/*
   * RTC driver for Maxim MAX8925
   *
   * Copyright (C) 2009-2010 Marvell International Ltd.
   *	Haojian Zhuang <haojian.zhuang@marvell.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/module.h>
  #include <linux/i2c.h>

  #include <linux/slab.h>

  #include <linux/rtc.h>
  #include <linux/platform_device.h>
  #include <linux/mfd/max8925.h>
  
  enum {
  	RTC_SEC = 0,
  	RTC_MIN,
  	RTC_HOUR,
  	RTC_WEEKDAY,
  	RTC_DATE,
  	RTC_MONTH,
  	RTC_YEAR1,
  	RTC_YEAR2,
  };
  
  #define MAX8925_RTC_SEC			0x00
  #define MAX8925_RTC_MIN			0x01
  #define MAX8925_RTC_HOUR		0x02
  #define MAX8925_RTC_WEEKDAY		0x03
  #define MAX8925_RTC_DATE		0x04
  #define MAX8925_RTC_MONTH		0x05
  #define MAX8925_RTC_YEAR1		0x06
  #define MAX8925_RTC_YEAR2		0x07
  #define MAX8925_ALARM0_SEC		0x08
  #define MAX8925_ALARM0_MIN		0x09
  #define MAX8925_ALARM0_HOUR		0x0a
  #define MAX8925_ALARM0_WEEKDAY		0x0b
  #define MAX8925_ALARM0_DATE		0x0c
  #define MAX8925_ALARM0_MON		0x0d
  #define MAX8925_ALARM0_YEAR1		0x0e
  #define MAX8925_ALARM0_YEAR2		0x0f
  #define MAX8925_ALARM1_SEC		0x10
  #define MAX8925_ALARM1_MIN		0x11
  #define MAX8925_ALARM1_HOUR		0x12
  #define MAX8925_ALARM1_WEEKDAY		0x13
  #define MAX8925_ALARM1_DATE		0x14
  #define MAX8925_ALARM1_MON		0x15
  #define MAX8925_ALARM1_YEAR1		0x16
  #define MAX8925_ALARM1_YEAR2		0x17
  #define MAX8925_RTC_CNTL		0x1b
  #define MAX8925_RTC_STATUS		0x20
  
  #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 max8925_rtc_info {
  	struct rtc_device	*rtc_dev;
  	struct max8925_chip	*chip;
  	struct i2c_client	*rtc;
  	struct device		*dev;
  };
  
  static irqreturn_t rtc_update_handler(int irq, void *data)
  {
  	struct max8925_rtc_info *info = (struct max8925_rtc_info *)data;
  
  	/* disable ALARM0 except for 1SEC alarm */
  	max8925_set_bits(info->rtc, MAX8925_ALARM0_CNTL, 0x7f, 0);
  	rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
  	return IRQ_HANDLED;
  }
  
  static int tm_calc(struct rtc_time *tm, unsigned char *buf, int len)
  {
  	if (len < TIME_NUM)
  		return -EINVAL;
  	tm->tm_year = (buf[RTC_YEAR2] >> 4) * 1000
  			+ (buf[RTC_YEAR2] & 0xf) * 100
  			+ (buf[RTC_YEAR1] >> 4) * 10
  			+ (buf[RTC_YEAR1] & 0xf);
  	tm->tm_year -= 1900;
  	tm->tm_mon = ((buf[RTC_MONTH] >> 4) & 0x01) * 10
  			+ (buf[RTC_MONTH] & 0x0f);
  	tm->tm_mday = ((buf[RTC_DATE] >> 4) & 0x03) * 10
  			+ (buf[RTC_DATE] & 0x0f);
  	tm->tm_wday = buf[RTC_WEEKDAY] & 0x07;
  	if (buf[RTC_HOUR] & HOUR_12) {
  		tm->tm_hour = ((buf[RTC_HOUR] >> 4) & 0x1) * 10
  				+ (buf[RTC_HOUR] & 0x0f);
  		if (buf[RTC_HOUR] & HOUR_AM_PM)
  			tm->tm_hour += 12;
  	} else
  		tm->tm_hour = ((buf[RTC_HOUR] >> 4) & 0x03) * 10
  				+ (buf[RTC_HOUR] & 0x0f);
  	tm->tm_min = ((buf[RTC_MIN] >> 4) & 0x7) * 10
  			+ (buf[RTC_MIN] & 0x0f);
  	tm->tm_sec = ((buf[RTC_SEC] >> 4) & 0x7) * 10
  			+ (buf[RTC_SEC] & 0x0f);
  	return 0;
  }
  
