/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
* User level driver support for input subsystem
* Heavily based on evdev.c by Vojtech Pavlik
* 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
* Author: Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
* 0.5 08/13/2015 (David Herrmann <dh.herrmann@gmail.com> &
* Benjamin Tissoires <benjamin.tissoires@redhat.com>)
* - add UI_DEV_SETUP ioctl
* - add UI_ABS_SETUP ioctl
* - add UI_GET_VERSION ioctl
* 0.4 01/09/2014 (Benjamin Tissoires <benjamin.tissoires@redhat.com>)
* - add UI_GET_SYSNAME ioctl
* 0.3 24/05/2006 (Anssi Hannula <anssi.hannulagmail.com>)
* - update ff support for the changes in kernel interface
* 0.2 16/10/2004 (Micah Dowty <micah@navi.cx>)
* - added force feedback support
#define UINPUT_MAX_NAME_SIZE 80
struct uinput_ff_upload {
#define UINPUT_IOCTL_BASE 'U'
#define UI_DEV_CREATE _IO(UINPUT_IOCTL_BASE, 1)
#define UI_DEV_DESTROY _IO(UINPUT_IOCTL_BASE, 2)
char name[UINPUT_MAX_NAME_SIZE];
* UI_DEV_SETUP - Set device parameters for setup
* This ioctl sets parameters for the input device to be created. It
* supersedes the old "struct uinput_user_dev" method, which wrote this data
* via write(). To actually set the absolute axes UI_ABS_SETUP should be
* The ioctl takes a "struct uinput_setup" object as argument. The fields of
* this object are as follows:
* id: See the description of "struct input_id". This field is
* copied unchanged into the new device.
* name: This is used unchanged as name for the new device.
* ff_effects_max: This limits the maximum numbers of force-feedback effects.
* See below for a description of FF with uinput.
* This ioctl can be called multiple times and will overwrite previous values.
* If this ioctl fails with -EINVAL, it is recommended to use the old
* "uinput_user_dev" method via write() as a fallback, in case you run on an
* old kernel that does not support this ioctl.
* This ioctl may fail with -EINVAL if it is not supported or if you passed
* incorrect values, -ENOMEM if the kernel runs out of memory or -EFAULT if the
* passed uinput_setup object cannot be read/written.
* If this call fails, partial data may have already been applied to the
#define UI_DEV_SETUP _IOW(UINPUT_IOCTL_BASE, 3, struct uinput_setup)
struct uinput_abs_setup {
__u16 code; /* axis code */
struct input_absinfo absinfo;
* UI_ABS_SETUP - Set absolute axis information for the device to setup
* This ioctl sets one absolute axis information for the input device to be
* created. It supersedes the old "struct uinput_user_dev" method, which wrote
* part of this data and the content of UI_DEV_SETUP via write().
* The ioctl takes a "struct uinput_abs_setup" object as argument. The fields
* of this object are as follows:
* code: The corresponding input code associated with this axis
* absinfo: See "struct input_absinfo" for a description of this field.
* This field is copied unchanged into the kernel for the
* specified axis. If the axis is not enabled via
* UI_SET_ABSBIT, this ioctl will enable it.
* This ioctl can be called multiple times and will overwrite previous values.
* If this ioctl fails with -EINVAL, it is recommended to use the old
* "uinput_user_dev" method via write() as a fallback, in case you run on an
* old kernel that does not support this ioctl.
* This ioctl may fail with -EINVAL if it is not supported or if you passed
* incorrect values, -ENOMEM if the kernel runs out of memory or -EFAULT if the
* passed uinput_setup object cannot be read/written.
