Merge ../linux-2.6

17 files changed, 3908 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
new file mode 100644
index 00000000000..929dd809057
--- /dev/null
+++ b/drivers/rtc/Kconfig
@@ -0,0 +1,165 @@
+\#
+# RTC class/drivers configuration
+#
+
+menu "Real Time Clock"
+
+config RTC_LIB
+	tristate
+
+config RTC_CLASS
+	tristate "RTC class"
+	depends on EXPERIMENTAL
+	default n
+	select RTC_LIB
+	help
+	  Generic RTC class support. If you say yes here, you will
+ 	  be allowed to plug one or more RTCs to your system. You will
+	  probably want to enable one of more of the interfaces below.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-class.
+
+config RTC_HCTOSYS
+	bool "Set system time from RTC on startup"
+	depends on RTC_CLASS = y
+	default y
+	help
+	  If you say yes here, the system time will be set using
+	  the value read from the specified RTC device. This is useful
+	  in order to avoid unnecessary fschk runs.
+
+config RTC_HCTOSYS_DEVICE
+	string "The RTC to read the time from"
+	depends on RTC_HCTOSYS = y
+	default "rtc0"
+	help
+	  The RTC device that will be used as the source for
+	  the system time, usually rtc0.
+
+comment "RTC interfaces"
+	depends on RTC_CLASS
+
+config RTC_INTF_SYSFS
+	tristate "sysfs"
+	depends on RTC_CLASS && SYSFS
+	default RTC_CLASS
+	help
+	  Say yes here if you want to use your RTC using the sysfs
+	  interface, /sys/class/rtc/rtcX .
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-sysfs.
+
+config RTC_INTF_PROC
+	tristate "proc"
+	depends on RTC_CLASS && PROC_FS
+	default RTC_CLASS
+	help
+	  Say yes here if you want to use your RTC using the proc
+	  interface, /proc/driver/rtc .
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-proc.
+
+config RTC_INTF_DEV
+	tristate "dev"
+	depends on RTC_CLASS
+	default RTC_CLASS
+	help
+	  Say yes here if you want to use your RTC using the dev
+	  interface, /dev/rtc .
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-dev.
+
+comment "RTC drivers"
+	depends on RTC_CLASS
+
+config RTC_DRV_X1205
+	tristate "Xicor/Intersil X1205"
+	depends on RTC_CLASS && I2C
+	help
+	  If you say yes here you get support for the
+	  Xicor/Intersil X1205 RTC chip.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-x1205.
+
+config RTC_DRV_DS1672
+	tristate "Dallas/Maxim DS1672"
+	depends on RTC_CLASS && I2C
+	help
+	  If you say yes here you get support for the
+	  Dallas/Maxim DS1672 timekeeping chip.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-ds1672.
+
+config RTC_DRV_PCF8563
+	tristate "Philips PCF8563/Epson RTC8564"
+	depends on RTC_CLASS && I2C
+	help
+	  If you say yes here you get support for the
+	  Philips PCF8563 RTC chip. The Epson RTC8564
+	  should work as well.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-pcf8563.
+
+config RTC_DRV_RS5C372
+	tristate "Ricoh RS5C372A/B"
+	depends on RTC_CLASS && I2C
+	help
+	  If you say yes here you get support for the
+	  Ricoh RS5C372A and RS5C372B RTC chips.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-rs5c372.
+
+config RTC_DRV_M48T86
+	tristate "ST M48T86/Dallas DS12887"
+	depends on RTC_CLASS
+	help
+	  If you say Y here you will get support for the
+	  ST M48T86 and Dallas DS12887 RTC chips.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-m48t86.
+
+config RTC_DRV_EP93XX
+	tristate "Cirrus Logic EP93XX"
+	depends on RTC_CLASS && ARCH_EP93XX
+	help
+	  If you say yes here you get support for the
+	  RTC embedded in the Cirrus Logic EP93XX processors.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-ep93xx.
