// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2017 Spreadtrum Communications Inc.
 *
 */

#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/rtc.h>

#define SPRD_RTC_SEC_CNT_VALUE          0x0
#define SPRD_RTC_MIN_CNT_VALUE          0x4
#define SPRD_RTC_HOUR_CNT_VALUE         0x8
#define SPRD_RTC_DAY_CNT_VALUE          0xc
#define SPRD_RTC_SEC_CNT_UPD            0x10
#define SPRD_RTC_MIN_CNT_UPD            0x14
#define SPRD_RTC_HOUR_CNT_UPD           0x18
#define SPRD_RTC_DAY_CNT_UPD            0x1c
#define SPRD_RTC_SEC_ALM_UPD            0x20
#define SPRD_RTC_MIN_ALM_UPD            0x24
#define SPRD_RTC_HOUR_ALM_UPD           0x28
#define SPRD_RTC_DAY_ALM_UPD            0x2c
#define SPRD_RTC_INT_EN                 0x30
#define SPRD_RTC_INT_RAW_STS            0x34
#define SPRD_RTC_INT_CLR                0x38
#define SPRD_RTC_INT_MASK_STS           0x3C
#define SPRD_RTC_SEC_ALM_VALUE          0x40
#define SPRD_RTC_MIN_ALM_VALUE          0x44
#define SPRD_RTC_HOUR_ALM_VALUE         0x48
#define SPRD_RTC_DAY_ALM_VALUE          0x4c
#define SPRD_RTC_SPG_VALUE              0x50
#define SPRD_RTC_SPG_UPD                0x54
#define SPRD_RTC_PWR_CTRL               0x58
#define SPRD_RTC_PWR_STS                0x5c
#define SPRD_RTC_SEC_AUXALM_UPD         0x60
#define SPRD_RTC_MIN_AUXALM_UPD         0x64
#define SPRD_RTC_HOUR_AUXALM_UPD        0x68
#define SPRD_RTC_DAY_AUXALM_UPD         0x6c

/* BIT & MASK definition for SPRD_RTC_INT_* registers */
#define SPRD_RTC_SEC_EN                 BIT(0)
#define SPRD_RTC_MIN_EN                 BIT(1)
#define SPRD_RTC_HOUR_EN                BIT(2)
#define SPRD_RTC_DAY_EN                 BIT(3)
#define SPRD_RTC_ALARM_EN               BIT(4)
#define SPRD_RTC_HRS_FORMAT_EN          BIT(5)
#define SPRD_RTC_AUXALM_EN              BIT(6)
#define SPRD_RTC_SPG_UPD_EN             BIT(7)
#define SPRD_RTC_SEC_UPD_EN             BIT(8)
#define SPRD_RTC_MIN_UPD_EN             BIT(9)
#define SPRD_RTC_HOUR_UPD_EN            BIT(10)
#define SPRD_RTC_DAY_UPD_EN             BIT(11)
#define SPRD_RTC_ALMSEC_UPD_EN          BIT(12)
#define SPRD_RTC_ALMMIN_UPD_EN          BIT(13)
#define SPRD_RTC_ALMHOUR_UPD_EN         BIT(14)
#define SPRD_RTC_ALMDAY_UPD_EN          BIT(15)
#define SPRD_RTC_INT_MASK               GENMASK(15, 0)

#define SPRD_RTC_TIME_INT_MASK                          \
        (SPRD_RTC_SEC_UPD_EN | SPRD_RTC_MIN_UPD_EN |    \
         SPRD_RTC_HOUR_UPD_EN | SPRD_RTC_DAY_UPD_EN)

#define SPRD_RTC_ALMTIME_INT_MASK                               \
        (SPRD_RTC_ALMSEC_UPD_EN | SPRD_RTC_ALMMIN_UPD_EN |      \
         SPRD_RTC_ALMHOUR_UPD_EN | SPRD_RTC_ALMDAY_UPD_EN)

#define SPRD_RTC_ALM_INT_MASK                   \
        (SPRD_RTC_SEC_EN | SPRD_RTC_MIN_EN |    \
         SPRD_RTC_HOUR_EN | SPRD_RTC_DAY_EN |   \
         SPRD_RTC_ALARM_EN | SPRD_RTC_AUXALM_EN)

