279 lines
6.8 KiB
C
279 lines
6.8 KiB
C
/*
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* APM X-Gene SoC Real Time Clock Driver
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*
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* Copyright (c) 2014, Applied Micro Circuits Corporation
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* Author: Rameshwar Prasad Sahu <rsahu@apm.com>
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* Loc Ho <lho@apm.com>
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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 as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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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/of.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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#include <linux/clk.h>
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#include <linux/delay.h>
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#include <linux/rtc.h>
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/* RTC CSR Registers */
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#define RTC_CCVR 0x00
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#define RTC_CMR 0x04
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#define RTC_CLR 0x08
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#define RTC_CCR 0x0C
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#define RTC_CCR_IE BIT(0)
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#define RTC_CCR_MASK BIT(1)
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#define RTC_CCR_EN BIT(2)
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#define RTC_CCR_WEN BIT(3)
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#define RTC_STAT 0x10
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#define RTC_STAT_BIT BIT(0)
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#define RTC_RSTAT 0x14
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#define RTC_EOI 0x18
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#define RTC_VER 0x1C
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struct xgene_rtc_dev {
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struct rtc_device *rtc;
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struct device *dev;
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unsigned long alarm_time;
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void __iomem *csr_base;
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struct clk *clk;
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unsigned int irq_wake;
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};
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static int xgene_rtc_read_time(struct device *dev, struct rtc_time *tm)
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{
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struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
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rtc_time_to_tm(readl(pdata->csr_base + RTC_CCVR), tm);
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return rtc_valid_tm(tm);
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}
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static int xgene_rtc_set_mmss(struct device *dev, unsigned long secs)
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{
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struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
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/*
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* NOTE: After the following write, the RTC_CCVR is only reflected
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* after the update cycle of 1 seconds.
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*/
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writel((u32) secs, pdata->csr_base + RTC_CLR);
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readl(pdata->csr_base + RTC_CLR); /* Force a barrier */
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return 0;
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}
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static int xgene_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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{
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struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
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rtc_time_to_tm(pdata->alarm_time, &alrm->time);
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alrm->enabled = readl(pdata->csr_base + RTC_CCR) & RTC_CCR_IE;
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return 0;
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}
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static int xgene_rtc_alarm_irq_enable(struct device *dev, u32 enabled)
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{
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struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
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u32 ccr;
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ccr = readl(pdata->csr_base + RTC_CCR);
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if (enabled) {
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ccr &= ~RTC_CCR_MASK;
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ccr |= RTC_CCR_IE;
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} else {
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ccr &= ~RTC_CCR_IE;
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ccr |= RTC_CCR_MASK;
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}
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writel(ccr, pdata->csr_base + RTC_CCR);
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return 0;
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}
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static int xgene_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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{
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struct xgene_rtc_dev *pdata = dev_get_drvdata(dev);
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unsigned long rtc_time;
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unsigned long alarm_time;
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rtc_time = readl(pdata->csr_base + RTC_CCVR);
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rtc_tm_to_time(&alrm->time, &alarm_time);
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pdata->alarm_time = alarm_time;
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writel((u32) pdata->alarm_time, pdata->csr_base + RTC_CMR);
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xgene_rtc_alarm_irq_enable(dev, alrm->enabled);
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return 0;
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}
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static const struct rtc_class_ops xgene_rtc_ops = {
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.read_time = xgene_rtc_read_time,
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.set_mmss = xgene_rtc_set_mmss,
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.read_alarm = xgene_rtc_read_alarm,
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.set_alarm = xgene_rtc_set_alarm,
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.alarm_irq_enable = xgene_rtc_alarm_irq_enable,
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};
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static irqreturn_t xgene_rtc_interrupt(int irq, void *id)
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{
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struct xgene_rtc_dev *pdata = (struct xgene_rtc_dev *) id;
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/* Check if interrupt asserted */
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if (!(readl(pdata->csr_base + RTC_STAT) & RTC_STAT_BIT))
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return IRQ_NONE;
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/* Clear interrupt */
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readl(pdata->csr_base + RTC_EOI);
