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Subject[PATCH] rtc: add mxc driver for i.MX53
Date
From: Patrick Bruenn <p.bruenn@beckhoff.com>

Neither rtc-imxdi nor rtc-mxc are compatible with i.MX53.
Add a modernized version of mxc_v2 from here:
http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/tree/drivers/rtc/rtc-mxc_v2.c?h=imx_2.6.35_11.09.01

Changes to that version:
- updated to v4.15-rc1
- removed ioctl()
- removed proc()
- removed manual(redundant) enable_irq flag

Signed-off-by: Patrick Bruenn <p.bruenn@beckhoff.com>

---

Open issues:
- driver naming, should it be merged with rtc-mxc.c ?
- document DT binding "fsl,imx53-rtc" accordingly
- Should unused defines be removed or kept for someone else to be
useful?
- Is the use of __raw_readl/writel() correct? Should it be replaced with
readl/writel()?
- suspend/resume() seems different to existing rtc-mxc.c, should I apply
the pattern from rtc-mxc.c?
- On Shawns tree imx53.dtsi has been reverted already[1][2]. Should I split
the imx53.dtsi change into a separate patch based on his tree? Or can
we still stop the full revert and just remove the imx25-rtc compatible?
I am not in a hurry, so we could just wait until the revert landed in
Linus tree. Whatever you think is best.

[1] https://www.spinics.net/lists/arm-kernel/msg617113.html
[2] commit ee76f7729babd2700afd6f3874449d8084dd85ea

To: Alessandro Zummo <a.zummo@towertech.it>
To: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com> (maintainer:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS)
Cc: linux-rtc@vger.kernel.org (open list:REAL TIME CLOCK (RTC) SUBSYSTEM)
Cc: devicetree@vger.kernel.org (open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS)
Cc: linux-kernel@vger.kernel.org (open list)
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Juergen Borleis <jbe@pengutronix.de>
Cc: Noel Vellemans <Noel.Vellemans@visionbms.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <kernel@pengutronix.de> (maintainer:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE)
Cc: Russell King <linux@armlinux.org.uk> (maintainer:ARM PORT)
Cc: linux-arm-kernel@lists.infradead.org (moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE)
---
arch/arm/boot/dts/imx53.dtsi | 2 +-
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-mxc_v2.c | 531 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 533 insertions(+), 1 deletion(-)
create mode 100644 drivers/rtc/rtc-mxc_v2.c

diff --git a/arch/arm/boot/dts/imx53.dtsi b/arch/arm/boot/dts/imx53.dtsi
index 589a67c5f796..3d1a55e11ea8 100644
--- a/arch/arm/boot/dts/imx53.dtsi
+++ b/arch/arm/boot/dts/imx53.dtsi
@@ -434,7 +434,7 @@
};

srtc: srtc@53fa4000 {
- compatible = "fsl,imx53-rtc", "fsl,imx25-rtc";
+ compatible = "fsl,imx53-rtc";
reg = <0x53fa4000 0x4000>;
interrupts = <24>;
interrupt-parent = <&tzic>;
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index f2f50c11dc38..fb3dc458c185 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -106,6 +106,7 @@ obj-$(CONFIG_RTC_DRV_MT6397) += rtc-mt6397.o
obj-$(CONFIG_RTC_DRV_MT7622) += rtc-mt7622.o
obj-$(CONFIG_RTC_DRV_MV) += rtc-mv.o
obj-$(CONFIG_RTC_DRV_MXC) += rtc-mxc.o
+obj-$(CONFIG_RTC_DRV_MXC) += rtc-mxc_v2.o
obj-$(CONFIG_RTC_DRV_NUC900) += rtc-nuc900.o
obj-$(CONFIG_RTC_DRV_OMAP) += rtc-omap.o
obj-$(CONFIG_RTC_DRV_OPAL) += rtc-opal.o
diff --git a/drivers/rtc/rtc-mxc_v2.c b/drivers/rtc/rtc-mxc_v2.c
new file mode 100644
index 000000000000..5049b521b38e
--- /dev/null
+++ b/drivers/rtc/rtc-mxc_v2.c
@@ -0,0 +1,531 @@
+/*
+ * Copyright (C) 2004-2011 Freescale Semiconductor, Inc. All Rights Reserved.
