Root/package/button-hotplug/src/button-hotplug.c

1/*
2 * Button Hotplug driver
3 *
4 * Copyright (C) 2008 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@openwrt.org>
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 <net/sock.h>
25
26#define DRV_NAME "button-hotplug"
27#define DRV_VERSION "0.3.1"
28#define DRV_DESC "Button Hotplug driver"
29
30#define BH_SKB_SIZE 2048
31
32#define BH_BTN_MIN BTN_0
33#define BH_BTN_MAX BTN_9
34
35#define BH_BTN_COUNT (BH_BTN_MAX - BH_BTN_MIN + 1)
36
37#define PFX DRV_NAME ": "
38
39#undef BH_DEBUG
40
41#ifdef BH_DEBUG
42#define BH_DBG(fmt, args...) printk(KERN_DEBUG "%s: " fmt, DRV_NAME, ##args )
43#else
44#define BH_DBG(fmt, args...) do {} while (0)
45#endif
46
47#define BH_ERR(fmt, args...) printk(KERN_ERR "%s: " fmt, DRV_NAME, ##args )
48
49#ifndef BIT_MASK
50#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
51#endif
52
53struct bh_priv {
54    unsigned long seen[BH_BTN_COUNT];
55    struct input_handle handle;
56};
57
58struct bh_event {
59    char *name;
60    char *action;
61    unsigned long seen;
62
63    struct sk_buff *skb;
64    struct work_struct work;
65};
66
67extern struct sock *uevent_sock;
68extern u64 uevent_next_seqnum(void);
69
70static char *button_names[BH_BTN_COUNT] = {
71    "BTN_0", "BTN_1", "BTN_2", "BTN_3", "BTN_4",
72    "BTN_5", "BTN_6", "BTN_7", "BTN_8", "BTN_9"
73};
74
75/* -------------------------------------------------------------------------*/
76
77static int bh_event_add_var(struct bh_event *event, int argv,
78        const char *format, ...)
79{
80    static char buf[128];
81    char *s;
82    va_list args;
83    int len;
84
85    if (argv)
86        return 0;
87
88    va_start(args, format);
89    len = vsnprintf(buf, sizeof(buf), format, args);
90    va_end(args);
91
92    if (len >= sizeof(buf)) {
93        BH_ERR("buffer size too small\n");
94        WARN_ON(1);
95        return -ENOMEM;
96    }
97
98    s = skb_put(event->skb, len + 1);
99    strcpy(s, buf);
100
101    BH_DBG("added variable '%s'\n", s);
102
103    return 0;
104}
105
106static int button_hotplug_fill_event(struct bh_event *event)
107{
108    int ret;
109
110    ret = bh_event_add_var(event, 0, "HOME=%s", "/");
111    if (ret)
112        return ret;
113
114    ret = bh_event_add_var(event, 0, "PATH=%s",
115                    "/sbin:/bin:/usr/sbin:/usr/bin");
116    if (ret)
117        return ret;
118
119    ret = bh_event_add_var(event, 0, "SUBSYSTEM=%s", "button");
120    if (ret)
121        return ret;
122
123    ret = bh_event_add_var(event, 0, "ACTION=%s", event->action);
124    if (ret)
125        return ret;
126
127    ret = bh_event_add_var(event, 0, "BUTTON=%s", event->name);
128    if (ret)
129        return ret;
130
131    ret = bh_event_add_var(event, 0, "SEEN=%ld", event->seen);
132    if (ret)
133        return ret;
134
135    ret = bh_event_add_var(event, 0, "SEQNUM=%llu", uevent_next_seqnum());
136
137    return ret;
138}
139
140static void button_hotplug_work(struct work_struct *work)
141{
142    struct bh_event *event = container_of(work, struct bh_event, work);
143    int ret = 0;
144
145    if (!uevent_sock)
146        goto out_free_event;
147
148    event->skb = alloc_skb(BH_SKB_SIZE, GFP_KERNEL);
149    if (!event->skb)
150        goto out_free_event;
151
152    ret = bh_event_add_var(event, 0, "%s@", event->action);
153    if (ret)
154        goto out_free_skb;
155
156    ret = button_hotplug_fill_event(event);
157    if (ret)
158        goto out_free_skb;
159
160    NETLINK_CB(event->skb).dst_group = 1;
161    netlink_broadcast(uevent_sock, event->skb, 0, 1, GFP_KERNEL);
162
163 out_free_skb:
164    if (ret) {
165        BH_ERR("work error %d\n", ret);
166        kfree_skb(event->skb);
167    }
168 out_free_event:
169    kfree(event);
170}
171
172static int button_hotplug_create_event(char *name, unsigned long seen,
173        int pressed)
174{
175    struct bh_event *event;
176
177    BH_DBG("create event, name=%s, seen=%lu, pressed=%d\n",