+
+config RTC_DRV_SA1100
+	tristate "SA11x0/PXA2xx"
+	depends on RTC_CLASS && (ARCH_SA1100 || ARCH_PXA)
+	help
+	  If you say Y here you will get access to the real time clock
+	  built into your SA11x0 or PXA2xx CPU.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called rtc-sa1100.
+
+config RTC_DRV_TEST
+	tristate "Test driver/device"
+	depends on RTC_CLASS
+	help
+	  If you say yes here you get support for the
+	  RTC test driver. It's a software RTC which can be
+	  used to test the RTC subsystem APIs. It gets
+	  the time from the system clock.
+	  You want this driver only if you are doing development
+	  on the RTC subsystem. Please read the source code
+	  for further details.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-test.
+
+endmenu
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
new file mode 100644
index 00000000000..8d4c7fe88d5
--- /dev/null
+++ b/drivers/rtc/Makefile
@@ -0,0 +1,21 @@
+#
+# Makefile for RTC class/drivers.
+#
+
+obj-$(CONFIG_RTC_LIB)		+= rtc-lib.o
+obj-$(CONFIG_RTC_HCTOSYS)	+= hctosys.o
+obj-$(CONFIG_RTC_CLASS)		+= rtc-core.o
+rtc-core-y			:= class.o interface.o
+
+obj-$(CONFIG_RTC_INTF_SYSFS)	+= rtc-sysfs.o
+obj-$(CONFIG_RTC_INTF_PROC)	+= rtc-proc.o
+obj-$(CONFIG_RTC_INTF_DEV)	+= rtc-dev.o
+
+obj-$(CONFIG_RTC_DRV_X1205)	+= rtc-x1205.o
+obj-$(CONFIG_RTC_DRV_TEST)	+= rtc-test.o
+obj-$(CONFIG_RTC_DRV_DS1672)	+= rtc-ds1672.o
+obj-$(CONFIG_RTC_DRV_PCF8563)	+= rtc-pcf8563.o
+obj-$(CONFIG_RTC_DRV_RS5C372)	+= rtc-rs5c372.o
+obj-$(CONFIG_RTC_DRV_M48T86)	+= rtc-m48t86.o
+obj-$(CONFIG_RTC_DRV_EP93XX)	+= rtc-ep93xx.o
+obj-$(CONFIG_RTC_DRV_SA1100)	+= rtc-sa1100.o
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
new file mode 100644
index 00000000000..8533936d50d
--- /dev/null
+++ b/drivers/rtc/class.c
@@ -0,0 +1,145 @@
+/*
+ * RTC subsystem, base class
+ *
+ * Copyright (C) 2005 Tower Technologies
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * class skeleton from drivers/hwmon/hwmon.c
+ *
+ * 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/rtc.h>
+#include <linux/kdev_t.h>
+#include <linux/idr.h>
+
+static DEFINE_IDR(rtc_idr);
+static DEFINE_MUTEX(idr_lock);
+struct class *rtc_class;
+
+static void rtc_device_release(struct class_device *class_dev)
+{
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+	mutex_lock(&idr_lock);
+	idr_remove(&rtc_idr, rtc->id);
+	mutex_unlock(&idr_lock);
+	kfree(rtc);
+}
+
+/**
+ * rtc_device_register - register w/ RTC class
+ * @dev: the device to register
+ *
+ * rtc_device_unregister() must be called when the class device is no
+ * longer needed.
+ *
+ * Returns the pointer to the new struct class device.