+ */
+
+/*
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+/*
+ * Implementation based on rtc-ds1553.c
+ */
+
+/*!
+ * @defgroup RTC Real Time Clock (RTC) Driver for i.MX53
+ */
+/*!
+ * @file rtc-mxc_v2.c
+ * @brief Real Time Clock interface
+ *
+ * This file contains Real Time Clock interface for Linux.
+ *
+ * @ingroup RTC
+ */
+
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/rtc.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+//#include <linux/mxc_srtc.h>
+#define RTC_READ_TIME_47BIT _IOR('p', 0x20, unsigned long long)
+/* blocks until LPSCMR is set, returns difference */
+#define RTC_WAIT_TIME_SET _IOR('p', 0x21, int64_t)
+
+#define SRTC_LPSCLR_LLPSC_LSH 17 /* start bit for LSB time value */
+
+#define SRTC_LPPDR_INIT 0x41736166 /* init for glitch detect */
+
+#define SRTC_LPCR_SWR_LP (1 << 0) /* lp software reset */
+#define SRTC_LPCR_EN_LP (1 << 3) /* lp enable */
+#define SRTC_LPCR_WAE (1 << 4) /* lp wakeup alarm enable */
+#define SRTC_LPCR_SAE (1 << 5) /* lp security alarm enable */
+#define SRTC_LPCR_SI (1 << 6) /* lp security interrupt enable */
+#define SRTC_LPCR_ALP (1 << 7) /* lp alarm flag */
+#define SRTC_LPCR_LTC (1 << 8) /* lp lock time counter */
+#define SRTC_LPCR_LMC (1 << 9) /* lp lock monotonic counter */
+#define SRTC_LPCR_SV (1 << 10) /* lp security violation */
+#define SRTC_LPCR_NSA (1 << 11) /* lp non secure access */
+#define SRTC_LPCR_NVEIE (1 << 12) /* lp non valid state exit int en */
+#define SRTC_LPCR_IEIE (1 << 13) /* lp init state exit int enable */
+#define SRTC_LPCR_NVE (1 << 14) /* lp non valid state exit bit */
+#define SRTC_LPCR_IE (1 << 15) /* lp init state exit bit */
+
+#define SRTC_LPCR_ALL_INT_EN (SRTC_LPCR_WAE | SRTC_LPCR_SAE | \
+ SRTC_LPCR_SI | SRTC_LPCR_ALP | \
+ SRTC_LPCR_NVEIE | SRTC_LPCR_IEIE)
+
+#define SRTC_LPSR_TRI (1 << 0) /* lp time read invalidate */
+#define SRTC_LPSR_PGD (1 << 1) /* lp power supply glitc detected */
+#define SRTC_LPSR_CTD (1 << 2) /* lp clock tampering detected */
+#define SRTC_LPSR_ALP (1 << 3) /* lp alarm flag */
+#define SRTC_LPSR_MR (1 << 4) /* lp monotonic counter rollover */
+#define SRTC_LPSR_TR (1 << 5) /* lp time rollover */
+#define SRTC_LPSR_EAD (1 << 6) /* lp external alarm detected */
+#define SRTC_LPSR_IT0 (1 << 7) /* lp IIM throttle */
+#define SRTC_LPSR_IT1 (1 << 8)
+#define SRTC_LPSR_IT2 (1 << 9)
+#define SRTC_LPSR_SM0 (1 << 10) /* lp security mode */
+#define SRTC_LPSR_SM1 (1 << 11)
+#define SRTC_LPSR_STATE_LP0 (1 << 12) /* lp state */
+#define SRTC_LPSR_STATE_LP1 (1 << 13)
+#define SRTC_LPSR_NVES (1 << 14) /* lp non-valid state exit status */
+#define SRTC_LPSR_IES (1 << 15) /* lp init state exit status */
+
+#define MAX_PIE_NUM 15
+#define MAX_PIE_FREQ 32768
+#define MIN_PIE_FREQ 1
+
+#define SRTC_PI0 (1 << 0)
+#define SRTC_PI1 (1 << 1)
+#define SRTC_PI2 (1 << 2)
+#define SRTC_PI3 (1 << 3)
+#define SRTC_PI4 (1 << 4)
+#define SRTC_PI5 (1 << 5)
