root/drivers/rtc/rtc-as3722.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * rtc-as3722.c - Real Time Clock driver for ams AS3722 PMICs
 *
 * Copyright (C) 2013 ams AG
 * Copyright (c) 2013, NVIDIA Corporation. All rights reserved.
 *
 * Author: Florian Lobmaier <florian.lobmaier@ams.com>
 * Author: Laxman Dewangan <ldewangan@nvidia.com>
 */

#include <linux/bcd.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/ioctl.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mfd/as3722.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/time.h>

#define AS3722_RTC_START_YEAR     2000
struct as3722_rtc {
        struct rtc_device       *rtc;
        struct device           *dev;
        struct as3722           *as3722;
        int                     alarm_irq;
        bool                    irq_enable;
};

static void as3722_time_to_reg(u8 *rbuff, struct rtc_time *tm)
{
        rbuff[0] = bin2bcd(tm->tm_sec);
        rbuff[1] = bin2bcd(tm->tm_min);
        rbuff[2] = bin2bcd(tm->tm_hour);
        rbuff[3] = bin2bcd(tm->tm_mday);
        rbuff[4] = bin2bcd(tm->tm_mon + 1);
        rbuff[5] = bin2bcd(tm->tm_year - (AS3722_RTC_START_YEAR - 1900));
}

static void as3722_reg_to_time(u8 *rbuff, struct rtc_time *tm)
{
        tm->tm_sec = bcd2bin(rbuff[0] & 0x7F);
        tm->tm_min = bcd2bin(rbuff[1] & 0x7F);
        tm->tm_hour = bcd2bin(rbuff[2] & 0x3F);
        tm->tm_mday = bcd2bin(rbuff[3] & 0x3F);
        tm->tm_mon = bcd2bin(rbuff[4] & 0x1F) - 1;
        tm->tm_year = (AS3722_RTC_START_YEAR - 1900) + bcd2bin(rbuff[5] & 0x7F);
        return;
}

static int as3722_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
        struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
        struct as3722 *as3722 = as3722_rtc->as3722;
        u8 as_time_array[6];
        int ret;

        ret = as3722_block_read(as3722, AS3722_RTC_SECOND_REG,
                        6, as_time_array);
        if (ret < 0) {
                dev_err(dev, "RTC_SECOND reg block read failed %d\n", ret);
                return ret;
        }
        as3722_reg_to_time(as_time_array, tm);
        return 0;
}

static int as3722_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
        struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
        struct as3722 *as3722 = as3722_rtc->as3722;
        u8 as_time_array[6];
        int ret;

        if (tm->tm_year < (AS3722_RTC_START_YEAR - 1900))
                return -EINVAL;

        as3722_time_to_reg(as_time_array, tm);
        ret = as3722_block_write(as3722, AS3722_RTC_SECOND_REG, 6,
                        as_time_array);
        if (ret < 0)
                dev_err(dev, "RTC_SECOND reg block write failed %d\n", ret);
        return ret;
}

static int as3722_rtc_alarm_irq_enable(struct device *dev,
                unsigned int enabled)
{
        struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);

        if (enabled && !as3722_rtc->irq_enable) {
                enable_irq(as3722_rtc->alarm_irq);
                as3722_rtc->irq_enable = true;
        } else if (!enabled && as3722_rtc->irq_enable)  {
                disable_irq(as3722_rtc->alarm_irq);
                as3722_rtc->irq_enable = false;
        }
        return 0;
}

static int as3722_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
        struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
        struct as3722 *as3722 = as3722_rtc->as3722;
        u8 as_time_array[6];
        int ret;

        ret = as3722_block_read(as3722, AS3722_RTC_ALARM_SECOND_REG, 6,
                        as_time_array);
        if (ret < 0) {
                dev_err(dev, "RTC_ALARM_SECOND block read failed %d\n", ret);
                return ret;
        }

        as3722_reg_to_time(as_time_array, &alrm->time);
        return 0;
}

static int as3722_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
        struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);
        struct as3722 *as3722 = as3722_rtc->as3722;
        u8 as_time_array[6];
        int ret;

        if (alrm->time.tm_year < (AS3722_RTC_START_YEAR - 1900))
                return -EINVAL;

        ret = as3722_rtc_alarm_irq_enable(dev, 0);
        if (ret < 0) {
                dev_err(dev, "Disable RTC alarm failed\n");
                return ret;
        }

