add button-hotplug driver, will be usable to check status of buttons connected to GPIO lines

SVN-Revision: 11401

1 files changed, 318 insertions, 0 deletions

diff --git a/package/button-hotplug/src/button-hotplug.c b/package/button-hotplug/src/button-hotplug.c
new file mode 100644
index 0000000..3b5527f
--- /dev/null
+++ b/package/button-hotplug/src/button-hotplug.c
@@ -0,0 +1,318 @@
+/*
+ *  Button Hotplug driver
+ *
+ *  Copyright (C) 2008 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/input.h>
+
+#include <linux/workqueue.h>
+#include <linux/skbuff.h>
+#include <linux/netlink.h>
+#include <net/sock.h>
+
+#define DRV_NAME	"button-hotplug"
+#define DRV_VERSION	"0.3.0"
+#define DRV_DESC	"Button Hotplug driver"
+
+#define BH_SKB_SIZE	2048
+
+#define BH_BTN_MIN	BTN_0
+#define BH_BTN_MAX	BTN_9
+
+#define BH_BTN_COUNT	(BH_BTN_MAX - BH_BTN_MIN + 1)
+
+#define PFX	DRV_NAME ": "
+
+/*#define BH_DEBUG*/
+
+#ifdef BH_DEBUG
+#define BH_DBG(fmt, args...) printk(KERN_DEBUG "%s" fmt, ##args )
+#else
+#define BH_DBG(fmt, args...) do {} while (0)
+#endif
+
+#define BH_ERR(fmt, args...) printk(KERN_ERR "%s" fmt, ##args )
+
+struct bh_priv {
+	unsigned long		seen[BH_BTN_COUNT];
+	struct input_handle	handle;
+};
+
+struct bh_event {
+	char			*name;
+	char			*action;
+	unsigned long		seen;
+
+	struct sk_buff		*skb;
+	struct work_struct	work;
+};
+
+extern struct sock *uevent_sock;
+extern u64 uevent_next_seqnum(void);
+
+static char *button_names[BH_BTN_COUNT] = {
+	"BTN_0", "BTN_1", "BTN_2", "BTN_3", "BTN_4",
+	"BTN_5", "BTN_6", "BTN_7", "BTN_8", "BTN_9"
+};
+
+/* -------------------------------------------------------------------------*/
+
+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;
+
+	if (!uevent_sock)
+		goto out_free_event;
+
+	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;
+	netlink_broadcast(uevent_sock, 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(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 void button_hotplug_event(struct input_handle *handle,
+			   unsigned int type, unsigned int code, int value)
+{
+	struct bh_priv *priv = handle->private;
+	unsigned long seen = jiffies;
+	unsigned int btn;
+
+	BH_DBG("event type=%u, code=%u, value=%d\n", type, code, value);
+
+	if (type != EV_KEY)
+		return;
+
+	if (code < BH_BTN_MIN || code > BH_BTN_MAX)
+		return;
+
+	btn = code - BH_BTN_MIN;
+	button_hotplug_create_event(button_names[btn],
+			(seen - priv->seen[btn]) / HZ, value);
+	priv->seen[btn] = seen;
+}
+#else
+static void button_hotplug_event(struct input_handle *handle,
+			   unsigned int type, unsigned int code, int value)
+{
+}
+#endif	/* CONFIG_HOTPLUG */
+
+static int button_hotplug_connect(struct input_handler *handler,
+		struct input_dev *dev, const struct input_device_id *id)
+{
+	struct bh_priv *priv;
+	int ret;
+	int i;
+
+	for (i = BH_BTN_MIN; i <= BH_BTN_MAX; i++)
+		if (test_bit(i, dev->keybit))
+			break;
+
+	if (i > BH_BTN_MAX)
+		return -ENODEV;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->handle.private = priv;
+	priv->handle.dev = dev;
+	priv->handle.handler = handler;
+	priv->handle.name = DRV_NAME;
+
+	ret = input_register_handle(&priv->handle);
+	if (ret)
+		goto err_free_priv;
+
+	ret = input_open_device(&priv->handle);
+	if (ret)
+		goto err_unregister_handle;
+
+	BH_DBG("connected to %s\n", dev->name);
+
+	return 0;
+
+ err_unregister_handle:
+	input_unregister_handle(&priv->handle);
+
+ err_free_priv:
+	kfree(priv);
+	return ret;
+}
+
+static void button_hotplug_disconnect(struct input_handle *handle)
+{
+	struct bh_priv *priv = handle->private;
+
+	input_close_device(handle);
+	input_unregister_handle(handle);
+
+	kfree(priv);
+}
+
+static const struct input_device_id button_hotplug_ids[] = {
+	{
+                .flags = INPUT_DEVICE_ID_MATCH_EVBIT,
+                .evbit = { BIT_MASK(EV_KEY) },
+        },
+	{
+		/* Terminating entry */
+	},
+};
+
+MODULE_DEVICE_TABLE(input, button_hotplug_ids);
+
+static struct input_handler button_hotplug_handler = {
+	.event =	button_hotplug_event,
+	.connect =	button_hotplug_connect,
+	.disconnect =	button_hotplug_disconnect,
+	.name =		DRV_NAME,
+	.id_table =	button_hotplug_ids,
+};
+
+/* -------------------------------------------------------------------------*/
+
+static int __init button_hotplug_init(void)
+{
+	int ret;
+
+	printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");
+	ret = input_register_handler(&button_hotplug_handler);
+	if (ret)
+		BH_ERR("unable to register input handler\n");
+
+	return ret;
+}
+module_init(button_hotplug_init);
+
+static void __exit button_hotplug_exit(void)
+{
+	input_unregister_handler(&button_hotplug_handler);
+}
+module_exit(button_hotplug_exit);
+
+MODULE_DESCRIPTION(DRV_DESC);
+MODULE_VERSION(DRV_VERSION);
+MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
+MODULE_LICENSE("GPL v2");
+