+#define SRTC_PI6 (1 << 6)
+#define SRTC_PI7 (1 << 7)
+#define SRTC_PI8 (1 << 8)
+#define SRTC_PI9 (1 << 9)
+#define SRTC_PI10 (1 << 10)
+#define SRTC_PI11 (1 << 11)
+#define SRTC_PI12 (1 << 12)
+#define SRTC_PI13 (1 << 13)
+#define SRTC_PI14 (1 << 14)
+#define SRTC_PI15 (1 << 15)
+
+#define PIT_ALL_ON (SRTC_PI1 | SRTC_PI2 | SRTC_PI3 | \
+ SRTC_PI4 | SRTC_PI5 | SRTC_PI6 | SRTC_PI7 | \
+ SRTC_PI8 | SRTC_PI9 | SRTC_PI10 | SRTC_PI11 | \
+ SRTC_PI12 | SRTC_PI13 | SRTC_PI14 | SRTC_PI15)
+
+#define SRTC_SWR_HP (1 << 0) /* hp software reset */
+#define SRTC_EN_HP (1 << 3) /* hp enable */
+#define SRTC_TS (1 << 4) /* time synchronize hp with lp */
+
+#define SRTC_IE_AHP (1 << 16) /* Alarm HP Interrupt Enable bit */
+#define SRTC_IE_WDHP (1 << 18) /* Write Done HP Interrupt Enable bit */
+#define SRTC_IE_WDLP (1 << 19) /* Write Done LP Interrupt Enable bit */
+
+#define SRTC_ISR_AHP (1 << 16) /* interrupt status: alarm hp */
+#define SRTC_ISR_WDHP (1 << 18) /* interrupt status: write done hp */
+#define SRTC_ISR_WDLP (1 << 19) /* interrupt status: write done lp */
+#define SRTC_ISR_WPHP (1 << 20) /* interrupt status: write pending hp */
+#define SRTC_ISR_WPLP (1 << 21) /* interrupt status: write pending lp */
+
+#define SRTC_LPSCMR 0x00 /* LP Secure Counter MSB Reg */
+#define SRTC_LPSCLR 0x04 /* LP Secure Counter LSB Reg */
+#define SRTC_LPSAR 0x08 /* LP Secure Alarm Reg */
+#define SRTC_LPSMCR 0x0C /* LP Secure Monotonic Counter Reg */
+#define SRTC_LPCR 0x10 /* LP Control Reg */
+#define SRTC_LPSR 0x14 /* LP Status Reg */
+#define SRTC_LPPDR 0x18 /* LP Power Supply Glitch Detector Reg */
+#define SRTC_LPGR 0x1C /* LP General Purpose Reg */
+#define SRTC_HPCMR 0x20 /* HP Counter MSB Reg */
+#define SRTC_HPCLR 0x24 /* HP Counter LSB Reg */
+#define SRTC_HPAMR 0x28 /* HP Alarm MSB Reg */
+#define SRTC_HPALR 0x2C /* HP Alarm LSB Reg */
+#define SRTC_HPCR 0x30 /* HP Control Reg */
+#define SRTC_HPISR 0x34 /* HP Interrupt Status Reg */
+#define SRTC_HPIENR 0x38 /* HP Interrupt Enable Reg */
+
+#define SRTC_SECMODE_MASK 0x3 /* the mask of SRTC security mode */
+#define SRTC_SECMODE_LOW 0x0 /* Low Security */
+#define SRTC_SECMODE_MED 0x1 /* Medium Security */
+#define SRTC_SECMODE_HIGH 0x2 /* High Security */
+#define SRTC_SECMODE_RESERVED 0x3 /* Reserved */
+
+struct rtc_drv_data {
+ struct rtc_device *rtc;
+ void __iomem *ioaddr;
+ int irq;
+ struct clk *clk;
+};
+
+static DEFINE_SPINLOCK(rtc_lock);
+
+/*!
+ * This function does write synchronization for writes to the lp srtc block.
+ * To take care of the asynchronous CKIL clock, all writes from the IP domain
+ * will be synchronized to the CKIL domain.
+ */
+static inline void rtc_write_sync_lp(void __iomem *ioaddr)
+{
+ unsigned int i, count;
+ /* Wait for 3 CKIL cycles */
+ for (i = 0; i < 3; i++) {
+ count = readl(ioaddr + SRTC_LPSCLR);
+ while ((readl(ioaddr + SRTC_LPSCLR)) == count)
+ ;
+ }
+}
+
+/*!
