rtc-mv.c

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/*
 * Driver for the RTC in Marvell SoCs.
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2.  This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/delay.h>
#include <linux/gfp.h>
#include <linux/module.h>


#define RTC_TIME_REG_OFFS   0
#define RTC_SECONDS_OFFS    0
#define RTC_MINUTES_OFFS    8
#define RTC_HOURS_OFFS      16
#define RTC_WDAY_OFFS       24
#define RTC_HOURS_12H_MODE      (1 << 22) /* 12 hours mode */

#define RTC_DATE_REG_OFFS   4
#define RTC_MDAY_OFFS       0
#define RTC_MONTH_OFFS      8
#define RTC_YEAR_OFFS       16

#define RTC_ALARM_TIME_REG_OFFS 8
#define RTC_ALARM_DATE_REG_OFFS 0xc
#define RTC_ALARM_VALID     (1 << 7)

#define RTC_ALARM_INTERRUPT_MASK_REG_OFFS   0x10
#define RTC_ALARM_INTERRUPT_CASUE_REG_OFFS  0x14

struct rtc_plat_data {
    struct rtc_device *rtc;
    void __iomem *ioaddr;
    int     irq;
};

static int mv_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
    struct rtc_plat_data *pdata = dev_get_drvdata(dev);
    void __iomem *ioaddr = pdata->ioaddr;
    u32 rtc_reg;

    rtc_reg = (bin2bcd(tm->tm_sec) << RTC_SECONDS_OFFS) |
        (bin2bcd(tm->tm_min) << RTC_MINUTES_OFFS) |
        (bin2bcd(tm->tm_hour) << RTC_HOURS_OFFS) |
        (bin2bcd(tm->tm_wday) << RTC_WDAY_OFFS);
    writel(rtc_reg, ioaddr + RTC_TIME_REG_OFFS);

    rtc_reg = (bin2bcd(tm->tm_mday) << RTC_MDAY_OFFS) |
        (bin2bcd(tm->tm_mon + 1) << RTC_MONTH_OFFS) |
        (bin2bcd(tm->tm_year % 100) << RTC_YEAR_OFFS);
    writel(rtc_reg, ioaddr + RTC_DATE_REG_OFFS);

    return 0;
}

static int mv_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
    struct rtc_plat_data *pdata = dev_get_drvdata(dev);
    void __iomem *ioaddr = pdata->ioaddr;
    u32 rtc_time, rtc_date;
    unsigned int year, month, day, hour, minute, second, wday;

    rtc_time = readl(ioaddr + RTC_TIME_REG_OFFS);
    rtc_date = readl(ioaddr + RTC_DATE_REG_OFFS);

    second = rtc_time & 0x7f;
    minute = (rtc_time >> RTC_MINUTES_OFFS) & 0x7f;
    hour = (rtc_time >> RTC_HOURS_OFFS) & 0x3f; /* assume 24 hours mode */
    wday = (rtc_time >> RTC_WDAY_OFFS) & 0x7;

    day = rtc_date & 0x3f;
    month = (rtc_date >> RTC_MONTH_OFFS) & 0x3f;
    year = (rtc_date >> RTC_YEAR_OFFS) & 0xff;

    tm->tm_sec = bcd2bin(second);
    tm->tm_min = bcd2bin(minute);
    tm->tm_hour = bcd2bin(hour);
    tm->tm_mday = bcd2bin(day);
    tm->tm_wday = bcd2bin(wday);
    tm->tm_mon = bcd2bin(month) - 1;
    /* hw counts from year 2000, but tm_year is relative to 1900 */
    tm->tm_year = bcd2bin(year) + 100;

    return rtc_valid_tm(tm);
}

static int mv_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
    struct rtc_plat_data *pdata = dev_get_drvdata(dev);
    void __iomem *ioaddr = pdata->ioaddr;
    u32 rtc_time, rtc_date;
    unsigned int year, month, day, hour, minute, second, wday;