/* second/minute/hour/day values mask definition */
#define SPRD_RTC_SEC_MASK               GENMASK(5, 0)
#define SPRD_RTC_MIN_MASK               GENMASK(5, 0)
#define SPRD_RTC_HOUR_MASK              GENMASK(4, 0)
#define SPRD_RTC_DAY_MASK               GENMASK(15, 0)

/* alarm lock definition for SPRD_RTC_SPG_UPD register */
#define SPRD_RTC_ALMLOCK_MASK           GENMASK(7, 0)
#define SPRD_RTC_ALM_UNLOCK             0xa5
#define SPRD_RTC_ALM_LOCK               (~SPRD_RTC_ALM_UNLOCK & \
                                         SPRD_RTC_ALMLOCK_MASK)

/* SPG values definition for SPRD_RTC_SPG_UPD register */
#define SPRD_RTC_POWEROFF_ALM_FLAG      BIT(8)

/* power control/status definition */
#define SPRD_RTC_POWER_RESET_VALUE      0x96
#define SPRD_RTC_POWER_STS_CLEAR        GENMASK(7, 0)
#define SPRD_RTC_POWER_STS_SHIFT        8
#define SPRD_RTC_POWER_STS_VALID        \
        (~SPRD_RTC_POWER_RESET_VALUE << SPRD_RTC_POWER_STS_SHIFT)

/* timeout of synchronizing time and alarm registers (us) */
#define SPRD_RTC_POLL_TIMEOUT           200000
#define SPRD_RTC_POLL_DELAY_US          20000

struct sprd_rtc {
        struct rtc_device       *rtc;
        struct regmap           *regmap;
        struct device           *dev;
        u32                     base;
        int                     irq;
        bool                    valid;
};

/*
 * The Spreadtrum RTC controller has 3 groups registers, including time, normal
 * alarm and auxiliary alarm. The time group registers are used to set RTC time,
 * the normal alarm registers are used to set normal alarm, and the auxiliary
 * alarm registers are used to set auxiliary alarm. Both alarm event and
 * auxiliary alarm event can wake up system from deep sleep, but only alarm
 * event can power up system from power down status.
 */
enum sprd_rtc_reg_types {
        SPRD_RTC_TIME,
        SPRD_RTC_ALARM,
        SPRD_RTC_AUX_ALARM,
};

static int sprd_rtc_clear_alarm_ints(struct sprd_rtc *rtc)
{
        return regmap_write(rtc->regmap, rtc->base + SPRD_RTC_INT_CLR,
                            SPRD_RTC_ALM_INT_MASK);
}

static int sprd_rtc_lock_alarm(struct sprd_rtc *rtc, bool lock)
{
        int ret;
        u32 val;

        ret = regmap_read(rtc->regmap, rtc->base + SPRD_RTC_SPG_VALUE, &val);
        if (ret)
                return ret;

        val &= ~SPRD_RTC_ALMLOCK_MASK;
        if (lock)
                val |= SPRD_RTC_ALM_LOCK;
        else
                val |= SPRD_RTC_ALM_UNLOCK | SPRD_RTC_POWEROFF_ALM_FLAG;

        ret = regmap_write(rtc->regmap, rtc->base + SPRD_RTC_SPG_UPD, val);
        if (ret)
                return ret;

        /* wait until the SPG value is updated successfully */
        ret = regmap_read_poll_timeout(rtc->regmap,
                                       rtc->base + SPRD_RTC_INT_RAW_STS, val,
                                       (val & SPRD_RTC_SPG_UPD_EN),
                                       SPRD_RTC_POLL_DELAY_US,
                                       SPRD_RTC_POLL_TIMEOUT);
        if (ret) {
                dev_err(rtc->dev, "failed to update SPG value:%d\n", ret);
                return ret;
        }

        return regmap_write(rtc->regmap, rtc->base + SPRD_RTC_INT_CLR,
                            SPRD_RTC_SPG_UPD_EN);
}

static int sprd_rtc_get_secs(struct sprd_rtc *rtc, enum sprd_rtc_reg_types type,
                             time64_t *secs)
{
        u32 sec_reg, min_reg, hour_reg, day_reg;
        u32 val, sec, min, hour, day;
        int ret;