+ * This function updates the RTC alarm registers and then clears all the
+ * interrupt status bits.
+ *
+ * @param alrm the new alarm value to be updated in the RTC
+ *
+ * @return 0 if successful; non-zero otherwise.
+ */
+static int rtc_update_alarm(struct device *dev, struct rtc_time *alrm)
+{
+ struct rtc_drv_data *pdata = dev_get_drvdata(dev);
+ void __iomem *ioaddr = pdata->ioaddr;
+ struct rtc_time alarm_tm, now_tm;
+ unsigned long now, time;
+ int ret;
+
+ now = __raw_readl(ioaddr + SRTC_LPSCMR);
+ rtc_time_to_tm(now, &now_tm);
+
+ alarm_tm.tm_year = now_tm.tm_year;
+ alarm_tm.tm_mon = now_tm.tm_mon;
+ alarm_tm.tm_mday = now_tm.tm_mday;
+
+ alarm_tm.tm_hour = alrm->tm_hour;
+ alarm_tm.tm_min = alrm->tm_min;
+ alarm_tm.tm_sec = alrm->tm_sec;
+
+ rtc_tm_to_time(&now_tm, &now);
+ rtc_tm_to_time(&alarm_tm, &time);
+
+ if (time < now) {
+ time += 60 * 60 * 24;
+ rtc_time_to_tm(time, &alarm_tm);
+ }
+ ret = rtc_tm_to_time(&alarm_tm, &time);
+
+ __raw_writel(time, ioaddr + SRTC_LPSAR);
+
+ /* clear alarm interrupt status bit */
+ __raw_writel(SRTC_LPSR_ALP, ioaddr + SRTC_LPSR);
+
+ return ret;
+}
+
+/*!
+ * This function is the RTC interrupt service routine.
+ *
+ * @param irq RTC IRQ number
+ * @param dev_id device ID which is not used
+ *
+ * @return IRQ_HANDLED as defined in the include/linux/interrupt.h file.
+ */
+static irqreturn_t mxc_rtc_interrupt(int irq, void *dev_id)
+{
+ struct platform_device *pdev = dev_id;
+ struct rtc_drv_data *pdata = platform_get_drvdata(pdev);
+ void __iomem *ioaddr = pdata->ioaddr;
+ u32 lp_status, lp_cr;
+ u32 events = 0;
+
+ lp_status = __raw_readl(ioaddr + SRTC_LPSR);
+ lp_cr = __raw_readl(ioaddr + SRTC_LPCR);
+
+ /* update irq data & counter */
+ if (lp_status & SRTC_LPSR_ALP) {
+ if (lp_cr & SRTC_LPCR_ALP)
+ events |= (RTC_AF | RTC_IRQF);
+
+ /* disable further lp alarm interrupts */
+ lp_cr &= ~(SRTC_LPCR_ALP | SRTC_LPCR_WAE);
+ }
+
+ /* Update interrupt enables */
+ __raw_writel(lp_cr, ioaddr + SRTC_LPCR);
+
+ /* clear interrupt status */
+ __raw_writel(lp_status, ioaddr + SRTC_LPSR);
+
+ rtc_write_sync_lp(ioaddr);
+ rtc_update_irq(pdata->rtc, 1, events);
+ return IRQ_HANDLED;
+}
+
+/*!
+ * This function reads the current RTC time into tm in Gregorian date.
+ *
+ * @param tm contains the RTC time value upon return
+ *
+ * @return 0 if successful; non-zero otherwise.
+ */
+static int mxc_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct rtc_drv_data *pdata = dev_get_drvdata(dev);
+ time_t now = readl(pdata->ioaddr + SRTC_LPSCMR);
+
+ rtc_time_to_tm(now, tm);
+ return rtc_valid_tm(tm);
+}
+
+/*!
+ * This function sets the internal RTC time based on tm in Gregorian date.
+ *
+ * @param tm the time value to be set in the RTC
+ *
+ * @return 0 if successful; non-zero otherwise.
