/*
   * Real-time clock driver for MPC5121
   *
   * Copyright 2007, Domen Puncer <domen.puncer@telargo.com>
   * Copyright 2008, Freescale Semiconductor, Inc. All rights reserved.

   * Copyright 2011, Dmitry Eremin-Solenikov

   *
   * 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/init.h>
  #include <linux/module.h>
  #include <linux/rtc.h>
  #include <linux/of_device.h>
  #include <linux/of_platform.h>
  #include <linux/io.h>

  #include <linux/slab.h>

  
  struct mpc5121_rtc_regs {
  	u8 set_time;		/* RTC + 0x00 */
  	u8 hour_set;		/* RTC + 0x01 */
  	u8 minute_set;		/* RTC + 0x02 */
  	u8 second_set;		/* RTC + 0x03 */
  
  	u8 set_date;		/* RTC + 0x04 */
  	u8 month_set;		/* RTC + 0x05 */
  	u8 weekday_set;		/* RTC + 0x06 */
  	u8 date_set;		/* RTC + 0x07 */
  
  	u8 write_sw;		/* RTC + 0x08 */
  	u8 sw_set;		/* RTC + 0x09 */
  	u16 year_set;		/* RTC + 0x0a */
  
  	u8 alm_enable;		/* RTC + 0x0c */
  	u8 alm_hour_set;	/* RTC + 0x0d */
  	u8 alm_min_set;		/* RTC + 0x0e */
  	u8 int_enable;		/* RTC + 0x0f */
  
  	u8 reserved1;
  	u8 hour;		/* RTC + 0x11 */
  	u8 minute;		/* RTC + 0x12 */
  	u8 second;		/* RTC + 0x13 */
  
  	u8 month;		/* RTC + 0x14 */
  	u8 wday_mday;		/* RTC + 0x15 */
  	u16 year;		/* RTC + 0x16 */
  
  	u8 int_alm;		/* RTC + 0x18 */
  	u8 int_sw;		/* RTC + 0x19 */
  	u8 alm_status;		/* RTC + 0x1a */
  	u8 sw_minute;		/* RTC + 0x1b */
  
  	u8 bus_error_1;		/* RTC + 0x1c */
  	u8 int_day;		/* RTC + 0x1d */
  	u8 int_min;		/* RTC + 0x1e */
  	u8 int_sec;		/* RTC + 0x1f */
  
  	/*
  	 * target_time:
  	 *	intended to be used for hibernation but hibernation
  	 *	does not work on silicon rev 1.5 so use it for non-volatile
  	 *	storage of offset between the actual_time register and linux
  	 *	time
  	 */
  	u32 target_time;	/* RTC + 0x20 */
  	/*
  	 * actual_time:
  	 * 	readonly time since VBAT_RTC was last connected
  	 */
  	u32 actual_time;	/* RTC + 0x24 */
  	u32 keep_alive;		/* RTC + 0x28 */
  };
  
  struct mpc5121_rtc_data {
  	unsigned irq;
  	unsigned irq_periodic;
  	struct mpc5121_rtc_regs __iomem *regs;
  	struct rtc_device *rtc;
  	struct rtc_wkalrm wkalarm;
  };
  
  /*
   * Update second/minute/hour registers.
   *
   * This is just so alarm will work.
   */
  static void mpc5121_rtc_update_smh(struct mpc5121_rtc_regs __iomem *regs,
  				   struct rtc_time *tm)
  {
  	out_8(&regs->second_set, tm->tm_sec);
  	out_8(&regs->minute_set, tm->tm_min);
  	out_8(&regs->hour_set, tm->tm_hour);
  
  	/* set time sequence */
  	out_8(&regs->set_time, 0x1);
  	out_8(&regs->set_time, 0x3);
  	out_8(&regs->set_time, 0x1);
  	out_8(&regs->set_time, 0x0);
  }
  
  static int mpc5121_rtc_read_time(struct device *dev, struct rtc_time *tm)
  {
  	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
  	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
  	unsigned long now;
  
  	/*
  	 * linux time is actual_time plus the offset saved in target_time
  	 */
  	now = in_be32(&regs->actual_time) + in_be32(&regs->target_time);
  
  	rtc_time_to_tm(now, tm);
  
  	/*
  	 * update second minute hour registers
  	 * so alarms will work
  	 */
  	mpc5121_rtc_update_smh(regs, tm);
  
  	return rtc_valid_tm(tm);
  }
  
  static int mpc5121_rtc_set_time(struct device *dev, struct rtc_time *tm)
  {
  	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
  	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
  	int ret;
  	unsigned long now;
  
  	/*
  	 * The actual_time register is read only so we write the offset
  	 * between it and linux time to the target_time register.
  	 */
  	ret = rtc_tm_to_time(tm, &now);
  	if (ret == 0)
  		out_be32(&regs->target_time, now - in_be32(&regs->actual_time));
  
