291 строка
7.2 KiB
C
291 строка
7.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2007-2009 ST-Ericsson AB
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* Real Time Clock interface for ST-Ericsson AB COH 901 331 RTC.
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* Author: Linus Walleij <linus.walleij@stericsson.com>
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* Based on rtc-pl031.c by Deepak Saxena <dsaxena@plexity.net>
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* Copyright 2006 (c) MontaVista Software, Inc.
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mod_devicetable.h>
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#include <linux/rtc.h>
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#include <linux/clk.h>
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#include <linux/interrupt.h>
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#include <linux/pm.h>
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#include <linux/platform_device.h>
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#include <linux/io.h>
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#include <linux/slab.h>
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/*
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* Registers in the COH 901 331
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*/
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/* Alarm value 32bit (R/W) */
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#define COH901331_ALARM 0x00U
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/* Used to set current time 32bit (R/W) */
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#define COH901331_SET_TIME 0x04U
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/* Indication if current time is valid 32bit (R/-) */
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#define COH901331_VALID 0x08U
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/* Read the current time 32bit (R/-) */
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#define COH901331_CUR_TIME 0x0cU
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/* Event register for the "alarm" interrupt */
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#define COH901331_IRQ_EVENT 0x10U
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/* Mask register for the "alarm" interrupt */
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#define COH901331_IRQ_MASK 0x14U
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/* Force register for the "alarm" interrupt */
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#define COH901331_IRQ_FORCE 0x18U
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/*
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* Reference to RTC block clock
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* Notice that the frequent clk_enable()/clk_disable() on this
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* clock is mainly to be able to turn on/off other clocks in the
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* hierarchy as needed, the RTC clock is always on anyway.
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*/
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struct coh901331_port {
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struct rtc_device *rtc;
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struct clk *clk;
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void __iomem *virtbase;
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int irq;
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#ifdef CONFIG_PM_SLEEP
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u32 irqmaskstore;
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#endif
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};
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static irqreturn_t coh901331_interrupt(int irq, void *data)
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{
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struct coh901331_port *rtap = data;
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clk_enable(rtap->clk);
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/* Ack IRQ */
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writel(1, rtap->virtbase + COH901331_IRQ_EVENT);
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/*
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* Disable the interrupt. This is necessary because
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* the RTC lives on a lower-clocked line and will
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* not release the IRQ line until after a few (slower)
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* clock cycles. The interrupt will be re-enabled when
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* a new alarm is set anyway.
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*/
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writel(0, rtap->virtbase + COH901331_IRQ_MASK);
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clk_disable(rtap->clk);
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/* Set alarm flag */
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rtc_update_irq(rtap->rtc, 1, RTC_AF);
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return IRQ_HANDLED;
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}
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static int coh901331_read_time(struct device *dev, struct rtc_time *tm)
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{
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struct coh901331_port *rtap = dev_get_drvdata(dev);
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clk_enable(rtap->clk);
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/* Check if the time is valid */
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if (!readl(rtap->virtbase + COH901331_VALID)) {
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clk_disable(rtap->clk);
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return -EINVAL;
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}
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rtc_time64_to_tm(readl(rtap->virtbase + COH901331_CUR_TIME), tm);
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clk_disable(rtap->clk);
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return 0;
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}
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static int coh901331_set_time(struct device *dev, struct rtc_time *tm)
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{
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struct coh901331_port *rtap = dev_get_drvdata(dev);
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clk_enable(rtap->clk);
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writel(rtc_tm_to_time64(tm), rtap->virtbase + COH901331_SET_TIME);
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clk_disable(rtap->clk);
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return 0;
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}
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static int coh901331_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
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{
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struct coh901331_port *rtap = dev_get_drvdata(dev);
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clk_enable(rtap->clk);
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rtc_time64_to_tm(readl(rtap->virtbase + COH901331_ALARM), &alarm->time);
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alarm->pending = readl(rtap->virtbase + COH901331_IRQ_EVENT) & 1U;
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alarm->enabled = readl(rtap->virtbase + COH901331_IRQ_MASK) & 1U;
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clk_disable(rtap->clk);
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return 0;
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}
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static int coh901331_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
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{
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struct coh901331_port *rtap = dev_get_drvdata(dev);
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unsigned long time = rtc_tm_to_time64(&alarm->time);
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clk_enable(rtap->clk);
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writel(time, rtap->virtbase + COH901331_ALARM);
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writel(alarm->enabled, rtap->virtbase + COH901331_IRQ_MASK);
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clk_disable(rtap->clk);
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return 0;
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}
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static int coh901331_alarm_irq_enable(struct device *dev, unsigned int enabled)
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{
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struct coh901331_port *rtap = dev_get_drvdata(dev);
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clk_enable(rtap->clk);
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if (enabled)
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writel(1, rtap->virtbase + COH901331_IRQ_MASK);
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else
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writel(0, rtap->virtbase + COH901331_IRQ_MASK);
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clk_disable(rtap->clk);
