rtc-wm8350.c

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/*
 *  Real Time Clock driver for Wolfson Microelectronics WM8350
 *
 *  Copyright (C) 2007, 2008 Wolfson Microelectronics PLC.
 *
 *  Author: Liam Girdwood
 *          [email protected]
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/interrupt.h>
#include <linux/ioctl.h>
#include <linux/completion.h>
#include <linux/mfd/wm8350/rtc.h>
#include <linux/mfd/wm8350/core.h>
#include <linux/delay.h>
#include <linux/platform_device.h>

#define WM8350_SET_ALM_RETRIES  5
#define WM8350_SET_TIME_RETRIES 5
#define WM8350_GET_TIME_RETRIES 5

#define to_wm8350_from_rtc_dev(d) container_of(d, struct wm8350, rtc.pdev.dev)

/*
 * Read current time and date in RTC
 */
static int wm8350_rtc_readtime(struct device *dev, struct rtc_time *tm)
{
    struct wm8350 *wm8350 = dev_get_drvdata(dev);
    u16 time1[4], time2[4];
    int retries = WM8350_GET_TIME_RETRIES, ret;

    /*
     * Read the time twice and compare.
     * If time1 == time2, then time is valid else retry.
     */
    do {
        ret = wm8350_block_read(wm8350, WM8350_RTC_SECONDS_MINUTES,
                    4, time1);
        if (ret < 0)
            return ret;
        ret = wm8350_block_read(wm8350, WM8350_RTC_SECONDS_MINUTES,
                    4, time2);
        if (ret < 0)
            return ret;

        if (memcmp(time1, time2, sizeof(time1)) == 0) {
            tm->tm_sec = time1[0] & WM8350_RTC_SECS_MASK;

            tm->tm_min = (time1[0] & WM8350_RTC_MINS_MASK)
                >> WM8350_RTC_MINS_SHIFT;

            tm->tm_hour = time1[1] & WM8350_RTC_HRS_MASK;

            tm->tm_wday = ((time1[1] >> WM8350_RTC_DAY_SHIFT)
                       & 0x7) - 1;

            tm->tm_mon = ((time1[2] & WM8350_RTC_MTH_MASK)
                      >> WM8350_RTC_MTH_SHIFT) - 1;

            tm->tm_mday = (time1[2] & WM8350_RTC_DATE_MASK);

            tm->tm_year = ((time1[3] & WM8350_RTC_YHUNDREDS_MASK)
                       >> WM8350_RTC_YHUNDREDS_SHIFT) * 100;
            tm->tm_year += time1[3] & WM8350_RTC_YUNITS_MASK;

            tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon,
                            tm->tm_year);
            tm->tm_year -= 1900;

            dev_dbg(dev, "Read (%d left): %04x %04x %04x %04x\n",
                retries,
                time1[0], time1[1], time1[2], time1[3]);

            return 0;
        }
    } while (retries--);

    dev_err(dev, "timed out reading RTC time\n");
    return -EIO;
}

/*
 * Set current time and date in RTC
 */
static int wm8350_rtc_settime(struct device *dev, struct rtc_time *tm)
{
    struct wm8350 *wm8350 = dev_get_drvdata(dev);
    u16 time[4];
    u16 rtc_ctrl;
    int ret, retries = WM8350_SET_TIME_RETRIES;

    time[0] = tm->tm_sec;
    time[0] |= tm->tm_min << WM8350_RTC_MINS_SHIFT;
    time[1] = tm->tm_hour;
    time[1] |= (tm->tm_wday + 1) << WM8350_RTC_DAY_SHIFT;
    time[2] = tm->tm_mday;
    time[2] |= (tm->tm_mon + 1) << WM8350_RTC_MTH_SHIFT;
    time[3] = ((tm->tm_year + 1900) / 100) << WM8350_RTC_YHUNDREDS_SHIFT;
    time[3] |= (tm->tm_year + 1900) % 100;

    dev_dbg(dev, "Setting: %04x %04x %04x %04x\n",
        time[0], time[1], time[2], time[3]);

    /* Set RTC_SET to stop the clock */
    ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL, WM8350_RTC_SET);
    if (ret < 0)
        return ret;

