--- /dev/null
+/*
+ * GPIO Button Hotplug driver
+ *
+ * Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
+ * Copyright (C) 2008-2010 Gabor Juhos <juhosg@openwrt.org>
+ *
+ * Based on the diag.c - GPIO interface driver for Broadcom boards
+ * Copyright (C) 2006 Mike Baker <mbm@openwrt.org>,
+ * Copyright (C) 2006-2007 Felix Fietkau <nbd@openwrt.org>
+ * Copyright (C) 2008 Andy Boyett <agb@openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/version.h>
+#include <linux/kmod.h>
+
+#include <linux/workqueue.h>
+#include <linux/skbuff.h>
+#include <linux/netlink.h>
+#include <linux/kobject.h>
+#include <linux/input.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/gpio_keys.h>
+
+#define DRV_NAME "gpio-keys-polled"
+
+#define BH_SKB_SIZE 2048
+
+#define PFX DRV_NAME ": "
+
+#undef BH_DEBUG
+
+#ifdef BH_DEBUG
+#define BH_DBG(fmt, args...) printk(KERN_DEBUG "%s: " fmt, DRV_NAME, ##args )
+#else
+#define BH_DBG(fmt, args...) do {} while (0)
+#endif
+
+#define BH_ERR(fmt, args...) printk(KERN_ERR "%s: " fmt, DRV_NAME, ##args )
+
+struct bh_priv {
+ unsigned long seen;
+};
+
+struct bh_event {
+ const char *name;
+ char *action;
+ unsigned long seen;
+
+ struct sk_buff *skb;
+ struct work_struct work;
+};
+
+struct bh_map {
+ unsigned int code;
+ const char *name;
+};
+
+struct gpio_keys_button_data {
+ struct delayed_work work;
+ struct bh_priv bh;
+ int last_state;
+ int count;
+ int threshold;
+ int can_sleep;
+};
+
+extern u64 uevent_next_seqnum(void);
+
+#define BH_MAP(_code, _name) \
+ { \
+ .code = (_code), \
+ .name = (_name), \
+ }
+
+static struct bh_map button_map[] = {
+ BH_MAP(BTN_0, "BTN_0"),
+ BH_MAP(BTN_1, "BTN_1"),
+ BH_MAP(BTN_2, "BTN_2"),
+ BH_MAP(BTN_3, "BTN_3"),
+ BH_MAP(BTN_4, "BTN_4"),
+ BH_MAP(BTN_5, "BTN_5"),
+ BH_MAP(BTN_6, "BTN_6"),
+ BH_MAP(BTN_7, "BTN_7"),
+ BH_MAP(BTN_8, "BTN_8"),
+ BH_MAP(BTN_9, "BTN_9"),
+ BH_MAP(KEY_RESTART, "reset"),
+#ifdef KEY_WPS_BUTTON
+ BH_MAP(KEY_WPS_BUTTON, "wps"),
+#endif /* KEY_WPS_BUTTON */
+};
+
+/* -------------------------------------------------------------------------*/
+
+static int bh_event_add_var(struct bh_event *event, int argv,
+ const char *format, ...)
+{
+ static char buf[128];
+ char *s;
+ va_list args;
+ int len;
+
+ if (argv)
+ return 0;
+
+ va_start(args, format);
+ len = vsnprintf(buf, sizeof(buf), format, args);
+ va_end(args);
+
+ if (len >= sizeof(buf)) {
+ BH_ERR("buffer size too small\n");
+ WARN_ON(1);
+ return -ENOMEM;
+ }
+
+ s = skb_put(event->skb, len + 1);
+ strcpy(s, buf);
+
+ BH_DBG("added variable '%s'\n", s);
+
+ return 0;
+}
+
+static int button_hotplug_fill_event(struct bh_event *event)
+{
+ int ret;
+
+ ret = bh_event_add_var(event, 0, "HOME=%s", "/");
+ if (ret)
+ return ret;
+
+ ret = bh_event_add_var(event, 0, "PATH=%s",
+ "/sbin:/bin:/usr/sbin:/usr/bin");
+ if (ret)
+ return ret;
+
+ ret = bh_event_add_var(event, 0, "SUBSYSTEM=%s", "button");
+ if (ret)
+ return ret;
+
+ ret = bh_event_add_var(event, 0, "ACTION=%s", event->action);
+ if (ret)
+ return ret;
+
+ ret = bh_event_add_var(event, 0, "BUTTON=%s", event->name);
+ if (ret)
+ return ret;
+
+ ret = bh_event_add_var(event, 0, "SEEN=%ld", event->seen);
+ if (ret)
+ return ret;
+
+ ret = bh_event_add_var(event, 0, "SEQNUM=%llu", uevent_next_seqnum());
+
+ return ret;
+}
+
+static void button_hotplug_work(struct work_struct *work)
+{
+ struct bh_event *event = container_of(work, struct bh_event, work);
+ int ret = 0;
+
