rtc-m48t59.c

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/*
 * ST M48T59 RTC driver
 *
 * Copyright (c) 2007 Wind River Systems, Inc.
 *
 * Author: Mark Zhan <[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/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/rtc/m48t59.h>
#include <linux/bcd.h>
#include <linux/slab.h>

#ifndef NO_IRQ
#define NO_IRQ  (-1)
#endif

#define M48T59_READ(reg) (pdata->read_byte(dev, pdata->offset + reg))
#define M48T59_WRITE(val, reg) \
    (pdata->write_byte(dev, pdata->offset + reg, val))

#define M48T59_SET_BITS(mask, reg)  \
    M48T59_WRITE((M48T59_READ(reg) | (mask)), (reg))
#define M48T59_CLEAR_BITS(mask, reg)    \
    M48T59_WRITE((M48T59_READ(reg) & ~(mask)), (reg))

struct m48t59_private {
    void __iomem *ioaddr;
    int irq;
    struct rtc_device *rtc;
    spinlock_t lock; /* serialize the NVRAM and RTC access */
};

/*
 * This is the generic access method when the chip is memory-mapped
 */
static void
m48t59_mem_writeb(struct device *dev, u32 ofs, u8 val)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct m48t59_private *m48t59 = platform_get_drvdata(pdev);

    writeb(val, m48t59->ioaddr+ofs);
}

static u8
m48t59_mem_readb(struct device *dev, u32 ofs)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct m48t59_private *m48t59 = platform_get_drvdata(pdev);

    return readb(m48t59->ioaddr+ofs);
}

/*
 * NOTE: M48T59 only uses BCD mode
 */
static int m48t59_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct m48t59_plat_data *pdata = pdev->dev.platform_data;
    struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
    unsigned long flags;
    u8 val;

    spin_lock_irqsave(&m48t59->lock, flags);
    /* Issue the READ command */
    M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);

    tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR));
    /* tm_mon is 0-11 */
    tm->tm_mon  = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
    tm->tm_mday = bcd2bin(M48T59_READ(M48T59_MDAY));

    val = M48T59_READ(M48T59_WDAY);
    if ((pdata->type == M48T59RTC_TYPE_M48T59) &&
        (val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB)) {
        dev_dbg(dev, "Century bit is enabled\n");
        tm->tm_year += 100; /* one century */
    }
#ifdef CONFIG_SPARC
    /* Sun SPARC machines count years since 1968 */
    tm->tm_year += 68;
#endif

    tm->tm_wday = bcd2bin(val & 0x07);
    tm->tm_hour = bcd2bin(M48T59_READ(M48T59_HOUR) & 0x3F);
    tm->tm_min  = bcd2bin(M48T59_READ(M48T59_MIN) & 0x7F);
    tm->tm_sec  = bcd2bin(M48T59_READ(M48T59_SEC) & 0x7F);

    /* Clear the READ bit */
    M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL);
    spin_unlock_irqrestore(&m48t59->lock, flags);

    dev_dbg(dev, "RTC read time %04d-%02d-%02d %02d/%02d/%02d\n",
        tm->tm_year + 1900, tm->tm_mon, tm->tm_mday,
        tm->tm_hour, tm->tm_min, tm->tm_sec);
    return rtc_valid_tm(tm);
}

static int m48t59_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct m48t59_plat_data *pdata = pdev->dev.platform_data;
    struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
    unsigned long flags;
    u8 val = 0;
    int year = tm->tm_year;

#ifdef CONFIG_SPARC
    /* Sun SPARC machines count years since 1968 */
    year -= 68;
#endif

    dev_dbg(dev, "RTC set time %04d-%02d-%02d %02d/%02d/%02d\n",
        year + 1900, tm->tm_mon, tm->tm_mday,
        tm->tm_hour, tm->tm_min, tm->tm_sec);

    if (year < 0)
        return -EINVAL;

    spin_lock_irqsave(&m48t59->lock, flags);
    /* Issue the WRITE command */
    M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);