+ */
+struct rtc_device *rtc_device_register(const char *name, struct device *dev,
+					struct rtc_class_ops *ops,
+					struct module *owner)
+{
+	struct rtc_device *rtc;
+	int id, err;
+
+	if (idr_pre_get(&rtc_idr, GFP_KERNEL) == 0) {
+		err = -ENOMEM;
+		goto exit;
+	}
+
+
+	mutex_lock(&idr_lock);
+	err = idr_get_new(&rtc_idr, NULL, &id);
+	mutex_unlock(&idr_lock);
+
+	if (err < 0)
+		goto exit;
+
+	id = id & MAX_ID_MASK;
+
+	rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);
+	if (rtc == NULL) {
+		err = -ENOMEM;
+		goto exit_idr;
+	}
+
+	rtc->id = id;
+	rtc->ops = ops;
+	rtc->owner = owner;
+	rtc->class_dev.dev = dev;
+	rtc->class_dev.class = rtc_class;
+	rtc->class_dev.release = rtc_device_release;
+
+	mutex_init(&rtc->ops_lock);
+	spin_lock_init(&rtc->irq_lock);
+	spin_lock_init(&rtc->irq_task_lock);
+
+	strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
+	snprintf(rtc->class_dev.class_id, BUS_ID_SIZE, "rtc%d", id);
+
+	err = class_device_register(&rtc->class_dev);
+	if (err)
+		goto exit_kfree;
+
+	dev_info(dev, "rtc core: registered %s as %s\n",
+			rtc->name, rtc->class_dev.class_id);
+
+	return rtc;
+
+exit_kfree:
+	kfree(rtc);
+
+exit_idr:
+	idr_remove(&rtc_idr, id);
+
+exit:
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(rtc_device_register);
+
+
+/**
+ * rtc_device_unregister - removes the previously registered RTC class device
+ *
+ * @rtc: the RTC class device to destroy
+ */
+void rtc_device_unregister(struct rtc_device *rtc)
+{
+	mutex_lock(&rtc->ops_lock);
+	rtc->ops = NULL;
+	mutex_unlock(&rtc->ops_lock);
+	class_device_unregister(&rtc->class_dev);
+}
+EXPORT_SYMBOL_GPL(rtc_device_unregister);
+
+int rtc_interface_register(struct class_interface *intf)
+{
+	intf->class = rtc_class;
+	return class_interface_register(intf);
+}
+EXPORT_SYMBOL_GPL(rtc_interface_register);
+
+static int __init rtc_init(void)
+{
+	rtc_class = class_create(THIS_MODULE, "rtc");
+	if (IS_ERR(rtc_class)) {
+		printk(KERN_ERR "%s: couldn't create class\n", __FILE__);
+		return PTR_ERR(rtc_class);
+	}
+	return 0;
+}
+
+static void __exit rtc_exit(void)
+{
+	class_destroy(rtc_class);
+}
+
+module_init(rtc_init);
+module_exit(rtc_exit);
+
+MODULE_AUTHOR("Alessandro Zummo <a.zummo@towerteh.it>");
+MODULE_DESCRIPTION("RTC class support");
+MODULE_LICENSE("GPL");
diff --git a/drivers/rtc/hctosys.c b/drivers/rtc/hctosys.c
new file mode 100644
index 00000000000..d02fe9a0001
--- /dev/null
+++ b/drivers/rtc/hctosys.c
@@ -0,0 +1,69 @@
+/*
+ * RTC subsystem, initialize system time on startup
+ *
+ * Copyright (C) 2005 Tower Technologies
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * 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/rtc.h>
+
+/* IMPORTANT: the RTC only stores whole seconds. It is arbitrary
+ * whether it stores the most close value or the value with partial
+ * seconds truncated. However, it is important that we use it to store
+ * the truncated value. This is because otherwise it is necessary,
+ * in an rtc sync function, to read both xtime.tv_sec and
+ * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read
+ * of >32bits is not possible. So storing the most close value would
+ * slow down the sync API. So here we have the truncated value and
+ * the best guess is to add 0.5s.
