289 lines
6.8 KiB
C
289 lines
6.8 KiB
C
/*
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* An RTC driver for the AVR32 AT32AP700x processor series.
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*
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* Copyright (C) 2007 Atmel Corporation
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published
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* by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/rtc.h>
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#include <linux/io.h>
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/*
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* This is a bare-bones RTC. It runs during most system sleep states, but has
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* no battery backup and gets reset during system restart. It must be
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* initialized from an external clock (network, I2C, etc) before it can be of
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* much use.
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*
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* The alarm functionality is limited by the hardware, not supporting
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* periodic interrupts.
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*/
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#define RTC_CTRL 0x00
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#define RTC_CTRL_EN 0
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#define RTC_CTRL_PCLR 1
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#define RTC_CTRL_TOPEN 2
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#define RTC_CTRL_PSEL 8
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#define RTC_VAL 0x04
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#define RTC_TOP 0x08
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#define RTC_IER 0x10
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#define RTC_IER_TOPI 0
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#define RTC_IDR 0x14
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#define RTC_IDR_TOPI 0
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#define RTC_IMR 0x18
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#define RTC_IMR_TOPI 0
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#define RTC_ISR 0x1c
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#define RTC_ISR_TOPI 0
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#define RTC_ICR 0x20
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#define RTC_ICR_TOPI 0
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#define RTC_BIT(name) (1 << RTC_##name)
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#define RTC_BF(name, value) ((value) << RTC_##name)
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#define rtc_readl(dev, reg) \
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__raw_readl((dev)->regs + RTC_##reg)
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#define rtc_writel(dev, reg, value) \
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__raw_writel((value), (dev)->regs + RTC_##reg)
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struct rtc_at32ap700x {
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struct rtc_device *rtc;
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void __iomem *regs;
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unsigned long alarm_time;
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unsigned long irq;
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/* Protect against concurrent register access. */
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spinlock_t lock;
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};
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static int at32_rtc_readtime(struct device *dev, struct rtc_time *tm)
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{
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struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
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unsigned long now;
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now = rtc_readl(rtc, VAL);
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rtc_time_to_tm(now, tm);
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return 0;
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}
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static int at32_rtc_settime(struct device *dev, struct rtc_time *tm)
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{
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struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
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unsigned long now;
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int ret;
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ret = rtc_tm_to_time(tm, &now);
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if (ret == 0)
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rtc_writel(rtc, VAL, now);
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return ret;
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}
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static int at32_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
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{
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struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
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spin_lock_irq(&rtc->lock);
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rtc_time_to_tm(rtc->alarm_time, &alrm->time);
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alrm->enabled = rtc_readl(rtc, IMR) & RTC_BIT(IMR_TOPI) ? 1 : 0;
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alrm->pending = rtc_readl(rtc, ISR) & RTC_BIT(ISR_TOPI) ? 1 : 0;
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spin_unlock_irq(&rtc->lock);
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return 0;
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}
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static int at32_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
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{
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struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
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unsigned long rtc_unix_time;
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unsigned long alarm_unix_time;
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int ret;
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rtc_unix_time = rtc_readl(rtc, VAL);
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ret = rtc_tm_to_time(&alrm->time, &alarm_unix_time);
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if (ret)
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return ret;
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if (alarm_unix_time < rtc_unix_time)
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return -EINVAL;
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spin_lock_irq(&rtc->lock);
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rtc->alarm_time = alarm_unix_time;
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rtc_writel(rtc, TOP, rtc->alarm_time);
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if (alrm->enabled)
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rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
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| RTC_BIT(CTRL_TOPEN));
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else
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rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
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& ~RTC_BIT(CTRL_TOPEN));
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spin_unlock_irq(&rtc->lock);
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return ret;
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}
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static int at32_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
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{
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struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
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int ret = 0;
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spin_lock_irq(&rtc->lock);
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if (enabled) {
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if (rtc_readl(rtc, VAL) > rtc->alarm_time) {
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ret = -EINVAL;
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goto out;
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}
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rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
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| RTC_BIT(CTRL_TOPEN));
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rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