    rtc_time = readl(ioaddr + RTC_ALARM_TIME_REG_OFFS);
    rtc_date = readl(ioaddr + RTC_ALARM_DATE_REG_OFFS);

    second = rtc_time & 0x7f;
    minute = (rtc_time >> RTC_MINUTES_OFFS) & 0x7f;
    hour = (rtc_time >> RTC_HOURS_OFFS) & 0x3f; /* assume 24 hours mode */
    wday = (rtc_time >> RTC_WDAY_OFFS) & 0x7;

    day = rtc_date & 0x3f;
    month = (rtc_date >> RTC_MONTH_OFFS) & 0x3f;
    year = (rtc_date >> RTC_YEAR_OFFS) & 0xff;

    alm->time.tm_sec = bcd2bin(second);
    alm->time.tm_min = bcd2bin(minute);
    alm->time.tm_hour = bcd2bin(hour);
    alm->time.tm_mday = bcd2bin(day);
    alm->time.tm_wday = bcd2bin(wday);
    alm->time.tm_mon = bcd2bin(month) - 1;
    /* hw counts from year 2000, but tm_year is relative to 1900 */
    alm->time.tm_year = bcd2bin(year) + 100;

    if (rtc_valid_tm(&alm->time) < 0) {
        dev_err(dev, "retrieved alarm date/time is not valid.\n");
        rtc_time_to_tm(0, &alm->time);
    }

    alm->enabled = !!readl(ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);
    return 0;
}

static int mv_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
    struct rtc_plat_data *pdata = dev_get_drvdata(dev);
    void __iomem *ioaddr = pdata->ioaddr;
    u32 rtc_reg = 0;

    if (alm->time.tm_sec >= 0)
        rtc_reg |= (RTC_ALARM_VALID | bin2bcd(alm->time.tm_sec))
            << RTC_SECONDS_OFFS;
    if (alm->time.tm_min >= 0)
        rtc_reg |= (RTC_ALARM_VALID | bin2bcd(alm->time.tm_min))
            << RTC_MINUTES_OFFS;
    if (alm->time.tm_hour >= 0)
        rtc_reg |= (RTC_ALARM_VALID | bin2bcd(alm->time.tm_hour))
            << RTC_HOURS_OFFS;

    writel(rtc_reg, ioaddr + RTC_ALARM_TIME_REG_OFFS);

    if (alm->time.tm_mday >= 0)
        rtc_reg = (RTC_ALARM_VALID | bin2bcd(alm->time.tm_mday))
            << RTC_MDAY_OFFS;
    else
        rtc_reg = 0;

    if (alm->time.tm_mon >= 0)
        rtc_reg |= (RTC_ALARM_VALID | bin2bcd(alm->time.tm_mon + 1))
            << RTC_MONTH_OFFS;

    if (alm->time.tm_year >= 0)
        rtc_reg |= (RTC_ALARM_VALID | bin2bcd(alm->time.tm_year % 100))
            << RTC_YEAR_OFFS;

    writel(rtc_reg, ioaddr + RTC_ALARM_DATE_REG_OFFS);
    writel(0, ioaddr + RTC_ALARM_INTERRUPT_CASUE_REG_OFFS);
    writel(alm->enabled ? 1 : 0,
           ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);

    return 0;
}

static int mv_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
    void __iomem *ioaddr = pdata->ioaddr;

    if (pdata->irq < 0)
        return -EINVAL; /* fall back into rtc-dev's emulation */

    if (enabled)
        writel(1, ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);
    else
        writel(0, ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);
    return 0;
}

static irqreturn_t mv_rtc_interrupt(int irq, void *data)
{
    struct rtc_plat_data *pdata = data;
    void __iomem *ioaddr = pdata->ioaddr;

    /* alarm irq? */
    if (!readl(ioaddr + RTC_ALARM_INTERRUPT_CASUE_REG_OFFS))
        return IRQ_NONE;