+ event->skb = alloc_skb(BH_SKB_SIZE, GFP_KERNEL);
+ if (!event->skb)
+ goto out_free_event;
+
+ ret = bh_event_add_var(event, 0, "%s@", event->action);
+ if (ret)
+ goto out_free_skb;
+
+ ret = button_hotplug_fill_event(event);
+ if (ret)
+ goto out_free_skb;
+
+ NETLINK_CB(event->skb).dst_group = 1;
+ broadcast_uevent(event->skb, 0, 1, GFP_KERNEL);
+
+ out_free_skb:
+ if (ret) {
+ BH_ERR("work error %d\n", ret);
+ kfree_skb(event->skb);
+ }
+ out_free_event:
+ kfree(event);
+}
+
+static int button_hotplug_create_event(const char *name, unsigned long seen,
+ int pressed)
+{
+ struct bh_event *event;
+
+ BH_DBG("create event, name=%s, seen=%lu, pressed=%d\n",
+ name, seen, pressed);
+
+ event = kzalloc(sizeof(*event), GFP_KERNEL);
+ if (!event)
+ return -ENOMEM;
+
+ event->name = name;
+ event->seen = seen;
+ event->action = pressed ? "pressed" : "released";
+
+ INIT_WORK(&event->work, (void *)(void *)button_hotplug_work);
+ schedule_work(&event->work);
+
+ return 0;
+}
+
+/* -------------------------------------------------------------------------*/
+
+#ifdef CONFIG_HOTPLUG
+static int button_get_index(unsigned int code)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(button_map); i++)
+ if (button_map[i].code == code)
+ return i;
+
+ return -1;
+}
+static void button_hotplug_event(struct gpio_keys_button_data *data,
+ unsigned int type, unsigned int code, int value)
+{
+ struct bh_priv *priv = &data->bh;
+ unsigned long seen = jiffies;
+ int btn;
+
+ BH_DBG("event type=%u, code=%u, value=%d\n", type, code, value);
+
+ if (type != EV_KEY)
+ return;
+
+ btn = button_get_index(code);
+ if (btn < 0)
+ return;
+
+ button_hotplug_create_event(button_map[btn].name,
+ (seen - priv->seen) / HZ, value);
+ priv->seen = seen;
+}
+#else
+static void button_hotplug_event(struct gpio_keys_button_data *data,
+ unsigned int type, unsigned int code, int value)
+{
+}
+#endif /* CONFIG_HOTPLUG */
+
+struct gpio_keys_polled_dev {
+ struct delayed_work work;
+
+ struct device *dev;
+ struct gpio_keys_platform_data *pdata;
+ struct gpio_keys_button_data data[0];
+};
+
+static void gpio_keys_polled_check_state(struct gpio_keys_button *button,
+ struct gpio_keys_button_data *bdata)
+{
+ int state;
+
+ if (bdata->can_sleep)
+ state = !!gpio_get_value_cansleep(button->gpio);
+ else
+ state = !!gpio_get_value(button->gpio);
+
+ state = !!(state ^ button->active_low);
+ if (state != bdata->last_state) {
+ unsigned int type = button->type ?: EV_KEY;
+
+ button_hotplug_event(bdata, type, button->code, state);
+ bdata->count = 0;
+ bdata->last_state = state;
+ }
+}
+
+static void gpio_keys_polled_queue_work(struct gpio_keys_polled_dev *bdev)
+{
+ struct gpio_keys_platform_data *pdata = bdev->pdata;
+ unsigned long delay = msecs_to_jiffies(pdata->poll_interval);
+
+ if (delay >= HZ)
+ delay = round_jiffies_relative(delay);
+ schedule_delayed_work(&bdev->work, delay);
+}
+
+static void gpio_keys_polled_poll(struct work_struct *work)
+{
+ struct gpio_keys_polled_dev *bdev =
+ container_of(work, struct gpio_keys_polled_dev, work.work);
+ struct gpio_keys_platform_data *pdata = bdev->pdata;
+ int i;
+
+ for (i = 0; i < bdev->pdata->nbuttons; i++) {
+ struct gpio_keys_button_data *bdata = &bdev->data[i];
+
+ if (bdata->count < bdata->threshold)
+ bdata->count++;
+ else
+ gpio_keys_polled_check_state(&pdata->buttons[i], bdata);
+ }
+ gpio_keys_polled_queue_work(bdev);
+}
+
+static void __devinit gpio_keys_polled_open(struct gpio_keys_polled_dev *bdev)
