rtc-max8907.c

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/*
 * RTC driver for Maxim MAX8907
 *
 * Copyright (c) 2011-2012, NVIDIA Corporation.
 *
 * Based on drivers/rtc/rtc-max8925.c,
 * Copyright (C) 2009-2010 Marvell International Ltd.
 *
 * 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/bcd.h>
#include <linux/i2c.h>
#include <linux/mfd/max8907.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/rtc.h>
#include <linux/slab.h>

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

#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 max8907_rtc {
    struct max8907      *max8907;
    struct regmap       *regmap;
    struct rtc_device   *rtc_dev;
    int         irq;
};

static irqreturn_t max8907_irq_handler(int irq, void *data)
{
    struct max8907_rtc *rtc = data;

    regmap_update_bits(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0x7f, 0);

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

    return IRQ_HANDLED;
}

static void regs_to_tm(u8 *regs, struct rtc_time *tm)
{
    tm->tm_year = bcd2bin(regs[RTC_YEAR2]) * 100 +
        bcd2bin(regs[RTC_YEAR1]) - 1900;
    tm->tm_mon = bcd2bin(regs[RTC_MONTH] & 0x1f) - 1;
    tm->tm_mday = bcd2bin(regs[RTC_DATE] & 0x3f);
    tm->tm_wday = (regs[RTC_WEEKDAY] & 0x07) - 1;
    if (regs[RTC_HOUR] & HOUR_12) {
        tm->tm_hour = bcd2bin(regs[RTC_HOUR] & 0x01f);
        if (tm->tm_hour == 12)
            tm->tm_hour = 0;
        if (regs[RTC_HOUR] & HOUR_AM_PM)
            tm->tm_hour += 12;
    } else {
        tm->tm_hour = bcd2bin(regs[RTC_HOUR] & 0x03f);
    }
    tm->tm_min = bcd2bin(regs[RTC_MIN] & 0x7f);
    tm->tm_sec = bcd2bin(regs[RTC_SEC] & 0x7f);
}

static void tm_to_regs(struct rtc_time *tm, u8 *regs)
{
    u8 high, low;

    high = (tm->tm_year + 1900) / 100;
    low = tm->tm_year % 100;
    regs[RTC_YEAR2] = bin2bcd(high);
    regs[RTC_YEAR1] = bin2bcd(low);
    regs[RTC_MONTH] = bin2bcd(tm->tm_mon + 1);
    regs[RTC_DATE] = bin2bcd(tm->tm_mday);
    regs[RTC_WEEKDAY] = tm->tm_wday + 1;
    regs[RTC_HOUR] = bin2bcd(tm->tm_hour);
    regs[RTC_MIN] = bin2bcd(tm->tm_min);
    regs[RTC_SEC] = bin2bcd(tm->tm_sec);
}

static int max8907_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
    struct max8907_rtc *rtc = dev_get_drvdata(dev);
    u8 regs[TIME_NUM];
    int ret;

    ret = regmap_bulk_read(rtc->regmap, MAX8907_REG_RTC_SEC, regs,
                   TIME_NUM);
    if (ret < 0)
        return ret;

    regs_to_tm(regs, tm);

    return 0;
}

static int max8907_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
    struct max8907_rtc *rtc = dev_get_drvdata(dev);
    u8 regs[TIME_NUM];

    tm_to_regs(tm, regs);

    return regmap_bulk_write(rtc->regmap, MAX8907_REG_RTC_SEC, regs,
                 TIME_NUM);
}

static int max8907_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct max8907_rtc *rtc = dev_get_drvdata(dev);
    u8 regs[TIME_NUM];
    unsigned int val;
    int ret;

    ret = regmap_bulk_read(rtc->regmap, MAX8907_REG_ALARM0_SEC, regs,
                   TIME_NUM);
    if (ret < 0)
        return ret;

    regs_to_tm(regs, &alrm->time);

    ret = regmap_read(rtc->regmap, MAX8907_REG_ALARM0_CNTL, &val);
    if (ret < 0)
        return ret;

    alrm->enabled = !!(val & 0x7f);

    return 0;
}

static int max8907_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct max8907_rtc *rtc = dev_get_drvdata(dev);
    u8 regs[TIME_NUM];
    int ret;

    tm_to_regs(&alrm->time, regs);

    /* Disable alarm while we update the target time */
    ret = regmap_update_bits(rtc->regmap, MAX8907_REG_ALARM0_CNTL, 0x7f, 0);
    if (ret < 0)
        return ret;

    ret = regmap_bulk_write(rtc->regmap, MAX8907_REG_ALARM0_SEC, regs,
                TIME_NUM);
    if (ret < 0)
        return ret;

    if (alrm->enabled)
        ret = regmap_update_bits(rtc->regmap, MAX8907_REG_ALARM0_CNTL,
                     0x7f, 0x7f);

    return ret;
}

static const struct rtc_class_ops max8907_rtc_ops = {
    .read_time  = max8907_rtc_read_time,
    .set_time   = max8907_rtc_set_time,
    .read_alarm = max8907_rtc_read_alarm,
    .set_alarm  = max8907_rtc_set_alarm,
};

static int __devinit max8907_rtc_probe(struct platform_device *pdev)
{
    struct max8907 *max8907 = dev_get_drvdata(pdev->dev.parent);
    struct max8907_rtc *rtc;
    int ret;

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

    rtc->max8907 = max8907;
    rtc->regmap = max8907->regmap_rtc;

    rtc->rtc_dev = rtc_device_register("max8907-rtc", &pdev->dev,
                    &max8907_rtc_ops, THIS_MODULE);
    if (IS_ERR(rtc->rtc_dev)) {
        ret = PTR_ERR(rtc->rtc_dev);
        dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
        return ret;
    }

    rtc->irq = regmap_irq_get_virq(max8907->irqc_rtc,
                       MAX8907_IRQ_RTC_ALARM0);
    if (rtc->irq < 0) {
        ret = rtc->irq;
        goto err_unregister;
    }

    ret = request_threaded_irq(rtc->irq, NULL, max8907_irq_handler,
                   IRQF_ONESHOT, "max8907-alarm0", rtc);
    if (ret < 0) {
        dev_err(&pdev->dev, "Failed to request IRQ%d: %d\n",
            rtc->irq, ret);
        goto err_unregister;
    }

    return 0;

err_unregister:
    rtc_device_unregister(rtc->rtc_dev);
    return ret;
}

static int __devexit max8907_rtc_remove(struct platform_device *pdev)
{
    struct max8907_rtc *rtc = platform_get_drvdata(pdev);

    free_irq(rtc->irq, rtc);
    rtc_device_unregister(rtc->rtc_dev);

    return 0;
}

static struct platform_driver max8907_rtc_driver = {
    .driver = {
        .name = "max8907-rtc",
        .owner = THIS_MODULE,
    },
    .probe = max8907_rtc_probe,
    .remove = __devexit_p(max8907_rtc_remove),
};
module_platform_driver(max8907_rtc_driver);

MODULE_DESCRIPTION("Maxim MAX8907 RTC driver");
MODULE_LICENSE("GPL v2");