+ */
+
+static int __init rtc_hctosys(void)
+{
+	int err;
+	struct rtc_time tm;
+	struct class_device *class_dev = rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE);
+
+	if (class_dev == NULL) {
+		printk("%s: unable to open rtc device (%s)\n",
+			__FILE__, CONFIG_RTC_HCTOSYS_DEVICE);
+		return -ENODEV;
+	}
+
+	err = rtc_read_time(class_dev, &tm);
+	if (err == 0) {
+		err = rtc_valid_tm(&tm);
+		if (err == 0) {
+			struct timespec tv;
+
+			tv.tv_nsec = NSEC_PER_SEC >> 1;
+
+			rtc_tm_to_time(&tm, &tv.tv_sec);
+
+			do_settimeofday(&tv);
+
+			dev_info(class_dev->dev,
+				"setting the system clock to "
+				"%d-%02d-%02d %02d:%02d:%02d (%u)\n",
+				tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
+				tm.tm_hour, tm.tm_min, tm.tm_sec,
+				(unsigned int) tv.tv_sec);
+		}
+		else
+			dev_err(class_dev->dev,
+				"hctosys: invalid date/time\n");
+	}
+	else
+		dev_err(class_dev->dev,
+			"hctosys: unable to read the hardware clock\n");
+
+	rtc_class_close(class_dev);
+
+	return 0;
+}
+
+late_initcall(rtc_hctosys);
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
new file mode 100644
index 00000000000..56e490709b8
--- /dev/null
+++ b/drivers/rtc/interface.c
@@ -0,0 +1,277 @@
+/*
+ * RTC subsystem, interface functions
+ *
+ * Copyright (C) 2005 Tower Technologies
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * based on arch/arm/common/rtctime.c
+ *
+ * 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/rtc.h>
+
+int rtc_read_time(struct class_device *class_dev, struct rtc_time *tm)
+{
+	int err;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return -EBUSY;
+
+	if (!rtc->ops)
+		err = -ENODEV;
+	else if (!rtc->ops->read_time)
+		err = -EINVAL;
+	else {
+		memset(tm, 0, sizeof(struct rtc_time));
+		err = rtc->ops->read_time(class_dev->dev, tm);
+	}
+
+	mutex_unlock(&rtc->ops_lock);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_read_time);
+
+int rtc_set_time(struct class_device *class_dev, struct rtc_time *tm)
+{
+	int err;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	err = rtc_valid_tm(tm);
+	if (err != 0)
+		return err;
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return -EBUSY;
+
+	if (!rtc->ops)
+		err = -ENODEV;
+	else if (!rtc->ops->set_time)
+		err = -EINVAL;
+	else
+		err = rtc->ops->set_time(class_dev->dev, tm);
+
+	mutex_unlock(&rtc->ops_lock);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_set_time);
+
+int rtc_set_mmss(struct class_device *class_dev, unsigned long secs)
+{
+	int err;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return -EBUSY;
+
+	if (!rtc->ops)
+		err = -ENODEV;
+	else if (rtc->ops->set_mmss)
+		err = rtc->ops->set_mmss(class_dev->dev, secs);
+	else if (rtc->ops->read_time && rtc->ops->set_time) {
+		struct rtc_time new, old;
+
+		err = rtc->ops->read_time(class_dev->dev, &old);
+		if (err == 0) {
+			rtc_time_to_tm(secs, &new);
+
+			/*
+			 * avoid writing when we're going to change the day of
+			 * the month. We will retry in the next minute. This
+			 * basically means that if the RTC must not drift
+			 * by more than 1 minute in 11 minutes.
