mac_hid.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * drivers/macintosh/mac_hid.c
  4 *
  5 * HID support stuff for Macintosh computers.
  6 *
  7 * Copyright (C) 2000 Franz Sirl.
  8 *
  9 * This file will soon be removed in favor of an uinput userspace tool.
 10 */
 11
 12#include <linux/init.h>
 13#include <linux/proc_fs.h>
 14#include <linux/sysctl.h>
 15#include <linux/input.h>
 16#include <linux/module.h>
 17#include <linux/slab.h>
 18
 19MODULE_DESCRIPTION("Mouse button 2+3 emulation");
 20MODULE_LICENSE("GPL");
 21
 22static int mouse_emulate_buttons;
 23static int mouse_button2_keycode = KEY_RIGHTCTRL;	/* right control key */
 24static int mouse_button3_keycode = KEY_RIGHTALT;	/* right option key */
 25
 26static struct input_dev *mac_hid_emumouse_dev;
 27
 28static DEFINE_MUTEX(mac_hid_emumouse_mutex);
 29
 30static int mac_hid_create_emumouse(void)
 31{
 32	static struct lock_class_key mac_hid_emumouse_dev_event_class;
 33	static struct lock_class_key mac_hid_emumouse_dev_mutex_class;
 34	int err;
 35
 36	mac_hid_emumouse_dev = input_allocate_device();
 37	if (!mac_hid_emumouse_dev)
 38		return -ENOMEM;
 39
 40	lockdep_set_class(&mac_hid_emumouse_dev->event_lock,
 41			  &mac_hid_emumouse_dev_event_class);
 42	lockdep_set_class(&mac_hid_emumouse_dev->mutex,
 43			  &mac_hid_emumouse_dev_mutex_class);
 44
 45	mac_hid_emumouse_dev->name = "Macintosh mouse button emulation";
 46	mac_hid_emumouse_dev->id.bustype = BUS_ADB;
 47	mac_hid_emumouse_dev->id.vendor = 0x0001;
 48	mac_hid_emumouse_dev->id.product = 0x0001;
 49	mac_hid_emumouse_dev->id.version = 0x0100;
 50
 51	mac_hid_emumouse_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REL);
 52	mac_hid_emumouse_dev->keybit[BIT_WORD(BTN_MOUSE)] =
 53		BIT_MASK(BTN_LEFT) | BIT_MASK(BTN_MIDDLE) | BIT_MASK(BTN_RIGHT);
 54	mac_hid_emumouse_dev->relbit[0] = BIT_MASK(REL_X) | BIT_MASK(REL_Y);
 55
 56	err = input_register_device(mac_hid_emumouse_dev);
 57	if (err) {
 58		input_free_device(mac_hid_emumouse_dev);
 59		mac_hid_emumouse_dev = NULL;
 60		return err;
 61	}
 62
 63	return 0;
 64}
 65
 66static void mac_hid_destroy_emumouse(void)
 67{
 68	input_unregister_device(mac_hid_emumouse_dev);
 69	mac_hid_emumouse_dev = NULL;
 70}
 71
 72static bool mac_hid_emumouse_filter(struct input_handle *handle,
 73				    unsigned int type, unsigned int code,
 74				    int value)
 75{
 76	unsigned int btn;
 77
 78	if (type != EV_KEY)
 79		return false;
 80
 81	if (code == mouse_button2_keycode)
 82		btn = BTN_MIDDLE;
 83	else if (code == mouse_button3_keycode)
 84		btn = BTN_RIGHT;
 85	else
 86		return false;
 87
 88	input_report_key(mac_hid_emumouse_dev, btn, value);
 89	input_sync(mac_hid_emumouse_dev);
 90
 91	return true;
 92}
 93
 94static int mac_hid_emumouse_connect(struct input_handler *handler,
 95				    struct input_dev *dev,
 96				    const struct input_device_id *id)
 97{
 98	struct input_handle *handle;
 99	int error;
100
101	/* Don't bind to ourselves */
102	if (dev == mac_hid_emumouse_dev)
103		return -ENODEV;
104
105	handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL);
106	if (!handle)
107		return -ENOMEM;
108
109	handle->dev = dev;
110	handle->handler = handler;
111	handle->name = "mac-button-emul";
112
113	error = input_register_handle(handle);
114	if (error) {
115		printk(KERN_ERR
116			"mac_hid: Failed to register button emulation handle, "