    M48T59_WRITE((bin2bcd(tm->tm_sec) & 0x7F), M48T59_SEC);
    M48T59_WRITE((bin2bcd(tm->tm_min) & 0x7F), M48T59_MIN);
    M48T59_WRITE((bin2bcd(tm->tm_hour) & 0x3F), M48T59_HOUR);
    M48T59_WRITE((bin2bcd(tm->tm_mday) & 0x3F), M48T59_MDAY);
    /* tm_mon is 0-11 */
    M48T59_WRITE((bin2bcd(tm->tm_mon + 1) & 0x1F), M48T59_MONTH);
    M48T59_WRITE(bin2bcd(year % 100), M48T59_YEAR);

    if (pdata->type == M48T59RTC_TYPE_M48T59 && (year / 100))
        val = (M48T59_WDAY_CEB | M48T59_WDAY_CB);
    val |= (bin2bcd(tm->tm_wday) & 0x07);
    M48T59_WRITE(val, M48T59_WDAY);

    /* Clear the WRITE bit */
    M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
    spin_unlock_irqrestore(&m48t59->lock, flags);
    return 0;
}

/*
 * Read alarm time and date in RTC
 */
static int m48t59_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct m48t59_plat_data *pdata = pdev->dev.platform_data;
    struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
    struct rtc_time *tm = &alrm->time;
    unsigned long flags;
    u8 val;

    /* If no irq, we don't support ALARM */
    if (m48t59->irq == NO_IRQ)
        return -EIO;

    spin_lock_irqsave(&m48t59->lock, flags);
    /* Issue the READ command */
    M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);

    tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR));
#ifdef CONFIG_SPARC
    /* Sun SPARC machines count years since 1968 */
    tm->tm_year += 68;
#endif
    /* tm_mon is 0-11 */
    tm->tm_mon = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;

    val = M48T59_READ(M48T59_WDAY);
    if ((val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB))
        tm->tm_year += 100; /* one century */

    tm->tm_mday = bcd2bin(M48T59_READ(M48T59_ALARM_DATE));
    tm->tm_hour = bcd2bin(M48T59_READ(M48T59_ALARM_HOUR));
    tm->tm_min = bcd2bin(M48T59_READ(M48T59_ALARM_MIN));
    tm->tm_sec = bcd2bin(M48T59_READ(M48T59_ALARM_SEC));

    /* Clear the READ bit */
    M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL);
    spin_unlock_irqrestore(&m48t59->lock, flags);

    dev_dbg(dev, "RTC read alarm time %04d-%02d-%02d %02d/%02d/%02d\n",
        tm->tm_year + 1900, tm->tm_mon, tm->tm_mday,
        tm->tm_hour, tm->tm_min, tm->tm_sec);
    return rtc_valid_tm(tm);
}

/*
 * Set alarm time and date in RTC
 */
static int m48t59_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct m48t59_plat_data *pdata = pdev->dev.platform_data;
    struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
    struct rtc_time *tm = &alrm->time;
    u8 mday, hour, min, sec;
    unsigned long flags;
    int year = tm->tm_year;

#ifdef CONFIG_SPARC
    /* Sun SPARC machines count years since 1968 */
    year -= 68;
#endif

    /* If no irq, we don't support ALARM */
    if (m48t59->irq == NO_IRQ)
        return -EIO;

    if (year < 0)
        return -EINVAL;

    /*
     * 0xff means "always match"
     */
    mday = tm->tm_mday;
    mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
    if (mday == 0xff)
        mday = M48T59_READ(M48T59_MDAY);

    hour = tm->tm_hour;
    hour = (hour < 24) ? bin2bcd(hour) : 0x00;

    min = tm->tm_min;
    min = (min < 60) ? bin2bcd(min) : 0x00;

    sec = tm->tm_sec;
    sec = (sec < 60) ? bin2bcd(sec) : 0x00;

    spin_lock_irqsave(&m48t59->lock, flags);
    /* Issue the WRITE command */
    M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);

    M48T59_WRITE(mday, M48T59_ALARM_DATE);
    M48T59_WRITE(hour, M48T59_ALARM_HOUR);
    M48T59_WRITE(min, M48T59_ALARM_MIN);
    M48T59_WRITE(sec, M48T59_ALARM_SEC);

    /* Clear the WRITE bit */
    M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
    spin_unlock_irqrestore(&m48t59->lock, flags);

    dev_dbg(dev, "RTC set alarm time %04d-%02d-%02d %02d/%02d/%02d\n",
        year + 1900, tm->tm_mon, tm->tm_mday,
        tm->tm_hour, tm->tm_min, tm->tm_sec);
    return 0;
}

