// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Real time clock driver for DA9055
 *
 * Copyright(c) 2012 Dialog Semiconductor Ltd.
 *
 * Author: Dajun Dajun Chen <dajun.chen@diasemi.com>
 */

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>

#include <linux/mfd/da9055/core.h>
#include <linux/mfd/da9055/reg.h>
#include <linux/mfd/da9055/pdata.h>

struct da9055_rtc {
        struct rtc_device *rtc;
        struct da9055 *da9055;
        int alarm_enable;
};

static int da9055_rtc_enable_alarm(struct da9055_rtc *rtc, bool enable)
{
        int ret;
        if (enable) {
                ret = da9055_reg_update(rtc->da9055, DA9055_REG_ALARM_Y,
                                        DA9055_RTC_ALM_EN,
                                        DA9055_RTC_ALM_EN);
                if (ret != 0)
                        dev_err(rtc->da9055->dev, "Failed to enable ALM: %d\n",
                                ret);
                rtc->alarm_enable = 1;
        } else {
                ret = da9055_reg_update(rtc->da9055, DA9055_REG_ALARM_Y,
                                        DA9055_RTC_ALM_EN, 0);
                if (ret != 0)
                        dev_err(rtc->da9055->dev,
                                "Failed to disable ALM: %d\n", ret);
                rtc->alarm_enable = 0;
        }
        return ret;
}

static irqreturn_t da9055_rtc_alm_irq(int irq, void *data)
{
        struct da9055_rtc *rtc = data;

        da9055_rtc_enable_alarm(rtc, 0);
        rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);

        return IRQ_HANDLED;
}

static int da9055_read_alarm(struct da9055 *da9055, struct rtc_time *rtc_tm)
{
        int ret;
        uint8_t v[5];

        ret = da9055_group_read(da9055, DA9055_REG_ALARM_MI, 5, v);
        if (ret != 0) {
                dev_err(da9055->dev, "Failed to group read ALM: %d\n", ret);
                return ret;
        }

        rtc_tm->tm_year = (v[4] & DA9055_RTC_ALM_YEAR) + 100;
        rtc_tm->tm_mon  = (v[3] & DA9055_RTC_ALM_MONTH) - 1;
        rtc_tm->tm_mday = v[2] & DA9055_RTC_ALM_DAY;
        rtc_tm->tm_hour = v[1] & DA9055_RTC_ALM_HOUR;
        rtc_tm->tm_min  = v[0] & DA9055_RTC_ALM_MIN;
        rtc_tm->tm_sec = 0;

        return rtc_valid_tm(rtc_tm);
}

static int da9055_set_alarm(struct da9055 *da9055, struct rtc_time *rtc_tm)
{
        int ret;
        uint8_t v[2];

        rtc_tm->tm_year -= 100;
        rtc_tm->tm_mon += 1;

        ret = da9055_reg_update(da9055, DA9055_REG_ALARM_MI,
                                DA9055_RTC_ALM_MIN, rtc_tm->tm_min);
        if (ret != 0) {
                dev_err(da9055->dev, "Failed to write ALRM MIN: %d\n", ret);
                return ret;
        }

        v[0] = rtc_tm->tm_hour;
        v[1] = rtc_tm->tm_mday;

        ret = da9055_group_write(da9055, DA9055_REG_ALARM_H, 2, v);
        if (ret < 0)
                return ret;

        ret = da9055_reg_update(da9055, DA9055_REG_ALARM_MO,
                                DA9055_RTC_ALM_MONTH, rtc_tm->tm_mon);
        if (ret < 0)
                dev_err(da9055->dev, "Failed to write ALM Month:%d\n", ret);

        ret = da9055_reg_update(da9055, DA9055_REG_ALARM_Y,
                                DA9055_RTC_ALM_YEAR, rtc_tm->tm_year);
        if (ret < 0)
                dev_err(da9055->dev, "Failed to write ALM Year:%d\n", ret);

        return ret;
}

static int da9055_rtc_get_alarm_status(struct da9055 *da9055)
{
        int ret;

        ret = da9055_reg_read(da9055, DA9055_REG_ALARM_Y);
        if (ret < 0) {
                dev_err(da9055->dev, "Failed to read ALM: %d\n", ret);
                return ret;
        }
        ret &= DA9055_RTC_ALM_EN;
        return (ret > 0) ? 1 : 0;
}

static int da9055_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
{
        struct da9055_rtc *rtc = dev_get_drvdata(dev);
        uint8_t v[6];
        int ret;

        ret = da9055_reg_read(rtc->da9055, DA9055_REG_COUNT_S);
        if (ret < 0)
                return ret;

