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rtc: rtc-lpc32xx: introduce RTC driver for the LPC32XX SoC
Add an RTC driver for the built-in RTC in the LPC32XX SoC. This patch includes updates from the initial review comments and updates from the v3 review. Signed-off-by: Kevin Wells <wellsk40@gmail.com> Signed-off-by: Durgesh Pattamatta <durgesh.pattamatta@nxp.com> Reviewed-by: Wolfram Sang <w.sang@pengutronix.de> Cc: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kevin Wells
Linus Torvalds
parent
1e0ad2881d
commit
9aa449bed2
@ -952,4 +952,13 @@ config RTC_DRV_JZ4740
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This driver can also be buillt as a module. If so, the module
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will be called rtc-jz4740.
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config RTC_DRV_LPC32XX
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depends on ARCH_LPC32XX
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tristate "NXP LPC32XX RTC"
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help
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This enables support for the NXP RTC in the LPC32XX
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This driver can also be buillt as a module. If so, the module
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will be called rtc-lpc32xx.
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endif # RTC_CLASS
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@ -51,6 +51,7 @@ obj-$(CONFIG_RTC_DRV_IMXDI) += rtc-imxdi.o
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obj-$(CONFIG_RTC_DRV_ISL1208) += rtc-isl1208.o
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obj-$(CONFIG_RTC_DRV_ISL12022) += rtc-isl12022.o
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obj-$(CONFIG_RTC_DRV_JZ4740) += rtc-jz4740.o
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obj-$(CONFIG_RTC_DRV_LPC32XX) += rtc-lpc32xx.o
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obj-$(CONFIG_RTC_DRV_M41T80) += rtc-m41t80.o
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obj-$(CONFIG_RTC_DRV_M41T94) += rtc-m41t94.o
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obj-$(CONFIG_RTC_DRV_M48T35) += rtc-m48t35.o
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414
drivers/rtc/rtc-lpc32xx.c
Normal file
414
drivers/rtc/rtc-lpc32xx.c
Normal file
@ -0,0 +1,414 @@
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/*
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* Copyright (C) 2010 NXP Semiconductors
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/spinlock.h>
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#include <linux/rtc.h>
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#include <linux/slab.h>
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#include <linux/io.h>
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/*
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* Clock and Power control register offsets
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*/
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#define LPC32XX_RTC_UCOUNT 0x00
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#define LPC32XX_RTC_DCOUNT 0x04
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#define LPC32XX_RTC_MATCH0 0x08
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#define LPC32XX_RTC_MATCH1 0x0C
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#define LPC32XX_RTC_CTRL 0x10
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#define LPC32XX_RTC_INTSTAT 0x14
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#define LPC32XX_RTC_KEY 0x18
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#define LPC32XX_RTC_SRAM 0x80
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#define LPC32XX_RTC_CTRL_MATCH0 (1 << 0)
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#define LPC32XX_RTC_CTRL_MATCH1 (1 << 1)
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#define LPC32XX_RTC_CTRL_ONSW_MATCH0 (1 << 2)
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#define LPC32XX_RTC_CTRL_ONSW_MATCH1 (1 << 3)
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#define LPC32XX_RTC_CTRL_SW_RESET (1 << 4)
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#define LPC32XX_RTC_CTRL_CNTR_DIS (1 << 6)
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#define LPC32XX_RTC_CTRL_ONSW_FORCE_HI (1 << 7)
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#define LPC32XX_RTC_INTSTAT_MATCH0 (1 << 0)
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#define LPC32XX_RTC_INTSTAT_MATCH1 (1 << 1)
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#define LPC32XX_RTC_INTSTAT_ONSW (1 << 2)
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#define LPC32XX_RTC_KEY_ONSW_LOADVAL 0xB5C13F27
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#define RTC_NAME "rtc-lpc32xx"
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#define rtc_readl(dev, reg) \
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__raw_readl((dev)->rtc_base + (reg))
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#define rtc_writel(dev, reg, val) \
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__raw_writel((val), (dev)->rtc_base + (reg))
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struct lpc32xx_rtc {
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void __iomem *rtc_base;
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int irq;
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unsigned char alarm_enabled;
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struct rtc_device *rtc;
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spinlock_t lock;
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};
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static int lpc32xx_rtc_read_time(struct device *dev, struct rtc_time *time)
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{
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unsigned long elapsed_sec;
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struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
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elapsed_sec = rtc_readl(rtc, LPC32XX_RTC_UCOUNT);
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rtc_time_to_tm(elapsed_sec, time);
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return rtc_valid_tm(time);
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}
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static int lpc32xx_rtc_set_mmss(struct device *dev, unsigned long secs)
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{
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struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