  static int data_calc(unsigned char *buf, struct rtc_time *tm, int len)
  {
  	unsigned char high, low;
  
  	if (len < TIME_NUM)
  		return -EINVAL;
  
  	high = (tm->tm_year + 1900) / 1000;
  	low = (tm->tm_year + 1900) / 100;
  	low = low - high * 10;
  	buf[RTC_YEAR2] = (high << 4) + low;
  	high = (tm->tm_year + 1900) / 10;
  	low = tm->tm_year + 1900;
  	low = low - high * 10;
  	high = high - (high / 10) * 10;
  	buf[RTC_YEAR1] = (high << 4) + low;
  	high = tm->tm_mon / 10;
  	low = tm->tm_mon;
  	low = low - high * 10;
  	buf[RTC_MONTH] = (high << 4) + low;
  	high = tm->tm_mday / 10;
  	low = tm->tm_mday;
  	low = low - high * 10;
  	buf[RTC_DATE] = (high << 4) + low;
  	buf[RTC_WEEKDAY] = tm->tm_wday;
  	high = tm->tm_hour / 10;
  	low = tm->tm_hour;
  	low = low - high * 10;
  	buf[RTC_HOUR] = (high << 4) + low;
  	high = tm->tm_min / 10;
  	low = tm->tm_min;
  	low = low - high * 10;
  	buf[RTC_MIN] = (high << 4) + low;
  	high = tm->tm_sec / 10;
  	low = tm->tm_sec;
  	low = low - high * 10;
  	buf[RTC_SEC] = (high << 4) + low;
  	return 0;
  }
  
  static int max8925_rtc_read_time(struct device *dev, struct rtc_time *tm)
  {
  	struct max8925_rtc_info *info = dev_get_drvdata(dev);
  	unsigned char buf[TIME_NUM];
  	int ret;
  
  	ret = max8925_bulk_read(info->rtc, MAX8925_RTC_SEC, TIME_NUM, buf);
  	if (ret < 0)
  		goto out;
  	ret = tm_calc(tm, buf, TIME_NUM);
  out:
  	return ret;
  }
  
  static int max8925_rtc_set_time(struct device *dev, struct rtc_time *tm)
  {
  	struct max8925_rtc_info *info = dev_get_drvdata(dev);
  	unsigned char buf[TIME_NUM];
  	int ret;
  
  	ret = data_calc(buf, tm, TIME_NUM);
  	if (ret < 0)
  		goto out;
  	ret = max8925_bulk_write(info->rtc, MAX8925_RTC_SEC, TIME_NUM, buf);
  out:
  	return ret;
  }
  
  static int max8925_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  {
  	struct max8925_rtc_info *info = dev_get_drvdata(dev);
  	unsigned char buf[TIME_NUM];
  	int ret;
  
  	ret = max8925_bulk_read(info->rtc, MAX8925_ALARM0_SEC, TIME_NUM, buf);
  	if (ret < 0)
  		goto out;
  	ret = tm_calc(&alrm->time, buf, TIME_NUM);
  	if (ret < 0)
  		goto out;
  	ret = max8925_reg_read(info->rtc, MAX8925_RTC_IRQ_MASK);
  	if (ret < 0)
  		goto out;
  	if ((ret & ALARM0_IRQ) == 0)
  		alrm->enabled = 1;
  	else
  		alrm->enabled = 0;
  	ret = max8925_reg_read(info->rtc, MAX8925_RTC_STATUS);
  	if (ret < 0)
  		goto out;
  	if (ret & ALARM0_STATUS)
  		alrm->pending = 1;
  	else
  		alrm->pending = 0;
  out:
  	return ret;
  }
  
  static int max8925_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  {
  	struct max8925_rtc_info *info = dev_get_drvdata(dev);
  	unsigned char buf[TIME_NUM];
  	int ret;
  
