/*
   * 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>

  #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 = dev_get_platdata(&pdev->dev);

  	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
  ");
  		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
  ",
  		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 = dev_get_platdata(&pdev->dev);

  	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
  ",

  		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 = dev_get_platdata(&pdev->dev);

  	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
  ",
  		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 = dev_get_platdata(&pdev->dev);

  	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
  ",

  		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 = dev_get_platdata(&pdev->dev);

  	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 = dev_get_platdata(&pdev->dev);

  	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
  ",
  		 (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 = dev_get_platdata(&pdev->dev);

  	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 = dev_get_platdata(&pdev->dev);

  	struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
  	ssize_t cnt = 0;
  	unsigned long flags;

  	spin_lock_irqsave(&m48t59->lock, flags);
  
  	for (; cnt < size; cnt++)

  		*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 = dev_get_platdata(&pdev->dev);

  	struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
  	ssize_t cnt = 0;
  	unsigned long flags;

  	spin_lock_irqsave(&m48t59->lock, flags);
  
  	for (; cnt < size; cnt++)

  		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 m48t59_rtc_probe(struct platform_device *pdev)

  {

  	struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);

  	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 = devm_kzalloc(&pdev->dev, 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 = devm_kzalloc(&pdev->dev, sizeof(*m48t59), GFP_KERNEL);

  	if (!m48t59)
  		return -ENOMEM;

  	m48t59->ioaddr = pdata->ioaddr;
  
  	if (!m48t59->ioaddr) {
  		/* ioaddr not mapped externally */

  		m48t59->ioaddr = devm_ioremap(&pdev->dev, res->start,
  						resource_size(res));

  		if (!m48t59->ioaddr)

  			return ret;

  	}

  
  	/* 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 = devm_request_irq(&pdev->dev, m48t59->irq,
  				m48t59_rtc_interrupt, IRQF_SHARED,
  				"rtc-m48t59", &pdev->dev);

  		if (ret)

  			return ret;

  	}

  	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
  ");

  		return -ENODEV;

  	}

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

  	m48t59->rtc = devm_rtc_device_register(&pdev->dev, name, ops,
  						THIS_MODULE);
  	if (IS_ERR(m48t59->rtc))
  		return PTR_ERR(m48t59->rtc);

  	m48t59_nvram_attr.size = pdata->offset;

  	ret = sysfs_create_bin_file(&pdev->dev.kobj, &m48t59_nvram_attr);

  	if (ret)
  		return ret;

  	return 0;

  }

  static int m48t59_rtc_remove(struct platform_device *pdev)

  {

  	sysfs_remove_bin_file(&pdev->dev.kobj, &m48t59_nvram_attr);

  	return 0;
  }

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

  static struct platform_driver m48t59_rtc_driver = {

  	.driver		= {
  		.name	= "rtc-m48t59",

  	},
  	.probe		= m48t59_rtc_probe,

  	.remove		= m48t59_rtc_remove,

  };

  module_platform_driver(m48t59_rtc_driver);

  
  MODULE_AUTHOR("Mark Zhan <rongkai.zhan@windriver.com>");

  MODULE_DESCRIPTION("M48T59/M48T02/M48T08 RTC driver");

  MODULE_LICENSE("GPL");