/*
 * Handle commands from user-space
 */
static int m48t59_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct m48t59_plat_data *pdata = pdev->dev.platform_data;
    struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
    unsigned long flags;

    spin_lock_irqsave(&m48t59->lock, flags);
    if (enabled)
        M48T59_WRITE(M48T59_INTR_AFE, M48T59_INTR);
    else
        M48T59_WRITE(0x00, M48T59_INTR);
    spin_unlock_irqrestore(&m48t59->lock, flags);

    return 0;
}

static int m48t59_rtc_proc(struct device *dev, struct seq_file *seq)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct m48t59_plat_data *pdata = pdev->dev.platform_data;
    struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
    unsigned long flags;
    u8 val;

    spin_lock_irqsave(&m48t59->lock, flags);
    val = M48T59_READ(M48T59_FLAGS);
    spin_unlock_irqrestore(&m48t59->lock, flags);

    seq_printf(seq, "battery\t\t: %s\n",
         (val & M48T59_FLAGS_BF) ? "low" : "normal");
    return 0;
}

/*
 * IRQ handler for the RTC
 */
static irqreturn_t m48t59_rtc_interrupt(int irq, void *dev_id)
{
    struct device *dev = (struct device *)dev_id;
    struct platform_device *pdev = to_platform_device(dev);
    struct m48t59_plat_data *pdata = pdev->dev.platform_data;
    struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
    u8 event;

    spin_lock(&m48t59->lock);
    event = M48T59_READ(M48T59_FLAGS);
    spin_unlock(&m48t59->lock);

    if (event & M48T59_FLAGS_AF) {
        rtc_update_irq(m48t59->rtc, 1, (RTC_AF | RTC_IRQF));
        return IRQ_HANDLED;
    }

    return IRQ_NONE;
}

static const struct rtc_class_ops m48t59_rtc_ops = {
    .read_time  = m48t59_rtc_read_time,
    .set_time   = m48t59_rtc_set_time,
    .read_alarm = m48t59_rtc_readalarm,
    .set_alarm  = m48t59_rtc_setalarm,
    .proc       = m48t59_rtc_proc,
    .alarm_irq_enable = m48t59_rtc_alarm_irq_enable,
};

static const struct rtc_class_ops m48t02_rtc_ops = {
    .read_time  = m48t59_rtc_read_time,
    .set_time   = m48t59_rtc_set_time,
};

static ssize_t m48t59_nvram_read(struct file *filp, struct kobject *kobj,
                struct bin_attribute *bin_attr,
                char *buf, loff_t pos, size_t size)
{
    struct device *dev = container_of(kobj, struct device, kobj);
    struct platform_device *pdev = to_platform_device(dev);
    struct m48t59_plat_data *pdata = pdev->dev.platform_data;
    struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
    ssize_t cnt = 0;
    unsigned long flags;

    for (; size > 0 && pos < pdata->offset; cnt++, size--) {
        spin_lock_irqsave(&m48t59->lock, flags);
        *buf++ = M48T59_READ(cnt);
        spin_unlock_irqrestore(&m48t59->lock, flags);
    }

    return cnt;
}

static ssize_t m48t59_nvram_write(struct file *filp, struct kobject *kobj,
                struct bin_attribute *bin_attr,
                char *buf, loff_t pos, size_t size)
{
    struct device *dev = container_of(kobj, struct device, kobj);
    struct platform_device *pdev = to_platform_device(dev);
    struct m48t59_plat_data *pdata = pdev->dev.platform_data;
    struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
    ssize_t cnt = 0;
    unsigned long flags;

    for (; size > 0 && pos < pdata->offset; cnt++, size--) {
        spin_lock_irqsave(&m48t59->lock, flags);
        M48T59_WRITE(*buf++, cnt);
        spin_unlock_irqrestore(&m48t59->lock, flags);
    }

    return cnt;
}

static struct bin_attribute m48t59_nvram_attr = {
    .attr = {
        .name = "nvram",
        .mode = S_IRUGO | S_IWUSR,
    },
    .read = m48t59_nvram_read,
    .write = m48t59_nvram_write,
};

static int __devinit m48t59_rtc_probe(struct platform_device *pdev)
{
    struct m48t59_plat_data *pdata = pdev->dev.platform_data;
    struct m48t59_private *m48t59 = NULL;
    struct resource *res;
    int ret = -ENOMEM;
    char *name;
    const struct rtc_class_ops *ops;