+			 */
+			if (!((old.tm_hour == 23 && old.tm_min == 59) ||
+				(new.tm_hour == 23 && new.tm_min == 59)))
+				err = rtc->ops->set_time(class_dev->dev, &new);
+		}
+	}
+	else
+		err = -EINVAL;
+
+	mutex_unlock(&rtc->ops_lock);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_set_mmss);
+
+int rtc_read_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
+{
+	int err;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return -EBUSY;
+
+	if (rtc->ops == NULL)
+		err = -ENODEV;
+	else if (!rtc->ops->read_alarm)
+		err = -EINVAL;
+	else {
+		memset(alarm, 0, sizeof(struct rtc_wkalrm));
+		err = rtc->ops->read_alarm(class_dev->dev, alarm);
+	}
+
+	mutex_unlock(&rtc->ops_lock);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_read_alarm);
+
+int rtc_set_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
+{
+	int err;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return -EBUSY;
+
+	if (!rtc->ops)
+		err = -ENODEV;
+	else if (!rtc->ops->set_alarm)
+		err = -EINVAL;
+	else
+		err = rtc->ops->set_alarm(class_dev->dev, alarm);
+
+	mutex_unlock(&rtc->ops_lock);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_set_alarm);
+
+void rtc_update_irq(struct class_device *class_dev,
+		unsigned long num, unsigned long events)
+{
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	spin_lock(&rtc->irq_lock);
+	rtc->irq_data = (rtc->irq_data + (num << 8)) | events;
+	spin_unlock(&rtc->irq_lock);
+
+	spin_lock(&rtc->irq_task_lock);
+	if (rtc->irq_task)
+		rtc->irq_task->func(rtc->irq_task->private_data);
+	spin_unlock(&rtc->irq_task_lock);
+
+	wake_up_interruptible(&rtc->irq_queue);
+	kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
+}
+EXPORT_SYMBOL_GPL(rtc_update_irq);
+
+struct class_device *rtc_class_open(char *name)
+{
+	struct class_device *class_dev = NULL,
+				*class_dev_tmp;
+
+	down(&rtc_class->sem);
+	list_for_each_entry(class_dev_tmp, &rtc_class->children, node) {
+		if (strncmp(class_dev_tmp->class_id, name, BUS_ID_SIZE) == 0) {
+			class_dev = class_dev_tmp;
+			break;
+		}
+	}
+
+	if (class_dev) {
+		if (!try_module_get(to_rtc_device(class_dev)->owner))
+			class_dev = NULL;
+	}
+	up(&rtc_class->sem);
+
+	return class_dev;
+}
+EXPORT_SYMBOL_GPL(rtc_class_open);
+
+void rtc_class_close(struct class_device *class_dev)
+{
+	module_put(to_rtc_device(class_dev)->owner);
+}
+EXPORT_SYMBOL_GPL(rtc_class_close);
+
+int rtc_irq_register(struct class_device *class_dev, struct rtc_task *task)
+{
+	int retval = -EBUSY;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	if (task == NULL || task->func == NULL)
+		return -EINVAL;
+
+	spin_lock(&rtc->irq_task_lock);
+	if (rtc->irq_task == NULL) {
+		rtc->irq_task = task;
+		retval = 0;
+	}
+	spin_unlock(&rtc->irq_task_lock);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(rtc_irq_register);
+
+void rtc_irq_unregister(struct class_device *class_dev, struct rtc_task *task)
+{
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	spin_lock(&rtc->irq_task_lock);
+	if (rtc->irq_task == task)
+		rtc->irq_task = NULL;
+	spin_unlock(&rtc->irq_task_lock);
+}
+EXPORT_SYMBOL_GPL(rtc_irq_unregister);
+
+int rtc_irq_set_state(struct class_device *class_dev, struct rtc_task *task, int enabled)
+{
+	int err = 0;
+	unsigned long flags;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	spin_lock_irqsave(&rtc->irq_task_lock, flags);
+	if (rtc->irq_task != task)
+		err = -ENXIO;
+	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
+
+	if (err == 0)
+		err = rtc->ops->irq_set_state(class_dev->dev, enabled);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_irq_set_state);
+
+int rtc_irq_set_freq(struct class_device *class_dev, struct rtc_task *task, int freq)
+{
+	int err = 0, tmp = 0;
+	unsigned long flags;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	/* allowed range is 2-8192 */
+	if (freq < 2 || freq > 8192)
+		return -EINVAL;
+/*
+	FIXME: this does not belong here, will move where appropriate
+	at a later stage. It cannot hurt right now, trust me :)
