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

1/*
2 * GPIO Button Hotplug driver
3 *
4 * Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
5 * Copyright (C) 2008-2010 Gabor Juhos <juhosg@openwrt.org>
6 *
7 * Based on the diag.c - GPIO interface driver for Broadcom boards
8 * Copyright (C) 2006 Mike Baker <mbm@openwrt.org>,
9 * Copyright (C) 2006-2007 Felix Fietkau <nbd@openwrt.org>
10 * Copyright (C) 2008 Andy Boyett <agb@openwrt.org>
11 *
12 * This program is free software; you can redistribute it and/or modify it
13 * under the terms of the GNU General Public License version 2 as published
14 * by the Free Software Foundation.
15 */
16
17#include <linux/module.h>
18#include <linux/version.h>
19#include <linux/kmod.h>
20
21#include <linux/workqueue.h>
22#include <linux/skbuff.h>
23#include <linux/netlink.h>
24#include <linux/kobject.h>
25#include <linux/input.h>
26#include <linux/platform_device.h>
27#include <linux/of_gpio.h>
28#include <linux/gpio_keys.h>
29
30#define DRV_NAME "gpio-keys-polled"
31
32#define BH_SKB_SIZE 2048
33
34#define PFX DRV_NAME ": "
35
36#undef BH_DEBUG
37
38#ifdef BH_DEBUG
39#define BH_DBG(fmt, args...) printk(KERN_DEBUG "%s: " fmt, DRV_NAME, ##args )
40#else
41#define BH_DBG(fmt, args...) do {} while (0)
42#endif
43
44#define BH_ERR(fmt, args...) printk(KERN_ERR "%s: " fmt, DRV_NAME, ##args )
45
46struct bh_priv {
47    unsigned long seen;
48};
49
50struct bh_event {
51    const char *name;
52    char *action;
53    unsigned long seen;
54
55    struct sk_buff *skb;
56    struct work_struct work;
57};
58
59struct bh_map {
60    unsigned int code;
61    const char *name;
62};
63
64struct gpio_keys_button_data {
65    struct delayed_work work;
66    struct bh_priv bh;
67    int last_state;
68    int count;
69    int threshold;
70    int can_sleep;
71};
72
73extern u64 uevent_next_seqnum(void);
74
75#define BH_MAP(_code, _name) \
76    { \
77        .code = (_code), \
78        .name = (_name), \
79    }
80
81static struct bh_map button_map[] = {
82    BH_MAP(BTN_0, "BTN_0"),
83    BH_MAP(BTN_1, "BTN_1"),
84    BH_MAP(BTN_2, "BTN_2"),
85    BH_MAP(BTN_3, "BTN_3"),
86    BH_MAP(BTN_4, "BTN_4"),
87    BH_MAP(BTN_5, "BTN_5"),
88    BH_MAP(BTN_6, "BTN_6"),
89    BH_MAP(BTN_7, "BTN_7"),
90    BH_MAP(BTN_8, "BTN_8"),
91    BH_MAP(BTN_9, "BTN_9"),
92    BH_MAP(KEY_RESTART, "reset"),
93    BH_MAP(KEY_RFKILL, "rfkill"),
94#ifdef KEY_WPS_BUTTON
95    BH_MAP(KEY_WPS_BUTTON, "wps"),
96#endif /* KEY_WPS_BUTTON */
97};
98
99/* -------------------------------------------------------------------------*/
100
101static int bh_event_add_var(struct bh_event *event, int argv,
102        const char *format, ...)