        switch (type) {
        case SPRD_RTC_TIME:
                sec_reg = SPRD_RTC_SEC_CNT_VALUE;
                min_reg = SPRD_RTC_MIN_CNT_VALUE;
                hour_reg = SPRD_RTC_HOUR_CNT_VALUE;
                day_reg = SPRD_RTC_DAY_CNT_VALUE;
                break;
        case SPRD_RTC_ALARM:
                sec_reg = SPRD_RTC_SEC_ALM_VALUE;
                min_reg = SPRD_RTC_MIN_ALM_VALUE;
                hour_reg = SPRD_RTC_HOUR_ALM_VALUE;
                day_reg = SPRD_RTC_DAY_ALM_VALUE;
                break;
        case SPRD_RTC_AUX_ALARM:
                sec_reg = SPRD_RTC_SEC_AUXALM_UPD;
                min_reg = SPRD_RTC_MIN_AUXALM_UPD;
                hour_reg = SPRD_RTC_HOUR_AUXALM_UPD;
                day_reg = SPRD_RTC_DAY_AUXALM_UPD;
                break;
        default:
                return -EINVAL;
        }

        ret = regmap_read(rtc->regmap, rtc->base + sec_reg, &val);
        if (ret)
                return ret;

        sec = val & SPRD_RTC_SEC_MASK;

        ret = regmap_read(rtc->regmap, rtc->base + min_reg, &val);
        if (ret)
                return ret;

        min = val & SPRD_RTC_MIN_MASK;

        ret = regmap_read(rtc->regmap, rtc->base + hour_reg, &val);
        if (ret)
                return ret;

        hour = val & SPRD_RTC_HOUR_MASK;

        ret = regmap_read(rtc->regmap, rtc->base + day_reg, &val);
        if (ret)
                return ret;

        day = val & SPRD_RTC_DAY_MASK;
        *secs = (((time64_t)(day * 24) + hour) * 60 + min) * 60 + sec;
        return 0;
}

static int sprd_rtc_set_secs(struct sprd_rtc *rtc, enum sprd_rtc_reg_types type,
                             time64_t secs)
{
        u32 sec_reg, min_reg, hour_reg, day_reg, sts_mask;
        u32 sec, min, hour, day, val;
        int ret, rem;

        /* convert seconds to RTC time format */
        day = div_s64_rem(secs, 86400, &rem);
        hour = rem / 3600;
        rem -= hour * 3600;
        min = rem / 60;
        sec = rem - min * 60;

        switch (type) {
        case SPRD_RTC_TIME:
                sec_reg = SPRD_RTC_SEC_CNT_UPD;
                min_reg = SPRD_RTC_MIN_CNT_UPD;
                hour_reg = SPRD_RTC_HOUR_CNT_UPD;
                day_reg = SPRD_RTC_DAY_CNT_UPD;
                sts_mask = SPRD_RTC_TIME_INT_MASK;
                break;
        case SPRD_RTC_ALARM:
                sec_reg = SPRD_RTC_SEC_ALM_UPD;
                min_reg = SPRD_RTC_MIN_ALM_UPD;
                hour_reg = SPRD_RTC_HOUR_ALM_UPD;
                day_reg = SPRD_RTC_DAY_ALM_UPD;
                sts_mask = SPRD_RTC_ALMTIME_INT_MASK;
                break;
        case SPRD_RTC_AUX_ALARM:
                sec_reg = SPRD_RTC_SEC_AUXALM_UPD;
                min_reg = SPRD_RTC_MIN_AUXALM_UPD;
                hour_reg = SPRD_RTC_HOUR_AUXALM_UPD;
                day_reg = SPRD_RTC_DAY_AUXALM_UPD;
                sts_mask = 0;
                break;
        default:
                return -EINVAL;
        }

        ret = regmap_write(rtc->regmap, rtc->base + sec_reg, sec);
        if (ret)
                return ret;

        ret = regmap_write(rtc->regmap, rtc->base + min_reg, min);
        if (ret)
                return ret;

        ret = regmap_write(rtc->regmap, rtc->base + hour_reg, hour);
        if (ret)
                return ret;

        ret = regmap_write(rtc->regmap, rtc->base + day_reg, day);
        if (ret)
                return ret;

        if (type == SPRD_RTC_AUX_ALARM)
                return 0;