        as3722_time_to_reg(as_time_array, &alrm->time);
        ret = as3722_block_write(as3722, AS3722_RTC_ALARM_SECOND_REG, 6,
                        as_time_array);
        if (ret < 0) {
                dev_err(dev, "RTC_ALARM_SECOND block write failed %d\n", ret);
                return ret;
        }

        if (alrm->enabled)
                ret = as3722_rtc_alarm_irq_enable(dev, alrm->enabled);
        return ret;
}

static irqreturn_t as3722_alarm_irq(int irq, void *data)
{
        struct as3722_rtc *as3722_rtc = data;

        rtc_update_irq(as3722_rtc->rtc, 1, RTC_IRQF | RTC_AF);
        return IRQ_HANDLED;
}

static const struct rtc_class_ops as3722_rtc_ops = {
        .read_time = as3722_rtc_read_time,
        .set_time = as3722_rtc_set_time,
        .read_alarm = as3722_rtc_read_alarm,
        .set_alarm = as3722_rtc_set_alarm,
        .alarm_irq_enable = as3722_rtc_alarm_irq_enable,
};

static int as3722_rtc_probe(struct platform_device *pdev)
{
        struct as3722 *as3722 = dev_get_drvdata(pdev->dev.parent);
        struct as3722_rtc *as3722_rtc;
        int ret;

        as3722_rtc = devm_kzalloc(&pdev->dev, sizeof(*as3722_rtc), GFP_KERNEL);
        if (!as3722_rtc)
                return -ENOMEM;

        as3722_rtc->as3722 = as3722;
        as3722_rtc->dev = &pdev->dev;
        platform_set_drvdata(pdev, as3722_rtc);

        /* Enable the RTC to make sure it is running. */
        ret = as3722_update_bits(as3722, AS3722_RTC_CONTROL_REG,
                        AS3722_RTC_ON | AS3722_RTC_ALARM_WAKEUP_EN,
                        AS3722_RTC_ON | AS3722_RTC_ALARM_WAKEUP_EN);
        if (ret < 0) {
                dev_err(&pdev->dev, "RTC_CONTROL reg write failed: %d\n", ret);
                return ret;
        }

        device_init_wakeup(&pdev->dev, true);

        as3722_rtc->rtc = devm_rtc_device_register(&pdev->dev, "as3722-rtc",
                                &as3722_rtc_ops, THIS_MODULE);
        if (IS_ERR(as3722_rtc->rtc)) {
                ret = PTR_ERR(as3722_rtc->rtc);
                dev_err(&pdev->dev, "RTC register failed: %d\n", ret);
                return ret;
        }

        as3722_rtc->alarm_irq = platform_get_irq(pdev, 0);
        dev_info(&pdev->dev, "RTC interrupt %d\n", as3722_rtc->alarm_irq);

        ret = devm_request_threaded_irq(&pdev->dev, as3722_rtc->alarm_irq, NULL,
                        as3722_alarm_irq, IRQF_ONESHOT,
                        "rtc-alarm", as3722_rtc);
        if (ret < 0) {
                dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
                                as3722_rtc->alarm_irq, ret);
                return ret;
        }
        disable_irq(as3722_rtc->alarm_irq);
        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int as3722_rtc_suspend(struct device *dev)
{
        struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);

        if (device_may_wakeup(dev))
                enable_irq_wake(as3722_rtc->alarm_irq);

        return 0;
}

static int as3722_rtc_resume(struct device *dev)
{
        struct as3722_rtc *as3722_rtc = dev_get_drvdata(dev);

        if (device_may_wakeup(dev))
                disable_irq_wake(as3722_rtc->alarm_irq);
        return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(as3722_rtc_pm_ops, as3722_rtc_suspend,
                         as3722_rtc_resume);

static struct platform_driver as3722_rtc_driver = {
        .probe = as3722_rtc_probe,
        .driver = {
                .name = "as3722-rtc",
                .pm = &as3722_rtc_pm_ops,
        },
};
module_platform_driver(as3722_rtc_driver);

MODULE_DESCRIPTION("RTC driver for AS3722 PMICs");
MODULE_ALIAS("platform:as3722-rtc");
MODULE_AUTHOR("Florian Lobmaier <florian.lobmaier@ams.com>");
MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
MODULE_LICENSE("GPL");