        /*
         * Registers are only valid when RTC_READ
         * status bit is asserted
         */
        if (!(ret & DA9055_RTC_READ))
                return -EBUSY;

        ret = da9055_group_read(rtc->da9055, DA9055_REG_COUNT_S, 6, v);
        if (ret < 0) {
                dev_err(rtc->da9055->dev, "Failed to read RTC time : %d\n",
                        ret);
                return ret;
        }

        rtc_tm->tm_year = (v[5] & DA9055_RTC_YEAR) + 100;
        rtc_tm->tm_mon  = (v[4] & DA9055_RTC_MONTH) - 1;
        rtc_tm->tm_mday = v[3] & DA9055_RTC_DAY;
        rtc_tm->tm_hour = v[2] & DA9055_RTC_HOUR;
        rtc_tm->tm_min  = v[1] & DA9055_RTC_MIN;
        rtc_tm->tm_sec  = v[0] & DA9055_RTC_SEC;

        return 0;
}

static int da9055_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
        struct da9055_rtc *rtc;
        uint8_t v[6];

        rtc = dev_get_drvdata(dev);

        v[0] = tm->tm_sec;
        v[1] = tm->tm_min;
        v[2] = tm->tm_hour;
        v[3] = tm->tm_mday;
        v[4] = tm->tm_mon + 1;
        v[5] = tm->tm_year - 100;

        return da9055_group_write(rtc->da9055, DA9055_REG_COUNT_S, 6, v);
}

static int da9055_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
        int ret;
        struct rtc_time *tm = &alrm->time;
        struct da9055_rtc *rtc = dev_get_drvdata(dev);

        ret = da9055_read_alarm(rtc->da9055, tm);

        if (ret)
                return ret;

        alrm->enabled = da9055_rtc_get_alarm_status(rtc->da9055);

        return 0;
}

static int da9055_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
        int ret;
        struct rtc_time *tm = &alrm->time;
        struct da9055_rtc *rtc = dev_get_drvdata(dev);

        ret = da9055_rtc_enable_alarm(rtc, 0);
        if (ret < 0)
                return ret;

        ret = da9055_set_alarm(rtc->da9055, tm);
        if (ret)
                return ret;

        ret = da9055_rtc_enable_alarm(rtc, 1);

        return ret;
}

static int da9055_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
        struct da9055_rtc *rtc = dev_get_drvdata(dev);

        return da9055_rtc_enable_alarm(rtc, enabled);
}

static const struct rtc_class_ops da9055_rtc_ops = {
        .read_time      = da9055_rtc_read_time,
        .set_time       = da9055_rtc_set_time,
        .read_alarm     = da9055_rtc_read_alarm,
        .set_alarm      = da9055_rtc_set_alarm,
        .alarm_irq_enable = da9055_rtc_alarm_irq_enable,
};

static int da9055_rtc_device_init(struct da9055 *da9055,
                                        struct da9055_pdata *pdata)
{
        int ret;

        /* Enable RTC and the internal Crystal */
        ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
                                DA9055_RTC_EN, DA9055_RTC_EN);
        if (ret < 0)
                return ret;
        ret = da9055_reg_update(da9055, DA9055_REG_EN_32K,
                                DA9055_CRYSTAL_EN, DA9055_CRYSTAL_EN);
        if (ret < 0)
                return ret;

        /* Enable RTC in Power Down mode */
        ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
                                DA9055_RTC_MODE_PD, DA9055_RTC_MODE_PD);
        if (ret < 0)
                return ret;

        /* Enable RTC in Reset mode */
        if (pdata && pdata->reset_enable) {
                ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B,
                                        DA9055_RTC_MODE_SD,
                                        DA9055_RTC_MODE_SD <<
                                        DA9055_RTC_MODE_SD_SHIFT);
                if (ret < 0)
                        return ret;
        }