    /* Wait until confirmation of stopping */
    do {
        rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
        schedule_timeout_uninterruptible(msecs_to_jiffies(1));
    } while (--retries && !(rtc_ctrl & WM8350_RTC_STS));

    if (!retries) {
        dev_err(dev, "timed out on set confirmation\n");
        return -EIO;
    }

    /* Write time to RTC */
    ret = wm8350_block_write(wm8350, WM8350_RTC_SECONDS_MINUTES, 4, time);
    if (ret < 0)
        return ret;

    /* Clear RTC_SET to start the clock */
    ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
                WM8350_RTC_SET);
    return ret;
}

/*
 * Read alarm time and date in RTC
 */
static int wm8350_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct wm8350 *wm8350 = dev_get_drvdata(dev);
    struct rtc_time *tm = &alrm->time;
    u16 time[4];
    int ret;

    ret = wm8350_block_read(wm8350, WM8350_ALARM_SECONDS_MINUTES, 4, time);
    if (ret < 0)
        return ret;

    tm->tm_sec = time[0] & WM8350_RTC_ALMSECS_MASK;
    if (tm->tm_sec == WM8350_RTC_ALMSECS_MASK)
        tm->tm_sec = -1;

    tm->tm_min = time[0] & WM8350_RTC_ALMMINS_MASK;
    if (tm->tm_min == WM8350_RTC_ALMMINS_MASK)
        tm->tm_min = -1;
    else
        tm->tm_min >>= WM8350_RTC_ALMMINS_SHIFT;

    tm->tm_hour = time[1] & WM8350_RTC_ALMHRS_MASK;
    if (tm->tm_hour == WM8350_RTC_ALMHRS_MASK)
        tm->tm_hour = -1;

    tm->tm_wday = ((time[1] >> WM8350_RTC_ALMDAY_SHIFT) & 0x7) - 1;
    if (tm->tm_wday > 7)
        tm->tm_wday = -1;

    tm->tm_mon = time[2] & WM8350_RTC_ALMMTH_MASK;
    if (tm->tm_mon == WM8350_RTC_ALMMTH_MASK)
        tm->tm_mon = -1;
    else
        tm->tm_mon = (tm->tm_mon >> WM8350_RTC_ALMMTH_SHIFT) - 1;

    tm->tm_mday = (time[2] & WM8350_RTC_ALMDATE_MASK);
    if (tm->tm_mday == WM8350_RTC_ALMDATE_MASK)
        tm->tm_mday = -1;

    tm->tm_year = -1;

    alrm->enabled = !(time[3] & WM8350_RTC_ALMSTS);

    return 0;
}

static int wm8350_rtc_stop_alarm(struct wm8350 *wm8350)
{
    int retries = WM8350_SET_ALM_RETRIES;
    u16 rtc_ctrl;
    int ret;

    /* Set RTC_SET to stop the clock */
    ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL,
                  WM8350_RTC_ALMSET);
    if (ret < 0)
        return ret;

    /* Wait until confirmation of stopping */
    do {
        rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
        schedule_timeout_uninterruptible(msecs_to_jiffies(1));
    } while (retries-- && !(rtc_ctrl & WM8350_RTC_ALMSTS));

    if (!(rtc_ctrl & WM8350_RTC_ALMSTS))
        return -ETIMEDOUT;

    return 0;
}

static int wm8350_rtc_start_alarm(struct wm8350 *wm8350)
{
    int ret;
    int retries = WM8350_SET_ALM_RETRIES;
    u16 rtc_ctrl;

    ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
                WM8350_RTC_ALMSET);
    if (ret < 0)
        return ret;

