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