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u32 tmp;
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spin_lock_irq(&rtc->lock);
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/* RTC must be disabled during count update */
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tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
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rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp | LPC32XX_RTC_CTRL_CNTR_DIS);
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rtc_writel(rtc, LPC32XX_RTC_UCOUNT, secs);
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rtc_writel(rtc, LPC32XX_RTC_DCOUNT, 0xFFFFFFFF - secs);
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rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp &= ~LPC32XX_RTC_CTRL_CNTR_DIS);
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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 lpc32xx_rtc_read_alarm(struct device *dev,
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struct rtc_wkalrm *wkalrm)
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{
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struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
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rtc_time_to_tm(rtc_readl(rtc, LPC32XX_RTC_MATCH0), &wkalrm->time);
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wkalrm->enabled = rtc->alarm_enabled;
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wkalrm->pending = !!(rtc_readl(rtc, LPC32XX_RTC_INTSTAT) &
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LPC32XX_RTC_INTSTAT_MATCH0);
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return rtc_valid_tm(&wkalrm->time);
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}
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static int lpc32xx_rtc_set_alarm(struct device *dev,
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struct rtc_wkalrm *wkalrm)
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{
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struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
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unsigned long alarmsecs;
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u32 tmp;
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int ret;
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ret = rtc_tm_to_time(&wkalrm->time, &alarmsecs);
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if (ret < 0) {
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dev_warn(dev, "Failed to convert time: %d\n", ret);
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return ret;
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}
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spin_lock_irq(&rtc->lock);
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/* Disable alarm during update */
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tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
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rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp & ~LPC32XX_RTC_CTRL_MATCH0);
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rtc_writel(rtc, LPC32XX_RTC_MATCH0, alarmsecs);
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rtc->alarm_enabled = wkalrm->enabled;
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if (wkalrm->enabled) {
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rtc_writel(rtc, LPC32XX_RTC_INTSTAT,
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LPC32XX_RTC_INTSTAT_MATCH0);
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rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp |
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LPC32XX_RTC_CTRL_MATCH0);
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}
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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 lpc32xx_rtc_alarm_irq_enable(struct device *dev,
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unsigned int enabled)
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{
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struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
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u32 tmp;
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spin_lock_irq(&rtc->lock);
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tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
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if (enabled) {
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rtc->alarm_enabled = 1;
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tmp |= LPC32XX_RTC_CTRL_MATCH0;
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} else {
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rtc->alarm_enabled = 0;
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tmp &= ~LPC32XX_RTC_CTRL_MATCH0;
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}
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rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp);
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spin_unlock_irq(&rtc->lock);
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return 0;
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}
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static irqreturn_t lpc32xx_rtc_alarm_interrupt(int irq, void *dev)
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{
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struct lpc32xx_rtc *rtc = dev;
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spin_lock(&rtc->lock);
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/* Disable alarm interrupt */
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rtc_writel(rtc, LPC32XX_RTC_CTRL,
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rtc_readl(rtc, LPC32XX_RTC_CTRL) &
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~LPC32XX_RTC_CTRL_MATCH0);
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rtc->alarm_enabled = 0;
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/*
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* Write a large value to the match value so the RTC won't
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* keep firing the match status
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*/
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rtc_writel(rtc, LPC32XX_RTC_MATCH0, 0xFFFFFFFF);
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rtc_writel(rtc, LPC32XX_RTC_INTSTAT, LPC32XX_RTC_INTSTAT_MATCH0);
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spin_unlock(&rtc->lock);
