[PATCH 01/11] RTC subsystem, class

[PATCH 01/11] RTC subsystem, class

[Alessandro Zummo]

[-- Attachment #1: rtc-class.patch --]
[-- Type: text/plain, Size: 20062 bytes --]

This patch adds the basic RTC subsytem infrastructure
to the kernel.

rtc/class.c - registration facilities for RTC drivers
rtc/interface.c - kernel/rtc interface functions 
rtc/utils.c - misc rtc-related utility functions
rtc/hctosys.c - snippet of code that copies hw clock to sw clock
		at bootup, if configured to do so.

Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
--
 drivers/Kconfig         |    2 
 drivers/Makefile        |    1 
 drivers/rtc/Kconfig     |   42 ++++++++
 drivers/rtc/Makefile    |    9 +
 drivers/rtc/class.c     |  143 +++++++++++++++++++++++++++++
 drivers/rtc/hctosys.c   |   62 ++++++++++++
 drivers/rtc/interface.c |  232 ++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/rtc/utils.c     |   97 ++++++++++++++++++++
 include/linux/rtc.h     |   85 +++++++++++++++++
 9 files changed, 673 insertions(+)

--- linux-rtc.orig/include/linux/rtc.h	2006-02-13 19:34:46.000000000 +0100
+++ linux-rtc/include/linux/rtc.h	2006-02-13 19:35:30.000000000 +0100
@@ -93,8 +93,93 @@ struct rtc_pll_info {
 #define RTC_PLL_GET	_IOR('p', 0x11, struct rtc_pll_info)  /* Get PLL correction */
 #define RTC_PLL_SET	_IOW('p', 0x12, struct rtc_pll_info)  /* Set PLL correction */
 
+/* interrupt flags */
+#define RTC_IRQF 0x80 /* any of the following is active */
+#define RTC_PF 0x40
+#define RTC_AF 0x20
+#define RTC_UF 0x10
+
 #ifdef __KERNEL__
 
+#include <linux/device.h>
+#include <linux/seq_file.h>
+#include <linux/cdev.h>
+#include <linux/poll.h>
+
+struct rtc_class_ops {
+	int (*open)(struct device *);
+	void (*release)(struct device *);
+	int (*ioctl)(struct device *, unsigned int, unsigned long);
+	int (*read_time)(struct device *, struct rtc_time *);
+	int (*set_time)(struct device *, struct rtc_time *);
+	int (*read_alarm)(struct device *, struct rtc_wkalrm *);
+	int (*set_alarm)(struct device *, struct rtc_wkalrm *);
+	int (*proc)(struct device *, struct seq_file *);
+	int (*set_mmss)(struct device *, unsigned long secs);
+	int (*irq_set_state)(struct device *, int enabled);
+	int (*irq_set_freq)(struct device *, int freq);
+	int (*read_callback)(struct device *, int data);
+};
+
+#define RTC_DEVICE_NAME_SIZE 20
+struct rtc_task;
+
+struct rtc_device
+{
+	int id;
+	struct module *owner;
+	struct class_device class_dev;
+	struct semaphore ops_lock;
+	struct rtc_class_ops *ops;
+	char name[RTC_DEVICE_NAME_SIZE];
+
+	struct cdev char_dev;
+	struct semaphore char_sem;
+
+	unsigned long irq_data;
+	spinlock_t irq_lock;
+	wait_queue_head_t irq_queue;
+	struct fasync_struct *async_queue;
+
+	spinlock_t irq_task_lock;
+	struct rtc_task *irq_task;
+	int irq_freq;
+};
+#define to_rtc_device(d) container_of(d, struct rtc_device, class_dev)
+
+extern struct rtc_device *rtc_device_register(const char *name,
+					struct device *dev,
+					struct rtc_class_ops *ops,
+					struct module *owner);
+extern void rtc_device_unregister(struct rtc_device *rdev);
+extern int rtc_interface_register(struct class_interface *intf);
+
+extern int rtc_month_days(unsigned int month, unsigned int year);
+extern int rtc_valid_tm(struct rtc_time *tm);
+extern int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time);
+extern void rtc_time_to_tm(unsigned long time, struct rtc_time *tm);
+
+extern int rtc_read_time(struct class_device *class_dev, struct rtc_time *tm);
+extern int rtc_set_time(struct class_device *class_dev, struct rtc_time *tm);
+extern int rtc_read_alarm(struct class_device *class_dev,
+				struct rtc_wkalrm *alrm);
+extern int rtc_set_alarm(struct class_device *class_dev,
+				struct rtc_wkalrm *alrm);
+extern void rtc_update_irq(struct class_device *class_dev,
+			unsigned long num, unsigned long events);
+
+extern struct class_device *rtc_class_open(char *name);
+extern void rtc_class_close(struct class_device *class_dev);
+
+extern int rtc_irq_register(struct class_device *class_dev,
+				struct rtc_task *task);
+extern void rtc_irq_unregister(struct class_device *class_dev,
+				struct rtc_task *task);
+extern int rtc_irq_set_state(struct class_device *class_dev,
+				struct rtc_task *task, int enabled);
+extern int rtc_irq_set_freq(struct class_device *class_dev,
+				struct rtc_task *task, int freq);
+
 typedef struct rtc_task {
 	void (*func)(void *private_data);
 	void *private_data;
--- linux-rtc.orig/drivers/Kconfig	2006-02-13 19:34:35.000000000 +0100
+++ linux-rtc/drivers/Kconfig	2006-02-13 19:35:30.000000000 +0100
@@ -70,4 +70,6 @@ source "drivers/sn/Kconfig"
 
