rtc: add support for the ST M48T59 RTC

[akpm@linux-foundation.org: x86_64 build fix]
[akpm@linux-foundation.org: The acpi guys changed the bin_attribute code]
Signed-off-by: Mark Zhan <rongkai.zhan@windriver.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 559 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 359323378c55..bcd18765a4ad 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -310,6 +310,16 @@ config RTC_DRV_M48T86
           This driver can also be built as a module. If so, the module
           will be called rtc-m48t86.
 
+config RTC_DRV_M48T59
+        tristate "ST M48T59"
+        depends on RTC_CLASS
+        help
+          If you say Y here you will get support for the
+          ST M48T59 RTC chip.
+
+          This driver can also be built as a module, if so, the module
+          will be called "rtc-m48t59".
+
 config RTC_DRV_V3020
         tristate "EM Microelectronic V3020"
         depends on RTC_CLASS
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 6da5102e0f21..ca9166d319b8 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -43,3 +43,4 @@ obj-$(CONFIG_RTC_DRV_V3020)	+= rtc-v3020.o
 obj-$(CONFIG_RTC_DRV_AT91RM9200)+= rtc-at91rm9200.o
 obj-$(CONFIG_RTC_DRV_SH)        += rtc-sh.o
 obj-$(CONFIG_RTC_DRV_BFIN)      += rtc-bfin.o
+obj-$(CONFIG_RTC_DRV_M48T59)    += rtc-m48t59.o
diff --git a/drivers/rtc/rtc-m48t59.c b/drivers/rtc/rtc-m48t59.c
new file mode 100644
index 000000000000..33b752350ab5
--- /dev/null
+++ b/drivers/rtc/rtc-m48t59.c
@@ -0,0 +1,491 @@
+/*
+ * ST M48T59 RTC driver
+ *
+ * Copyright (c) 2007 Wind River Systems, Inc.
+ *
+ * Author: Mark Zhan <rongkai.zhan@windriver.com>
+ *
+ * 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>
+
+#ifndef NO_IRQ
+#define NO_IRQ  (-1)
+#endif
+
+#define M48T59_READ(reg)        pdata->read_byte(dev, reg)
+#define M48T59_WRITE(val, reg)  pdata->write_byte(dev, 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;
+        unsigned int size; /* iomem size */
+        unsigned 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 ((val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB)) {
+                dev_dbg(dev, "Century bit is enabled\n");
+                tm->tm_year += 100;     /* one century */
+        }
+
+        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 0;
+}
+
+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;
+
+        dev_dbg(dev, "RTC set 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);
+
+        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(tm->tm_year % 100), M48T59_YEAR);
+
+        if (tm->tm_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));
+        /* 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 0;
+}
+
+/*
+ * 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;
+
+        /* If no irq, we don't support ALARM */
+        if (m48t59->irq == NO_IRQ)
+                return -EIO;
+
+        /*
+         * 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",
+                tm->tm_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_ioctl(struct device *dev, unsigned int cmd,
+                        unsigned long arg)
+{
+        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;
+        int ret = 0;
+
+        spin_lock_irqsave(&m48t59->lock, flags);
+        switch (cmd) {
+        case RTC_AIE_OFF:       /* alarm interrupt off */
+                M48T59_WRITE(0x00, M48T59_INTR);
+                break;
+        case RTC_AIE_ON:        /* alarm interrupt on */
+                M48T59_WRITE(M48T59_INTR_AFE, M48T59_INTR);
+                break;
+        default:
+                ret = -ENOIOCTLCMD;
+                break;
+        }
+        spin_unlock_irqrestore(&m48t59->lock, flags);
+
+        return ret;
+}
+
+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 = {
+        .ioctl          = m48t59_rtc_ioctl,
+        .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,
+};
+
+static ssize_t m48t59_nvram_read(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 < M48T59_NVRAM_SIZE; 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 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 < M48T59_NVRAM_SIZE; 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_IWUGO,
+                .owner = THIS_MODULE,
+        },
+        .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;
+
+        /* 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;
+                }
+
