/* rtc-bq4802.c: TI BQ4802 RTC driver.
   *
   * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/io.h>
  #include <linux/platform_device.h>
  #include <linux/rtc.h>
  #include <linux/bcd.h>

  #include <linux/slab.h>

  
  MODULE_AUTHOR("David S. Miller <davem@davemloft.net>");
  MODULE_DESCRIPTION("TI BQ4802 RTC driver");
  MODULE_LICENSE("GPL");
  
  struct bq4802 {
  	void __iomem		*regs;

  	unsigned long		ioport;

  	struct rtc_device	*rtc;
  	spinlock_t		lock;
  	struct resource		*r;
  	u8 (*read)(struct bq4802 *, int);
  	void (*write)(struct bq4802 *, int, u8);
  };
  
  static u8 bq4802_read_io(struct bq4802 *p, int off)
  {

  	return inb(p->ioport + off);

  }
  
  static void bq4802_write_io(struct bq4802 *p, int off, u8 val)
  {

  	outb(val, p->ioport + off);

  }
  
  static u8 bq4802_read_mem(struct bq4802 *p, int off)
  {
  	return readb(p->regs + off);
  }
  
  static void bq4802_write_mem(struct bq4802 *p, int off, u8 val)
  {

  	writeb(val, p->regs + off);

  }
  
  static int bq4802_read_time(struct device *dev, struct rtc_time *tm)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct bq4802 *p = platform_get_drvdata(pdev);
  	unsigned long flags;
  	unsigned int century;
  	u8 val;
  
  	spin_lock_irqsave(&p->lock, flags);
  
  	val = p->read(p, 0x0e);
  	p->write(p, 0xe, val | 0x08);
  
  	tm->tm_sec = p->read(p, 0x00);
  	tm->tm_min = p->read(p, 0x02);
  	tm->tm_hour = p->read(p, 0x04);
  	tm->tm_mday = p->read(p, 0x06);
  	tm->tm_mon = p->read(p, 0x09);
  	tm->tm_year = p->read(p, 0x0a);
  	tm->tm_wday = p->read(p, 0x08);
  	century = p->read(p, 0x0f);
  
  	p->write(p, 0x0e, val);
  
  	spin_unlock_irqrestore(&p->lock, flags);

  	tm->tm_sec = bcd2bin(tm->tm_sec);
  	tm->tm_min = bcd2bin(tm->tm_min);
  	tm->tm_hour = bcd2bin(tm->tm_hour);
  	tm->tm_mday = bcd2bin(tm->tm_mday);
  	tm->tm_mon = bcd2bin(tm->tm_mon);
  	tm->tm_year = bcd2bin(tm->tm_year);
  	tm->tm_wday = bcd2bin(tm->tm_wday);
  	century = bcd2bin(century);

  
  	tm->tm_year += (century * 100);
  	tm->tm_year -= 1900;
  
  	tm->tm_mon--;
  
  	return 0;
  }
  
  static int bq4802_set_time(struct device *dev, struct rtc_time *tm)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct bq4802 *p = platform_get_drvdata(pdev);
  	u8 sec, min, hrs, day, mon, yrs, century, val;
  	unsigned long flags;
  	unsigned int year;
  
  	year = tm->tm_year + 1900;
  	century = year / 100;
  	yrs = year % 100;
  
  	mon = tm->tm_mon + 1;   /* tm_mon starts at zero */
  	day = tm->tm_mday;
  	hrs = tm->tm_hour;
  	min = tm->tm_min;
  	sec = tm->tm_sec;

  	sec = bin2bcd(sec);
  	min = bin2bcd(min);
  	hrs = bin2bcd(hrs);
  	day = bin2bcd(day);
  	mon = bin2bcd(mon);
  	yrs = bin2bcd(yrs);
  	century = bin2bcd(century);

  
  	spin_lock_irqsave(&p->lock, flags);
  
  	val = p->read(p, 0x0e);
  	p->write(p, 0x0e, val | 0x08);
  
  	p->write(p, 0x00, sec);
  	p->write(p, 0x02, min);
  	p->write(p, 0x04, hrs);
  	p->write(p, 0x06, day);
  	p->write(p, 0x09, mon);
  	p->write(p, 0x0a, yrs);
  	p->write(p, 0x0f, century);
  
  	p->write(p, 0x0e, val);
  
  	spin_unlock_irqrestore(&p->lock, flags);
  
  	return 0;
  }
  
  static const struct rtc_class_ops bq4802_ops = {
  	.read_time	= bq4802_read_time,
  	.set_time	= bq4802_set_time,
  };

  static int bq4802_probe(struct platform_device *pdev)

  {

  	struct bq4802 *p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);

  	int err = -ENOMEM;
  
  	if (!p)
  		goto out;
  
  	spin_lock_init(&p->lock);
  
  	p->r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	if (!p->r) {
  		p->r = platform_get_resource(pdev, IORESOURCE_IO, 0);
  		err = -EINVAL;
  		if (!p->r)

  			goto out;

  	}
  	if (p->r->flags & IORESOURCE_IO) {

  		p->ioport = p->r->start;

  		p->read = bq4802_read_io;
  		p->write = bq4802_write_io;
  	} else if (p->r->flags & IORESOURCE_MEM) {

  		p->regs = devm_ioremap(&pdev->dev, p->r->start,
  					resource_size(p->r));

  		p->read = bq4802_read_mem;
  		p->write = bq4802_write_mem;
  	} else {
  		err = -EINVAL;

  		goto out;

  	}

  	platform_set_drvdata(pdev, p);

  	p->rtc = devm_rtc_device_register(&pdev->dev, "bq4802",
  					&bq4802_ops, THIS_MODULE);

  	if (IS_ERR(p->rtc)) {
  		err = PTR_ERR(p->rtc);

  		goto out;

  	}

  	err = 0;
  out:
  	return err;

  }

  /* work with hotplug and coldplug */
  MODULE_ALIAS("platform:rtc-bq4802");
  
  static struct platform_driver bq4802_driver = {
  	.driver		= {
  		.name	= "rtc-bq4802",
  		.owner	= THIS_MODULE,
  	},
  	.probe		= bq4802_probe,

  };

  module_platform_driver(bq4802_driver);