        /*
         * Since the time and normal alarm registers are put in always-power-on
         * region supplied by VDDRTC, then these registers changing time will
         * be very long, about 125ms. Thus here we should wait until all
         * values are updated successfully.
         */
        ret = regmap_read_poll_timeout(rtc->regmap,
                                       rtc->base + SPRD_RTC_INT_RAW_STS, val,
                                       ((val & sts_mask) == sts_mask),
                                       SPRD_RTC_POLL_DELAY_US,
                                       SPRD_RTC_POLL_TIMEOUT);
        if (ret < 0) {
                dev_err(rtc->dev, "set time/alarm values timeout\n");
                return ret;
        }

        return regmap_write(rtc->regmap, rtc->base + SPRD_RTC_INT_CLR,
                            sts_mask);
}

static int sprd_rtc_set_aux_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
        struct sprd_rtc *rtc = dev_get_drvdata(dev);
        time64_t secs = rtc_tm_to_time64(&alrm->time);
        int ret;

        /* clear the auxiliary alarm interrupt status */
        ret = regmap_write(rtc->regmap, rtc->base + SPRD_RTC_INT_CLR,
                           SPRD_RTC_AUXALM_EN);
        if (ret)
                return ret;

        ret = sprd_rtc_set_secs(rtc, SPRD_RTC_AUX_ALARM, secs);
        if (ret)
                return ret;

        if (alrm->enabled) {
                ret = regmap_update_bits(rtc->regmap,
                                         rtc->base + SPRD_RTC_INT_EN,
                                         SPRD_RTC_AUXALM_EN,
                                         SPRD_RTC_AUXALM_EN);
        } else {
                ret = regmap_update_bits(rtc->regmap,
                                         rtc->base + SPRD_RTC_INT_EN,
                                         SPRD_RTC_AUXALM_EN, 0);
        }

        return ret;
}

static int sprd_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
        struct sprd_rtc *rtc = dev_get_drvdata(dev);
        time64_t secs;
        int ret;

        if (!rtc->valid) {
                dev_warn(dev, "RTC values are invalid\n");
                return -EINVAL;
        }

        ret = sprd_rtc_get_secs(rtc, SPRD_RTC_TIME, &secs);
        if (ret)
                return ret;

        rtc_time64_to_tm(secs, tm);
        return 0;
}

static int sprd_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
        struct sprd_rtc *rtc = dev_get_drvdata(dev);
        time64_t secs = rtc_tm_to_time64(tm);
        int ret;

        ret = sprd_rtc_set_secs(rtc, SPRD_RTC_TIME, secs);
        if (ret)
                return ret;

        if (!rtc->valid) {
                /* Clear RTC power status firstly */
                ret = regmap_write(rtc->regmap, rtc->base + SPRD_RTC_PWR_CTRL,
                                   SPRD_RTC_POWER_STS_CLEAR);
                if (ret)
                        return ret;

                /*
                 * Set RTC power status to indicate now RTC has valid time
                 * values.
                 */
                ret = regmap_write(rtc->regmap, rtc->base + SPRD_RTC_PWR_CTRL,
                                   SPRD_RTC_POWER_STS_VALID);
                if (ret)
                        return ret;

                rtc->valid = true;
        }

        return 0;
}

static int sprd_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
        struct sprd_rtc *rtc = dev_get_drvdata(dev);
        time64_t secs;
        int ret;
        u32 val;

