1/*
2 *  Button Hotplug driver
3 *
4 *  Copyright (C) 2008-2010 Gabor Juhos <juhosg@openwrt.org>
5 *
6 *  Based on the diag.c - GPIO interface driver for Broadcom boards
7 *    Copyright (C) 2006 Mike Baker <mbm@openwrt.org>,
8 *    Copyright (C) 2006-2007 Felix Fietkau <nbd@nbd.name>
9 *    Copyright (C) 2008 Andy Boyett <agb@openwrt.org>
10 *
11 *  This program is free software; you can redistribute it and/or modify it
12 *  under the terms of the GNU General Public License version 2 as published
13 *  by the Free Software Foundation.
14 */
15
16#include <linux/module.h>
17#include <linux/version.h>
18#include <linux/kmod.h>
19#include <linux/input.h>
20
21#include <linux/workqueue.h>
22#include <linux/skbuff.h>
23#include <linux/netlink.h>
24#include <linux/kobject.h>
25
26#define DRV_NAME	"button-hotplug"
27#define DRV_VERSION	"0.4.1"
28#define DRV_DESC	"Button Hotplug driver"
29
30#define BH_SKB_SIZE	2048
31
32#define PFX	DRV_NAME ": "
33
34#undef BH_DEBUG
35
36#ifdef BH_DEBUG
37#define BH_DBG(fmt, args...) printk(KERN_DEBUG "%s: " fmt, DRV_NAME, ##args )
38#else
39#define BH_DBG(fmt, args...) do {} while (0)
40#endif
41
42#define BH_ERR(fmt, args...) printk(KERN_ERR "%s: " fmt, DRV_NAME, ##args )
43
44#ifndef BIT_MASK
45#define BIT_MASK(nr)            (1UL << ((nr) % BITS_PER_LONG))
46#endif
47
48struct bh_priv {
49	unsigned long		*seen;
50	struct input_handle	handle;
51};
52
53struct bh_event {
54	const char		*name;
55	char			*action;
56	unsigned long		seen;
57
58	struct sk_buff		*skb;
59	struct work_struct	work;
60};
61
62struct bh_map {
63	unsigned int	code;
64	const char	*name;
65};
66
67extern u64 uevent_next_seqnum(void);
68
69#define BH_MAP(_code, _name)		\
70	{				\
71		.code = (_code),	\
72		.name = (_name),	\
73	}
74
75static struct bh_map button_map[] = {
76	BH_MAP(BTN_0,		"BTN_0"),
77	BH_MAP(BTN_1,		"BTN_1"),
78	BH_MAP(BTN_2,		"BTN_2"),
79	BH_MAP(BTN_3,		"BTN_3"),
80	BH_MAP(BTN_4,		"BTN_4"),
81	BH_MAP(BTN_5,		"BTN_5"),
82	BH_MAP(BTN_6,		"BTN_6"),
83	BH_MAP(BTN_7,		"BTN_7"),
84	BH_MAP(BTN_8,		"BTN_8"),
85	BH_MAP(BTN_9,		"BTN_9"),
86	BH_MAP(KEY_RESTART,	"reset"),
87	BH_MAP(KEY_POWER,	"power"),
88	BH_MAP(KEY_RFKILL,	"rfkill"),
89	BH_MAP(KEY_WPS_BUTTON,	"wps"),
90	BH_MAP(KEY_WIMAX,	"wwan"),
91};
92
93/* -------------------------------------------------------------------------*/
94
95static int bh_event_add_var(struct bh_event *event, int argv,
96		const char *format, ...)
97{
98	static char buf[128];
99	char *s;
100	va_list args;
101	int len;
102
103	if (argv)
104		return 0;
105
106	va_start(args, format);
107	len = vsnprintf(buf, sizeof(buf), format, args);
108	va_end(args);
109
110	if (len >= sizeof(buf)) {
111		BH_ERR("buffer size too small\n");
112		WARN_ON(1);
113		return -ENOMEM;
114	}
115
116	s = skb_put(event->skb, len + 1);
117	strcpy(s, buf);
118
119	BH_DBG("added variable '%s'\n", s);
120
121	return 0;
122}
123
124static int button_hotplug_fill_event(struct bh_event *event)
125{
126	int ret;
127
128	ret = bh_event_add_var(event, 0, "HOME=%s", "/");
129	if (ret)
130		return ret;
131
132	ret = bh_event_add_var(event, 0, "PATH=%s",
133					"/sbin:/bin:/usr/sbin:/usr/bin");
134	if (ret)
135		return ret;
136
137	ret = bh_event_add_var(event, 0, "SUBSYSTEM=%s", "button");
138	if (ret)
139		return ret;
140
141	ret = bh_event_add_var(event, 0, "ACTION=%s", event->action);
142	if (ret)
143		return ret;
144
145	ret = bh_event_add_var(event, 0, "BUTTON=%s", event->name);
146	if (ret)
147		return ret;
148
149	ret = bh_event_add_var(event, 0, "SEEN=%ld", event->seen);
150	if (ret)
151		return ret;
152
153	ret = bh_event_add_var(event, 0, "SEQNUM=%llu", uevent_next_seqnum());
154
155	return ret;
156}
157
158static void button_hotplug_work(struct work_struct *work)
159{
160	struct bh_event *event = container_of(work, struct bh_event, work);
161	int ret = 0;
162
163	event->skb = alloc_skb(BH_SKB_SIZE, GFP_KERNEL);
164	if (!event->skb)
165		goto out_free_event;
166
167	ret = bh_event_add_var(event, 0, "%s@", event->action);
168	if (ret)
169		goto out_free_skb;
170
171	ret = button_hotplug_fill_event(event);
172	if (ret)
173		goto out_free_skb;
174
175	NETLINK_CB(event->skb).dst_group = 1;