  	ret = data_calc(buf, &alrm->time, TIME_NUM);
  	if (ret < 0)
  		goto out;
  	ret = max8925_bulk_write(info->rtc, MAX8925_ALARM0_SEC, TIME_NUM, buf);
  	if (ret < 0)
  		goto out;
  	/* only enable alarm on year/month/day/hour/min/sec */
  	ret = max8925_reg_write(info->rtc, MAX8925_ALARM0_CNTL, 0x77);
  	if (ret < 0)
  		goto out;
  out:
  	return ret;
  }
  
  static const struct rtc_class_ops max8925_rtc_ops = {
  	.read_time	= max8925_rtc_read_time,
  	.set_time	= max8925_rtc_set_time,
  	.read_alarm	= max8925_rtc_read_alarm,
  	.set_alarm	= max8925_rtc_set_alarm,
  };
  
  static int __devinit max8925_rtc_probe(struct platform_device *pdev)
  {
  	struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);
  	struct max8925_rtc_info *info;
  	int irq, ret;
  
  	info = kzalloc(sizeof(struct max8925_rtc_info), GFP_KERNEL);
  	if (!info)
  		return -ENOMEM;
  	info->chip = chip;
  	info->rtc = chip->rtc;
  	info->dev = &pdev->dev;
  	irq = chip->irq_base + MAX8925_IRQ_RTC_ALARM0;
  
  	ret = request_threaded_irq(irq, NULL, rtc_update_handler,
  				   IRQF_ONESHOT, "rtc-alarm0", info);
  	if (ret < 0) {
  		dev_err(chip->dev, "Failed to request IRQ: #%d: %d
  ",
  			irq, ret);
  		goto out_irq;
  	}

  	dev_set_drvdata(&pdev->dev, info);

  	/* XXX - isn't this redundant? */
  	platform_set_drvdata(pdev, info);

  	device_init_wakeup(&pdev->dev, 1);

  	info->rtc_dev = rtc_device_register("max8925-rtc", &pdev->dev,
  					&max8925_rtc_ops, THIS_MODULE);
  	ret = PTR_ERR(info->rtc_dev);
  	if (IS_ERR(info->rtc_dev)) {
  		dev_err(&pdev->dev, "Failed to register RTC device: %d
  ", ret);
  		goto out_rtc;
  	}

  	return 0;
  out_rtc:

  	platform_set_drvdata(pdev, NULL);

  	free_irq(chip->irq_base + MAX8925_IRQ_RTC_ALARM0, info);
  out_irq:
  	kfree(info);
  	return ret;
  }
  
  static int __devexit max8925_rtc_remove(struct platform_device *pdev)
  {
  	struct max8925_rtc_info *info = platform_get_drvdata(pdev);
  
  	if (info) {
  		free_irq(info->chip->irq_base + MAX8925_IRQ_RTC_ALARM0, info);
  		rtc_device_unregister(info->rtc_dev);
  		kfree(info);
  	}
  	return 0;
  }

  #ifdef CONFIG_PM_SLEEP
  static int max8925_rtc_suspend(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);
  
  	if (device_may_wakeup(dev))
  		chip->wakeup_flag |= 1 << MAX8925_IRQ_RTC_ALARM0;
  	return 0;
  }
  static int max8925_rtc_resume(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);
  
  	if (device_may_wakeup(dev))
  		chip->wakeup_flag &= ~(1 << MAX8925_IRQ_RTC_ALARM0);
  	return 0;
  }
  #endif
  
  static SIMPLE_DEV_PM_OPS(max8925_rtc_pm_ops, max8925_rtc_suspend, max8925_rtc_resume);

  static struct platform_driver max8925_rtc_driver = {
  	.driver		= {
  		.name	= "max8925-rtc",
  		.owner	= THIS_MODULE,

  		.pm     = &max8925_rtc_pm_ops,

  	},
  	.probe		= max8925_rtc_probe,
  	.remove		= __devexit_p(max8925_rtc_remove),
  };

  module_platform_driver(max8925_rtc_driver);

  
  MODULE_DESCRIPTION("Maxim MAX8925 RTC driver");
  MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
  MODULE_LICENSE("GPL");