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rtc_writel(rtc, IER, RTC_BIT(IER_TOPI));
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} else {
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rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
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& ~RTC_BIT(CTRL_TOPEN));
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rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
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rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
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}
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out:
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spin_unlock_irq(&rtc->lock);
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return ret;
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}
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static irqreturn_t at32_rtc_interrupt(int irq, void *dev_id)
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{
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struct rtc_at32ap700x *rtc = (struct rtc_at32ap700x *)dev_id;
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unsigned long isr = rtc_readl(rtc, ISR);
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unsigned long events = 0;
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int ret = IRQ_NONE;
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spin_lock(&rtc->lock);
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if (isr & RTC_BIT(ISR_TOPI)) {
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rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
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rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
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rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
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& ~RTC_BIT(CTRL_TOPEN));
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rtc_writel(rtc, VAL, rtc->alarm_time);
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events = RTC_AF | RTC_IRQF;
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rtc_update_irq(rtc->rtc, 1, events);
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ret = IRQ_HANDLED;
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}
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spin_unlock(&rtc->lock);
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return ret;
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}
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static struct rtc_class_ops at32_rtc_ops = {
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.read_time = at32_rtc_readtime,
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.set_time = at32_rtc_settime,
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.read_alarm = at32_rtc_readalarm,
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.set_alarm = at32_rtc_setalarm,
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.alarm_irq_enable = at32_rtc_alarm_irq_enable,
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};
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static int __init at32_rtc_probe(struct platform_device *pdev)
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{
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struct resource *regs;
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struct rtc_at32ap700x *rtc;
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int irq;
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int ret;
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rtc = devm_kzalloc(&pdev->dev, sizeof(struct rtc_at32ap700x),
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GFP_KERNEL);
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if (!rtc)
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return -ENOMEM;
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regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!regs) {
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dev_dbg(&pdev->dev, "no mmio resource defined\n");
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return -ENXIO;
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}
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irq = platform_get_irq(pdev, 0);
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if (irq <= 0) {
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dev_dbg(&pdev->dev, "could not get irq\n");
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return -ENXIO;
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}
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rtc->irq = irq;
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rtc->regs = devm_ioremap(&pdev->dev, regs->start, resource_size(regs));
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if (!rtc->regs) {
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dev_dbg(&pdev->dev, "could not map I/O memory\n");
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return -ENOMEM;
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}
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spin_lock_init(&rtc->lock);
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/*
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* Maybe init RTC: count from zero at 1 Hz, disable wrap irq.
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*
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* Do not reset VAL register, as it can hold an old time
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* from last JTAG reset.
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*/
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if (!(rtc_readl(rtc, CTRL) & RTC_BIT(CTRL_EN))) {
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rtc_writel(rtc, CTRL, RTC_BIT(CTRL_PCLR));
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rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
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rtc_writel(rtc, CTRL, RTC_BF(CTRL_PSEL, 0xe)
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| RTC_BIT(CTRL_EN));
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}
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ret = devm_request_irq(&pdev->dev, irq, at32_rtc_interrupt, IRQF_SHARED,
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"rtc", rtc);
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if (ret) {
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dev_dbg(&pdev->dev, "could not request irq %d\n", irq);
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return ret;
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}
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platform_set_drvdata(pdev, rtc);
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rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
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&at32_rtc_ops, THIS_MODULE);
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if (IS_ERR(rtc->rtc)) {
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dev_dbg(&pdev->dev, "could not register rtc device\n");
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return PTR_ERR(rtc->rtc);
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}
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device_init_wakeup(&pdev->dev, 1);
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dev_info(&pdev->dev, "Atmel RTC for AT32AP700x at %08lx irq %ld\n",
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(unsigned long)rtc->regs, rtc->irq);
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return 0;
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}
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static int __exit at32_rtc_remove(struct platform_device *pdev)
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{
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device_init_wakeup(&pdev->dev, 0);
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return 0;
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}
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MODULE_ALIAS("platform:at32ap700x_rtc");
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static struct platform_driver at32_rtc_driver = {
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.remove = __exit_p(at32_rtc_remove),
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.driver = {
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.name = "at32ap700x_rtc",
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.owner = THIS_MODULE,
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},
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};
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module_platform_driver_probe(at32_rtc_driver, at32_rtc_probe);
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MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
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MODULE_DESCRIPTION("Real time clock for AVR32 AT32AP700x");
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MODULE_LICENSE("GPL");
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