/*
* RTC class driver for "CMOS RTC": PCs, ACPI, etc
*
* Copyright (C) 1996 Paul Gortmaker (drivers/char/rtc.c)
* Copyright (C) 2006 David Brownell (convert to new framework)
*
* 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.
*/
/*
* The original "cmos clock" chip was an MC146818 chip, now obsolete.
* That defined the register interface now provided by all PCs, some
* non-PC systems, and incorporated into ACPI. Modern PC chipsets
* integrate an MC146818 clone in their southbridge, and boards use
* that instead of discrete clones like the DS12887 or M48T86. There
* are also clones that connect using the LPC bus.
*
* That register API is also used directly by various other drivers
* (notably for integrated NVRAM), infrastructure (x86 has code to
* bypass the RTC framework, directly reading the RTC during boot
* and updating minutes/seconds for systems using NTP synch) and
* utilities (like userspace 'hwclock', if no /dev node exists).
*
* So **ALL** calls to CMOS_READ and CMOS_WRITE must be done with
* interrupts disabled, holding the global rtc_lock, to exclude those
* other drivers and utilities on correctly configured systems.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/platform_device.h>
#include <linux/log2.h>
#include <linux/pm.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#ifdef CONFIG_X86
#include <asm/i8259.h>
#include <asm/processor.h>
#include <linux/dmi.h>
#endif
/* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
#include <linux/mc146818rtc.h>
#ifdef CONFIG_ACPI
/*
* Use ACPI SCI to replace HPET interrupt for RTC Alarm event
*
* If cleared, ACPI SCI is only used to wake up the system from suspend
*
* If set, ACPI SCI is used to handle UIE/AIE and system wakeup
*/
static