 source "drivers/edac/Kconfig"
 
+source "drivers/rtc/Kconfig"
+
 endmenu
--- linux-rtc.orig/drivers/Makefile	2006-02-13 19:34:35.000000000 +0100
+++ linux-rtc/drivers/Makefile	2006-02-13 19:35:30.000000000 +0100
@@ -56,6 +56,7 @@ obj-$(CONFIG_USB_GADGET)	+= usb/gadget/
 obj-$(CONFIG_GAMEPORT)		+= input/gameport/
 obj-$(CONFIG_INPUT)		+= input/
 obj-$(CONFIG_I2O)		+= message/
+obj-y				+= rtc/
 obj-$(CONFIG_I2C)		+= i2c/
 obj-$(CONFIG_W1)		+= w1/
 obj-$(CONFIG_HWMON)		+= hwmon/
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-rtc/drivers/rtc/class.c	2006-02-13 19:35:30.000000000 +0100
@@ -0,0 +1,143 @@
+/*
+ * 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 as published by
+ * the Free Software Foundation; version 2 of the License.
+*/
+
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/kdev_t.h>
+#include <linux/idr.h>
+
+static DEFINE_IDR(rtc_idr);
+static DECLARE_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);
+	down(&idr_lock);
+	idr_remove(&rtc_idr, rtc->id);
+	up(&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;
+	}
+
+
+	down(&idr_lock);
+	err = idr_get_new(&rtc_idr, NULL, &id);
+	up(&idr_lock);
+
+	if (err < 0)
+		goto exit;
+
+	id = id & MAX_ID_MASK;
+
+	if ((rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL)) == 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;
+
+	init_MUTEX(&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);
+
+	if ((err = class_device_register(&rtc->class_dev)))
+		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)
+{
+	down(&rtc->ops_lock);
+	rtc->ops = NULL;
+	up(&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");
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-rtc/drivers/rtc/Kconfig	2006-02-13 19:39:59.000000000 +0100
@@ -0,0 +1,42 @@
+#
+# RTC class/drivers configuration
+#
+
+menu "Real Time Clock"
+
+config RTC_CLASS
+	tristate "RTC class"
+	depends on EXPERIMENTAL
+	default y
+	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
+
+comment "RTC drivers"
+	depends on RTC_CLASS
+
+endmenu
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-rtc/drivers/rtc/Makefile	2006-02-13 19:39:59.000000000 +0100
@@ -0,0 +1,9 @@
+#
+# Makefile for RTC class/drivers.
+#
+
+obj-y				+= utils.o
+obj-$(CONFIG_RTC_HCTOSYS)	+= hctosys.o
+obj-$(CONFIG_RTC_CLASS)		+= rtc-core.o
+rtc-core-y			:= class.o interface.o
+
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-rtc/drivers/rtc/interface.c	2006-02-13 19:35:30.000000000 +0100
@@ -0,0 +1,232 @@
+/*
+ * 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 as published by
+ * the Free Software Foundation; version 2 of the License.
+*/
+
+#include <linux/rtc.h>
+
+extern struct class *rtc_class;
+
+int rtc_read_time(struct class_device *class_dev, struct rtc_time *tm)
+{
+	int err;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	if ((err = down_interruptible(&rtc->ops_lock)))
+		return err;
+
+	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);
+	}
+
+	up(&rtc->ops_lock);
+	return err;
+}
+EXPORT_SYMBOL(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);
+
+	if ((err = rtc_valid_tm(tm)) != 0)
+		return err;
+
+	if ((err = down_interruptible(&rtc->ops_lock)))
+		return err;
+
+	if (!rtc->ops)
+		err = -ENODEV;
+	else if (!rtc->ops->set_time)
+		err = -EINVAL;
+	else
+		err = rtc->ops->set_time(class_dev->dev, tm);
+
+	up(&rtc->ops_lock);
+	return err;
+}
+EXPORT_SYMBOL(rtc_set_time);
+
+int rtc_read_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
+{
+	int err;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	if ((err = down_interruptible(&rtc->ops_lock)))
+		return err;
+
+	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);
+	}
+
+	up(&rtc->ops_lock);
+	return err;
+}
+EXPORT_SYMBOL(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);
+
+	if ((err = down_interruptible(&rtc->ops_lock)))
+		return err;
+
+	if (!rtc->ops)
+		err = -ENODEV;
+	else if (!rtc->ops->set_alarm)
+		err = -EINVAL;
+	else
+		err = rtc->ops->set_alarm(class_dev->dev, alarm);
+
+	up(&rtc->ops_lock);
+	return err;
+}
+EXPORT_SYMBOL(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(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(rtc_class_open);