+{
+ struct gpio_keys_platform_data *pdata = bdev->pdata;
+ int i;
+
+ if (pdata->enable)
+ pdata->enable(bdev->dev);
+
+ /* report initial state of the buttons */
+ for (i = 0; i < pdata->nbuttons; i++)
+ gpio_keys_polled_check_state(&pdata->buttons[i], &bdev->data[i]);
+
+ gpio_keys_polled_queue_work(bdev);
+}
+
+static void __devexit gpio_keys_polled_close(struct gpio_keys_polled_dev *bdev)
+{
+ struct gpio_keys_platform_data *pdata = bdev->pdata;
+
+ cancel_delayed_work_sync(&bdev->work);
+
+ if (pdata->disable)
+ pdata->disable(bdev->dev);
+}
+
+static int __devinit gpio_keys_polled_probe(struct platform_device *pdev)
+{
+ struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
+ struct device *dev = &pdev->dev;
+ struct gpio_keys_polled_dev *bdev;
+ int error;
+ int i;
+
+ if (!pdata || !pdata->poll_interval)
+ return -EINVAL;
+
+ bdev = kzalloc(sizeof(struct gpio_keys_polled_dev) +
+ pdata->nbuttons * sizeof(struct gpio_keys_button_data),
+ GFP_KERNEL);
+ if (!bdev) {
+ dev_err(dev, "no memory for private data\n");
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < pdata->nbuttons; i++) {
+ struct gpio_keys_button *button = &pdata->buttons[i];
+ struct gpio_keys_button_data *bdata = &bdev->data[i];
+ unsigned int gpio = button->gpio;
+
+ if (button->wakeup) {
+ dev_err(dev, DRV_NAME " does not support wakeup\n");
+ error = -EINVAL;
+ goto err_free_gpio;
+ }
+
+ error = gpio_request(gpio,
+ button->desc ? button->desc : DRV_NAME);
+ if (error) {
+ dev_err(dev, "unable to claim gpio %u, err=%d\n",
+ gpio, error);
+ goto err_free_gpio;
+ }
+
+ error = gpio_direction_input(gpio);
+ if (error) {
+ dev_err(dev,
+ "unable to set direction on gpio %u, err=%d\n",
+ gpio, error);
+ goto err_free_gpio;
+ }
+
+ bdata->can_sleep = gpio_cansleep(gpio);
+ bdata->last_state = 0;
+ bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
+ pdata->poll_interval);
+ }
+
+ bdev->dev = &pdev->dev;
+ bdev->pdata = pdata;
+ platform_set_drvdata(pdev, bdev);
+
+ INIT_DELAYED_WORK(&bdev->work, gpio_keys_polled_poll);
+
+ gpio_keys_polled_open(bdev);
+
+ return 0;
+
+err_free_gpio:
+ while (--i >= 0)
+ gpio_free(pdata->buttons[i].gpio);
+
+ kfree(bdev);
+ platform_set_drvdata(pdev, NULL);
+
+ return error;
+}
+
+static int __devexit gpio_keys_polled_remove(struct platform_device *pdev)
+{
+ struct gpio_keys_polled_dev *bdev = platform_get_drvdata(pdev);
+ struct gpio_keys_platform_data *pdata = bdev->pdata;
+ int i = pdata->nbuttons;
+
+ gpio_keys_polled_close(bdev);
+
+ while (--i >= 0)
+ gpio_free(pdata->buttons[i].gpio);
+
+ kfree(bdev);
+ platform_set_drvdata(pdev, NULL);
+
+ return 0;
+}
+
+static struct platform_driver gpio_keys_polled_driver = {
+ .probe = gpio_keys_polled_probe,
+ .remove = __devexit_p(gpio_keys_polled_remove),
+ .driver = {
+ .name = DRV_NAME,
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init gpio_keys_polled_init(void)
+{
+ return platform_driver_register(&gpio_keys_polled_driver);
+}
+
+static void __exit gpio_keys_polled_exit(void)
+{
+ platform_driver_unregister(&gpio_keys_polled_driver);
+}
+
+module_init(gpio_keys_polled_init);
+module_exit(gpio_keys_polled_exit);
+
+MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
+MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
+MODULE_DESCRIPTION("Polled GPIO Buttons hotplug driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRV_NAME);
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