103{
104    static char buf[128];
105    char *s;
106    va_list args;
107    int len;
108
109    if (argv)
110        return 0;
111
112    va_start(args, format);
113    len = vsnprintf(buf, sizeof(buf), format, args);
114    va_end(args);
115
116    if (len >= sizeof(buf)) {
117        BH_ERR("buffer size too small\n");
118        WARN_ON(1);
119        return -ENOMEM;
120    }
121
122    s = skb_put(event->skb, len + 1);
123    strcpy(s, buf);
124
125    BH_DBG("added variable '%s'\n", s);
126
127    return 0;
128}
129
130static int button_hotplug_fill_event(struct bh_event *event)
131{
132    int ret;
133
134    ret = bh_event_add_var(event, 0, "HOME=%s", "/");
135    if (ret)
136        return ret;
137
138    ret = bh_event_add_var(event, 0, "PATH=%s",
139                    "/sbin:/bin:/usr/sbin:/usr/bin");
140    if (ret)
141        return ret;
142
143    ret = bh_event_add_var(event, 0, "SUBSYSTEM=%s", "button");
144    if (ret)
145        return ret;
146
147    ret = bh_event_add_var(event, 0, "ACTION=%s", event->action);
148    if (ret)
149        return ret;
150
151    ret = bh_event_add_var(event, 0, "BUTTON=%s", event->name);
152    if (ret)
153        return ret;
154
155    ret = bh_event_add_var(event, 0, "SEEN=%ld", event->seen);
156    if (ret)
157        return ret;
158
159    ret = bh_event_add_var(event, 0, "SEQNUM=%llu", uevent_next_seqnum());
160
161    return ret;
162}
163
164static void button_hotplug_work(struct work_struct *work)
165{
166    struct bh_event *event = container_of(work, struct bh_event, work);
167    int ret = 0;
168
169    event->skb = alloc_skb(BH_SKB_SIZE, GFP_KERNEL);
170    if (!event->skb)
171        goto out_free_event;
172
173    ret = bh_event_add_var(event, 0, "%s@", event->action);
174    if (ret)
175        goto out_free_skb;
176
177    ret = button_hotplug_fill_event(event);
178    if (ret)
179        goto out_free_skb;
180
181    NETLINK_CB(event->skb).dst_group = 1;
182    broadcast_uevent(event->skb, 0, 1, GFP_KERNEL);
183
184 out_free_skb:
185    if (ret) {
186        BH_ERR("work error %d\n", ret);
187        kfree_skb(event->skb);
188    }
189 out_free_event:
190    kfree(event);
191}
192
193static int button_hotplug_create_event(const char *name, unsigned long seen,
194        int pressed)
195{
196    struct bh_event *event;
197
198    BH_DBG("create event, name=%s, seen=%lu, pressed=%d\n",
199        name, seen, pressed);
200
201    event = kzalloc(sizeof(*event), GFP_KERNEL);
202    if (!event)
203        return -ENOMEM;
204
205    event->name = name;
206    event->seen = seen;
207    event->action = pressed ? "pressed" : "released";
208
209    INIT_WORK(&event->work, (void *)(void *)button_hotplug_work);
210    schedule_work(&event->work);
211
212    return 0;
213}
214
215/* -------------------------------------------------------------------------*/
216
217#ifdef CONFIG_HOTPLUG
218static int button_get_index(unsigned int code)
219{
220    int i;
221
222    for (i = 0; i < ARRAY_SIZE(button_map); i++)
223        if (button_map[i].code == code)
224            return i;
225
226    return -1;
227}
228static void button_hotplug_event(struct gpio_keys_button_data *data,
229               unsigned int type, unsigned int code, int value)
230{
231    struct bh_priv *priv = &data->bh;
232    unsigned long seen = jiffies;
233    int btn;
234
235    BH_DBG("event type=%u, code=%u, value=%d\n", type, code, value);
236
237    if (type != EV_KEY)
238        return;
239
240    btn = button_get_index(code);
241    if (btn < 0)
242        return;
243
244    button_hotplug_create_event(button_map[btn].name,
245            (seen - priv->seen) / HZ, value);
246    priv->seen = seen;
247}
248#else
249static void button_hotplug_event(struct gpio_keys_button_data *data,
250               unsigned int type, unsigned int code, int value)
251{
252}
253#endif /* CONFIG_HOTPLUG */
254
255struct gpio_keys_polled_dev {
256    struct delayed_work work;
257
258    struct device *dev;
259    struct gpio_keys_platform_data *pdata;
260    struct gpio_keys_button_data data[0];
261};
262
263static void gpio_keys_polled_check_state(struct gpio_keys_button *button,
264                     struct gpio_keys_button_data *bdata)
265{
266    int state;
267
268    if (bdata->can_sleep)
269        state = !!gpio_get_value_cansleep(button->gpio);
270    else
271        state = !!gpio_get_value(button->gpio);