        /* Disable the RTC TICK ALM */
        ret = da9055_reg_update(da9055, DA9055_REG_ALARM_MO,
                                DA9055_RTC_TICK_WAKE_MASK, 0);
        if (ret < 0)
                return ret;

        return 0;
}

static int da9055_rtc_probe(struct platform_device *pdev)
{
        struct da9055_rtc *rtc;
        struct da9055_pdata *pdata = NULL;
        int ret, alm_irq;

        rtc = devm_kzalloc(&pdev->dev, sizeof(struct da9055_rtc), GFP_KERNEL);
        if (!rtc)
                return -ENOMEM;

        rtc->da9055 = dev_get_drvdata(pdev->dev.parent);
        pdata = dev_get_platdata(rtc->da9055->dev);
        platform_set_drvdata(pdev, rtc);

        ret = da9055_rtc_device_init(rtc->da9055, pdata);
        if (ret < 0)
                goto err_rtc;

        ret = da9055_reg_read(rtc->da9055, DA9055_REG_ALARM_Y);
        if (ret < 0)
                goto err_rtc;

        if (ret & DA9055_RTC_ALM_EN)
                rtc->alarm_enable = 1;

        device_init_wakeup(&pdev->dev, true);

        rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
                                        &da9055_rtc_ops, THIS_MODULE);
        if (IS_ERR(rtc->rtc)) {
                ret = PTR_ERR(rtc->rtc);
                goto err_rtc;
        }

        alm_irq = platform_get_irq_byname(pdev, "ALM");
        if (alm_irq < 0)
                return alm_irq;

        ret = devm_request_threaded_irq(&pdev->dev, alm_irq, NULL,
                                        da9055_rtc_alm_irq,
                                        IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
                                        "ALM", rtc);
        if (ret != 0)
                dev_err(rtc->da9055->dev, "irq registration failed: %d\n", ret);

err_rtc:
        return ret;

}

#ifdef CONFIG_PM
/* Turn off the alarm if it should not be a wake source. */
static int da9055_rtc_suspend(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct da9055_rtc *rtc = dev_get_drvdata(&pdev->dev);
        int ret;

        if (!device_may_wakeup(&pdev->dev)) {
                /* Disable the ALM IRQ */
                ret = da9055_rtc_enable_alarm(rtc, 0);
                if (ret < 0)
                        dev_err(&pdev->dev, "Failed to disable RTC ALM\n");
        }

        return 0;
}

/* Enable the alarm if it should be enabled (in case it was disabled to
 * prevent use as a wake source).
 */
static int da9055_rtc_resume(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct da9055_rtc *rtc = dev_get_drvdata(&pdev->dev);
        int ret;

        if (!device_may_wakeup(&pdev->dev)) {
                if (rtc->alarm_enable) {
                        ret = da9055_rtc_enable_alarm(rtc, 1);
                        if (ret < 0)
                                dev_err(&pdev->dev,
                                        "Failed to restart RTC ALM\n");
                }
        }

        return 0;
}

/* Unconditionally disable the alarm */
static int da9055_rtc_freeze(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct da9055_rtc *rtc = dev_get_drvdata(&pdev->dev);
        int ret;

        ret = da9055_rtc_enable_alarm(rtc, 0);
        if (ret < 0)
                dev_err(&pdev->dev, "Failed to freeze RTC ALMs\n");

        return 0;

}
#else
#define da9055_rtc_suspend NULL
#define da9055_rtc_resume NULL
#define da9055_rtc_freeze NULL
#endif

static const struct dev_pm_ops da9055_rtc_pm_ops = {
        .suspend = da9055_rtc_suspend,
        .resume = da9055_rtc_resume,

        .freeze = da9055_rtc_freeze,
        .thaw = da9055_rtc_resume,
        .restore = da9055_rtc_resume,

        .poweroff = da9055_rtc_suspend,
};

static struct platform_driver da9055_rtc_driver = {
        .probe  = da9055_rtc_probe,
        .driver = {
                .name   = "da9055-rtc",
                .pm = &da9055_rtc_pm_ops,
        },
};

module_platform_driver(da9055_rtc_driver);

MODULE_AUTHOR("David Dajun Chen <dchen@diasemi.com>");
MODULE_DESCRIPTION("RTC driver for Dialog DA9055 PMIC");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:da9055-rtc");