Add a simple rtc framework

This patch adds a simple rtc framework
for reading and setting board's RTC time.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

drivers/Kconfig

@@ -28,5 +28,6 @@ source "drivers/bus/Kconfig"
 source "drivers/regulator/Kconfig"
 source "drivers/reset/Kconfig"
 source "drivers/pci/Kconfig"
+source "drivers/rtc/Kconfig"
 
 endmenu

drivers/Makefile

@@ -27,3 +27,4 @@ obj-y += bus/
 obj-$(CONFIG_REGULATOR) += regulator/
 obj-$(CONFIG_RESET_CONTROLLER) += reset/
 obj-$(CONFIG_PCI) += pci/
+obj-y += rtc/

drivers/rtc/Kconfig

@@ -0,0 +1,15 @@
+#
+# RTC class/drivers configuration
+#
+
+config RTC_LIB
+	bool
+
+menuconfig RTC_CLASS
+	bool "Real Time Clock"
+	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 or more of the interfaces below.

drivers/rtc/Makefile

@@ -0,0 +1,6 @@
+#
+# Makefile for RTC class/drivers.
+#
+
+obj-$(CONFIG_RTC_LIB)           += rtc-lib.o
+obj-$(CONFIG_RTC_CLASS)         += class.o

drivers/rtc/class.c

@@ -0,0 +1,70 @@
+/*
+ * RTC barebox subsystem, base class
+ *
+ * Copyright (C) 2014 Antony Pavlov <antonynpavlov@gmail.com>
+ *
+ * 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; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/err.h>
+#include <rtc.h>
+#include <linux/rtc.h>
+
+LIST_HEAD(rtc_list);
+EXPORT_SYMBOL(rtc_list);
+
+struct rtc_device *rtc_lookup(const char *name)
+{
+	struct rtc_device *r;
+
+	if (!name)
+		return ERR_PTR(-ENODEV);
+
+	list_for_each_entry(r, &rtc_list, list) {
+		if (!strcmp(dev_name(&r->class_dev), name))
+			return r;
+	}
+
+	return ERR_PTR(-ENODEV);
+}
+EXPORT_SYMBOL(rtc_lookup);
+
+int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
+{
+	return rtc->ops->read_time(rtc, tm);
+}
+EXPORT_SYMBOL(rtc_read_time);
+
+int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
+{
+	return rtc->ops->set_time(rtc, tm);
+}
+EXPORT_SYMBOL(rtc_set_time);
+
+int rtc_register(struct rtc_device *rtcdev)
+{
+	struct device_d *dev = &rtcdev->class_dev;
+
+	if (!rtcdev->ops)
+		return -EINVAL;
+
+	dev->id = DEVICE_ID_DYNAMIC;
+	strcpy(dev->name, "rtc");
+	if (rtcdev->dev)
+		dev->parent = rtcdev->dev;
+	platform_device_register(dev);
+
+	list_add_tail(&rtcdev->list, &rtc_list);
+
+	return 0;
+}
+EXPORT_SYMBOL(rtc_register);

drivers/rtc/rtc-lib.c

@@ -0,0 +1,68 @@
+/*
+ * rtc and date/time utility functions
+ *
+ * This code was ported from linux-3.15 kernel by Antony Pavlov.
+ *
+ * Copyright (C) 2005-06 Tower Technologies
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * based on arch/arm/common/rtctime.c and other bits
+ *
+ * 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 <rtc.h>
+#include <linux/rtc.h>
+
+static const unsigned char rtc_days_in_month[] = {
+	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+};
+
+static const unsigned short rtc_ydays[2][13] = {
+	/* Normal years */
+	{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
+	/* Leap years */
+	{ 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
+};
+
+#define LEAPS_THRU_END_OF(y) ((y)/4 - (y)/100 + (y)/400)
+
+/*
+ * The number of days in the month.
+ */
+int rtc_month_days(unsigned int month, unsigned int year)
+{
+	return rtc_days_in_month[month] + (is_leap_year(year) && month == 1);
+}
+EXPORT_SYMBOL(rtc_month_days);
+
+/*
+ * Does the rtc_time represent a valid date/time?
+ */
+int rtc_valid_tm(struct rtc_time *tm)
+{
+	if (tm->tm_year < 70
+		|| ((unsigned)tm->tm_mon) >= 12
+		|| tm->tm_mday < 1
+		|| tm->tm_mday > rtc_month_days(tm->tm_mon, tm->tm_year + 1900)
+		|| ((unsigned)tm->tm_hour) >= 24
+		|| ((unsigned)tm->tm_min) >= 60
+		|| ((unsigned)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);

include/linux/rtc.h

@@ -0,0 +1,46 @@
+/*
+ * Generic RTC interface.
+ * This version contains the part of the user interface to the Real Time Clock
+ * service. It is used with both the legacy mc146818 and also  EFI
+ * Struct rtc_time and first 12 ioctl by Paul Gortmaker, 1996 - separated out
+ * from <linux/mc146818rtc.h> to this file for 2.4 kernels.
+ *
+ * Copyright (C) 1999 Hewlett-Packard Co.
+ * Copyright (C) 1999 Stephane Eranian <eranian@hpl.hp.com>
+ */
+#ifndef _LINUX_RTC_H_
+#define _LINUX_RTC_H_
+
+#include <common.h>
+#include <linux/types.h>
+
+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);
+
+struct rtc_class_ops;
+
+struct rtc_device {
+	struct device_d *dev;
+	struct device_d class_dev;
+	struct list_head list;
+
+	const struct rtc_class_ops *ops;
+};
+
+struct rtc_class_ops {
+	int (*read_time)(struct rtc_device *, struct rtc_time *);
+	int (*set_time)(struct rtc_device *, struct rtc_time *);
+};
+
+extern int rtc_register(struct rtc_device *rtcdev);
+
+extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
+extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
+
+static inline bool is_leap_year(unsigned int year)
+{
+	return (!(year % 4) && (year % 100)) || !(year % 400);
+}
+
+#endif /* _LINUX_RTC_H_ */

include/rtc.h

@@ -53,4 +53,6 @@ void to_tm (int, struct rtc_time *);
 unsigned long mktime (unsigned int, unsigned int, unsigned int,
 		      unsigned int, unsigned int, unsigned int);
 
+extern struct rtc_device *rtc_lookup(const char *name);
+
 #endif	/* _RTC_H_ */