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rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
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return IRQ_HANDLED;
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}
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static const struct rtc_class_ops lpc32xx_rtc_ops = {
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.read_time = lpc32xx_rtc_read_time,
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.set_mmss = lpc32xx_rtc_set_mmss,
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.read_alarm = lpc32xx_rtc_read_alarm,
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.set_alarm = lpc32xx_rtc_set_alarm,
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.alarm_irq_enable = lpc32xx_rtc_alarm_irq_enable,
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};
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static int __devinit lpc32xx_rtc_probe(struct platform_device *pdev)
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{
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struct resource *res;
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struct lpc32xx_rtc *rtc;
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resource_size_t size;
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int rtcirq;
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u32 tmp;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res) {
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dev_err(&pdev->dev, "Can't get memory resource\n");
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return -ENOENT;
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}
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rtcirq = platform_get_irq(pdev, 0);
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if (rtcirq < 0 || rtcirq >= NR_IRQS) {
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dev_warn(&pdev->dev, "Can't get interrupt resource\n");
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rtcirq = -1;
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}
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rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
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if (unlikely(!rtc)) {
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dev_err(&pdev->dev, "Can't allocate memory\n");
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return -ENOMEM;
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}
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rtc->irq = rtcirq;
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size = resource_size(res);
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if (!devm_request_mem_region(&pdev->dev, res->start, size,
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pdev->name)) {
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dev_err(&pdev->dev, "RTC registers are not free\n");
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return -EBUSY;
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}
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rtc->rtc_base = devm_ioremap(&pdev->dev, res->start, size);
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if (!rtc->rtc_base) {
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dev_err(&pdev->dev, "Can't map 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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* The RTC is on a seperate power domain and can keep it's state
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* across a chip power cycle. If the RTC has never been previously
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* setup, then set it up now for the first time.
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*/
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tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
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if (rtc_readl(rtc, LPC32XX_RTC_KEY) != LPC32XX_RTC_KEY_ONSW_LOADVAL) {
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tmp &= ~(LPC32XX_RTC_CTRL_SW_RESET |
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LPC32XX_RTC_CTRL_CNTR_DIS |
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LPC32XX_RTC_CTRL_MATCH0 |
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LPC32XX_RTC_CTRL_MATCH1 |
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LPC32XX_RTC_CTRL_ONSW_MATCH0 |
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LPC32XX_RTC_CTRL_ONSW_MATCH1 |
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LPC32XX_RTC_CTRL_ONSW_FORCE_HI);
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rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp);
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/* Clear latched interrupt states */
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rtc_writel(rtc, LPC32XX_RTC_MATCH0, 0xFFFFFFFF);
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rtc_writel(rtc, LPC32XX_RTC_INTSTAT,
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LPC32XX_RTC_INTSTAT_MATCH0 |
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LPC32XX_RTC_INTSTAT_MATCH1 |
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LPC32XX_RTC_INTSTAT_ONSW);
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/* Write key value to RTC so it won't reload on reset */
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rtc_writel(rtc, LPC32XX_RTC_KEY,
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LPC32XX_RTC_KEY_ONSW_LOADVAL);
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} else {
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rtc_writel(rtc, LPC32XX_RTC_CTRL,
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tmp & ~LPC32XX_RTC_CTRL_MATCH0);
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}
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platform_set_drvdata(pdev, rtc);
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rtc->rtc = rtc_device_register(RTC_NAME, &pdev->dev, &lpc32xx_rtc_ops,
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THIS_MODULE);
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if (IS_ERR(rtc->rtc)) {
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dev_err(&pdev->dev, "Can't get RTC\n");
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platform_set_drvdata(pdev, NULL);
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return PTR_ERR(rtc->rtc);
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}
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/*
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* IRQ is enabled after device registration in case alarm IRQ
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* is pending upon suspend exit.