+
+void rtc_class_close(struct class_device *class_dev)
+{
+	module_put(to_rtc_device(class_dev)->owner);
+}
+EXPORT_SYMBOL(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(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(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(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;
+
+/*	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) {
+		if ((err = rtc->ops->irq_set_freq(class_dev->dev, freq)) == 0)
+			rtc->irq_freq = freq;
+	}
+	return err;
+
+}
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-rtc/drivers/rtc/utils.c	2006-02-13 19:35:30.000000000 +0100
@@ -0,0 +1,97 @@
+/*
+ * RTC subsystem, utility 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 as published by
+ * the Free Software Foundation; version 2 of the License.
+*/
+
+#include <linux/rtc.h>
+
+static const unsigned char rtc_days_in_month[] = {
+	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+};
+
+#define LEAPS_THRU_END_OF(y) ((y)/4 - (y)/100 + (y)/400)
+#define LEAP_YEAR(year) ((!(year % 4) && (year % 100)) || !(year % 400))
+
+int rtc_month_days(unsigned int month, unsigned int year)
+{
+	return rtc_days_in_month[month] + (LEAP_YEAR(year) && month == 1);
+}
+EXPORT_SYMBOL(rtc_month_days);
+
+/*
+ * Convert seconds since 01-01-1970 00:00:00 to Gregorian date.
+ */
+void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
+{
+	int days, month, year;
+
+	days = time / 86400;
+	time -= days * 86400;
+
+	tm->tm_wday = (days + 4) % 7;
+
+	year = 1970 + days / 365;
+	days -= (year - 1970) * 365
+	        + LEAPS_THRU_END_OF(year - 1)
+	        - LEAPS_THRU_END_OF(1970 - 1);
+	if (days < 0) {
+		year -= 1;
+		days += 365 + LEAP_YEAR(year);
+	}
+	tm->tm_year = year - 1900;
+	tm->tm_yday = days + 1;
+
+	for (month = 0; month < 11; month++) {
+		int newdays;
+
+		newdays = days - rtc_month_days(month, year);
+		if (newdays < 0)
+			break;
+		days = newdays;
+	}
+	tm->tm_mon = month;
+	tm->tm_mday = days + 1;
+
+	tm->tm_hour = time / 3600;
+	time -= tm->tm_hour * 3600;
+	tm->tm_min = time / 60;
+	tm->tm_sec = time - tm->tm_min * 60;
+}
+EXPORT_SYMBOL(rtc_time_to_tm);
+
+/*
+ * Does the rtc_time represent a valid date/time?
+ */
+int rtc_valid_tm(struct rtc_time *tm)
+{
+	if (tm->tm_year < 70 ||
+	    tm->tm_mon >= 12 ||
+	    tm->tm_mday < 1 ||
+	    tm->tm_mday > rtc_month_days(tm->tm_mon, tm->tm_year + 1900) ||
+	    tm->tm_hour >= 24 ||
+	    tm->tm_min >= 60 ||
+	    tm->tm_sec >= 60)
+		return -EINVAL;
+
+	return 0;
+}
+EXPORT_SYMBOL(rtc_valid_tm);
+
+/*
+ * Convert Gregorian date to seconds since 01-01-1970 00:00:00.
+ */
+int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time)
+{
+	*time = mktime(tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
+		       tm->tm_hour, tm->tm_min, tm->tm_sec);
+	return 0;
+}
+EXPORT_SYMBOL(rtc_tm_to_time);
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-rtc/drivers/rtc/hctosys.c	2006-02-13 19:35:30.000000000 +0100
@@ -0,0 +1,62 @@
+/*
+ * 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 as published by
+ * the Free Software Foundation; version 2 of the License.
+*/
+
+#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 class_device *class_dev = rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE);
+
+	if (class_dev) {
+		struct rtc_time tm;
+
+		if ((err = rtc_read_time(class_dev, &tm)) == 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,
+				"unable to set the system clock\n");
+
+		rtc_class_close(class_dev);
+	}
+	else
+		printk("%s: unable to open rtc device (%s)\n",
+			__FILE__, CONFIG_RTC_HCTOSYS_DEVICE);
+
+	return 0;
+}
+
+late_initcall(rtc_hctosys);

--

Re: [PATCH 01/11] RTC subsystem, class

[Dmitry Torokhov]

On Monday 13 February 2006 17:54, Alessandro Zummo wrote:
> +
> +struct rtc_device
> +{
> +	int id;
> +	struct module *owner;
> +	struct class_device class_dev;
> +	struct semaphore ops_lock;

Alessandro,

I believe we are moving from struct semaphore to mutex whenever possible.
It would be nice if new code used new primitives.