+	if ((freq > rtc_max_user_freq) && (!capable(CAP_SYS_RESOURCE)))
+		return -EACCES;
+*/
+	/* check if freq is a power of 2 */
+	while (freq > (1 << tmp))
+		tmp++;
+
+	if (freq != (1 << tmp))
+		return -EINVAL;
+
+	spin_lock_irqsave(&rtc->irq_task_lock, flags);
+	if (rtc->irq_task != task)
+		err = -ENXIO;
+	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
+
+	if (err == 0) {
+		err = rtc->ops->irq_set_freq(class_dev->dev, freq);
+		if (err == 0)
+			rtc->irq_freq = freq;
+	}
+	return err;
+}
diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c
new file mode 100644
index 00000000000..b1e3e6179e5
--- /dev/null
+++ b/drivers/rtc/rtc-dev.c
@@ -0,0 +1,382 @@
+/*
+ * RTC subsystem, dev interface
+ *
+ * Copyright (C) 2005 Tower Technologies
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * based on arch/arm/common/rtctime.c
+ *
+ * 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/rtc.h>
+
+static struct class *rtc_dev_class;
+static dev_t rtc_devt;
+
+#define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */
+
+static int rtc_dev_open(struct inode *inode, struct file *file)
+{
+	int err;
+	struct rtc_device *rtc = container_of(inode->i_cdev,
+					struct rtc_device, char_dev);
+	struct rtc_class_ops *ops = rtc->ops;
+
+	/* We keep the lock as long as the device is in use
+	 * and return immediately if busy
+	 */
+	if (!(mutex_trylock(&rtc->char_lock)))
+		return -EBUSY;
+
+	file->private_data = &rtc->class_dev;
+
+	err = ops->open ? ops->open(rtc->class_dev.dev) : 0;
+	if (err == 0) {
+		spin_lock_irq(&rtc->irq_lock);
+		rtc->irq_data = 0;
+		spin_unlock_irq(&rtc->irq_lock);
+
+		return 0;
+	}
+
+	/* something has gone wrong, release the lock */
+	mutex_unlock(&rtc->char_lock);
+	return err;
+}
+
+
+static ssize_t
+rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+	struct rtc_device *rtc = to_rtc_device(file->private_data);
+
+	DECLARE_WAITQUEUE(wait, current);
+	unsigned long data;
+	ssize_t ret;
+
+	if (count < sizeof(unsigned long))
+		return -EINVAL;
+
+	add_wait_queue(&rtc->irq_queue, &wait);
+	do {
+		__set_current_state(TASK_INTERRUPTIBLE);
+
+		spin_lock_irq(&rtc->irq_lock);
+		data = rtc->irq_data;
+		rtc->irq_data = 0;
+		spin_unlock_irq(&rtc->irq_lock);
+
+		if (data != 0) {
+			ret = 0;
+			break;
+		}
+		if (file->f_flags & O_NONBLOCK) {
+			ret = -EAGAIN;
+			break;
+		}
+		if (signal_pending(current)) {
+			ret = -ERESTARTSYS;
+			break;
+		}
+		schedule();
+	} while (1);
+	set_current_state(TASK_RUNNING);
+	remove_wait_queue(&rtc->irq_queue, &wait);
+
+	if (ret == 0) {
+		/* Check for any data updates */
+		if (rtc->ops->read_callback)
+			data = rtc->ops->read_callback(rtc->class_dev.dev, data);
+
+		ret = put_user(data, (unsigned long __user *)buf);
+		if (ret == 0)
+			ret = sizeof(unsigned long);
+	}
+	return ret;
+}
+
+static unsigned int rtc_dev_poll(struct file *file, poll_table *wait)
+{
+	struct rtc_device *rtc = to_rtc_device(file->private_data);
+	unsigned long data;
+
+	poll_wait(file, &rtc->irq_queue, wait);
+
+	data = rtc->irq_data;
+
+	return (data != 0) ? (POLLIN | POLLRDNORM) : 0;
+}
+
+static int rtc_dev_ioctl(struct inode *inode, struct file *file,
+		unsigned int cmd, unsigned long arg)
+{
+	int err = 0;
+	struct class_device *class_dev = file->private_data;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+	struct rtc_class_ops *ops = rtc->ops;
+	struct rtc_time tm;
+	struct rtc_wkalrm alarm;
+	void __user *uarg = (void __user *) arg;
+
+	/* avoid conflicting IRQ users */
+	if (cmd == RTC_PIE_ON || cmd == RTC_PIE_OFF || cmd == RTC_IRQP_SET) {
+		spin_lock(&rtc->irq_task_lock);
+		if (rtc->irq_task)
+			err = -EBUSY;
+		spin_unlock(&rtc->irq_task_lock);
+
+		if (err < 0)
+			return err;
+	}
+
+	/* try the driver's ioctl interface */
+	if (ops->ioctl) {
+		err = ops->ioctl(class_dev->dev, cmd, arg);
+		if (err != -EINVAL)
+			return err;
+	}
+
+	/* if the driver does not provide the ioctl interface
+	 * or if that particular ioctl was not implemented
+	 * (-EINVAL), we will try to emulate here.
