Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input

Force feedback for Linux.

By Johann Deneux <deneux@ifrance.com> on 2001/04/22.

Updated by Anssi Hannula <anssi.hannula@gmail.com> on 2006/04/09.

You may redistribute this file. Please remember to include shape.fig and

interactive.fig as well.

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

0. Introduction

1. Introduction

~~~~~~~~~~~~~~~

This document describes how to use force feedback devices under Linux. The

goal is not to support these devices as if they were simple input-only devices

(as it is already the case), but to really enable the rendering of force

effects.

At the moment, only I-Force devices are supported, and not officially. That

means I had to find out how the protocol works on my own. Of course, the

information I managed to grasp is far from being complete, and I can not

guarranty that this driver will work for you.

This document only describes the force feedback part of the driver for I-Force

devices. Please read joystick.txt before reading further this document.

This document only describes the force feedback part of the Linux input

interface. Please read joystick.txt and input.txt before reading further this

document.

2. Instructions to the user

~~~~~~~~~~~~~~~~~~~~~~~~~~~

Here are instructions on how to compile and use the driver. In fact, this

driver is the normal iforce, input and evdev drivers written by Vojtech

Pavlik, plus additions to support force feedback.

To enable force feedback, you have to:

1. have your kernel configured with evdev and a driver that supports your

   device.

2. make sure evdev module is loaded and /dev/input/event* device files are

   created.

Before you start, let me WARN you that some devices shake violently during the

initialisation phase. This happens for example with my "AVB Top Shot Pegasus".

To stop this annoying behaviour, move you joystick to its limits. Anyway, you

should keep a hand on your device, in order to avoid it to brake down if

should keep a hand on your device, in order to avoid it to break down if

something goes wrong.

At the kernel's compilation:

	- Enable IForce/Serial

	- Enable Event interface

Compile the modules, install them.

You also need inputattach.

You then need to insert the modules into the following order:

% modprobe joydev

% modprobe serport		# Only for serial

% modprobe iforce

% modprobe evdev

% ./inputattach -ifor $2 &	# Only for serial

If you are using USB, you don't need the inputattach step.

Please check that you have all the /dev/input entries needed:

cd /dev

rm js*

mkdir input

mknod input/js0 c 13 0

mknod input/js1 c 13 1

mknod input/js2 c 13 2

mknod input/js3 c 13 3

ln -s input/js0 js0

ln -s input/js1 js1

ln -s input/js2 js2

ln -s input/js3 js3

mknod input/event0 c 13 64

mknod input/event1 c 13 65

mknod input/event2 c 13 66

mknod input/event3 c 13 67

If you have a serial iforce device, you need to start inputattach. See

joystick.txt for details.

2.1 Does it work ?

~~~~~~~~~~~~~~~~~~

Returns the features supported by the device. features is a bitfield with the

following bits:

- FF_X		has an X axis (usually joysticks)

- FF_Y		has an Y axis (usually joysticks)

- FF_WHEEL	has a wheel (usually sterring wheels)

- FF_CONSTANT	can render constant force effects

- FF_PERIODIC	can render periodic effects (sine, triangle, square...)

- FF_PERIODIC	can render periodic effects with the following waveforms:

  - FF_SQUARE	  square waveform

  - FF_TRIANGLE	  triangle waveform

  - FF_SINE	  sine waveform

  - FF_SAW_UP	  sawtooth up waveform

  - FF_SAW_DOWN	  sawtooth down waveform

  - FF_CUSTOM	  custom waveform

- FF_RAMP       can render ramp effects

- FF_SPRING	can simulate the presence of a spring

- FF_FRICTION	can simulate friction

- FF_DAMPER	can simulate damper effects

- FF_RUMBLE	rumble effects (normally the only effect supported by rumble

		pads)

- FF_RUMBLE	rumble effects

- FF_INERTIA    can simulate inertia

- FF_GAIN	gain is adjustable

- FF_AUTOCENTER	autocenter is adjustable

Note: In most cases you should use FF_PERIODIC instead of FF_RUMBLE. All

      devices that support FF_RUMBLE support FF_PERIODIC (square, triangle,

      sine) and the other way around.

Note: The exact syntax FF_CUSTOM is undefined for the time being as no driver

      supports it yet.

int ioctl(int fd, EVIOCGEFFECTS, int *n);

some operations (removing an effect, controlling the playback).

This if field must be set to -1 by the user in order to tell the driver to

allocate a new effect.

Effects are file descriptor specific.

See <linux/input.h> for a description of the ff_effect struct. You should also

find help in a few sketches, contained in files shape.fig and interactive.fig.

You need xfig to visualize these files.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

int ioctl(int fd, EVIOCRMFF, effect.id);

This makes room for new effects in the device's memory. Please note this won't

stop the effect if it was playing.

This makes room for new effects in the device's memory. Note that this also

stops the effect if it was playing.

3.4 Controlling the playback of effects

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

~~~~~~~~~~~~~~~~~~~~

Not all devices have the same strength. Therefore, users should set a gain

factor depending on how strong they want effects to be. This setting is

persistent across access to the driver, so you should not care about it if

you are writing games, as another utility probably already set this for you.

persistent across access to the driver.

