/*
   * RTC driver for Maxim MAX8998
   *
   * Copyright (C) 2010 Samsung Electronics Co.Ltd
   * Author: Minkyu Kang <mk7.kang@samsung.com>
   * Author: Joonyoung Shim <jy0922.shim@samsung.com>
   *
   *  This program is free software; you can redistribute  it and/or modify it
   *  under  the terms of  the GNU General  Public License as published by the
   *  Free Software Foundation;  either version 2 of the  License, or (at your
   *  option) any later version.
   *
   */
  
  #include <linux/module.h>
  #include <linux/i2c.h>
  #include <linux/slab.h>
  #include <linux/bcd.h>
  #include <linux/rtc.h>
  #include <linux/platform_device.h>
  #include <linux/mfd/max8998.h>
  #include <linux/mfd/max8998-private.h>

  #include <linux/delay.h>

  
  #define MAX8998_RTC_SEC			0x00
  #define MAX8998_RTC_MIN			0x01
  #define MAX8998_RTC_HOUR		0x02
  #define MAX8998_RTC_WEEKDAY		0x03
  #define MAX8998_RTC_DATE		0x04
  #define MAX8998_RTC_MONTH		0x05
  #define MAX8998_RTC_YEAR1		0x06
  #define MAX8998_RTC_YEAR2		0x07
  #define MAX8998_ALARM0_SEC		0x08
  #define MAX8998_ALARM0_MIN		0x09
  #define MAX8998_ALARM0_HOUR		0x0a
  #define MAX8998_ALARM0_WEEKDAY		0x0b
  #define MAX8998_ALARM0_DATE		0x0c
  #define MAX8998_ALARM0_MONTH		0x0d
  #define MAX8998_ALARM0_YEAR1		0x0e
  #define MAX8998_ALARM0_YEAR2		0x0f
  #define MAX8998_ALARM1_SEC		0x10
  #define MAX8998_ALARM1_MIN		0x11
  #define MAX8998_ALARM1_HOUR		0x12
  #define MAX8998_ALARM1_WEEKDAY		0x13
  #define MAX8998_ALARM1_DATE		0x14
  #define MAX8998_ALARM1_MONTH		0x15
  #define MAX8998_ALARM1_YEAR1		0x16
  #define MAX8998_ALARM1_YEAR2		0x17
  #define MAX8998_ALARM0_CONF		0x18
  #define MAX8998_ALARM1_CONF		0x19
  #define MAX8998_RTC_STATUS		0x1a
  #define MAX8998_WTSR_SMPL_CNTL		0x1b
  #define MAX8998_TEST			0x1f
  
  #define HOUR_12				(1 << 7)
  #define HOUR_PM				(1 << 5)
  #define ALARM0_STATUS			(1 << 1)
  #define ALARM1_STATUS			(1 << 2)
  
  enum {
  	RTC_SEC = 0,
  	RTC_MIN,
  	RTC_HOUR,
  	RTC_WEEKDAY,
  	RTC_DATE,
  	RTC_MONTH,
  	RTC_YEAR1,
  	RTC_YEAR2,
  };
  
  struct max8998_rtc_info {
  	struct device		*dev;
  	struct max8998_dev	*max8998;
  	struct i2c_client	*rtc;
  	struct rtc_device	*rtc_dev;
  	int irq;

  	bool lp3974_bug_workaround;

  };
  
  static void max8998_data_to_tm(u8 *data, struct rtc_time *tm)
  {
  	tm->tm_sec = bcd2bin(data[RTC_SEC]);
  	tm->tm_min = bcd2bin(data[RTC_MIN]);
  	if (data[RTC_HOUR] & HOUR_12) {
  		tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x1f);
  		if (data[RTC_HOUR] & HOUR_PM)
  			tm->tm_hour += 12;
  	} else
  		tm->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3f);
  
  	tm->tm_wday = data[RTC_WEEKDAY] & 0x07;
  	tm->tm_mday = bcd2bin(data[RTC_DATE]);
  	tm->tm_mon = bcd2bin(data[RTC_MONTH]);
  	tm->tm_year = bcd2bin(data[RTC_YEAR1]) + bcd2bin(data[RTC_YEAR2]) * 100;
  	tm->tm_year -= 1900;
  }
  