+	 */
+
+	switch (cmd) {
+	case RTC_ALM_READ:
+		err = rtc_read_alarm(class_dev, &alarm);
+		if (err < 0)
+			return err;
+
+		if (copy_to_user(uarg, &alarm.time, sizeof(tm)))
+			return -EFAULT;
+		break;
+
+	case RTC_ALM_SET:
+		if (copy_from_user(&alarm.time, uarg, sizeof(tm)))
+			return -EFAULT;
+
+		alarm.enabled = 0;
+		alarm.pending = 0;
+		alarm.time.tm_mday = -1;
+		alarm.time.tm_mon = -1;
+		alarm.time.tm_year = -1;
+		alarm.time.tm_wday = -1;
+		alarm.time.tm_yday = -1;
+		alarm.time.tm_isdst = -1;
+		err = rtc_set_alarm(class_dev, &alarm);
+		break;
+
+	case RTC_RD_TIME:
+		err = rtc_read_time(class_dev, &tm);
+		if (err < 0)
+			return err;
+
+		if (copy_to_user(uarg, &tm, sizeof(tm)))
+			return -EFAULT;
+		break;
+
+	case RTC_SET_TIME:
+		if (!capable(CAP_SYS_TIME))
+			return -EACCES;
+
+		if (copy_from_user(&tm, uarg, sizeof(tm)))
+			return -EFAULT;
+
+		err = rtc_set_time(class_dev, &tm);
+		break;
+#if 0
+	case RTC_EPOCH_SET:
+#ifndef rtc_epoch
+		/*
+		 * There were no RTC clocks before 1900.
+		 */
+		if (arg < 1900) {
+			err = -EINVAL;
+			break;
+		}
+		if (!capable(CAP_SYS_TIME)) {
+			err = -EACCES;
+			break;
+		}
+		rtc_epoch = arg;
+		err = 0;
+#endif
+		break;
+
+	case RTC_EPOCH_READ:
+		err = put_user(rtc_epoch, (unsigned long __user *)uarg);
+		break;
+#endif
+	case RTC_WKALM_SET:
+		if (copy_from_user(&alarm, uarg, sizeof(alarm)))
+			return -EFAULT;
+
+		err = rtc_set_alarm(class_dev, &alarm);
+		break;
+
+	case RTC_WKALM_RD:
+		err = rtc_read_alarm(class_dev, &alarm);
+		if (err < 0)
+			return err;
+
+		if (copy_to_user(uarg, &alarm, sizeof(alarm)))
+			return -EFAULT;
+		break;
+
+	default:
+		err = -EINVAL;
+		break;
+	}
+
+	return err;
+}
+
+static int rtc_dev_release(struct inode *inode, struct file *file)
+{
+	struct rtc_device *rtc = to_rtc_device(file->private_data);
+
+	if (rtc->ops->release)
+		rtc->ops->release(rtc->class_dev.dev);
+
+	mutex_unlock(&rtc->char_lock);
+	return 0;
+}
+
+static int rtc_dev_fasync(int fd, struct file *file, int on)
+{
+	struct rtc_device *rtc = to_rtc_device(file->private_data);
+	return fasync_helper(fd, file, on, &rtc->async_queue);
+}
+
+static struct file_operations rtc_dev_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.read		= rtc_dev_read,
+	.poll		= rtc_dev_poll,
+	.ioctl		= rtc_dev_ioctl,
+	.open		= rtc_dev_open,
+	.release	= rtc_dev_release,
+	.fasync		= rtc_dev_fasync,
+};
+
+/* insertion/removal hooks */
+
+static int rtc_dev_add_device(struct class_device *class_dev,