-- 
Dmitry

Re: [PATCH 01/11] RTC subsystem, class

[Thomas Petazzoni]

Hi,

[ Sorry for possibly messing up the threads and killing the Cc:, but I'm
not subscribed to linux-kernel. I'm reading through the newsgroups. ]

Alessandro Zummo a écrit :

> +MODULE_AUTHOR("Alessandro Zummo <a.zummo@towerteh.it>");
                                                 ^^^^^
                                                 Typo !

-- 
Thomas Petazzoni - thomas.petazzoni@enix.org
http://{thomas,kos,sos}.enix.org

Re: [PATCH 01/11] RTC subsystem, class

[Paul Mundt]

[-- Attachment #1: Type: text/plain, Size: 548 bytes --]

On Mon, Feb 13, 2006 at 11:54:17PM +0100, Alessandro Zummo wrote:
> --- linux-rtc.orig/drivers/Makefile	2006-02-13 19:34:35.000000000 +0100
> +++ linux-rtc/drivers/Makefile	2006-02-13 19:35:30.000000000 +0100
> @@ -56,6 +56,7 @@ obj-$(CONFIG_USB_GADGET)	+= usb/gadget/
>  obj-$(CONFIG_GAMEPORT)		+= input/gameport/
>  obj-$(CONFIG_INPUT)		+= input/
>  obj-$(CONFIG_I2O)		+= message/
> +obj-y				+= rtc/
>  obj-$(CONFIG_I2C)		+= i2c/
>  obj-$(CONFIG_W1)		+= w1/
>  obj-$(CONFIG_HWMON)		+= hwmon/

Why is this obj-y? obj-$(CONFIG_RTC_CLASS) perhaps?

[-- Attachment #2: Type: application/pgp-signature, Size: 189 bytes --]

Re: [PATCH 01/11] RTC subsystem, class

[Alessandro Zummo]

On Tue, 14 Feb 2006 11:02:53 +0200
Paul Mundt <lethal@linux-sh.org> wrote:

> On Mon, Feb 13, 2006 at 11:54:17PM +0100, Alessandro Zummo wrote:
> > --- linux-rtc.orig/drivers/Makefile	2006-02-13 19:34:35.000000000 +0100
> > +++ linux-rtc/drivers/Makefile	2006-02-13 19:35:30.000000000 +0100
> > @@ -56,6 +56,7 @@ obj-$(CONFIG_USB_GADGET)	+= usb/gadget/
> >  obj-$(CONFIG_GAMEPORT)		+= input/gameport/
> >  obj-$(CONFIG_INPUT)		+= input/
> >  obj-$(CONFIG_I2O)		+= message/
> > +obj-y				+= rtc/
> >  obj-$(CONFIG_I2C)		+= i2c/
> >  obj-$(CONFIG_W1)		+= w1/
> >  obj-$(CONFIG_HWMON)		+= hwmon/
> 
> Why is this obj-y? obj-$(CONFIG_RTC_CLASS) perhaps?

 there are a couple of primitives that are used
 in different places in the kernel, even when rtc class
 is not in use. mostly time struture conversion
 and validation.

-- 

 Best regards,

 Alessandro Zummo,
  Tower Technologies - Turin, Italy

  http://www.towertech.it

Re: [PATCH 01/11] RTC subsystem, class

[Alessandro Zummo]

On Mon, 13 Feb 2006 22:49:12 -0500
Dmitry Torokhov <dtor_core@ameritech.net> wrote:

> On Monday 13 February 2006 17:54, Alessandro Zummo wrote:
> > +
> > +struct rtc_device
> > +{
> > +	int id;
> > +	struct module *owner;
> > +	struct class_device class_dev;
> > +	struct semaphore ops_lock;
> 
> Alessandro,
> 
> I believe we are moving from struct semaphore to mutex whenever possible.
> It would be nice if new code used new primitives.

 will convert, thanks.
-- 

 Best regards,

 Alessandro Zummo,
  Tower Technologies - Turin, Italy

  http://www.towertech.it

[PATCH 01/11] RTC subsystem, class

[Alessandro Zummo]

[-- Attachment #1: rtc-class.patch --]
[-- Type: text/plain, Size: 21529 bytes --]

This patch adds the basic RTC subsytem infrastructure
to the kernel.

rtc/class.c - registration facilities for RTC drivers
rtc/interface.c - kernel/rtc interface functions 
rtc/utils.c - misc rtc-related utility functions
rtc/hctosys.c - snippet of code that copies hw clock to sw clock
		at bootup, if configured to do so.

Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
--
 drivers/Kconfig         |    2 
 drivers/Makefile        |    1 
 drivers/rtc/Kconfig     |   42 +++++++
 drivers/rtc/Makefile    |    9 +
 drivers/rtc/class.c     |  143 +++++++++++++++++++++++++
 drivers/rtc/hctosys.c   |   67 +++++++++++
 drivers/rtc/interface.c |  274 ++++++++++++++++++++++++++++++++++++++++++++++++
 drivers/rtc/utils.c     |   97 ++++++++++++++++
 include/linux/rtc.h     |   89 +++++++++++++++
 9 files changed, 724 insertions(+)

--- linux-rtc.orig/include/linux/rtc.h	2006-02-15 03:24:36.000000000 +0100
+++ linux-rtc/include/linux/rtc.h	2006-02-15 04:13:58.000000000 +0100
@@ -93,8 +93,97 @@ struct rtc_pll_info {
 #define RTC_PLL_GET	_IOR('p', 0x11, struct rtc_pll_info)  /* Get PLL correction */
 #define RTC_PLL_SET	_IOW('p', 0x12, struct rtc_pll_info)  /* Set PLL correction */
 
+/* interrupt flags */
+#define RTC_IRQF 0x80 /* any of the following is active */
+#define RTC_PF 0x40
+#define RTC_AF 0x20
+#define RTC_UF 0x10
+
 #ifdef __KERNEL__
 
+#include <linux/device.h>
+#include <linux/seq_file.h>
+#include <linux/cdev.h>
+#include <linux/poll.h>
+#include <linux/mutex.h>
+
+struct rtc_class_ops {
+	int (*open)(struct device *);
+	void (*release)(struct device *);
+	int (*ioctl)(struct device *, unsigned int, unsigned long);
+	int (*read_time)(struct device *, struct rtc_time *);
+	int (*set_time)(struct device *, struct rtc_time *);
+	int (*read_alarm)(struct device *, struct rtc_wkalrm *);
+	int (*set_alarm)(struct device *, struct rtc_wkalrm *);
+	int (*proc)(struct device *, struct seq_file *);
+	int (*set_mmss)(struct device *, unsigned long secs);
+	int (*irq_set_state)(struct device *, int enabled);
+	int (*irq_set_freq)(struct device *, int freq);
+	int (*read_callback)(struct device *, int data);
+};
+
+#define RTC_DEVICE_NAME_SIZE 20
+struct rtc_task;
+
+struct rtc_device
+{
+	struct class_device class_dev;
+	struct module *owner;
+
+	int id;
+	char name[RTC_DEVICE_NAME_SIZE];
+
+	struct rtc_class_ops *ops;
+	struct mutex ops_lock;
+
+	struct cdev char_dev;
+	struct mutex char_lock;
+
+	unsigned long irq_data;
+	spinlock_t irq_lock;
+	wait_queue_head_t irq_queue;
+	struct fasync_struct *async_queue;
+
+	struct rtc_task *irq_task;
+	spinlock_t irq_task_lock;
+	int irq_freq;
+};
+#define to_rtc_device(d) container_of(d, struct rtc_device, class_dev)
+
+extern struct rtc_device *rtc_device_register(const char *name,
+					struct device *dev,
+					struct rtc_class_ops *ops,
+					struct module *owner);
+extern void rtc_device_unregister(struct rtc_device *rdev);
+extern int rtc_interface_register(struct class_interface *intf);
+
+extern int rtc_month_days(unsigned int month, unsigned int year);
+extern int rtc_valid_tm(struct rtc_time *tm);
+extern int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time);
+extern void rtc_time_to_tm(unsigned long time, struct rtc_time *tm);
+
+extern int rtc_read_time(struct class_device *class_dev, struct rtc_time *tm);
+extern int rtc_set_time(struct class_device *class_dev, struct rtc_time *tm);
+extern int rtc_set_mmss(struct class_device *class_dev, unsigned long secs);
+extern int rtc_read_alarm(struct class_device *class_dev,
+			struct rtc_wkalrm *alrm);
+extern int rtc_set_alarm(struct class_device *class_dev,
+				struct rtc_wkalrm *alrm);
+extern void rtc_update_irq(struct class_device *class_dev,
+			unsigned long num, unsigned long events);
+
+extern struct class_device *rtc_class_open(char *name);
+extern void rtc_class_close(struct class_device *class_dev);
+
+extern int rtc_irq_register(struct class_device *class_dev,
+				struct rtc_task *task);
+extern void rtc_irq_unregister(struct class_device *class_dev,
+				struct rtc_task *task);
+extern int rtc_irq_set_state(struct class_device *class_dev,
+				struct rtc_task *task, int enabled);
+extern int rtc_irq_set_freq(struct class_device *class_dev,
+				struct rtc_task *task, int freq);
+
 typedef struct rtc_task {
 	void (*func)(void *private_data);
 	void *private_data;
--- linux-rtc.orig/drivers/Kconfig	2006-02-15 03:24:36.000000000 +0100
+++ linux-rtc/drivers/Kconfig	2006-02-15 03:24:47.000000000 +0100
@@ -70,4 +70,6 @@ source "drivers/sn/Kconfig"
 