    /* Wait until confirmation */
    do {
        rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
        schedule_timeout_uninterruptible(msecs_to_jiffies(1));
    } while (retries-- && rtc_ctrl & WM8350_RTC_ALMSTS);

    if (rtc_ctrl & WM8350_RTC_ALMSTS)
        return -ETIMEDOUT;

    return 0;
}

static int wm8350_rtc_alarm_irq_enable(struct device *dev,
                       unsigned int enabled)
{
    struct wm8350 *wm8350 = dev_get_drvdata(dev);

    if (enabled)
        return wm8350_rtc_start_alarm(wm8350);
    else
        return wm8350_rtc_stop_alarm(wm8350);
}

static int wm8350_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct wm8350 *wm8350 = dev_get_drvdata(dev);
    struct rtc_time *tm = &alrm->time;
    u16 time[3];
    int ret;

    memset(time, 0, sizeof(time));

    if (tm->tm_sec != -1)
        time[0] |= tm->tm_sec;
    else
        time[0] |= WM8350_RTC_ALMSECS_MASK;

    if (tm->tm_min != -1)
        time[0] |= tm->tm_min << WM8350_RTC_ALMMINS_SHIFT;
    else
        time[0] |= WM8350_RTC_ALMMINS_MASK;

    if (tm->tm_hour != -1)
        time[1] |= tm->tm_hour;
    else
        time[1] |= WM8350_RTC_ALMHRS_MASK;

    if (tm->tm_wday != -1)
        time[1] |= (tm->tm_wday + 1) << WM8350_RTC_ALMDAY_SHIFT;
    else
        time[1] |= WM8350_RTC_ALMDAY_MASK;

    if (tm->tm_mday != -1)
        time[2] |= tm->tm_mday;
    else
        time[2] |= WM8350_RTC_ALMDATE_MASK;

    if (tm->tm_mon != -1)
        time[2] |= (tm->tm_mon + 1) << WM8350_RTC_ALMMTH_SHIFT;
    else
        time[2] |= WM8350_RTC_ALMMTH_MASK;

    ret = wm8350_rtc_stop_alarm(wm8350);
    if (ret < 0)
        return ret;

    /* Write time to RTC */
    ret = wm8350_block_write(wm8350, WM8350_ALARM_SECONDS_MINUTES,
                 3, time);
    if (ret < 0)
        return ret;

    if (alrm->enabled)
        ret = wm8350_rtc_start_alarm(wm8350);

    return ret;
}

static irqreturn_t wm8350_rtc_alarm_handler(int irq, void *data)
{
    struct wm8350 *wm8350 = data;
    struct rtc_device *rtc = wm8350->rtc.rtc;
    int ret;

    rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);

    /* Make it one shot */
    ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL,
                  WM8350_RTC_ALMSET);
    if (ret != 0) {
        dev_err(&(wm8350->rtc.pdev->dev),
            "Failed to disable alarm: %d\n", ret);
    }

    return IRQ_HANDLED;
}

static irqreturn_t wm8350_rtc_update_handler(int irq, void *data)
{
    struct wm8350 *wm8350 = data;
    struct rtc_device *rtc = wm8350->rtc.rtc;

    rtc_update_irq(rtc, 1, RTC_IRQF | RTC_UF);

    return IRQ_HANDLED;
}

static const struct rtc_class_ops wm8350_rtc_ops = {
    .read_time = wm8350_rtc_readtime,
    .set_time = wm8350_rtc_settime,
    .read_alarm = wm8350_rtc_readalarm,
    .set_alarm = wm8350_rtc_setalarm,
    .alarm_irq_enable = wm8350_rtc_alarm_irq_enable,
};

#ifdef CONFIG_PM
static int wm8350_rtc_suspend(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct wm8350 *wm8350 = dev_get_drvdata(&pdev->dev);
    int ret = 0;
    u16 reg;

    reg = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);

    if (device_may_wakeup(&wm8350->rtc.pdev->dev) &&
        reg & WM8350_RTC_ALMSTS) {
        ret = wm8350_rtc_stop_alarm(wm8350);
        if (ret != 0)
            dev_err(&pdev->dev, "Failed to stop RTC alarm: %d\n",
                ret);
    }

    return ret;
}

static int wm8350_rtc_resume(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct wm8350 *wm8350 = dev_get_drvdata(&pdev->dev);
    int ret;

    if (wm8350->rtc.alarm_enabled) {
        ret = wm8350_rtc_start_alarm(wm8350);
        if (ret != 0)
            dev_err(&pdev->dev,
                "Failed to restart RTC alarm: %d\n", ret);
    }