  static void max8998_tm_to_data(struct rtc_time *tm, u8 *data)
  {
  	data[RTC_SEC] = bin2bcd(tm->tm_sec);
  	data[RTC_MIN] = bin2bcd(tm->tm_min);
  	data[RTC_HOUR] = bin2bcd(tm->tm_hour);
  	data[RTC_WEEKDAY] = tm->tm_wday;
  	data[RTC_DATE] = bin2bcd(tm->tm_mday);
  	data[RTC_MONTH] = bin2bcd(tm->tm_mon);
  	data[RTC_YEAR1] = bin2bcd(tm->tm_year % 100);
  	data[RTC_YEAR2] = bin2bcd((tm->tm_year + 1900) / 100);
  }
  
  static int max8998_rtc_read_time(struct device *dev, struct rtc_time *tm)
  {
  	struct max8998_rtc_info *info = dev_get_drvdata(dev);
  	u8 data[8];
  	int ret;
  
  	ret = max8998_bulk_read(info->rtc, MAX8998_RTC_SEC, 8, data);
  	if (ret < 0)
  		return ret;
  
  	max8998_data_to_tm(data, tm);
  
  	return rtc_valid_tm(tm);
  }
  
  static int max8998_rtc_set_time(struct device *dev, struct rtc_time *tm)
  {
  	struct max8998_rtc_info *info = dev_get_drvdata(dev);
  	u8 data[8];

  	int ret;

  
  	max8998_tm_to_data(tm, data);

  	ret = max8998_bulk_write(info->rtc, MAX8998_RTC_SEC, 8, data);
  
  	if (info->lp3974_bug_workaround)
  		msleep(2000);
  
  	return ret;

  }
  
  static int max8998_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  {
  	struct max8998_rtc_info *info = dev_get_drvdata(dev);
  	u8 data[8];
  	u8 val;
  	int ret;
  
  	ret = max8998_bulk_read(info->rtc, MAX8998_ALARM0_SEC, 8, data);
  	if (ret < 0)
  		return ret;
  
  	max8998_data_to_tm(data, &alrm->time);
  
  	ret = max8998_read_reg(info->rtc, MAX8998_ALARM0_CONF, &val);
  	if (ret < 0)
  		return ret;
  
  	alrm->enabled = !!val;
  
  	ret = max8998_read_reg(info->rtc, MAX8998_RTC_STATUS, &val);
  	if (ret < 0)
  		return ret;
  
  	if (val & ALARM0_STATUS)
  		alrm->pending = 1;
  	else
  		alrm->pending = 0;
  
  	return 0;
  }
  
  static int max8998_rtc_stop_alarm(struct max8998_rtc_info *info)
  {

  	int ret = max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, 0);
  
  	if (info->lp3974_bug_workaround)
  		msleep(2000);
  
  	return ret;

  }
  
  static int max8998_rtc_start_alarm(struct max8998_rtc_info *info)
  {

  	int ret;
  	u8 alarm0_conf = 0x77;
  
  	/* LP3974 with delay bug chips has rtc alarm bugs with "MONTH" field */
  	if (info->lp3974_bug_workaround)
  		alarm0_conf = 0x57;
  
  	ret = max8998_write_reg(info->rtc, MAX8998_ALARM0_CONF, alarm0_conf);
  
  	if (info->lp3974_bug_workaround)
  		msleep(2000);
  
  	return ret;

  }
  
  static int max8998_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  {
  	struct max8998_rtc_info *info = dev_get_drvdata(dev);
  	u8 data[8];
  	int ret;
  
  	max8998_tm_to_data(&alrm->time, data);
  
  	ret = max8998_rtc_stop_alarm(info);
  	if (ret < 0)
  		return ret;
  
  	ret = max8998_bulk_write(info->rtc, MAX8998_ALARM0_SEC, 8, data);
  	if (ret < 0)
  		return ret;

  	if (info->lp3974_bug_workaround)
  		msleep(2000);

  	if (alrm->enabled)

  		ret = max8998_rtc_start_alarm(info);

  	return ret;