+ */
+static int mxc_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct rtc_drv_data *pdata = dev_get_drvdata(dev);
+ time64_t time = rtc_tm_to_time64(tm);
+
+ if (time > UINT_MAX) {
+ dev_warn(dev, "time_t has overflow\n");
+ }
+
+ writel(time, pdata->ioaddr + SRTC_LPSCMR);
+ rtc_write_sync_lp(pdata->ioaddr);
+ return 0;
+}
+
+/*!
+ * This function reads the current alarm value into the passed in \b alrm
+ * argument. It updates the \b alrm's pending field value based on the whether
+ * an alarm interrupt occurs or not.
+ *
+ * @param alrm contains the RTC alarm value upon return
+ *
+ * @return 0 if successful; non-zero otherwise.
+ */
+static int mxc_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct rtc_drv_data *pdata = dev_get_drvdata(dev);
+ void __iomem *ioaddr = pdata->ioaddr;
+
+ rtc_time_to_tm(__raw_readl(ioaddr + SRTC_LPSAR), &alrm->time);
+ alrm->pending =
+ ((__raw_readl(ioaddr + SRTC_LPSR) & SRTC_LPSR_ALP) != 0) ? 1 : 0;
+
+ return 0;
+}
+
+static int mxc_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
+{
+ struct rtc_drv_data *pdata = dev_get_drvdata(dev);
+ unsigned long lock_flags = 0;
+ u32 lp_cr;
+
+ spin_lock_irqsave(&rtc_lock, lock_flags);
+ lp_cr = __raw_readl(pdata->ioaddr + SRTC_LPCR);
+
+ if (enable)
+ lp_cr |= (SRTC_LPCR_ALP | SRTC_LPCR_WAE);
+ else
+ lp_cr &= ~(SRTC_LPCR_ALP | SRTC_LPCR_WAE);
+
+ __raw_writel(lp_cr, pdata->ioaddr + SRTC_LPCR);
+ spin_unlock_irqrestore(&rtc_lock, lock_flags);
+ return 0;
+}
+
+/*!
+ * This function sets the RTC alarm based on passed in alrm.
+ *
+ * @param alrm the alarm value to be set in the RTC
+ *
+ * @return 0 if successful; non-zero otherwise.
+ */
+static int mxc_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct rtc_drv_data *pdata = dev_get_drvdata(dev);
+ void __iomem *ioaddr = pdata->ioaddr;
+ int ret;
+
+ ret = rtc_update_alarm(dev, &alrm->time);
+ if (!ret)
+ mxc_rtc_alarm_irq_enable(dev, alrm->enabled);
+
+ rtc_write_sync_lp(ioaddr);
+ return ret;
+}
+
+/*!
+ * The RTC driver structure
+ */
+static const struct rtc_class_ops mxc_rtc_ops = {
+ .read_time = mxc_rtc_read_time,
+ .set_time = mxc_rtc_set_time,
+ .read_alarm = mxc_rtc_read_alarm,
+ .set_alarm = mxc_rtc_set_alarm,
+ .alarm_irq_enable = mxc_rtc_alarm_irq_enable,
+};
+
+/*! MXC RTC Power management control */
+static int mxc_rtc_probe(struct platform_device *pdev)
+{
+ struct timespec tv;
+ struct resource *res;
+ struct rtc_drv_data *pdata = NULL;
+ void __iomem *ioaddr;
+ int ret = 0;
+
+ pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+ if (!pdata)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENODEV;
+
+ pdata->ioaddr = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(pdata->ioaddr))
+ return PTR_ERR(pdata->ioaddr);
+
+ ioaddr = pdata->ioaddr;
+
+ pdata->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(pdata->clk)) {
+ dev_err(&pdev->dev, "unable to get rtc clock!\n");
+ return PTR_ERR(pdata->clk);
+ }
+ ret = clk_prepare_enable(pdata->clk);
+ if (ret)
+ return ret;
+
+ /* Configure and enable the RTC */
+ pdata->irq = platform_get_irq(pdev, 0);
+ if (pdata->irq >= 0
+ && devm_request_irq(&pdev->dev, pdata->irq, mxc_rtc_interrupt,
+ IRQF_SHARED, pdev->name, pdev) < 0) {
