rtc-max8925.c

Go to the documentation of this file.

/*
 * RTC driver for Maxim MAX8925
 *
 * Copyright (C) 2009-2010 Marvell International Ltd.
 *  Haojian Zhuang <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <linux/mfd/max8925.h>

enum {
    RTC_SEC = 0,
    RTC_MIN,
    RTC_HOUR,
    RTC_WEEKDAY,
    RTC_DATE,
    RTC_MONTH,
    RTC_YEAR1,
    RTC_YEAR2,
};

#define MAX8925_RTC_SEC         0x00
#define MAX8925_RTC_MIN         0x01
#define MAX8925_RTC_HOUR        0x02
#define MAX8925_RTC_WEEKDAY     0x03
#define MAX8925_RTC_DATE        0x04
#define MAX8925_RTC_MONTH       0x05
#define MAX8925_RTC_YEAR1       0x06
#define MAX8925_RTC_YEAR2       0x07
#define MAX8925_ALARM0_SEC      0x08
#define MAX8925_ALARM0_MIN      0x09
#define MAX8925_ALARM0_HOUR     0x0a
#define MAX8925_ALARM0_WEEKDAY      0x0b
#define MAX8925_ALARM0_DATE     0x0c
#define MAX8925_ALARM0_MON      0x0d
#define MAX8925_ALARM0_YEAR1        0x0e
#define MAX8925_ALARM0_YEAR2        0x0f
#define MAX8925_ALARM1_SEC      0x10
#define MAX8925_ALARM1_MIN      0x11
#define MAX8925_ALARM1_HOUR     0x12
#define MAX8925_ALARM1_WEEKDAY      0x13
#define MAX8925_ALARM1_DATE     0x14
#define MAX8925_ALARM1_MON      0x15
#define MAX8925_ALARM1_YEAR1        0x16
#define MAX8925_ALARM1_YEAR2        0x17
#define MAX8925_RTC_CNTL        0x1b
#define MAX8925_RTC_STATUS      0x20

#define TIME_NUM            8
#define ALARM_1SEC          (1 << 7)
#define HOUR_12             (1 << 7)
#define HOUR_AM_PM          (1 << 5)
#define ALARM0_IRQ          (1 << 3)
#define ALARM1_IRQ          (1 << 2)
#define ALARM0_STATUS           (1 << 2)
#define ALARM1_STATUS           (1 << 1)


struct max8925_rtc_info {
    struct rtc_device   *rtc_dev;
    struct max8925_chip *chip;
    struct i2c_client   *rtc;
    struct device       *dev;
    int         irq;
};

static irqreturn_t rtc_update_handler(int irq, void *data)
{
    struct max8925_rtc_info *info = (struct max8925_rtc_info *)data;

    /* disable ALARM0 except for 1SEC alarm */
    max8925_set_bits(info->rtc, MAX8925_ALARM0_CNTL, 0x7f, 0);
    rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
    return IRQ_HANDLED;
}

static int tm_calc(struct rtc_time *tm, unsigned char *buf, int len)
{
    if (len < TIME_NUM)
        return -EINVAL;
    tm->tm_year = (buf[RTC_YEAR2] >> 4) * 1000
            + (buf[RTC_YEAR2] & 0xf) * 100
            + (buf[RTC_YEAR1] >> 4) * 10
            + (buf[RTC_YEAR1] & 0xf);
    tm->tm_year -= 1900;
    tm->tm_mon = ((buf[RTC_MONTH] >> 4) & 0x01) * 10
            + (buf[RTC_MONTH] & 0x0f);
    tm->tm_mday = ((buf[RTC_DATE] >> 4) & 0x03) * 10
            + (buf[RTC_DATE] & 0x0f);
    tm->tm_wday = buf[RTC_WEEKDAY] & 0x07;
    if (buf[RTC_HOUR] & HOUR_12) {
        tm->tm_hour = ((buf[RTC_HOUR] >> 4) & 0x1) * 10
                + (buf[RTC_HOUR] & 0x0f);
        if (buf[RTC_HOUR] & HOUR_AM_PM)
            tm->tm_hour += 12;
    } else
        tm->tm_hour = ((buf[RTC_HOUR] >> 4) & 0x03) * 10
                + (buf[RTC_HOUR] & 0x0f);
    tm->tm_min = ((buf[RTC_MIN] >> 4) & 0x7) * 10
            + (buf[RTC_MIN] & 0x0f);
    tm->tm_sec = ((buf[RTC_SEC] >> 4) & 0x7) * 10
            + (buf[RTC_SEC] & 0x0f);
    return 0;
}