/* Set the gain of the device

int gain;		/* between 0 and 100 */

the direction of an effect cannot be updated with iforce devices. In this

case, the driver stops the effect, up-load it, and restart it.

Therefore it is recommended to dynamically change direction while the effect

is playing only when it is ok to restart the effect with a replay count of 1.

3.8 Information about the status of effects

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Every time the status of an effect is changed, an event is sent. The values

and meanings of the fields of the event are as follows:

struct input_event {

/* When the status of the effect changed */

	struct timeval time;

FF_STATUS_STOPPED	The effect stopped playing

FF_STATUS_PLAYING	The effect started to play

NOTE: Status feedback is only supported by iforce driver. If you have

      a really good reason to use this, please contact

      linux-joystick@atrey.karlin.mff.cuni.cz or anssi.hannula@gmail.com

      so that support for it can be added to the rest of the drivers.

 */

static struct input_handle *kbd_connect(struct input_handler *handler,

					struct input_dev *dev,

					struct input_device_id *id)

					const struct input_device_id *id)

{

	struct input_handle *handle;

	int i;

	tasklet_enable(&keyboard_tasklet);

}

static struct input_device_id kbd_ids[] = {

static const struct input_device_id kbd_ids[] = {

	{

                .flags = INPUT_DEVICE_ID_MATCH_EVBIT,

                .evbit = { BIT(EV_KEY) },

int __init kbd_init(void)

{

	int i;

	int error;

        for (i = 0; i < MAX_NR_CONSOLES; i++) {

		kbd_table[i].ledflagstate = KBD_DEFLEDS;

		kbd_table[i].kbdmode = VC_XLATE;

	}

	input_register_handler(&kbd_handler);

	error = input_register_handler(&kbd_handler);

	if (error)

		return error;

	tasklet_enable(&keyboard_tasklet);

	tasklet_schedule(&keyboard_tasklet);

if INPUT

config INPUT_FF_MEMLESS

	tristate "Support for memoryless force-feedback devices"

	default n

	---help---

	  Say Y here if you have memoryless force-feedback input device

	  such as Logitech WingMan Force 3D, ThrustMaster FireStorm Dual

	  Power 2, or similar. You will also need to enable hardware-specific

	  driver.

	  If unsure, say N.

	  To compile this driver as a module, choose M here: the

	  module will be called ff-memless.

comment "Userland interfaces"

config INPUT_MOUSEDEV

# Each configuration option enables a list of files.

obj-$(CONFIG_INPUT)		+= input.o

obj-$(CONFIG_INPUT)		+= input-core.o

input-core-objs := input.o ff-core.o

obj-$(CONFIG_INPUT_FF_MEMLESS)	+= ff-memless.o

obj-$(CONFIG_INPUT_MOUSEDEV)	+= mousedev.o

obj-$(CONFIG_INPUT_JOYDEV)	+= joydev.o

obj-$(CONFIG_INPUT_EVDEV)	+= evdev.o

static void evbug_event(struct input_handle *handle, unsigned int type, unsigned int code, int value)

{

	printk(KERN_DEBUG "evbug.c: Event. Dev: %s, Type: %d, Code: %d, Value: %d\n", handle->dev->phys, type, code, value);

	printk(KERN_DEBUG "evbug.c: Event. Dev: %s, Type: %d, Code: %d, Value: %d\n",

		handle->dev->phys, type, code, value);

}

static struct input_handle *evbug_connect(struct input_handler *handler, struct input_dev *dev, struct input_device_id *id)

static struct input_handle *evbug_connect(struct input_handler *handler, struct input_dev *dev,

					  const struct input_device_id *id)

{

	struct input_handle *handle;

	kfree(handle);

}

static struct input_device_id evbug_ids[] = {

static const struct input_device_id evbug_ids[] = {

	{ .driver_info = 1 },	/* Matches all devices */

	{ },			/* Terminating zero entry */

};

static int __init evbug_init(void)

{

	input_register_handler(&evbug_handler);

	return 0;

	return input_register_handler(&evbug_handler);

}

static void __exit evbug_exit(void)