117			"error %d\n", error);
118		goto err_free;
119	}
120
121	error = input_open_device(handle);
122	if (error) {
123		printk(KERN_ERR
124			"mac_hid: Failed to open input device, error %d\n",
125			error);
126		goto err_unregister;
127	}
128
129	return 0;
130
131 err_unregister:
132	input_unregister_handle(handle);
133 err_free:
134	kfree(handle);
135	return error;
136}
137
138static void mac_hid_emumouse_disconnect(struct input_handle *handle)
139{
140	input_close_device(handle);
141	input_unregister_handle(handle);
142	kfree(handle);
143}
144
145static const struct input_device_id mac_hid_emumouse_ids[] = {
146	{
147		.flags = INPUT_DEVICE_ID_MATCH_EVBIT,
148		.evbit = { BIT_MASK(EV_KEY) },
149	},
150	{ },
151};
152
153MODULE_DEVICE_TABLE(input, mac_hid_emumouse_ids);
154
155static struct input_handler mac_hid_emumouse_handler = {
156	.filter		= mac_hid_emumouse_filter,
157	.connect	= mac_hid_emumouse_connect,
158	.disconnect	= mac_hid_emumouse_disconnect,
159	.name		= "mac-button-emul",
160	.id_table	= mac_hid_emumouse_ids,
161};
162
163static int mac_hid_start_emulation(void)
164{
165	int err;
166
167	err = mac_hid_create_emumouse();
168	if (err)
169		return err;
170
171	err = input_register_handler(&mac_hid_emumouse_handler);
172	if (err) {
173		mac_hid_destroy_emumouse();
174		return err;
175	}
176
177	return 0;
178}
179
180static void mac_hid_stop_emulation(void)
181{
182	input_unregister_handler(&mac_hid_emumouse_handler);
183	mac_hid_destroy_emumouse();
184}
185
186static int mac_hid_toggle_emumouse(const struct ctl_table *table, int write,
187				   void *buffer, size_t *lenp, loff_t *ppos)
188{
189	int *valp = table->data;
190	int old_val;
191	int rc;
192
193	rc = mutex_lock_killable(&mac_hid_emumouse_mutex);
194	if (rc)
195		return rc;
196
197	old_val = *valp;
198	rc = proc_dointvec(table, write, buffer, lenp, ppos);
199
200	if (rc == 0 && write && *valp != old_val) {
201		if (*valp == 1)
202			rc = mac_hid_start_emulation();
203		else if (*valp == 0)
204			mac_hid_stop_emulation();
205		else
206			rc = -EINVAL;
207	}
208
209	/* Restore the old value in case of error */
210	if (rc)
211		*valp = old_val;
212
213	mutex_unlock(&mac_hid_emumouse_mutex);
214
215	return rc;
216}
217
218/* file(s) in /proc/sys/dev/mac_hid */
219static const struct ctl_table mac_hid_files[] = {
220	{
221		.procname	= "mouse_button_emulation",
222		.data		= &mouse_emulate_buttons,
223		.maxlen		= sizeof(int),
224		.mode		= 0644,
225		.proc_handler	= mac_hid_toggle_emumouse,
226	},
227	{
228		.procname	= "mouse_button2_keycode",
229		.data		= &mouse_button2_keycode,
230		.maxlen		= sizeof(int),
231		.mode		= 0644,
232		.proc_handler	= proc_dointvec,
233	},
234	{
235		.procname	= "mouse_button3_keycode",
236		.data		= &mouse_button3_keycode,
237		.maxlen		= sizeof(int),
238		.mode		= 0644,
239		.proc_handler	= proc_dointvec,
240	},
241};
242
243static struct ctl_table_header *mac_hid_sysctl_header;
244
245static int __init mac_hid_init(void)
246{
247	mac_hid_sysctl_header = register_sysctl("dev/mac_hid", mac_hid_files);
248	if (!mac_hid_sysctl_header)
249		return -ENOMEM;
250
251	return 0;
252}
253module_init(mac_hid_init);
254
255static void __exit mac_hid_exit(void)
256{
257	unregister_sysctl_table(mac_hid_sysctl_header);
258
259	if (mouse_emulate_buttons)
260		mac_hid_stop_emulation();
261}
262module_exit(mac_hid_exit);