+ dev_warn(&pdev->dev, "interrupt not available.\n");
+ pdata->irq = -1;
+ }
+
+ if (pdata->irq >= 0)
+ device_init_wakeup(&pdev->dev, 1);
+
+ /* initialize glitch detect */
+ __raw_writel(SRTC_LPPDR_INIT, ioaddr + SRTC_LPPDR);
+ udelay(100);
+
+ /* clear lp interrupt status */
+ __raw_writel(0xFFFFFFFF, ioaddr + SRTC_LPSR);
+ udelay(100);
+
+ /* move out of init state */
+ __raw_writel((SRTC_LPCR_IE | SRTC_LPCR_NSA), ioaddr + SRTC_LPCR);
+
+ udelay(100);
+
+ while ((__raw_readl(ioaddr + SRTC_LPSR) & SRTC_LPSR_IES) == 0)
+ ;
+
+ /* move out of non-valid state */
+ __raw_writel((SRTC_LPCR_IE | SRTC_LPCR_NVE | SRTC_LPCR_NSA |
+ SRTC_LPCR_EN_LP), ioaddr + SRTC_LPCR);
+
+ udelay(100);
+
+ while ((__raw_readl(ioaddr + SRTC_LPSR) & SRTC_LPSR_NVES) == 0)
+ ;
+
+ __raw_writel(0xFFFFFFFF, ioaddr + SRTC_LPSR);
+ udelay(100);
+
+ platform_set_drvdata(pdev, pdata);
+ pdata->rtc =
+ devm_rtc_device_register(&pdev->dev, pdev->name, &mxc_rtc_ops,
+ THIS_MODULE);
+ if (IS_ERR(pdata->rtc)) {
+ ret = PTR_ERR(pdata->rtc);
+ goto exit_put_clk;
+ }
+
+ tv.tv_nsec = 0;
+ tv.tv_sec = __raw_readl(ioaddr + SRTC_LPSCMR);
+
+ /* By default, devices should wakeup if they can */
+ /* So srtc is set as "should wakeup" as it can */
+ device_init_wakeup(&pdev->dev, 1);
+
+ return ret;
+
+exit_put_clk:
+ clk_disable_unprepare(pdata->clk);
+ return ret;
+}
+
+static int __exit mxc_rtc_remove(struct platform_device *pdev)
+{
+ struct rtc_drv_data *pdata = platform_get_drvdata(pdev);
+
+ clk_disable_unprepare(pdata->clk);
+ return 0;
+}
+
+/*!
+ * This function is called to save the system time delta relative to
+ * the MXC RTC when enterring a low power state. This time delta is
+ * then used on resume to adjust the system time to account for time
+ * loss while suspended.
+ *
+ * @param pdev not used
+ * @param state Power state to enter.
+ *
+ * @return The function always returns 0.
+ */
+static int mxc_rtc_suspend(struct platform_device *pdev, pm_message_t state)
+{
+ struct rtc_drv_data *pdata = platform_get_drvdata(pdev);
+
+ if (device_may_wakeup(&pdev->dev))
+ enable_irq_wake(pdata->irq);
+
+ return 0;
+}
+
+/*!
+ * This function is called to correct the system time based on the
+ * current MXC RTC time relative to the time delta saved during
+ * suspend.
+ *
+ * @param pdev not used
+ *
+ * @return The function always returns 0.
+ */
+static int mxc_rtc_resume(struct platform_device *pdev)
+{
+ struct rtc_drv_data *pdata = platform_get_drvdata(pdev);
+
+ if (device_may_wakeup(&pdev->dev))
+ disable_irq_wake(pdata->irq);
+
+ return 0;
+}
+
+static const struct of_device_id mxc_ids[] = {
+ {.compatible = "fsl,imx53-rtc",},
+ {}
+};
+
+/*!
+ * Contains pointers to the power management callback functions.
+ */
+static struct platform_driver mxc_rtc_driver = {
+ .driver = {
+ .name = "mxc_rtc_v8",
+ .of_match_table = mxc_ids,
+ },
+ .probe = mxc_rtc_probe,
+ .remove = mxc_rtc_remove,
+ .suspend = mxc_rtc_suspend,
+ .resume = mxc_rtc_resume,
+};
+
+module_platform_driver(mxc_rtc_driver);
+
+MODULE_AUTHOR("Freescale Semiconductor, Inc.");
+MODULE_DESCRIPTION("Realtime Clock Driver (RTC)");
+MODULE_LICENSE("GPL");
--
2.11.0

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