178        name, seen, pressed);
179
180    event = kzalloc(sizeof(*event), GFP_KERNEL);
181    if (!event)
182        return -ENOMEM;
183
184    event->name = name;
185    event->seen = seen;
186    event->action = pressed ? "pressed" : "released";
187
188    INIT_WORK(&event->work, (void *)(void *)button_hotplug_work);
189    schedule_work(&event->work);
190
191    return 0;
192}
193
194/* -------------------------------------------------------------------------*/
195
196#ifdef CONFIG_HOTPLUG
197static void button_hotplug_event(struct input_handle *handle,
198               unsigned int type, unsigned int code, int value)
199{
200    struct bh_priv *priv = handle->private;
201    unsigned long seen = jiffies;
202    unsigned int btn;
203
204    BH_DBG("event type=%u, code=%u, value=%d\n", type, code, value);
205
206    if (type != EV_KEY)
207        return;
208
209    if (code < BH_BTN_MIN || code > BH_BTN_MAX)
210        return;
211
212    btn = code - BH_BTN_MIN;
213    button_hotplug_create_event(button_names[btn],
214            (seen - priv->seen[btn]) / HZ, value);
215    priv->seen[btn] = seen;
216}
217#else
218static void button_hotplug_event(struct input_handle *handle,
219               unsigned int type, unsigned int code, int value)
220{
221}
222#endif /* CONFIG_HOTPLUG */
223
224static int button_hotplug_connect(struct input_handler *handler,
225        struct input_dev *dev, const struct input_device_id *id)
226{
227    struct bh_priv *priv;
228    int ret;
229    int i;
230
231    for (i = BH_BTN_MIN; i <= BH_BTN_MAX; i++)
232        if (test_bit(i, dev->keybit))
233            break;
234
235    if (i > BH_BTN_MAX)
236        return -ENODEV;
237
238    priv = kzalloc(sizeof(*priv), GFP_KERNEL);
239    if (!priv)
240        return -ENOMEM;
241
242    priv->handle.private = priv;
243    priv->handle.dev = dev;
244    priv->handle.handler = handler;
245    priv->handle.name = DRV_NAME;
246
247    ret = input_register_handle(&priv->handle);
248    if (ret)
249        goto err_free_priv;
250
251    ret = input_open_device(&priv->handle);
252    if (ret)
253        goto err_unregister_handle;
254
255    BH_DBG("connected to %s\n", dev->name);
256
257    return 0;
258
259 err_unregister_handle:
260    input_unregister_handle(&priv->handle);
261
262 err_free_priv:
263    kfree(priv);
264    return ret;
265}
266
267static void button_hotplug_disconnect(struct input_handle *handle)
268{
269    struct bh_priv *priv = handle->private;
270
271    input_close_device(handle);
272    input_unregister_handle(handle);
273
274    kfree(priv);
275}
276
277static const struct input_device_id button_hotplug_ids[] = {
278    {
279                .flags = INPUT_DEVICE_ID_MATCH_EVBIT,
280                .evbit = { BIT_MASK(EV_KEY) },
281        },
282    {
283        /* Terminating entry */
284    },
285};
286
287MODULE_DEVICE_TABLE(input, button_hotplug_ids);
288
289static struct input_handler button_hotplug_handler = {
290    .event = button_hotplug_event,
291    .connect = button_hotplug_connect,
292    .disconnect = button_hotplug_disconnect,
293    .name = DRV_NAME,
294    .id_table = button_hotplug_ids,
295};
296
297/* -------------------------------------------------------------------------*/
298
299static int __init button_hotplug_init(void)
300{
301    int ret;
302
303    printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");
304    ret = input_register_handler(&button_hotplug_handler);
305    if (ret)
306        BH_ERR("unable to register input handler\n");
307
308    return ret;
309}
310module_init(button_hotplug_init);
311
312static void __exit button_hotplug_exit(void)
313{
314    input_unregister_handler(&button_hotplug_handler);
315}
316module_exit(button_hotplug_exit);
317
318MODULE_DESCRIPTION(DRV_DESC);
319MODULE_VERSION(DRV_VERSION);
320MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
321MODULE_LICENSE("GPL v2");
322
323

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