+				struct class_interface *class_intf)
+{
+	int err = 0;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	if (rtc->id >= RTC_DEV_MAX) {
+		dev_err(class_dev->dev, "too many RTCs\n");
+		return -EINVAL;
+	}
+
+	mutex_init(&rtc->char_lock);
+	spin_lock_init(&rtc->irq_lock);
+	init_waitqueue_head(&rtc->irq_queue);
+
+	cdev_init(&rtc->char_dev, &rtc_dev_fops);
+	rtc->char_dev.owner = rtc->owner;
+
+	if (cdev_add(&rtc->char_dev, MKDEV(MAJOR(rtc_devt), rtc->id), 1)) {
+		cdev_del(&rtc->char_dev);
+		dev_err(class_dev->dev,
+			"failed to add char device %d:%d\n",
+			MAJOR(rtc_devt), rtc->id);
+		return -ENODEV;
+	}
+
+	rtc->rtc_dev = class_device_create(rtc_dev_class, NULL,
+						MKDEV(MAJOR(rtc_devt), rtc->id),
+						class_dev->dev, "rtc%d", rtc->id);
+	if (IS_ERR(rtc->rtc_dev)) {
+		dev_err(class_dev->dev, "cannot create rtc_dev device\n");
+		err = PTR_ERR(rtc->rtc_dev);
+		goto err_cdev_del;
+	}
+
+	dev_info(class_dev->dev, "rtc intf: dev (%d:%d)\n",
+		MAJOR(rtc->rtc_dev->devt),
+		MINOR(rtc->rtc_dev->devt));
+
+	return 0;
+
+err_cdev_del:
+
+	cdev_del(&rtc->char_dev);
+	return err;
+}
+
+static void rtc_dev_remove_device(struct class_device *class_dev,
+					struct class_interface *class_intf)
+{
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	if (rtc->rtc_dev) {
+		dev_dbg(class_dev->dev, "removing char %d:%d\n",
+			MAJOR(rtc->rtc_dev->devt),
+			MINOR(rtc->rtc_dev->devt));
+
+		class_device_unregister(rtc->rtc_dev);
+		cdev_del(&rtc->char_dev);
+	}
+}
+
+/* interface registration */
+
+static struct class_interface rtc_dev_interface = {
+	.add = &rtc_dev_add_device,
+	.remove = &rtc_dev_remove_device,
+};
+
+static int __init rtc_dev_init(void)
+{
+	int err;
+
+	rtc_dev_class = class_create(THIS_MODULE, "rtc-dev");
+	if (IS_ERR(rtc_dev_class))
+		return PTR_ERR(rtc_dev_class);
+
+	err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc");
+	if (err < 0) {
+		printk(KERN_ERR "%s: failed to allocate char dev region\n",
+			__FILE__);
+		goto err_destroy_class;
+	}
+
+	err = rtc_interface_register(&rtc_dev_interface);
+	if (err < 0) {
+		printk(KERN_ERR "%s: failed to register the interface\n",
+			__FILE__);
+		goto err_unregister_chrdev;
+	}
+
+	return 0;
+
+err_unregister_chrdev:
+	unregister_chrdev_region(rtc_devt, RTC_DEV_MAX);
+
+err_destroy_class:
+	class_destroy(rtc_dev_class);
+
+	return err;
+}
+
+static void __exit rtc_dev_exit(void)
+{
+	class_interface_unregister(&rtc_dev_interface);
+	class_destroy(rtc_dev_class);
+	unregist