    return 0;
}

#else
#define wm8350_rtc_suspend NULL
#define wm8350_rtc_resume NULL
#endif

static int wm8350_rtc_probe(struct platform_device *pdev)
{
    struct wm8350 *wm8350 = platform_get_drvdata(pdev);
    struct wm8350_rtc *wm_rtc = &wm8350->rtc;
    int ret = 0;
    u16 timectl, power5;

    timectl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
    if (timectl & WM8350_RTC_BCD) {
        dev_err(&pdev->dev, "RTC BCD mode not supported\n");
        return -EINVAL;
    }
    if (timectl & WM8350_RTC_12HR) {
        dev_err(&pdev->dev, "RTC 12 hour mode not supported\n");
        return -EINVAL;
    }

    /* enable the RTC if it's not already enabled */
    power5 = wm8350_reg_read(wm8350, WM8350_POWER_MGMT_5);
    if (!(power5 &  WM8350_RTC_TICK_ENA)) {
        dev_info(wm8350->dev, "Starting RTC\n");

        wm8350_reg_unlock(wm8350);

        ret = wm8350_set_bits(wm8350, WM8350_POWER_MGMT_5,
                      WM8350_RTC_TICK_ENA);
        if (ret < 0) {
            dev_err(&pdev->dev, "failed to enable RTC: %d\n", ret);
            return ret;
        }

        wm8350_reg_lock(wm8350);
    }

    if (timectl & WM8350_RTC_STS) {
        int retries;

        ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
                    WM8350_RTC_SET);
        if (ret < 0) {
            dev_err(&pdev->dev, "failed to start: %d\n", ret);
            return ret;
        }

        retries = WM8350_SET_TIME_RETRIES;
        do {
            timectl = wm8350_reg_read(wm8350,
                          WM8350_RTC_TIME_CONTROL);
        } while (timectl & WM8350_RTC_STS && --retries);

        if (retries == 0) {
            dev_err(&pdev->dev, "failed to start: timeout\n");
            return -ENODEV;
        }
    }

    device_init_wakeup(&pdev->dev, 1);

    wm_rtc->rtc = rtc_device_register("wm8350", &pdev->dev,
                      &wm8350_rtc_ops, THIS_MODULE);
    if (IS_ERR(wm_rtc->rtc)) {
        ret = PTR_ERR(wm_rtc->rtc);
        dev_err(&pdev->dev, "failed to register RTC: %d\n", ret);
        return ret;
    }

    wm8350_register_irq(wm8350, WM8350_IRQ_RTC_SEC,
                wm8350_rtc_update_handler, 0,
                "RTC Seconds", wm8350);
    wm8350_mask_irq(wm8350, WM8350_IRQ_RTC_SEC);

    wm8350_register_irq(wm8350, WM8350_IRQ_RTC_ALM,
                wm8350_rtc_alarm_handler, 0,
                "RTC Alarm", wm8350);

    return 0;
}

static int __devexit wm8350_rtc_remove(struct platform_device *pdev)
{
    struct wm8350 *wm8350 = platform_get_drvdata(pdev);
    struct wm8350_rtc *wm_rtc = &wm8350->rtc;

    wm8350_free_irq(wm8350, WM8350_IRQ_RTC_SEC, wm8350);
    wm8350_free_irq(wm8350, WM8350_IRQ_RTC_ALM, wm8350);

    rtc_device_unregister(wm_rtc->rtc);

    return 0;
}

static struct dev_pm_ops wm8350_rtc_pm_ops = {
    .suspend = wm8350_rtc_suspend,
    .resume = wm8350_rtc_resume,
};

static struct platform_driver wm8350_rtc_driver = {
    .probe = wm8350_rtc_probe,
    .remove = __devexit_p(wm8350_rtc_remove),
    .driver = {
        .name = "wm8350-rtc",
        .pm = &wm8350_rtc_pm_ops,
    },
};

module_platform_driver(wm8350_rtc_driver);

MODULE_AUTHOR("Mark Brown <[email protected]>");
MODULE_DESCRIPTION("RTC driver for the WM8350");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm8350-rtc");