+                /* 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->size = res->end - res->start + 1;
+        m48t59->ioaddr = ioremap(res->start, m48t59->size);
+        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;
+        }
+
+        m48t59->rtc = rtc_device_register("m48t59", &pdev->dev,
+                                &m48t59_rtc_ops, THIS_MODULE);
+        if (IS_ERR(m48t59->rtc)) {
+                ret = PTR_ERR(m48t59->rtc);
+                goto out;
+        }
+
+        ret = sysfs_create_bin_file(&pdev->dev.kobj, &m48t59_nvram_attr);
+        if (ret)
+                goto out;
+
+        spin_lock_init(&m48t59->lock);
+        platform_set_drvdata(pdev, m48t59);
+        return 0;
+
+out:
+        if (!IS_ERR(m48t59->rtc))
+                rtc_device_unregister(m48t59->rtc);
+        if (m48t59->irq != NO_IRQ)
+                free_irq(m48t59->irq, &pdev->dev);
+        if (m48t59->ioaddr)
+                iounmap(m48t59->ioaddr);
+        if (m48t59)
+                kfree(m48t59);
+        return ret;
+}
+
+static int __devexit m48t59_rtc_remove(struct platform_device *pdev)
+{
+        struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
+
+        sysfs_remove_bin_file(&pdev->dev.kobj, &m48t59_nvram_attr);
+        if (!IS_ERR(m48t59->rtc))
+                rtc_device_unregister(m48t59->rtc);
+        if (m48t59->ioaddr)
+                iounmap(m48t59->ioaddr);
+        if (m48t59->irq != NO_IRQ)
+                free_irq(m48t59->irq, &pdev->dev);
+        platform_set_drvdata(pdev, NULL);
+        kfree(m48t59);
+        return 0;
+}
+
+static struct platform_driver m48t59_rtc_platdrv = {
+        .driver         = {
+                .name   = "rtc-m48t59",
+                .owner  = THIS_MODULE,
+        },
+        .probe          = m48t59_rtc_probe,
+        .remove         = __devexit_p(m48t59_rtc_remove),
+};
+
+static int __init m48t59_rtc_init(void)
+{
+        return platform_driver_register(&m48t59_rtc_platdrv);
+}
+
+static void __exit m48t59_rtc_exit(void)
+{
+        platform_driver_unregister(&m48t59_rtc_platdrv);
+}
+
+module_init(m48t59_rtc_init);
+module_exit(m48t59_rtc_exit);
+
+MODULE_AUTHOR("Mark Zhan <rongkai.zhan@windriver.com>");
+MODULE_DESCRIPTION("M48T59 RTC driver");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/rtc/m48t59.h b/include/linux/rtc/m48t59.h
new file mode 100644
index 000000000000..e8c7c21ceb1f
--- /dev/null
+++ b/include/linux/rtc/m48t59.h
@@ -0,0 +1,57 @@
+/*
+ * include/linux/rtc/m48t59.h
+ *
+ * Definitions for the platform data of m48t59 RTC chip driver.
+ *
+ * Copyright (c) 2007 Wind River Systems, Inc.
+ *
+ * Mark Zhan <rongkai.zhan@windriver.com>
+ *
+ * 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.
+ */
+
+#ifndef _LINUX_RTC_M48T59_H_
+#define _LINUX_RTC_M48T59_H_
+
+/*
+ * M48T59 Register Offset
+ */
+#define M48T59_YEAR             0x1fff
+#define M48T59_MONTH            0x1ffe
+#define M48T59_MDAY             0x1ffd  /* Day of Month */
+#define M48T59_WDAY             0x1ffc  /* Day of Week */
+#define M48T59_WDAY_CB                  0x20    /* Century Bit */
+#define M48T59_WDAY_CEB                 0x10    /* Century Enable Bit */
+#define M48T59_HOUR             0x1ffb
+#define M48T59_MIN              0x1ffa
+#define M48T59_SEC              0x1ff9
+#define M48T59_CNTL             0x1ff8
+#define M48T59_CNTL_READ                0x40
+#define M48T59_CNTL_WRITE               0x80
+#define M48T59_WATCHDOG         0x1ff7
+#define M48T59_INTR             0x1ff6
+#define M48T59_INTR_AFE                 0x80    /* Alarm Interrupt Enable */
+#define M48T59_INTR_ABE                 0x20
+#define M48T59_ALARM_DATE       0x1ff5
+#define M48T59_ALARM_HOUR       0x1ff4
+#define M48T59_ALARM_MIN        0x1ff3
+#define M48T59_ALARM_SEC        0x1ff2
+#define M48T59_UNUSED           0x1ff1
+#define M48T59_FLAGS            0x1ff0
+#define M48T59_FLAGS_WDT                0x80    /* watchdog timer expired */
+#define M48T59_FLAGS_AF                 0x40    /* alarm */
+#define M48T59_FLAGS_BF                 0x10    /* low battery */
+
+#define M48T59_NVRAM_SIZE       0x1ff0
+
+struct m48t59_plat_data {
+        /* The method to access M48T59 registers,
+         * NOTE: The 'ofs' should be 0x00~0x1fff
+         */
+        void (*write_byte)(struct device *dev, u32 ofs, u8 val);
+        unsigned char (*read_byte)(struct device *dev, u32 ofs);
+};
+
+#endif /* _LINUX_RTC_M48T59_H_ */