDBP
|
|
protocol. This also means the mice must support this simpler protocol. Not
|
|
all do. If you don't have any strong reason to use this module, use usbhid
|
|
instead.
|
|
|
|
3.1.3 usbkbd
|
|
~~~~~~~~~~~~
|
|
Much like usbmouse, this module talks to keyboards with a simplified
|
|
HIDBP protocol. It's smaller, but doesn't support any extra special keys.
|
|
Use usbhid instead if there isn't any special reason to use this.
|
|
|
|
3.1.4 wacom
|
|
~~~~~~~~~~~
|
|
This is a driver for Wacom Graphire and Intuos tablets. Not for Wacom
|
|
PenPartner, that one is handled by the HID driver. Although the Intuos and
|
|
Graphire tablets claim that they are HID tablets as well, they are not and
|
|
thus need this specific driver.
|
|
|
|
3.1.5 iforce
|
|
~~~~~~~~~~~~
|
|
A driver for I-Force joysticks and wheels, both over USB and RS232.
|
|
It includes ForceFeedback support now, even though Immersion
|
|
Corp. considers the protocol a trade secret and won't disclose a word
|
|
about it.
|
|
|
|
3.2 Event handlers
|
|
~~~~~~~~~~~~~~~~~~
|
|
Event handlers distribute the events from the devices to userland and
|
|
kernel, as needed.
|
|
|
|
3.2.1 keybdev
|
|
~~~~~~~~~~~~~
|
|
keybdev is currently a rather ugly hack that translates the input
|
|
events into architecture-specific keyboard raw mode (Xlated AT Set2 on
|
|
x86), and passes them into the handle_scancode function of the
|
|
keyboard.c module. This works well enough on all architectures that
|
|
keybdev can generate rawmode on, other architectures can be added to
|
|
it.
|
|
|
|
The right way would be to pass the events to keyboard.c directly,
|
|
best if keyboard.c would itself be an event handler. This is done in
|
|
the input patch, available on the webpage mentioned below.
|
|
|
|
3.2.2 mousedev
|
|
~~~~~~~~~~~~~~
|
|
mousedev is also a hack to make programs that use mouse input
|
|
work. It takes events from either mice or digitizers/tablets and makes
|
|
a PS/2-style (a la /dev/psaux) mouse device available to the
|
|
userland. Ideally, the programs could use a more reasonable interface,
|
|
for example evdev
|
|
|
|
Mousedev devices in /dev/input (as shown above) are:
|
|
|
|
crw-r--r-- 1 root root 13, 32 Mar 28 22:45 mouse0
|
|
crw-r--r-- 1 root root 13, 33 Mar 29 00:41 mouse1
|
|
crw-r--r-- 1 root root 13, 34 Mar 29 00:41 mouse2
|
|
crw-r--r-- 1 root root 13, 35 Apr 1 10:50 mouse3
|
|
...
|
|
...
|
|
crw-r--r-- 1 root root 13, 62 Apr 1 10:50 mouse30
|
|
crw-r--r-- 1 root root 13, 63 Apr 1 10:50 mice
|
|
|
|
Each 'mouse' device is assigned to a single mouse or digitizer, except
|
|
the last one - 'mice'. This single character device is shared by all
|
|
mice and digitizers, and even if none are connected, the device is
|
|
present. This is useful for hotplugging USB mice, so that programs
|
|
can open the device even when no mice are present.
|
|
|
|
CONFIG_INPUT_MOUSEDEV_SCREEN_[XY] in the kernel configuration are
|
|
the size of your screen (in pixels) in XFree86. This is needed if you
|
|
want to use your digitizer in X, because its movement is sent to X
|
|
via a virtual PS/2 mouse and thus needs to be scaled
|
|
accordingly. These values won't be used if you use a mouse only.
|
|
|
|
Mousedev will generate either PS/2, ImPS/2 (Microsoft IntelliMouse) or
|
|
ExplorerPS/2 (IntelliMouse Explorer) protocols, depending on what the
|
|
program reading the data wishes. You can set GPM and X to any of
|
|
these. You'll need ImPS/2 if you want to make use of a wheel on a USB
|
|
mouse and ExplorerPS/2 if you want to use extra (up to 5) buttons.