static int data_calc(unsigned char *buf, struct rtc_time *tm, int len)
{
    unsigned char high, low;

    if (len < TIME_NUM)
        return -EINVAL;

    high = (tm->tm_year + 1900) / 1000;
    low = (tm->tm_year + 1900) / 100;
    low = low - high * 10;
    buf[RTC_YEAR2] = (high << 4) + low;
    high = (tm->tm_year + 1900) / 10;
    low = tm->tm_year + 1900;
    low = low - high * 10;
    high = high - (high / 10) * 10;
    buf[RTC_YEAR1] = (high << 4) + low;
    high = tm->tm_mon / 10;
    low = tm->tm_mon;
    low = low - high * 10;
    buf[RTC_MONTH] = (high << 4) + low;
    high = tm->tm_mday / 10;
    low = tm->tm_mday;
    low = low - high * 10;
    buf[RTC_DATE] = (high << 4) + low;
    buf[RTC_WEEKDAY] = tm->tm_wday;
    high = tm->tm_hour / 10;
    low = tm->tm_hour;
    low = low - high * 10;
    buf[RTC_HOUR] = (high << 4) + low;
    high = tm->tm_min / 10;
    low = tm->tm_min;
    low = low - high * 10;
    buf[RTC_MIN] = (high << 4) + low;
    high = tm->tm_sec / 10;
    low = tm->tm_sec;
    low = low - high * 10;
    buf[RTC_SEC] = (high << 4) + low;
    return 0;
}

static int max8925_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
    struct max8925_rtc_info *info = dev_get_drvdata(dev);
    unsigned char buf[TIME_NUM];
    int ret;

    ret = max8925_bulk_read(info->rtc, MAX8925_RTC_SEC, TIME_NUM, buf);
    if (ret < 0)
        goto out;
    ret = tm_calc(tm, buf, TIME_NUM);
out:
    return ret;
}

static int max8925_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
    struct max8925_rtc_info *info = dev_get_drvdata(dev);
    unsigned char buf[TIME_NUM];
    int ret;

    ret = data_calc(buf, tm, TIME_NUM);
    if (ret < 0)
        goto out;
    ret = max8925_bulk_write(info->rtc, MAX8925_RTC_SEC, TIME_NUM, buf);
out:
    return ret;
}

static int max8925_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct max8925_rtc_info *info = dev_get_drvdata(dev);
    unsigned char buf[TIME_NUM];
    int ret;

    ret = max8925_bulk_read(info->rtc, MAX8925_ALARM0_SEC, TIME_NUM, buf);
    if (ret < 0)
        goto out;
    ret = tm_calc(&alrm->time, buf, TIME_NUM);
    if (ret < 0)
        goto out;
    ret = max8925_reg_read(info->rtc, MAX8925_RTC_IRQ_MASK);
    if (ret < 0)
        goto out;
    if (ret & ALARM0_IRQ) {
        alrm->enabled = 0;
    } else {
        ret = max8925_reg_read(info->rtc, MAX8925_ALARM0_CNTL);
        if (ret < 0)
            goto out;
        if (!ret)
            alrm->enabled = 0;
        else
            alrm->enabled = 1;
    }
    ret = max8925_reg_read(info->rtc, MAX8925_RTC_STATUS);
    if (ret < 0)
        goto out;
    if (ret & ALARM0_STATUS)
        alrm->pending = 1;
    else
        alrm->pending = 0;
    return 0;
out:
    return ret;
}