    /* clear interrupt */
    writel(0, ioaddr + RTC_ALARM_INTERRUPT_CASUE_REG_OFFS);
    rtc_update_irq(pdata->rtc, 1, RTC_IRQF | RTC_AF);
    return IRQ_HANDLED;
}

static const struct rtc_class_ops mv_rtc_ops = {
    .read_time  = mv_rtc_read_time,
    .set_time   = mv_rtc_set_time,
};

static const struct rtc_class_ops mv_rtc_alarm_ops = {
    .read_time  = mv_rtc_read_time,
    .set_time   = mv_rtc_set_time,
    .read_alarm = mv_rtc_read_alarm,
    .set_alarm  = mv_rtc_set_alarm,
    .alarm_irq_enable = mv_rtc_alarm_irq_enable,
};

static int __devinit mv_rtc_probe(struct platform_device *pdev)
{
    struct resource *res;
    struct rtc_plat_data *pdata;
    resource_size_t size;
    u32 rtc_time;

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!res)
        return -ENODEV;

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

    size = resource_size(res);
    if (!devm_request_mem_region(&pdev->dev, res->start, size,
                     pdev->name))
        return -EBUSY;

    pdata->ioaddr = devm_ioremap(&pdev->dev, res->start, size);
    if (!pdata->ioaddr)
        return -ENOMEM;

    /* make sure the 24 hours mode is enabled */
    rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
    if (rtc_time & RTC_HOURS_12H_MODE) {
        dev_err(&pdev->dev, "24 Hours mode not supported.\n");
        return -EINVAL;
    }

    /* make sure it is actually functional */
    if (rtc_time == 0x01000000) {
        ssleep(1);
        rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
        if (rtc_time == 0x01000000) {
            dev_err(&pdev->dev, "internal RTC not ticking\n");
            return -ENODEV;
        }
    }

    pdata->irq = platform_get_irq(pdev, 0);

    platform_set_drvdata(pdev, pdata);

    if (pdata->irq >= 0) {
        device_init_wakeup(&pdev->dev, 1);
        pdata->rtc = rtc_device_register(pdev->name, &pdev->dev,
                         &mv_rtc_alarm_ops,
                         THIS_MODULE);
    } else
        pdata->rtc = rtc_device_register(pdev->name, &pdev->dev,
                         &mv_rtc_ops, THIS_MODULE);
    if (IS_ERR(pdata->rtc))
        return PTR_ERR(pdata->rtc);

    if (pdata->irq >= 0) {
        writel(0, pdata->ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);
        if (devm_request_irq(&pdev->dev, pdata->irq, mv_rtc_interrupt,
                     IRQF_SHARED,
                     pdev->name, pdata) < 0) {
            dev_warn(&pdev->dev, "interrupt not available.\n");
            pdata->irq = -1;
        }
    }

    return 0;
}

static int __exit mv_rtc_remove(struct platform_device *pdev)
{
    struct rtc_plat_data *pdata = platform_get_drvdata(pdev);

    if (pdata->irq >= 0)
        device_init_wakeup(&pdev->dev, 0);

    rtc_device_unregister(pdata->rtc);
    return 0;
}

#ifdef CONFIG_OF
static struct of_device_id rtc_mv_of_match_table[] = {
    { .compatible = "marvell,orion-rtc", },
    {}
};
#endif

static struct platform_driver mv_rtc_driver = {
    .remove     = __exit_p(mv_rtc_remove),
    .driver     = {
        .name   = "rtc-mv",
        .owner  = THIS_MODULE,
        .of_match_table = of_match_ptr(rtc_mv_of_match_table),
    },
};

static __init int mv_init(void)
{
    return platform_driver_probe(&mv_rtc_driver, mv_rtc_probe);
}

static __exit void mv_exit(void)
{
    platform_driver_unregister(&mv_rtc_driver);
}

module_init(mv_init);
module_exit(mv_exit);

MODULE_AUTHOR("Saeed Bishara <[email protected]>");
MODULE_DESCRIPTION("Marvell RTC driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:rtc-mv");