        /*
         * The RTC core checks to see if there is an alarm already set in RTC
         * hardware, and we always read the normal alarm at this time.
         */
        ret = sprd_rtc_get_secs(rtc, SPRD_RTC_ALARM, &secs);
        if (ret)
                return ret;

        rtc_time64_to_tm(secs, &alrm->time);

        ret = regmap_read(rtc->regmap, rtc->base + SPRD_RTC_INT_EN, &val);
        if (ret)
                return ret;

        alrm->enabled = !!(val & SPRD_RTC_ALARM_EN);

        ret = regmap_read(rtc->regmap, rtc->base + SPRD_RTC_INT_RAW_STS, &val);
        if (ret)
                return ret;

        alrm->pending = !!(val & SPRD_RTC_ALARM_EN);
        return 0;
}

static int sprd_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
        struct sprd_rtc *rtc = dev_get_drvdata(dev);
        time64_t secs = rtc_tm_to_time64(&alrm->time);
        struct rtc_time aie_time =
                rtc_ktime_to_tm(rtc->rtc->aie_timer.node.expires);
        int ret;

        /*
         * We have 2 groups alarms: normal alarm and auxiliary alarm. Since
         * both normal alarm event and auxiliary alarm event can wake up system
         * from deep sleep, but only alarm event can power up system from power
         * down status. Moreover we do not need to poll about 125ms when
         * updating auxiliary alarm registers. Thus we usually set auxiliary
         * alarm when wake up system from deep sleep, and for other scenarios,
         * we should set normal alarm with polling status.
         *
         * So here we check if the alarm time is set by aie_timer, if yes, we
         * should set normal alarm, if not, we should set auxiliary alarm which
         * means it is just a wake event.
         */
        if (!rtc->rtc->aie_timer.enabled || rtc_tm_sub(&aie_time, &alrm->time))
                return sprd_rtc_set_aux_alarm(dev, alrm);

        /* clear the alarm interrupt status firstly */
        ret = regmap_write(rtc->regmap, rtc->base + SPRD_RTC_INT_CLR,
                           SPRD_RTC_ALARM_EN);
        if (ret)
                return ret;

        ret = sprd_rtc_set_secs(rtc, SPRD_RTC_ALARM, secs);
        if (ret)
                return ret;

        if (alrm->enabled) {
                ret = regmap_update_bits(rtc->regmap,
                                         rtc->base + SPRD_RTC_INT_EN,
                                         SPRD_RTC_ALARM_EN,
                                         SPRD_RTC_ALARM_EN);
                if (ret)
                        return ret;

                /* unlock the alarm to enable the alarm function. */
                ret = sprd_rtc_lock_alarm(rtc, false);
        } else {
                regmap_update_bits(rtc->regmap,
                                   rtc->base + SPRD_RTC_INT_EN,
                                   SPRD_RTC_ALARM_EN, 0);

                /*
                 * Lock the alarm function in case fake alarm event will power
                 * up systems.
                 */
                ret = sprd_rtc_lock_alarm(rtc, true);
        }

        return ret;
}

static int sprd_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
        struct sprd_rtc *rtc = dev_get_drvdata(dev);
        int ret;

        if (enabled) {
                ret = regmap_update_bits(rtc->regmap,
                                         rtc->base + SPRD_RTC_INT_EN,
                                         SPRD_RTC_ALARM_EN | SPRD_RTC_AUXALM_EN,
                                         SPRD_RTC_ALARM_EN | SPRD_RTC_AUXALM_EN);
                if (ret)
                        return ret;

                ret = sprd_rtc_lock_alarm(rtc, false);
        } else {
                regmap_update_bits(rtc->regmap, rtc->base + SPRD_RTC_INT_EN,
                                   SPRD_RTC_ALARM_EN | SPRD_RTC_AUXALM_EN, 0);

                ret = sprd_rtc_lock_alarm(rtc, true);
        }

        return ret;
}

static const struct rtc_class_ops sprd_rtc_ops = {
        .read_time = sprd_rtc_read_time,
        .set_time = sprd_rtc_set_time,
        .read_alarm = sprd_rtc_read_alarm,
        .set_alarm = sprd_rtc_set_alarm,
        .alarm_irq_enable = sprd_rtc_alarm_irq_enable,
};

static irqreturn_t sprd_rtc_handler(int irq, void *dev_id)
{
        struct sprd_rtc *rtc = dev_id;
        int ret;

        ret = sprd_rtc_clear_alarm_ints(rtc);
        if (ret)
                return IRQ_RETVAL(ret);

        rtc_update_irq(rtc->rtc, 1, RTC_AF | RTC_IRQF);
        return IRQ_HANDLED;
}

static int sprd_rtc_check_power_down(struct sprd_rtc *rtc)
{
        u32 val;
        int ret;

        ret = regmap_read(rtc->regmap, rtc->base + SPRD_RTC_PWR_STS, &val);
        if (ret)
                return ret;