static int max8925_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct max8925_rtc_info *info = dev_get_drvdata(dev);
    unsigned char buf[TIME_NUM];
    int ret;

    ret = data_calc(buf, &alrm->time, TIME_NUM);
    if (ret < 0)
        goto out;
    ret = max8925_bulk_write(info->rtc, MAX8925_ALARM0_SEC, TIME_NUM, buf);
    if (ret < 0)
        goto out;
    if (alrm->enabled)
        /* only enable alarm on year/month/day/hour/min/sec */
        ret = max8925_reg_write(info->rtc, MAX8925_ALARM0_CNTL, 0x77);
    else
        ret = max8925_reg_write(info->rtc, MAX8925_ALARM0_CNTL, 0x0);
    if (ret < 0)
        goto out;
out:
    return ret;
}

static const struct rtc_class_ops max8925_rtc_ops = {
    .read_time  = max8925_rtc_read_time,
    .set_time   = max8925_rtc_set_time,
    .read_alarm = max8925_rtc_read_alarm,
    .set_alarm  = max8925_rtc_set_alarm,
};

static int __devinit max8925_rtc_probe(struct platform_device *pdev)
{
    struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);
    struct max8925_rtc_info *info;
    int ret;

    info = kzalloc(sizeof(struct max8925_rtc_info), GFP_KERNEL);
    if (!info)
        return -ENOMEM;
    info->chip = chip;
    info->rtc = chip->rtc;
    info->dev = &pdev->dev;
    info->irq = platform_get_irq(pdev, 0);

    ret = request_threaded_irq(info->irq, NULL, rtc_update_handler,
                   IRQF_ONESHOT, "rtc-alarm0", info);
    if (ret < 0) {
        dev_err(chip->dev, "Failed to request IRQ: #%d: %d\n",
            info->irq, ret);
        goto out_irq;
    }

    dev_set_drvdata(&pdev->dev, info);
    /* XXX - isn't this redundant? */
    platform_set_drvdata(pdev, info);

    device_init_wakeup(&pdev->dev, 1);

    info->rtc_dev = rtc_device_register("max8925-rtc", &pdev->dev,
                    &max8925_rtc_ops, THIS_MODULE);
    ret = PTR_ERR(info->rtc_dev);
    if (IS_ERR(info->rtc_dev)) {
        dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
        goto out_rtc;
    }

    return 0;
out_rtc:
    platform_set_drvdata(pdev, NULL);
    free_irq(info->irq, info);
out_irq:
    kfree(info);
    return ret;
}

static int __devexit max8925_rtc_remove(struct platform_device *pdev)
{
    struct max8925_rtc_info *info = platform_get_drvdata(pdev);

    if (info) {
        free_irq(info->irq, info);
        rtc_device_unregister(info->rtc_dev);
        kfree(info);
    }
    return 0;
}

#ifdef CONFIG_PM_SLEEP
static int max8925_rtc_suspend(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);

    if (device_may_wakeup(dev))
        chip->wakeup_flag |= 1 << MAX8925_IRQ_RTC_ALARM0;
    return 0;
}
static int max8925_rtc_resume(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);

    if (device_may_wakeup(dev))
        chip->wakeup_flag &= ~(1 << MAX8925_IRQ_RTC_ALARM0);
    return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(max8925_rtc_pm_ops, max8925_rtc_suspend, max8925_rtc_resume);

static struct platform_driver max8925_rtc_driver = {
    .driver     = {
        .name   = "max8925-rtc",
        .owner  = THIS_MODULE,
        .pm     = &max8925_rtc_pm_ops,
    },
    .probe      = max8925_rtc_probe,
    .remove     = __devexit_p(max8925_rtc_remove),
};

module_platform_driver(max8925_rtc_driver);

MODULE_DESCRIPTION("Maxim MAX8925 RTC driver");
MODULE_AUTHOR("Haojian Zhuang <[email protected]>");
MODULE_LICENSE("GPL");