  	/*
  	 * update second minute hour registers
  	 * so alarms will work
  	 */
  	mpc5121_rtc_update_smh(regs, tm);
  
  	return 0;
  }

  static int mpc5200_rtc_read_time(struct device *dev, struct rtc_time *tm)
  {
  	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
  	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
  	int tmp;
  
  	tm->tm_sec = in_8(&regs->second);
  	tm->tm_min = in_8(&regs->minute);
  
  	/* 12 hour format? */
  	if (in_8(&regs->hour) & 0x20)
  		tm->tm_hour = (in_8(&regs->hour) >> 1) +
  			(in_8(&regs->hour) & 1 ? 12 : 0);
  	else
  		tm->tm_hour = in_8(&regs->hour);
  
  	tmp = in_8(&regs->wday_mday);
  	tm->tm_mday = tmp & 0x1f;
  	tm->tm_mon = in_8(&regs->month) - 1;
  	tm->tm_year = in_be16(&regs->year) - 1900;
  	tm->tm_wday = (tmp >> 5) % 7;
  	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
  	tm->tm_isdst = 0;
  
  	return 0;
  }
  
  static int mpc5200_rtc_set_time(struct device *dev, struct rtc_time *tm)
  {
  	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
  	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
  
  	mpc5121_rtc_update_smh(regs, tm);
  
  	/* date */
  	out_8(&regs->month_set, tm->tm_mon + 1);
  	out_8(&regs->weekday_set, tm->tm_wday ? tm->tm_wday : 7);
  	out_8(&regs->date_set, tm->tm_mday);
  	out_be16(&regs->year_set, tm->tm_year + 1900);
  
  	/* set date sequence */
  	out_8(&regs->set_date, 0x1);
  	out_8(&regs->set_date, 0x3);
  	out_8(&regs->set_date, 0x1);
  	out_8(&regs->set_date, 0x0);
  
  	return 0;
  }

  static int mpc5121_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
  {
  	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
  	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
  
  	*alarm = rtc->wkalarm;
  
  	alarm->pending = in_8(&regs->alm_status);
  
  	return 0;
  }
  
  static int mpc5121_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
  {
  	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
  	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
  
  	/*
  	 * the alarm has no seconds so deal with it
  	 */
  	if (alarm->time.tm_sec) {
  		alarm->time.tm_sec = 0;
  		alarm->time.tm_min++;
  		if (alarm->time.tm_min >= 60) {
  			alarm->time.tm_min = 0;
  			alarm->time.tm_hour++;
  			if (alarm->time.tm_hour >= 24)
  				alarm->time.tm_hour = 0;
  		}
  	}
  
  	alarm->time.tm_mday = -1;
  	alarm->time.tm_mon = -1;
  	alarm->time.tm_year = -1;
  
  	out_8(&regs->alm_min_set, alarm->time.tm_min);
  	out_8(&regs->alm_hour_set, alarm->time.tm_hour);
  
  	out_8(&regs->alm_enable, alarm->enabled);
  
  	rtc->wkalarm = *alarm;
  	return 0;
  }
  
  static irqreturn_t mpc5121_rtc_handler(int irq, void *dev)
  {
  	struct mpc5121_rtc_data *rtc = dev_get_drvdata((struct device *)dev);
  	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
  
  	if (in_8(&regs->int_alm)) {
  		/* acknowledge and clear status */
  		out_8(&regs->int_alm, 1);
  		out_8(&regs->alm_status, 1);
  
  		rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
  		return IRQ_HANDLED;
  	}
  
  	return IRQ_NONE;
  }
  
  static irqreturn_t mpc5121_rtc_handler_upd(int irq, void *dev)
  {
  	struct mpc5121_rtc_data *rtc = dev_get_drvdata((struct device *)dev);
  	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
  
  	if (in_8(&regs->int_sec) && (in_8(&regs->int_enable) & 0x1)) {
  		/* acknowledge */
  		out_8(&regs->int_sec, 1);
  
  		rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_UF);
  		return IRQ_HANDLED;
  	}
  
  	return IRQ_NONE;
  }
  
  static int mpc5121_rtc_alarm_irq_enable(struct device *dev,
  					unsigned int enabled)
  {
  	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
  	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
  	int val;
  
  	if (enabled)
  		val = 1;
  	else
  		val = 0;
  
  	out_8(&regs->alm_enable, val);
  	rtc->wkalarm.enabled = val;
  
  	return 0;
  }

  static const struct rtc_class_ops mpc5121_rtc_ops = {
  	.read_time = mpc5121_rtc_read_time,
  	.set_time = mpc5121_rtc_set_time,
  	.read_alarm = mpc5121_rtc_read_alarm,
  	.set_alarm = mpc5121_rtc_set_alarm,
  	.alarm_irq_enable = mpc5121_rtc_alarm_irq_enable,