* If this call fails, partial data may have already been applied to the
#define UI_ABS_SETUP _IOW(UINPUT_IOCTL_BASE, 4, struct uinput_abs_setup)
#define UI_SET_EVBIT _IOW(UINPUT_IOCTL_BASE, 100, int)
#define UI_SET_KEYBIT _IOW(UINPUT_IOCTL_BASE, 101, int)
#define UI_SET_RELBIT _IOW(UINPUT_IOCTL_BASE, 102, int)
#define UI_SET_ABSBIT _IOW(UINPUT_IOCTL_BASE, 103, int)
#define UI_SET_MSCBIT _IOW(UINPUT_IOCTL_BASE, 104, int)
#define UI_SET_LEDBIT _IOW(UINPUT_IOCTL_BASE, 105, int)
#define UI_SET_SNDBIT _IOW(UINPUT_IOCTL_BASE, 106, int)
#define UI_SET_FFBIT _IOW(UINPUT_IOCTL_BASE, 107, int)
#define UI_SET_PHYS _IOW(UINPUT_IOCTL_BASE, 108, char*)
#define UI_SET_SWBIT _IOW(UINPUT_IOCTL_BASE, 109, int)
#define UI_SET_PROPBIT _IOW(UINPUT_IOCTL_BASE, 110, int)
#define UI_BEGIN_FF_UPLOAD _IOWR(UINPUT_IOCTL_BASE, 200, struct uinput_ff_upload)
#define UI_END_FF_UPLOAD _IOW(UINPUT_IOCTL_BASE, 201, struct uinput_ff_upload)
#define UI_BEGIN_FF_ERASE _IOWR(UINPUT_IOCTL_BASE, 202, struct uinput_ff_erase)
#define UI_END_FF_ERASE _IOW(UINPUT_IOCTL_BASE, 203, struct uinput_ff_erase)
* UI_GET_SYSNAME - get the sysfs name of the created uinput device
* @return the sysfs name of the created virtual input device.
* The complete sysfs path is then /sys/devices/virtual/input/--NAME--
* Usually, it is in the form "inputN"
#define UI_GET_SYSNAME(len) _IOC(_IOC_READ, UINPUT_IOCTL_BASE, 44, len)
* UI_GET_VERSION - Return version of uinput protocol
* This writes uinput protocol version implemented by the kernel into
* the integer pointed to by the ioctl argument. The protocol version
* is hard-coded in the kernel and is independent of the uinput device.
#define UI_GET_VERSION _IOR(UINPUT_IOCTL_BASE, 45, unsigned int)
* To write a force-feedback-capable driver, the upload_effect
* and erase_effect callbacks in input_dev must be implemented.
* The uinput driver will generate a fake input event when one of
* these callbacks are invoked. The userspace code then uses
* ioctls to retrieve additional parameters and send the return code.
* The callback blocks until this return code is sent.
* The described callback mechanism is only used if ff_effects_max
* To implement upload_effect():
* 1. Wait for an event with type == EV_UINPUT and code == UI_FF_UPLOAD.
* A request ID will be given in 'value'.
* 2. Allocate a uinput_ff_upload struct, fill in request_id with
* the 'value' from the EV_UINPUT event.
* 3. Issue a UI_BEGIN_FF_UPLOAD ioctl, giving it the
* uinput_ff_upload struct. It will be filled in with the
* ff_effects passed to upload_effect().
* 4. Perform the effect upload, and place a return code back into
the uinput_ff_upload struct.
* 5. Issue a UI_END_FF_UPLOAD ioctl, also giving it the
* uinput_ff_upload_effect struct. This will complete execution
* of our upload_effect() handler.
* To implement erase_effect():
* 1. Wait for an event with type == EV_UINPUT and code == UI_FF_ERASE.
* A request ID will be given in 'value'.
* 2. Allocate a uinput_ff_erase struct, fill in request_id with
* the 'value' from the EV_UINPUT event.
* 3. Issue a UI_BEGIN_FF_ERASE ioctl, giving it the
* uinput_ff_erase struct. It will be filled in with the
* effect ID passed to erase_effect().
* 4. Perform the effect erasure, and place a return code back
* into the uinput_ff_erase struct.
* 5. Issue a UI_END_FF_ERASE ioctl, also giving it the
* uinput_ff_erase_effect struct. This will complete execution
* of our erase_effect() handler.
* This is the new event type, used only by uinput.
* 'code' is UI_FF_UPLOAD or UI_FF_ERASE, and 'value'
* is the unique request ID. This number was picked
* arbitrarily, above EV_MAX (since the input system
* never sees it) but in the range of a 16-bit int.
char name[UINPUT_MAX_NAME_SIZE];