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rtc_update_irq(pdata->rtc, 1, RTC_IRQF | RTC_AF);
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return IRQ_HANDLED;
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}
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static int xgene_rtc_probe(struct platform_device *pdev)
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{
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struct xgene_rtc_dev *pdata;
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struct resource *res;
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int ret;
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int irq;
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pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
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if (!pdata)
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return -ENOMEM;
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platform_set_drvdata(pdev, pdata);
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pdata->dev = &pdev->dev;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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pdata->csr_base = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(pdata->csr_base))
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return PTR_ERR(pdata->csr_base);
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irq = platform_get_irq(pdev, 0);
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if (irq < 0) {
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dev_err(&pdev->dev, "No IRQ resource\n");
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return irq;
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}
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ret = devm_request_irq(&pdev->dev, irq, xgene_rtc_interrupt, 0,
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dev_name(&pdev->dev), pdata);
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if (ret) {
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dev_err(&pdev->dev, "Could not request IRQ\n");
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return ret;
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}
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pdata->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(pdata->clk)) {
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dev_err(&pdev->dev, "Couldn't get the clock for RTC\n");
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return -ENODEV;
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}
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clk_prepare_enable(pdata->clk);
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/* Turn on the clock and the crystal */
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writel(RTC_CCR_EN, pdata->csr_base + RTC_CCR);
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device_init_wakeup(&pdev->dev, 1);
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pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
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&xgene_rtc_ops, THIS_MODULE);
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if (IS_ERR(pdata->rtc)) {
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clk_disable_unprepare(pdata->clk);
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return PTR_ERR(pdata->rtc);
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}
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/* HW does not support update faster than 1 seconds */
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pdata->rtc->uie_unsupported = 1;
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return 0;
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}
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static int xgene_rtc_remove(struct platform_device *pdev)
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{
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struct xgene_rtc_dev *pdata = platform_get_drvdata(pdev);
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xgene_rtc_alarm_irq_enable(&pdev->dev, 0);
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device_init_wakeup(&pdev->dev, 0);
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clk_disable_unprepare(pdata->clk);
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return 0;
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}
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#ifdef CONFIG_PM_SLEEP
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static int xgene_rtc_suspend(struct device *dev)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct xgene_rtc_dev *pdata = platform_get_drvdata(pdev);
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int irq;
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irq = platform_get_irq(pdev, 0);
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if (device_may_wakeup(&pdev->dev)) {
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if (!enable_irq_wake(irq))
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pdata->irq_wake = 1;
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} else {
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xgene_rtc_alarm_irq_enable(dev, 0);
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clk_disable(pdata->clk);
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}
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return 0;
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}
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static int xgene_rtc_resume(struct device *dev)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct xgene_rtc_dev *pdata = platform_get_drvdata(pdev);
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int irq;
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irq = platform_get_irq(pdev, 0);
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if (device_may_wakeup(&pdev->dev)) {
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if (pdata->irq_wake) {
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disable_irq_wake(irq);
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pdata->irq_wake = 0;
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}
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} else {
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clk_enable(pdata->clk);
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xgene_rtc_alarm_irq_enable(dev, 1);
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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(xgene_rtc_pm_ops, xgene_rtc_suspend, xgene_rtc_resume);
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#ifdef CONFIG_OF
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static const struct of_device_id xgene_rtc_of_match[] = {
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{.compatible = "apm,xgene-rtc" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, xgene_rtc_of_match);
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#endif
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static struct platform_driver xgene_rtc_driver = {
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.probe = xgene_rtc_probe,
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.remove = xgene_rtc_remove,
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.driver = {
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.owner = THIS_MODULE,
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.name = "xgene-rtc",
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.pm = &xgene_rtc_pm_ops,
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.of_match_table = of_match_ptr(xgene_rtc_of_match),
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},
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};
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module_platform_driver(xgene_rtc_driver);
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MODULE_DESCRIPTION("APM X-Gene SoC RTC driver");
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MODULE_AUTHOR("Rameshwar Sahu <rsahu@apm.com>");
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MODULE_LICENSE("GPL");
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