  };

  static const struct rtc_class_ops mpc5200_rtc_ops = {
  	.read_time = mpc5200_rtc_read_time,
  	.set_time = mpc5200_rtc_set_time,
  	.read_alarm = mpc5121_rtc_read_alarm,
  	.set_alarm = mpc5121_rtc_set_alarm,
  	.alarm_irq_enable = mpc5121_rtc_alarm_irq_enable,
  };

  static int __devinit mpc5121_rtc_probe(struct platform_device *op)

  {
  	struct mpc5121_rtc_data *rtc;
  	int err = 0;

  
  	rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
  	if (!rtc)
  		return -ENOMEM;

  	rtc->regs = of_iomap(op->dev.of_node, 0);

  	if (!rtc->regs) {
  		dev_err(&op->dev, "%s: couldn't map io space
  ", __func__);
  		err = -ENOSYS;
  		goto out_free;
  	}
  
  	device_init_wakeup(&op->dev, 1);
  
  	dev_set_drvdata(&op->dev, rtc);

  	rtc->irq = irq_of_parse_and_map(op->dev.of_node, 1);

  	err = request_irq(rtc->irq, mpc5121_rtc_handler, IRQF_DISABLED,
  						"mpc5121-rtc", &op->dev);
  	if (err) {
  		dev_err(&op->dev, "%s: could not request irq: %i
  ",
  							__func__, rtc->irq);
  		goto out_dispose;
  	}

  	rtc->irq_periodic = irq_of_parse_and_map(op->dev.of_node, 0);

  	err = request_irq(rtc->irq_periodic, mpc5121_rtc_handler_upd,
  				IRQF_DISABLED, "mpc5121-rtc_upd", &op->dev);
  	if (err) {
  		dev_err(&op->dev, "%s: could not request irq: %i
  ",
  						__func__, rtc->irq_periodic);
  		goto out_dispose2;
  	}

  	if (of_device_is_compatible(op->dev.of_node, "fsl,mpc5121-rtc")) {
  		u32 ka;
  		ka = in_be32(&rtc->regs->keep_alive);
  		if (ka & 0x02) {
  			dev_warn(&op->dev,
  				"mpc5121-rtc: Battery or oscillator failure!
  ");
  			out_be32(&rtc->regs->keep_alive, ka);
  		}
  
  		rtc->rtc = rtc_device_register("mpc5121-rtc", &op->dev,
  						&mpc5121_rtc_ops, THIS_MODULE);
  	} else {
  		rtc->rtc = rtc_device_register("mpc5200-rtc", &op->dev,
  						&mpc5200_rtc_ops, THIS_MODULE);

  	}

  	if (IS_ERR(rtc->rtc)) {
  		err = PTR_ERR(rtc->rtc);
  		goto out_free_irq;
  	}
  
  	return 0;
  
  out_free_irq:
  	free_irq(rtc->irq_periodic, &op->dev);
  out_dispose2:
  	irq_dispose_mapping(rtc->irq_periodic);
  	free_irq(rtc->irq, &op->dev);
  out_dispose:
  	irq_dispose_mapping(rtc->irq);
  	iounmap(rtc->regs);
  out_free:
  	kfree(rtc);
  
  	return err;
  }

  static int __devexit mpc5121_rtc_remove(struct platform_device *op)

  {
  	struct mpc5121_rtc_data *rtc = dev_get_drvdata(&op->dev);
  	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
  
  	/* disable interrupt, so there are no nasty surprises */
  	out_8(&regs->alm_enable, 0);
  	out_8(&regs->int_enable, in_8(&regs->int_enable) & ~0x1);
  
  	rtc_device_unregister(rtc->rtc);
  	iounmap(rtc->regs);
  	free_irq(rtc->irq, &op->dev);
  	free_irq(rtc->irq_periodic, &op->dev);
  	irq_dispose_mapping(rtc->irq);
  	irq_dispose_mapping(rtc->irq_periodic);
  	dev_set_drvdata(&op->dev, NULL);
  	kfree(rtc);
  
  	return 0;
  }
  
  static struct of_device_id mpc5121_rtc_match[] __devinitdata = {
  	{ .compatible = "fsl,mpc5121-rtc", },

  	{ .compatible = "fsl,mpc5200-rtc", },

  	{},
  };

  static struct platform_driver mpc5121_rtc_driver = {

  	.driver = {
  		.name = "mpc5121-rtc",
  		.owner = THIS_MODULE,
  		.of_match_table = mpc5121_rtc_match,
  	},

  	.probe = mpc5121_rtc_probe,
  	.remove = __devexit_p(mpc5121_rtc_remove),
  };

  module_platform_driver(mpc5121_rtc_driver);

  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("John Rigby <jcrigby@gmail.com>");