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return 0;
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}
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static const struct rtc_class_ops coh901331_ops = {
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.read_time = coh901331_read_time,
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.set_time = coh901331_set_time,
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.read_alarm = coh901331_read_alarm,
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.set_alarm = coh901331_set_alarm,
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.alarm_irq_enable = coh901331_alarm_irq_enable,
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};
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static int __exit coh901331_remove(struct platform_device *pdev)
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{
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struct coh901331_port *rtap = platform_get_drvdata(pdev);
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if (rtap)
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clk_unprepare(rtap->clk);
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return 0;
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}
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static int __init coh901331_probe(struct platform_device *pdev)
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{
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int ret;
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struct coh901331_port *rtap;
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rtap = devm_kzalloc(&pdev->dev,
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sizeof(struct coh901331_port), GFP_KERNEL);
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if (!rtap)
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return -ENOMEM;
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rtap->virtbase = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(rtap->virtbase))
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return PTR_ERR(rtap->virtbase);
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rtap->irq = platform_get_irq(pdev, 0);
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if (devm_request_irq(&pdev->dev, rtap->irq, coh901331_interrupt, 0,
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"RTC COH 901 331 Alarm", rtap))
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return -EIO;
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rtap->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(rtap->clk)) {
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ret = PTR_ERR(rtap->clk);
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dev_err(&pdev->dev, "could not get clock\n");
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return ret;
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}
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rtap->rtc = devm_rtc_allocate_device(&pdev->dev);
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if (IS_ERR(rtap->rtc))
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return PTR_ERR(rtap->rtc);
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rtap->rtc->ops = &coh901331_ops;
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rtap->rtc->range_max = U32_MAX;
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/* We enable/disable the clock only to assure it works */
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ret = clk_prepare_enable(rtap->clk);
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if (ret) {
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dev_err(&pdev->dev, "could not enable clock\n");
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return ret;
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}
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clk_disable(rtap->clk);
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platform_set_drvdata(pdev, rtap);
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ret = rtc_register_device(rtap->rtc);
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if (ret)
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goto out_no_rtc;
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return 0;
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out_no_rtc:
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clk_unprepare(rtap->clk);
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return ret;
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}
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#ifdef CONFIG_PM_SLEEP
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static int coh901331_suspend(struct device *dev)
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{
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struct coh901331_port *rtap = dev_get_drvdata(dev);
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/*
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* If this RTC alarm will be used for waking the system up,
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* don't disable it of course. Else we just disable the alarm
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* and await suspension.
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*/
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if (device_may_wakeup(dev)) {
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enable_irq_wake(rtap->irq);
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} else {
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clk_enable(rtap->clk);
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rtap->irqmaskstore = readl(rtap->virtbase + COH901331_IRQ_MASK);
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writel(0, rtap->virtbase + COH901331_IRQ_MASK);
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clk_disable(rtap->clk);
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}
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clk_unprepare(rtap->clk);
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return 0;
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}
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static int coh901331_resume(struct device *dev)
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{
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int ret;
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struct coh901331_port *rtap = dev_get_drvdata(dev);
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ret = clk_prepare(rtap->clk);
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if (ret)
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return ret;
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if (device_may_wakeup(dev)) {
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disable_irq_wake(rtap->irq);
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} else {
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clk_enable(rtap->clk);
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writel(rtap->irqmaskstore, rtap->virtbase + COH901331_IRQ_MASK);
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clk_disable(rtap->clk);
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}
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return 0;
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}
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#endif
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static SIMPLE_DEV_PM_OPS(coh901331_pm_ops, coh901331_suspend, coh901331_resume);
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static void coh901331_shutdown(struct platform_device *pdev)
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{
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struct coh901331_port *rtap = platform_get_drvdata(pdev);
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clk_enable(rtap->clk);
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writel(0, rtap->virtbase + COH901331_IRQ_MASK);
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clk_disable_unprepare(rtap->clk);
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}
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static const struct of_device_id coh901331_dt_match[] = {
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{ .compatible = "stericsson,coh901331" },
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{},
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};
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MODULE_DEVICE_TABLE(of, coh901331_dt_match);
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static struct platform_driver coh901331_driver = {
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.driver = {
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.name = "rtc-coh901331",
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.pm = &coh901331_pm_ops,
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.of_match_table = coh901331_dt_match,
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},
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.remove = __exit_p(coh901331_remove),
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.shutdown = coh901331_shutdown,
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};
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module_platform_driver_probe(coh901331_driver, coh901331_probe);
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MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
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MODULE_DESCRIPTION("ST-Ericsson AB COH 901 331 RTC Driver");
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MODULE_LICENSE("GPL");
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