 source "drivers/edac/Kconfig"
 
+source "drivers/rtc/Kconfig"
+
 endmenu
--- linux-rtc.orig/drivers/Makefile	2006-02-15 03:24:36.000000000 +0100
+++ linux-rtc/drivers/Makefile	2006-02-15 03:24:47.000000000 +0100
@@ -56,6 +56,7 @@ obj-$(CONFIG_USB_GADGET)	+= usb/gadget/
 obj-$(CONFIG_GAMEPORT)		+= input/gameport/
 obj-$(CONFIG_INPUT)		+= input/
 obj-$(CONFIG_I2O)		+= message/
+obj-y				+= rtc/
 obj-$(CONFIG_I2C)		+= i2c/
 obj-$(CONFIG_W1)		+= w1/
 obj-$(CONFIG_HWMON)		+= hwmon/
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-rtc/drivers/rtc/class.c	2006-02-15 03:25:54.000000000 +0100
@@ -0,0 +1,143 @@
+/*
+ * 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 as published by
+ * the Free Software Foundation; version 2 of the License.
+*/
+
+#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;
+
+	if ((rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL)) == 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);
+
+	if ((err = class_device_register(&rtc->class_dev)))
+		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");
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-rtc/drivers/rtc/Kconfig	2006-02-19 23:33:06.000000000 +0100
@@ -0,0 +1,42 @@
+#
+# RTC class/drivers configuration
+#
+
+menu "Real Time Clock"
+
+config RTC_CLASS
+	tristate "RTC class"
+	depends on EXPERIMENTAL
+	default y
+	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
+
+comment "RTC drivers"
+	depends on RTC_CLASS
+
+endmenu
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-rtc/drivers/rtc/Makefile	2006-02-19 23:33:06.000000000 +0100
@@ -0,0 +1,9 @@
+#
+# Makefile for RTC class/drivers.
+#
+
+obj-y				+= utils.o
+obj-$(CONFIG_RTC_HCTOSYS)	+= hctosys.o
+obj-$(CONFIG_RTC_CLASS)		+= rtc-core.o
+rtc-core-y			:= class.o interface.o
+
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-rtc/drivers/rtc/interface.c	2006-02-15 04:13:37.000000000 +0100
@@ -0,0 +1,274 @@
+/*
+ * 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 as published by
+ * the Free Software Foundation; version 2 of the License.
+*/
+
+#include <linux/rtc.h>
+
+extern struct class *rtc_class;
+
+int rtc_read_time(struct class_device *class_dev, struct rtc_time *tm)
+{
+	int err;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	if ((err = mutex_lock_interruptible(&rtc->ops_lock)))
+		return err;
+
+	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(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);
+
+	if ((err = rtc_valid_tm(tm)) != 0)
+		return err;
+
+	if ((err = mutex_lock_interruptible(&rtc->ops_lock)))
+		return err;
+
+	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(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);
+
+	if ((err = mutex_lock_interruptible(&rtc->ops_lock)))
+		return err;
+
+	if (!rtc->ops)
+		err = -ENODEV;
+	else if (!rtc->ops->set_mmss) {
+		if (rtc->ops->read_time && rtc->ops->set_time) {
+		        struct rtc_time new, old;
+
+		        new.tm_sec  = secs % 60;
+		        secs /= 60;
+		        new.tm_min  = secs % 60;
+		        secs /= 60;
+		        new.tm_hour = secs % 24;
+
+		       /*
+		        * 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;
+	}
+	else
+		err = rtc->ops->set_mmss(class_dev->dev, secs);
+
+	mutex_unlock(&rtc->ops_lock);
+
+	return err;
+}
+EXPORT_SYMBOL(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);
+
+	if ((err = mutex_lock_interruptible(&rtc->ops_lock)))
+		return err;
+
+	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(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);
+
+	if ((err = mutex_lock_interruptible(&rtc->ops_lock)))
+		return err;
+
+	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(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(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(rtc_class_open);
+
+void rtc_class_close(struct class_device *class_dev)
+{
+	module_put(to_rtc_device(class_dev)->owner);
+}