    /* This chip could be memory-mapped or I/O-mapped */
    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!res) {
        res = platform_get_resource(pdev, IORESOURCE_IO, 0);
        if (!res)
            return -EINVAL;
    }

    if (res->flags & IORESOURCE_IO) {
        /* If we are I/O-mapped, the platform should provide
         * the operations accessing chip registers.
         */
        if (!pdata || !pdata->write_byte || !pdata->read_byte)
            return -EINVAL;
    } else if (res->flags & IORESOURCE_MEM) {
        /* we are memory-mapped */
        if (!pdata) {
            pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
            if (!pdata)
                return -ENOMEM;
            /* Ensure we only kmalloc platform data once */
            pdev->dev.platform_data = pdata;
        }
        if (!pdata->type)
            pdata->type = M48T59RTC_TYPE_M48T59;

        /* Try to use the generic memory read/write ops */
        if (!pdata->write_byte)
            pdata->write_byte = m48t59_mem_writeb;
        if (!pdata->read_byte)
            pdata->read_byte = m48t59_mem_readb;
    }

    m48t59 = kzalloc(sizeof(*m48t59), GFP_KERNEL);
    if (!m48t59)
        return -ENOMEM;

    m48t59->ioaddr = pdata->ioaddr;

    if (!m48t59->ioaddr) {
        /* ioaddr not mapped externally */
        m48t59->ioaddr = ioremap(res->start, resource_size(res));
        if (!m48t59->ioaddr)
            goto out;
    }

    /* Try to get irq number. We also can work in
     * the mode without IRQ.
     */
    m48t59->irq = platform_get_irq(pdev, 0);
    if (m48t59->irq <= 0)
        m48t59->irq = NO_IRQ;

    if (m48t59->irq != NO_IRQ) {
        ret = request_irq(m48t59->irq, m48t59_rtc_interrupt,
            IRQF_SHARED, "rtc-m48t59", &pdev->dev);
        if (ret)
            goto out;
    }
    switch (pdata->type) {
    case M48T59RTC_TYPE_M48T59:
        name = "m48t59";
        ops = &m48t59_rtc_ops;
        pdata->offset = 0x1ff0;
        break;
    case M48T59RTC_TYPE_M48T02:
        name = "m48t02";
        ops = &m48t02_rtc_ops;
        pdata->offset = 0x7f0;
        break;
    case M48T59RTC_TYPE_M48T08:
        name = "m48t08";
        ops = &m48t02_rtc_ops;
        pdata->offset = 0x1ff0;
        break;
    default:
        dev_err(&pdev->dev, "Unknown RTC type\n");
        ret = -ENODEV;
        goto out;
    }

    spin_lock_init(&m48t59->lock);
    platform_set_drvdata(pdev, m48t59);

    m48t59->rtc = rtc_device_register(name, &pdev->dev, ops, THIS_MODULE);
    if (IS_ERR(m48t59->rtc)) {
        ret = PTR_ERR(m48t59->rtc);
        goto out;
    }

    m48t59_nvram_attr.size = pdata->offset;

    ret = sysfs_create_bin_file(&pdev->dev.kobj, &m48t59_nvram_attr);
    if (ret) {
        rtc_device_unregister(m48t59->rtc);
        goto out;
    }

    return 0;

out:
    if (m48t59->irq != NO_IRQ)
        free_irq(m48t59->irq, &pdev->dev);
    if (m48t59->ioaddr)
        iounmap(m48t59->ioaddr);
        kfree(m48t59);
    return ret;
}

static int __devexit m48t59_rtc_remove(struct platform_device *pdev)
{
    struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
    struct m48t59_plat_data *pdata = pdev->dev.platform_data;

    sysfs_remove_bin_file(&pdev->dev.kobj, &m48t59_nvram_attr);
    if (!IS_ERR(m48t59->rtc))
        rtc_device_unregister(m48t59->rtc);
    if (m48t59->ioaddr && !pdata->ioaddr)
        iounmap(m48t59->ioaddr);
    if (m48t59->irq != NO_IRQ)
        free_irq(m48t59->irq, &pdev->dev);
    platform_set_drvdata(pdev, NULL);
    kfree(m48t59);
    return 0;
}

/* work with hotplug and coldplug */
MODULE_ALIAS("platform:rtc-m48t59");

static struct platform_driver m48t59_rtc_driver = {
    .driver     = {
        .name   = "rtc-m48t59",
        .owner  = THIS_MODULE,
    },
    .probe      = m48t59_rtc_probe,
    .remove     = __devexit_p(m48t59_rtc_remove),
};

module_platform_driver(m48t59_rtc_driver);

MODULE_AUTHOR("Mark Zhan <[email protected]>");
MODULE_DESCRIPTION("M48T59/M48T02/M48T08 RTC driver");
MODULE_LICENSE("GPL");