linux/include/uapi/linux/uhid.h

/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
#ifndef __UHID_H_
#define __UHID_H_

/*
 * User-space I/O driver support for HID subsystem
 * Copyright (c) 2012 David Herrmann
 */

/*
 * 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.
 */

/*
 * Public header for user-space communication. We try to keep every structure
 * aligned but to be safe we also use __attribute__((__packed__)). Therefore,
 * the communication should be ABI compatible even between architectures.
 */

#include <linux/input.h>
#include <linux/types.h>
#include <linux/hid.h>

enum uhid_event_type { … };

struct uhid_create2_req { … } __attribute__((packed));

enum uhid_dev_flag { … };

struct uhid_start_req { … };

#define UHID_DATA_MAX …

enum uhid_report_type { … };

struct uhid_input2_req { … } __attribute__((packed));

struct uhid_output_req { … } __attribute__((packed));

struct uhid_get_report_req { … } __attribute__((packed));

struct uhid_get_report_reply_req { … } __attribute__((packed));

struct uhid_set_report_req { … } __attribute__((packed));

struct uhid_set_report_reply_req { … } __attribute__((packed));

/*
 * Compat Layer
 * All these commands and requests are obsolete. You should avoid using them in
 * new code. We support them for backwards-compatibility, but you might not get
 * access to new feature in case you use them.
 */

enum uhid_legacy_event_type { … };

/* Obsolete! Use UHID_CREATE2. */
struct uhid_create_req { … } __attribute__((packed));

/* Obsolete! Use UHID_INPUT2. */
struct uhid_input_req { … } __attribute__((packed));

/* Obsolete! Kernel uses UHID_OUTPUT exclusively now. */
struct uhid_output_ev_req { … } __attribute__((packed));

/* Obsolete! Kernel uses ABI compatible UHID_GET_REPORT. */
struct uhid_feature_req { … } __attribute__((packed));

/* Obsolete! Use ABI compatible UHID_GET_REPORT_REPLY. */
struct uhid_feature_answer_req { … } __attribute__((packed));

/*
 * UHID Events
 * All UHID events from and to the kernel are encoded as "struct uhid_event".
 * The "type" field contains a UHID_* type identifier. All payload depends on
 * that type and can be accessed via ev->u.XYZ accordingly.
 * If user-space writes short events, they're extended with 0s by the kernel. If
 * the kernel writes short events, user-space shall extend them with 0s.
 */

struct uhid_event { … } __attribute__((packed));

#endif /* __UHID_H_ */