|
|
|
|
3.2.3 joydev
|
|
~~~~~~~~~~~~
|
|
Joydev implements v0.x and v1.x Linux joystick api, much like
|
|
drivers/char/joystick/joystick.c used to in earlier versions. See
|
|
joystick-api.txt in the Documentation subdirectory for details. As
|
|
soon as any joystick is connected, it can be accessed in /dev/input
|
|
on:
|
|
|
|
crw-r--r-- 1 root root 13, 0 Apr 1 10:50 js0
|
|
crw-r--r-- 1 root root 13, 1 Apr 1 10:50 js1
|
|
crw-r--r-- 1 root root 13, 2 Apr 1 10:50 js2
|
|
crw-r--r-- 1 root root 13, 3 Apr 1 10:50 js3
|
|
...
|
|
|
|
And so on up to js31.
|
|
|
|
3.2.4 evdev
|
|
~~~~~~~~~~~
|
|
evdev is the generic input event interface. It passes the events
|
|
generated in the kernel straight to the program, with timestamps. The
|
|
API is still evolving, but should be useable now. It's described in
|
|
section 5.
|
|
|
|
This should be the way for GPM and X to get keyboard and mouse
|
|
events. It allows for multihead in X without any specific multihead
|
|
kernel support. The event codes are the same on all architectures and
|
|
are hardware independent.
|
|
|
|
The devices are in /dev/input:
|
|
|
|
crw-r--r-- 1 root root 13, 64 Apr 1 10:49 event0
|
|
crw-r--r-- 1 root root 13, 65 Apr 1 10:50 event1
|
|
crw-r--r-- 1 root root 13, 66 Apr 1 10:50 event2
|
|
crw-r--r-- 1 root root 13, 67 Apr 1 10:50 event3
|
|
...
|
|
|
|
And so on up to event31.
|
|
|
|
4. Verifying if it works
|
|
~~~~~~~~~~~~~~~~~~~~~~~~
|
|
Typing a couple keys on the keyboard should be enough to check that
|
|
a USB keyboard works and is correctly connected to the kernel keyboard
|
|
driver.
|
|
|
|
Doing a cat /dev/input/mouse0 (c, 13, 32) will verify that a mouse
|
|
is also emulated, characters should appear if you move it.
|
|
|
|
You can test the joystick emulation with the 'jstest' utility,
|
|
available in the joystick package (see Documentation/input/joystick.txt).
|
|
|
|
You can test the event devices with the 'evtest' utility available
|
|
in the LinuxConsole project CVS archive (see the URL below).
|
|
|
|
5. Event interface
|
|
~~~~~~~~~~~~~~~~~~
|
|
Should you want to add event device support into any application (X, gpm,
|
|
svgalib ...) I <vojtech@ucw.cz> will be happy to provide you any help I
|
|
can. Here goes a description of the current state of things, which is going
|
|
to be extended, but not changed incompatibly as time goes:
|
|
|
|
You can use blocking and nonblocking reads, also select() on the
|
|
/dev/input/eventX devices, and you'll always get a whole number of input
|
|
events on a read. Their layout is:
|
|
|
|
struct input_event {
|
|
struct timeval time;
|
|
unsigned short type;
|
|
unsigned short code;
|
|
unsigned int value;
|
|
};
|
|
|
|
'time' is the timestamp, it returns the time at which the event happened.
|
|
Type is for example EV_REL for relative moment, REL_KEY for a keypress or
|
|
release. More types are defined in include/linux/input.h.
|
|
|
|
'code' is event code, for example REL_X or KEY_BACKSPACE, again a complete
|
|
list is in include/linux/input.h.
|
|
|
|
'value' is the value the event carries. Either a relative change for
|
|
EV_REL, absolute new value for EV_ABS (joysticks ...), or 0 for EV_KEY for
|
|
release, 1 for keypress and 2 for autorepeat.
|
|
|