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*/
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if (rtc->irq >= 0) {
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if (devm_request_irq(&pdev->dev, rtc->irq,
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lpc32xx_rtc_alarm_interrupt,
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IRQF_DISABLED, pdev->name, rtc) < 0) {
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dev_warn(&pdev->dev, "Can't request interrupt.\n");
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rtc->irq = -1;
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} else {
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device_init_wakeup(&pdev->dev, 1);
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}
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}
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return 0;
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}
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static int __devexit lpc32xx_rtc_remove(struct platform_device *pdev)
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{
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struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
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if (rtc->irq >= 0)
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device_init_wakeup(&pdev->dev, 0);
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platform_set_drvdata(pdev, NULL);
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rtc_device_unregister(rtc->rtc);
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return 0;
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}
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#ifdef CONFIG_PM
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static int lpc32xx_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 lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
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if (rtc->irq >= 0) {
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if (device_may_wakeup(&pdev->dev))
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enable_irq_wake(rtc->irq);
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else
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disable_irq_wake(rtc->irq);
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}
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return 0;
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}
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static int lpc32xx_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 lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
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if (rtc->irq >= 0 && device_may_wakeup(&pdev->dev))
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disable_irq_wake(rtc->irq);
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return 0;
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}
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/* Unconditionally disable the alarm */
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static int lpc32xx_rtc_freeze(struct device *dev)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
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spin_lock_irq(&rtc->lock);
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rtc_writel(rtc, LPC32XX_RTC_CTRL,
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rtc_readl(rtc, LPC32XX_RTC_CTRL) &
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~LPC32XX_RTC_CTRL_MATCH0);
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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 lpc32xx_rtc_thaw(struct device *dev)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
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if (rtc->alarm_enabled) {
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spin_lock_irq(&rtc->lock);
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rtc_writel(rtc, LPC32XX_RTC_CTRL,
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rtc_readl(rtc, LPC32XX_RTC_CTRL) |
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LPC32XX_RTC_CTRL_MATCH0);
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spin_unlock_irq(&rtc->lock);
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}
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return 0;
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}
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static const struct dev_pm_ops lpc32xx_rtc_pm_ops = {
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.suspend = lpc32xx_rtc_suspend,
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.resume = lpc32xx_rtc_resume,
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.freeze = lpc32xx_rtc_freeze,
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.thaw = lpc32xx_rtc_thaw,
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.restore = lpc32xx_rtc_resume
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};
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#define LPC32XX_RTC_PM_OPS (&lpc32xx_rtc_pm_ops)
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#else
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#define LPC32XX_RTC_PM_OPS NULL
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#endif
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static struct platform_driver lpc32xx_rtc_driver = {
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.probe = lpc32xx_rtc_probe,
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.remove = __devexit_p(lpc32xx_rtc_remove),
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.driver = {
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.name = RTC_NAME,
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.owner = THIS_MODULE,
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.pm = LPC32XX_RTC_PM_OPS
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},
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};
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static int __init lpc32xx_rtc_init(void)
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{
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return platform_driver_register(&lpc32xx_rtc_driver);
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}
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module_init(lpc32xx_rtc_init);
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static void __exit lpc32xx_rtc_exit(void)
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{
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platform_driver_unregister(&lpc32xx_rtc_driver);
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}
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module_exit(lpc32xx_rtc_exit);
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MODULE_AUTHOR("Kevin Wells <wellsk40@gmail.com");
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MODULE_DESCRIPTION("RTC driver for the LPC32xx SoC");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:rtc-lpc32xx");
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||||
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