272
273    state = !!(state ^ button->active_low);
274    if (state != bdata->last_state) {
275        unsigned int type = button->type ?: EV_KEY;
276
277        button_hotplug_event(bdata, type, button->code, state);
278        bdata->count = 0;
279        bdata->last_state = state;
280    }
281}
282
283static void gpio_keys_polled_queue_work(struct gpio_keys_polled_dev *bdev)
284{
285    struct gpio_keys_platform_data *pdata = bdev->pdata;
286    unsigned long delay = msecs_to_jiffies(pdata->poll_interval);
287
288    if (delay >= HZ)
289        delay = round_jiffies_relative(delay);
290    schedule_delayed_work(&bdev->work, delay);
291}
292
293static void gpio_keys_polled_poll(struct work_struct *work)
294{
295    struct gpio_keys_polled_dev *bdev =
296        container_of(work, struct gpio_keys_polled_dev, work.work);
297    struct gpio_keys_platform_data *pdata = bdev->pdata;
298    int i;
299
300    for (i = 0; i < bdev->pdata->nbuttons; i++) {
301        struct gpio_keys_button_data *bdata = &bdev->data[i];
302
303        if (bdata->count < bdata->threshold)
304            bdata->count++;
305        else
306            gpio_keys_polled_check_state(&pdata->buttons[i], bdata);
307    }
308    gpio_keys_polled_queue_work(bdev);
309}
310
311static void __devinit gpio_keys_polled_open(struct gpio_keys_polled_dev *bdev)
312{
313    struct gpio_keys_platform_data *pdata = bdev->pdata;
314    int i;
315
316    if (pdata->enable)
317        pdata->enable(bdev->dev);
318
319    /* report initial state of the buttons */
320    for (i = 0; i < pdata->nbuttons; i++)
321        gpio_keys_polled_check_state(&pdata->buttons[i], &bdev->data[i]);
322
323    gpio_keys_polled_queue_work(bdev);
324}
325
326#ifdef CONFIG_OF
327static struct gpio_keys_platform_data * __devinit
328gpio_keys_polled_get_devtree_pdata(struct device *dev)
329{
330    struct device_node *node, *pp;
331    struct gpio_keys_platform_data *pdata;
332    struct gpio_keys_button *button;
333    int error;
334    int nbuttons;
335    int i;
336
337    node = dev->of_node;
338    if (!node)
339        return NULL;
340
341    nbuttons = of_get_child_count(node);
342    if (nbuttons == 0)
343        return NULL;
344
345    pdata = kzalloc(sizeof(*pdata) + nbuttons * (sizeof *button),
346        GFP_KERNEL);
347    if (!pdata) {
348        error = -ENOMEM;
349        goto err_out;
350    }
351
352    pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
353    pdata->nbuttons = nbuttons;
354
355    pdata->rep = !!of_get_property(node, "autorepeat", NULL);
356    of_property_read_u32(node, "poll-interval", &pdata->poll_interval);
357
358    i = 0;
359    for_each_child_of_node(node, pp) {
360        enum of_gpio_flags flags;
361
362        if (!of_find_property(pp, "gpios", NULL)) {
363            pdata->nbuttons--;
364            dev_warn(dev, "Found button without gpios\n");
365            continue;
366        }
367
368        button = &pdata->buttons[i++];
369
370        button->gpio = of_get_gpio_flags(pp, 0, &flags);
371        button->active_low = flags & OF_GPIO_ACTIVE_LOW;
372
373        if (of_property_read_u32(pp, "linux,code", &button->code)) {
374            dev_err(dev, "Button without keycode: 0x%x\n",
375                button->gpio);
376            error = -EINVAL;
377            goto err_free_pdata;
378        }
379
380        button->desc = of_get_property(pp, "label", NULL);
381
382        if (of_property_read_u32(pp, "linux,input-type", &button->type))
383            button->type = EV_KEY;
384
385        button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);
386
387        if (of_property_read_u32(pp, "debounce-interval",
388                    &button->debounce_interval))
389            button->debounce_interval = 5;
390    }
391
392    if (pdata->nbuttons == 0) {
393        error = -EINVAL;
394        goto err_free_pdata;
395    }
396
397    return pdata;
398
399err_free_pdata:
400    kfree(pdata);
401err_out:
402    return ERR_PTR(error);
403}
404
405static struct of_device_id gpio_keys_polled_of_match[] = {
406    { .compatible = "gpio-keys-polled", },
407    { },
408};
409MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);
410
411#else
412
413static inline struct gpio_keys_platform_data *
414gpio_keys_polled_get_devtree_pdata(struct device *dev)
415{
416    return NULL;
417}
418#endif
419