        /*
         * If the RTC power status value is SPRD_RTC_POWER_RESET_VALUE, which
         * means the RTC has been powered down, so the RTC time values are
         * invalid.
         */
        rtc->valid = val != SPRD_RTC_POWER_RESET_VALUE;
        return 0;
}

static int sprd_rtc_check_alarm_int(struct sprd_rtc *rtc)
{
        u32 val;
        int ret;

        ret = regmap_read(rtc->regmap, rtc->base + SPRD_RTC_SPG_VALUE, &val);
        if (ret)
                return ret;

        /*
         * The SPRD_RTC_INT_EN register is not put in always-power-on region
         * supplied by VDDRTC, so we should check if we need enable the alarm
         * interrupt when system booting.
         *
         * If we have set SPRD_RTC_POWEROFF_ALM_FLAG which is saved in
         * always-power-on region, that means we have set one alarm last time,
         * so we should enable the alarm interrupt to help RTC core to see if
         * there is an alarm already set in RTC hardware.
         */
        if (!(val & SPRD_RTC_POWEROFF_ALM_FLAG))
                return 0;

        return regmap_update_bits(rtc->regmap, rtc->base + SPRD_RTC_INT_EN,
                                  SPRD_RTC_ALARM_EN, SPRD_RTC_ALARM_EN);
}

static int sprd_rtc_probe(struct platform_device *pdev)
{
        struct device_node *node = pdev->dev.of_node;
        struct sprd_rtc *rtc;
        int ret;

        rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
        if (!rtc)
                return -ENOMEM;

        rtc->regmap = dev_get_regmap(pdev->dev.parent, NULL);
        if (!rtc->regmap)
                return -ENODEV;

        ret = of_property_read_u32(node, "reg", &rtc->base);
        if (ret) {
                dev_err(&pdev->dev, "failed to get RTC base address\n");
                return ret;
        }

        rtc->irq = platform_get_irq(pdev, 0);
        if (rtc->irq < 0)
                return rtc->irq;

        rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
        if (IS_ERR(rtc->rtc))
                return PTR_ERR(rtc->rtc);

        rtc->dev = &pdev->dev;
        platform_set_drvdata(pdev, rtc);

        /* check if we need set the alarm interrupt */
        ret = sprd_rtc_check_alarm_int(rtc);
        if (ret) {
                dev_err(&pdev->dev, "failed to check RTC alarm interrupt\n");
                return ret;
        }

        /* check if RTC time values are valid */
        ret = sprd_rtc_check_power_down(rtc);
        if (ret) {
                dev_err(&pdev->dev, "failed to check RTC time values\n");
                return ret;
        }

        ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
                                        sprd_rtc_handler,
                                        IRQF_ONESHOT | IRQF_EARLY_RESUME,
                                        pdev->name, rtc);
        if (ret < 0) {
                dev_err(&pdev->dev, "failed to request RTC irq\n");
                return ret;
        }

        device_init_wakeup(&pdev->dev, true);

        rtc->rtc->ops = &sprd_rtc_ops;
        rtc->rtc->range_min = 0;
        rtc->rtc->range_max = 5662310399LL;
        ret = devm_rtc_register_device(rtc->rtc);
        if (ret) {
                device_init_wakeup(&pdev->dev, false);
                return ret;
        }

        return 0;
}

static const struct of_device_id sprd_rtc_of_match[] = {
        { .compatible = "sprd,sc2731-rtc", },
        { },
};
MODULE_DEVICE_TABLE(of, sprd_rtc_of_match);

static struct platform_driver sprd_rtc_driver = {
        .driver = {
                .name = "sprd-rtc",
                .of_match_table = sprd_rtc_of_match,
        },
        .probe  = sprd_rtc_probe,
};
module_platform_driver(sprd_rtc_driver);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Spreadtrum RTC Device Driver");
MODULE_AUTHOR("Baolin Wang <baolin.wang@spreadtrum.com>");