  }
  
  static int max8998_rtc_alarm_irq_enable(struct device *dev,
  					unsigned int enabled)
  {
  	struct max8998_rtc_info *info = dev_get_drvdata(dev);
  
  	if (enabled)
  		return max8998_rtc_start_alarm(info);
  	else
  		return max8998_rtc_stop_alarm(info);
  }
  
  static irqreturn_t max8998_rtc_alarm_irq(int irq, void *data)
  {
  	struct max8998_rtc_info *info = data;
  
  	rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
  
  	return IRQ_HANDLED;
  }
  
  static const struct rtc_class_ops max8998_rtc_ops = {
  	.read_time = max8998_rtc_read_time,
  	.set_time = max8998_rtc_set_time,
  	.read_alarm = max8998_rtc_read_alarm,
  	.set_alarm = max8998_rtc_set_alarm,
  	.alarm_irq_enable = max8998_rtc_alarm_irq_enable,
  };
  
  static int __devinit max8998_rtc_probe(struct platform_device *pdev)
  {
  	struct max8998_dev *max8998 = dev_get_drvdata(pdev->dev.parent);

  	struct max8998_platform_data *pdata = dev_get_platdata(max8998->dev);

  	struct max8998_rtc_info *info;
  	int ret;
  
  	info = kzalloc(sizeof(struct max8998_rtc_info), GFP_KERNEL);
  	if (!info)
  		return -ENOMEM;
  
  	info->dev = &pdev->dev;
  	info->max8998 = max8998;
  	info->rtc = max8998->rtc;
  	info->irq = max8998->irq_base + MAX8998_IRQ_ALARM0;

  	platform_set_drvdata(pdev, info);

  	info->rtc_dev = rtc_device_register("max8998-rtc", &pdev->dev,
  			&max8998_rtc_ops, THIS_MODULE);
  
  	if (IS_ERR(info->rtc_dev)) {
  		ret = PTR_ERR(info->rtc_dev);
  		dev_err(&pdev->dev, "Failed to register RTC device: %d
  ", ret);
  		goto out_rtc;
  	}

  	ret = request_threaded_irq(info->irq, NULL, max8998_rtc_alarm_irq, 0,
  			"rtc-alarm0", info);

  	if (ret < 0)
  		dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d
  ",
  			info->irq, ret);

  	dev_info(&pdev->dev, "RTC CHIP NAME: %s
  ", pdev->id_entry->name);
  	if (pdata->rtc_delay) {
  		info->lp3974_bug_workaround = true;
  		dev_warn(&pdev->dev, "LP3974 with RTC REGERR option."
  				" RTC updates will be extremely slow.
  ");
  	}

  	return 0;
  
  out_rtc:

  	platform_set_drvdata(pdev, NULL);

  	kfree(info);
  	return ret;
  }
  
  static int __devexit max8998_rtc_remove(struct platform_device *pdev)
  {
  	struct max8998_rtc_info *info = platform_get_drvdata(pdev);
  
  	if (info) {
  		free_irq(info->irq, info);
  		rtc_device_unregister(info->rtc_dev);
  		kfree(info);
  	}
  
  	return 0;
  }

  static const struct platform_device_id max8998_rtc_id[] = {
  	{ "max8998-rtc", TYPE_MAX8998 },
  	{ "lp3974-rtc", TYPE_LP3974 },
  	{ }
  };

  static struct platform_driver max8998_rtc_driver = {
  	.driver		= {
  		.name	= "max8998-rtc",
  		.owner	= THIS_MODULE,
  	},
  	.probe		= max8998_rtc_probe,
  	.remove		= __devexit_p(max8998_rtc_remove),

  	.id_table	= max8998_rtc_id,

  };

  module_platform_driver(max8998_rtc_driver);

  
  MODULE_AUTHOR("Minkyu Kang <mk7.kang@samsung.com>");
  MODULE_AUTHOR("Joonyoung Shim <jy0922.shim@samsung.com>");
  MODULE_DESCRIPTION("Maxim MAX8998 RTC driver");
  MODULE_LICENSE("GPL");