summaryrefslogtreecommitdiffstats
path: root/drivers/hid/hid-wiimote-ext.c
blob: 3e3e1fc8d838750272b41edfcaa25aaa28d82cdf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
/*
 * HID driver for Nintendo Wiimote extension devices
 * Copyright (c) 2011 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.
 */

#include <linux/atomic.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include "hid-wiimote.h"

struct wiimote_ext {
	struct wiimote_data *wdata;
	struct work_struct worker;

	atomic_t opened;
	atomic_t mp_opened;
	bool plugged;
	bool motionp;
	__u8 ext_type;
};

enum wiiext_type {
	WIIEXT_NONE,		/* placeholder */
	WIIEXT_CLASSIC,		/* Nintendo classic controller */
	WIIEXT_NUNCHUCK,	/* Nintendo nunchuck controller */
};

/* diable all extensions */
static void ext_disable(struct wiimote_ext *ext)
{
	unsigned long flags;

	spin_lock_irqsave(&ext->wdata->state.lock, flags);
	ext->motionp = false;
	ext->ext_type = WIIEXT_NONE;
	spin_unlock_irqrestore(&ext->wdata->state.lock, flags);
}

static bool motionp_read(struct wiimote_ext *ext)
{
	return false;
}

static __u8 ext_read(struct wiimote_ext *ext)
{
	return WIIEXT_NONE;
}

static void ext_enable(struct wiimote_ext *ext, bool motionp, __u8 ext_type)
{
	unsigned long flags;

	spin_lock_irqsave(&ext->wdata->state.lock, flags);
	ext->motionp = motionp;
	ext->ext_type = ext_type;
	spin_unlock_irqrestore(&ext->wdata->state.lock, flags);
}

static void wiiext_worker(struct work_struct *work)
{
	struct wiimote_ext *ext = container_of(work, struct wiimote_ext,
									worker);
	bool motionp;
	__u8 ext_type;

	ext_disable(ext);
	motionp = motionp_read(ext);
	ext_type = ext_read(ext);
	ext_enable(ext, motionp, ext_type);
}

/* schedule work only once, otherwise mark for reschedule */
static void wiiext_schedule(struct wiimote_ext *ext)
{
	queue_work(system_nrt_wq, &ext->worker);
}

/*
 * Reacts on extension port events
 * Whenever the driver gets an event from the wiimote that an extension has been
 * plugged or unplugged, this funtion shall be called. It checks what extensions
 * are connected and initializes and activates them.
 * This can be called in atomic context. The initialization is done in a
 * separate worker thread. The state.lock spinlock must be held by the caller.
 */
void wiiext_event(struct wiimote_data *wdata, bool plugged)
{
	if (!wdata->ext)
		return;

	if (wdata->ext->plugged == plugged)
		return;

	wdata->ext->plugged = plugged;
	/*
	 * We need to call wiiext_schedule(wdata->ext) here, however, the
	 * extension initialization logic is not fully understood and so
	 * automatic initialization is not supported, yet.
	 */
}

/*
 * Returns true if the current DRM mode should contain extension data and false
 * if there is no interest in extension data.
 * All supported extensions send 6 byte extension data so any DRM that contains
 * extension bytes is fine.
 * The caller must hold the state.lock spinlock.
 */
bool wiiext_active(struct wiimote_data *wdata)
{
	if (!wdata->ext)
		return false;

	return wdata->ext->motionp || wdata->ext->ext_type;
}

/* Initializes the extension driver of a wiimote */
int wiiext_init(struct wiimote_data *wdata)
{
	struct wiimote_ext *ext;
	unsigned long flags;

	ext = kzalloc(sizeof(*ext), GFP_KERNEL);
	if (!ext)
		return -ENOMEM;

	ext->wdata = wdata;
	INIT_WORK(&ext->worker, wiiext_worker);

	spin_lock_irqsave(&wdata->state.lock, flags);
	wdata->ext = ext;
	spin_unlock_irqrestore(&wdata->state.lock, flags);

	return 0;
}

/* Deinitializes the extension driver of a wiimote */
void wiiext_deinit(struct wiimote_data *wdata)
{
	struct wiimote_ext *ext = wdata->ext;
	unsigned long flags;

	if (!ext)
		return;

	/*
	 * We first unset wdata->ext to avoid further input from the wiimote
	 * core. The worker thread does not access this pointer so it is not
	 * affected by this.
	 * We kill the worker after this so it does not get respawned during
	 * deinitialization.
	 */

	spin_lock_irqsave(&wdata->state.lock, flags);
	wdata->ext = NULL;
	spin_unlock_irqrestore(&wdata->state.lock, flags);

	cancel_work_sync(&ext->worker);
	kfree(ext);
}