+EXPORT_SYMBOL(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(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(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(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;
+
+/*	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) {
+		if ((err = rtc->ops->irq_set_freq(class_dev->dev, freq)) == 0)
+			rtc->irq_freq = freq;
+	}
+	return err;
+
+}
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-rtc/drivers/rtc/utils.c	2006-02-15 03:24:47.000000000 +0100
@@ -0,0 +1,97 @@
+/*
+ * RTC subsystem, utility 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 as published by
+ * the Free Software Foundation; version 2 of the License.
+*/
+
+#include <linux/rtc.h>
+
+static const unsigned char rtc_days_in_month[] = {
+	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+};
+
+#define LEAPS_THRU_END_OF(y) ((y)/4 - (y)/100 + (y)/400)
+#define LEAP_YEAR(year) ((!(year % 4) && (year % 100)) || !(year % 400))
+
+int rtc_month_days(unsigned int month, unsigned int year)
+{
+	return rtc_days_in_month[month] + (LEAP_YEAR(year) && month == 1);
+}
+EXPORT_SYMBOL(rtc_month_days);
+
+/*
+ * Convert seconds since 01-01-1970 00:00:00 to Gregorian date.
+ */
+void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
+{
+	int days, month, year;
+
+	days = time / 86400;
+	time -= days * 86400;
+
+	tm->tm_wday = (days + 4) % 7;
+
+	year = 1970 + days / 365;
+	days -= (year - 1970) * 365
+	        + LEAPS_THRU_END_OF(year - 1)
+	        - LEAPS_THRU_END_OF(1970 - 1);
+	if (days < 0) {
+		year -= 1;
+		days += 365 + LEAP_YEAR(year);
+	}
+	tm->tm_year = year - 1900;
+	tm->tm_yday = days + 1;
+
+	for (month = 0; month < 11; month++) {
+		int newdays;
+
+		newdays = days - rtc_month_days(month, year);
+		if (newdays < 0)
+			break;
+		days = newdays;
+	}
+	tm->tm_mon = month;
+	tm->tm_mday = days + 1;
+
+	tm->tm_hour = time / 3600;
+	time -= tm->tm_hour * 3600;
+	tm->tm_min = time / 60;
+	tm->tm_sec = time - tm->tm_min * 60;
+}
+EXPORT_SYMBOL(rtc_time_to_tm);
+
+/*
+ * Does the rtc_time represent a valid date/time?
+ */
+int rtc_valid_tm(struct rtc_time *tm)
+{
+	if (tm->tm_year < 70 ||
+	    tm->tm_mon >= 12 ||
+	    tm->tm_mday < 1 ||
+	    tm->tm_mday > rtc_month_days(tm->tm_mon, tm->tm_year + 1900) ||
+	    tm->tm_hour >= 24 ||
+	    tm->tm_min >= 60 ||
+	    tm->tm_sec >= 60)
+		return -EINVAL;
+
+	return 0;
+}
+EXPORT_SYMBOL(rtc_valid_tm);
+
+/*
+ * Convert Gregorian date to seconds since 01-01-1970 00:00:00.
+ */
+int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time)
+{
+	*time = mktime(tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
+		       tm->tm_hour, tm->tm_min, tm->tm_sec);
+	return 0;
+}
+EXPORT_SYMBOL(rtc_tm_to_time);
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-rtc/drivers/rtc/hctosys.c	2006-02-15 03:24:47.000000000 +0100
@@ -0,0 +1,67 @@
+/*
+ * 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 as published by
+ * the Free Software Foundation; version 2 of the License.
+*/
+
+#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;
+	}
+
+	if ((err = rtc_read_time(class_dev, &tm)) == 0) {
+		if (rtc_valid_tm(&tm)) {
+			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);

--

Re: [PATCH 01/11] RTC subsystem, class

[Andrew Morton]

Alessandro Zummo <a.zummo@towertech.it> wrote:
>
> This patch adds the basic RTC subsytem infrastructure
> to the kernel.
> 
> rtc/class.c - registration facilities for RTC drivers
> rtc/interface.c - kernel/rtc interface functions 
> rtc/utils.c - misc rtc-related utility functions
> rtc/hctosys.c - snippet of code that copies hw clock to sw clock
> 		at bootup, if configured to do so.

Couple of questions.

a) Is all this code 100% compatible with existing kernel interfaces?  No
   userspace-visible breakage?  Right down the all the same -EFOO return
   codes for all the same errors?

b) Will the kernel compile and run at each stage of your patch series? 
   I hit a nasty no-compile half an hour through a git-bisect session
   yesterday and it's still smarting.

Code looks nice and clean.