420static void __devexit gpio_keys_polled_close(struct gpio_keys_polled_dev *bdev)
421{
422    struct gpio_keys_platform_data *pdata = bdev->pdata;
423
424    cancel_delayed_work_sync(&bdev->work);
425
426    if (pdata->disable)
427        pdata->disable(bdev->dev);
428}
429
430static int __devinit gpio_keys_polled_probe(struct platform_device *pdev)
431{
432    struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
433    struct device *dev = &pdev->dev;
434    struct gpio_keys_polled_dev *bdev;
435    int error;
436    int i;
437
438    if (!pdata) {
439        pdata = gpio_keys_polled_get_devtree_pdata(dev);
440        if (IS_ERR(pdata))
441            return PTR_ERR(pdata);
442        if (!pdata) {
443            dev_err(dev, "missing platform data\n");
444            return -EINVAL;
445        }
446    }
447
448    if (!pdata->poll_interval) {
449        dev_err(dev, "missing poll_interval value\n");
450        error = -EINVAL;
451        goto err_free_pdata;
452    }
453
454    bdev = kzalloc(sizeof(struct gpio_keys_polled_dev) +
455               pdata->nbuttons * sizeof(struct gpio_keys_button_data),
456               GFP_KERNEL);
457    if (!bdev) {
458        dev_err(dev, "no memory for private data\n");
459        return -ENOMEM;
460    }
461
462    for (i = 0; i < pdata->nbuttons; i++) {
463        struct gpio_keys_button *button = &pdata->buttons[i];
464        struct gpio_keys_button_data *bdata = &bdev->data[i];
465        unsigned int gpio = button->gpio;
466
467        if (button->wakeup) {
468            dev_err(dev, DRV_NAME " does not support wakeup\n");
469            error = -EINVAL;
470            goto err_free_gpio;
471        }
472
473        error = gpio_request(gpio,
474                     button->desc ? button->desc : DRV_NAME);
475        if (error) {
476            dev_err(dev, "unable to claim gpio %u, err=%d\n",
477                gpio, error);
478            goto err_free_gpio;
479        }
480
481        error = gpio_direction_input(gpio);
482        if (error) {
483            dev_err(dev,
484                "unable to set direction on gpio %u, err=%d\n",
485                gpio, error);
486            goto err_free_gpio;
487        }
488
489        bdata->can_sleep = gpio_cansleep(gpio);
490        bdata->last_state = 0;
491        bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
492                        pdata->poll_interval);
493    }
494
495    bdev->dev = &pdev->dev;
496    bdev->pdata = pdata;
497    platform_set_drvdata(pdev, bdev);
498
499    INIT_DELAYED_WORK(&bdev->work, gpio_keys_polled_poll);
500
501    gpio_keys_polled_open(bdev);
502
503    return 0;
504
505err_free_gpio:
506    while (--i >= 0)
507        gpio_free(pdata->buttons[i].gpio);
508
509    kfree(bdev);
510    platform_set_drvdata(pdev, NULL);
511
512err_free_pdata:
513    /* If we have no platform_data, we allocated pdata dynamically. */
514    if (!dev_get_platdata(&pdev->dev))
515        kfree(pdata);
516
517    return error;
518}
519
520static int __devexit gpio_keys_polled_remove(struct platform_device *pdev)
521{
522    struct gpio_keys_polled_dev *bdev = platform_get_drvdata(pdev);
523    struct gpio_keys_platform_data *pdata = bdev->pdata;
524    int i = pdata->nbuttons;
525
526    gpio_keys_polled_close(bdev);
527
528    while (--i >= 0)
529        gpio_free(pdata->buttons[i].gpio);
530
531    kfree(bdev);
532    platform_set_drvdata(pdev, NULL);
533
534    return 0;
535}
536
537static struct platform_driver gpio_keys_polled_driver = {
538    .probe = gpio_keys_polled_probe,
539    .remove = __devexit_p(gpio_keys_polled_remove),
540    .driver = {
541        .name = DRV_NAME,
542        .owner = THIS_MODULE,
543        .of_match_table = of_match_ptr(gpio_keys_polled_of_match),
544    },
545};
546
547static int __init gpio_keys_polled_init(void)
548{
549    return platform_driver_register(&gpio_keys_polled_driver);
550}
551
552static void __exit gpio_keys_polled_exit(void)
553{
554    platform_driver_unregister(&gpio_keys_polled_driver);
555}
556
557module_init(gpio_keys_polled_init);
558module_exit(gpio_keys_polled_exit);
559
560MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
561MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
562MODULE_DESCRIPTION("Polled GPIO Buttons hotplug driver");
563MODULE_LICENSE("GPL v2");
564MODULE_ALIAS("platform:" DRV_NAME);
565

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