176	broadcast_uevent(event->skb, 0, 1, GFP_KERNEL);
177
178 out_free_skb:
179	if (ret) {
180		BH_ERR("work error %d\n", ret);
181		kfree_skb(event->skb);
182	}
183 out_free_event:
184	kfree(event);
185}
186
187static int button_hotplug_create_event(const char *name, unsigned long seen,
188		int pressed)
189{
190	struct bh_event *event;
191
192	BH_DBG("create event, name=%s, seen=%lu, pressed=%d\n",
193		name, seen, pressed);
194
195	event = kzalloc(sizeof(*event), GFP_KERNEL);
196	if (!event)
197		return -ENOMEM;
198
199	event->name = name;
200	event->seen = seen;
201	event->action = pressed ? "pressed" : "released";
202
203	INIT_WORK(&event->work, (void *)(void *)button_hotplug_work);
204	schedule_work(&event->work);
205
206	return 0;
207}
208
209/* -------------------------------------------------------------------------*/
210
211static int button_get_index(unsigned int code)
212{
213	int i;
214
215	for (i = 0; i < ARRAY_SIZE(button_map); i++)
216		if (button_map[i].code == code)
217			return i;
218
219	return -1;
220}
221static void button_hotplug_event(struct input_handle *handle,
222			   unsigned int type, unsigned int code, int value)
223{
224	struct bh_priv *priv = handle->private;
225	unsigned long seen = jiffies;
226	int btn;
227
228	BH_DBG("event type=%u, code=%u, value=%d\n", type, code, value);
229
230	if (type != EV_KEY)
231		return;
232
233	btn = button_get_index(code);
234	if (btn < 0)
235		return;
236
237	button_hotplug_create_event(button_map[btn].name,
238			(seen - priv->seen[btn]) / HZ, value);
239	priv->seen[btn] = seen;
240}
241
242static int button_hotplug_connect(struct input_handler *handler,
243		struct input_dev *dev, const struct input_device_id *id)
244{
245	struct bh_priv *priv;
246	int ret;
247	int i;
248
249	for (i = 0; i < ARRAY_SIZE(button_map); i++)
250		if (test_bit(button_map[i].code, dev->keybit))
251			break;
252
253	if (i == ARRAY_SIZE(button_map))
254		return -ENODEV;
255
256	priv = kzalloc(sizeof(*priv) +
257		       (sizeof(unsigned long) * ARRAY_SIZE(button_map)),
258		       GFP_KERNEL);
259	if (!priv)
260		return -ENOMEM;
261
262	priv->seen = (unsigned long *) &priv[1];
263	priv->handle.private = priv;
264	priv->handle.dev = dev;
265	priv->handle.handler = handler;
266	priv->handle.name = DRV_NAME;
267
268	ret = input_register_handle(&priv->handle);
269	if (ret)
270		goto err_free_priv;
271
272	ret = input_open_device(&priv->handle);
273	if (ret)
274		goto err_unregister_handle;
275
276	BH_DBG("connected to %s\n", dev->name);
277
278	return 0;
279
280 err_unregister_handle:
281	input_unregister_handle(&priv->handle);
282
283 err_free_priv:
284	kfree(priv);
285	return ret;
286}
287
288static void button_hotplug_disconnect(struct input_handle *handle)
289{
290	struct bh_priv *priv = handle->private;
291
292	input_close_device(handle);
293	input_unregister_handle(handle);
294
295	kfree(priv);
296}
297
298static const struct input_device_id button_hotplug_ids[] = {
299	{
300                .flags = INPUT_DEVICE_ID_MATCH_EVBIT,
301                .evbit = { BIT_MASK(EV_KEY) },
302        },
303	{
304		/* Terminating entry */
305	},
306};
307
308MODULE_DEVICE_TABLE(input, button_hotplug_ids);
309
310static struct input_handler button_hotplug_handler = {
311	.event =	button_hotplug_event,
312	.connect =	button_hotplug_connect,
313	.disconnect =	button_hotplug_disconnect,
314	.name =		DRV_NAME,
315	.id_table =	button_hotplug_ids,
316};
317
318/* -------------------------------------------------------------------------*/
319
320static int __init button_hotplug_init(void)
321{
322	int ret;
323
324	printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");
325	ret = input_register_handler(&button_hotplug_handler);
326	if (ret)
327		BH_ERR("unable to register input handler\n");
328
329	return ret;
330}
331module_init(button_hotplug_init);
332
333static void __exit button_hotplug_exit(void)
334{
335	input_unregister_handler(&button_hotplug_handler);
336}
337module_exit(button_hotplug_exit);
338
339MODULE_DESCRIPTION(DRV_DESC);
340MODULE_VERSION(DRV_VERSION);
341MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
342MODULE_LICENSE("GPL v2");
343
344