> +	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);

Oh the IDR API does suck.  Not your fault though.

> +	if ((rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL)) == NULL) {

You do a lot of

	if ((lhs = rhs) == something)

But preferred kernel style is

	lhs = rhs;
	if (lhs == something)

Generally, kernel style is to keep things as utterly simple as they can be.

+config RTC_CLASS
> +	tristate "RTC class"
> +	depends on EXPERIMENTAL
> +	default y
> +	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.

hm.  Doesn't the above disable RTC_HCTOSYS and RTC_HCTOSYS_DEVICE if
RTC_CLASS=m?

> --- /dev/null	1970-01-01 00:00:00.000000000 +0000
> +++ linux-rtc/drivers/rtc/interface.c	2006-02-15 04:13:37.000000000 +0100
> @@ -0,0 +1,274 @@
> +/*
> + * 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 as published by
> + * the Free Software Foundation; version 2 of the License.
> +*/
> +
> +#include <linux/rtc.h>
> +
> +extern struct class *rtc_class;

Please always put extern declarations in a header file.

> +}
> +EXPORT_SYMBOL(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(rtc_update_irq);

I don't know what this does.

Please document all non-static functions.  Preferably with kernel-doc
format.  Feel free to document static functions too..

> +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;
> +
> +/*	if ((freq > rtc_max_user_freq) && (!capable(CAP_SYS_RESOURCE)))
> +		return -EACCES;
> +*/

What happened to rtc_max_user_freq?

Re: [PATCH 01/11] RTC subsystem, class

[Alessandro Zummo]

On Wed, 22 Feb 2006 14:15:54 -0800
Andrew Morton <akpm@osdl.org> wrote:

> Couple of questions.
> 
> a) Is all this code 100% compatible with existing kernel interfaces?  No
>    userspace-visible breakage?  Right down the all the same -EFOO return
>    codes for all the same errors?

 this new class works only in places of the kernel were there were no
 RTCs before.. basically, I haven't touched the x86 or any other platform clock
 and focused only on i2c clocks which were actually not used.

 From the userspace point of view, the interface is the same. I noticed
 that hwclock does not like things like time that is not changing or
 an -EINVAL on a read, which can instead happen when you use
 i2c clocks. However, that is not an issue yet because hwclock has
 not been used on those i2c clocks until now. 

> 
> b) Will the kernel compile and run at each stage of your patch series? 
>    I hit a nasty no-compile half an hour through a git-bisect session
>    yesterday and it's still smarting.

 I' haven't tested it.. I think there may be problems because at some
 points some functions in the kernel needs to be renamed and/or
 changed.. i would say the first two patches should be applied
 together. 

> Code looks nice and clean.

 thanks.

> > +	if ((rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL)) == NULL) {
> 
> You do a lot of
> 
> 	if ((lhs = rhs) == something)
> 
> But preferred kernel style is
> 
> 	lhs = rhs;
> 	if (lhs == something)

 good to know, that is also my preferred style. I will happily change
 this, I just thought the kernel style was the other one :)


> Generally, kernel style is to keep things as utterly simple as they can be.

[..]

> > +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.
> 
> hm.  Doesn't the above disable RTC_HCTOSYS and RTC_HCTOSYS_DEVICE if
> RTC_CLASS=m?

 yes. I can't remember if it is intended, but the point of having
 hctosys was to copy the time early in the bootup process.

> > +
> > +extern struct class *rtc_class;
> 
> Please always put extern declarations in a header file.

 ack.

> > +EXPORT_SYMBOL(rtc_update_irq);
> 
> I don't know what this does.
> 
> Please document all non-static functions.  Preferably with kernel-doc
> format.  Feel free to document static functions too..

 will do.

> > +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;
> > +
> > +/*	if ((freq > rtc_max_user_freq) && (!capable(CAP_SYS_RESOURCE)))
> > +		return -EACCES;
> > +*/
> 
> What happened to rtc_max_user_freq?

 not implemented yet, I need to handle it in a different way. rtc_irq_set_freq
 is the kernel interface, I must move this check in the /dev/rtc code.

 How can I handle further updates, just repost the whole patchset
 to lkml ?

 thanks for you review!

-- 

 Best regards,

 Alessandro Zummo,
  Tower Technologies - Turin, Italy

  http://www.towertech.it

Re: [PATCH 01/11] RTC subsystem, class

[Andrew Morton]

Alessandro Zummo <alessandro.zummo@towertech.it> wrote:
>
>   How can I handle further updates, just repost the whole patchset
>   to lkml ?

Yes, that would be best.  Once the patches are settled down I prefer
incremental updates so we can see what changed, but at this stage in
proceedings a wholesale replacement is OK.

It would be good if you can arrange it so there are no build-breaks
anywhere in the series.