/*
   *	Real Time Clock driver for Wolfson Microelectronics WM8350
   *
   *	Copyright (C) 2007, 2008 Wolfson Microelectronics PLC.
   *
   *  Author: Liam Girdwood
   *          linux@wolfsonmicro.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/kernel.h>
  #include <linux/time.h>
  #include <linux/rtc.h>
  #include <linux/bcd.h>
  #include <linux/interrupt.h>
  #include <linux/ioctl.h>
  #include <linux/completion.h>
  #include <linux/mfd/wm8350/rtc.h>
  #include <linux/mfd/wm8350/core.h>
  #include <linux/delay.h>
  #include <linux/platform_device.h>
  
  #define WM8350_SET_ALM_RETRIES	5
  #define WM8350_SET_TIME_RETRIES	5
  #define WM8350_GET_TIME_RETRIES	5
  
  #define to_wm8350_from_rtc_dev(d) container_of(d, struct wm8350, rtc.pdev.dev)
  
  /*
   * Read current time and date in RTC
   */
  static int wm8350_rtc_readtime(struct device *dev, struct rtc_time *tm)
  {
  	struct wm8350 *wm8350 = dev_get_drvdata(dev);
  	u16 time1[4], time2[4];
  	int retries = WM8350_GET_TIME_RETRIES, ret;
  
  	/*
  	 * Read the time twice and compare.
  	 * If time1 == time2, then time is valid else retry.
  	 */
  	do {
  		ret = wm8350_block_read(wm8350, WM8350_RTC_SECONDS_MINUTES,
  					4, time1);
  		if (ret < 0)
  			return ret;
  		ret = wm8350_block_read(wm8350, WM8350_RTC_SECONDS_MINUTES,
  					4, time2);
  		if (ret < 0)
  			return ret;
  
  		if (memcmp(time1, time2, sizeof(time1)) == 0) {
  			tm->tm_sec = time1[0] & WM8350_RTC_SECS_MASK;
  
  			tm->tm_min = (time1[0] & WM8350_RTC_MINS_MASK)
  			    >> WM8350_RTC_MINS_SHIFT;
  
  			tm->tm_hour = time1[1] & WM8350_RTC_HRS_MASK;
  
  			tm->tm_wday = ((time1[1] >> WM8350_RTC_DAY_SHIFT)
  				       & 0x7) - 1;
  
  			tm->tm_mon = ((time1[2] & WM8350_RTC_MTH_MASK)
  				      >> WM8350_RTC_MTH_SHIFT) - 1;
  
  			tm->tm_mday = (time1[2] & WM8350_RTC_DATE_MASK);
  
  			tm->tm_year = ((time1[3] & WM8350_RTC_YHUNDREDS_MASK)
  				       >> WM8350_RTC_YHUNDREDS_SHIFT) * 100;
  			tm->tm_year += time1[3] & WM8350_RTC_YUNITS_MASK;
  
  			tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon,
  						    tm->tm_year);
  			tm->tm_year -= 1900;
  
  			dev_dbg(dev, "Read (%d left): %04x %04x %04x %04x
  ",
  				retries,
  				time1[0], time1[1], time1[2], time1[3]);
  
  			return 0;
  		}
  	} while (retries--);
  
  	dev_err(dev, "timed out reading RTC time
  ");
  	return -EIO;
  }
  
  /*
   * Set current time and date in RTC
   */
  static int wm8350_rtc_settime(struct device *dev, struct rtc_time *tm)
  {
  	struct wm8350 *wm8350 = dev_get_drvdata(dev);
  	u16 time[4];
  	u16 rtc_ctrl;
  	int ret, retries = WM8350_SET_TIME_RETRIES;
  
  	time[0] = tm->tm_sec;
  	time[0] |= tm->tm_min << WM8350_RTC_MINS_SHIFT;
  	time[1] = tm->tm_hour;
  	time[1] |= (tm->tm_wday + 1) << WM8350_RTC_DAY_SHIFT;
  	time[2] = tm->tm_mday;
  	time[2] |= (tm->tm_mon + 1) << WM8350_RTC_MTH_SHIFT;
  	time[3] = ((tm->tm_year + 1900) / 100) << WM8350_RTC_YHUNDREDS_SHIFT;
  	time[3] |= (tm->tm_year + 1900) % 100;
  
  	dev_dbg(dev, "Setting: %04x %04x %04x %04x
  ",
  		time[0], time[1], time[2], time[3]);
  
  	/* Set RTC_SET to stop the clock */
  	ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL, WM8350_RTC_SET);
  	if (ret < 0)
  		return ret;
  
  	/* Wait until confirmation of stopping */
  	do {
  		rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
  		schedule_timeout_uninterruptible(msecs_to_jiffies(1));
  	} while (--retries && !(rtc_ctrl & WM8350_RTC_STS));
  
  	if (!retries) {
  		dev_err(dev, "timed out on set confirmation
  ");
  		return -EIO;
  	}
  
  	/* Write time to RTC */
  	ret = wm8350_block_write(wm8350, WM8350_RTC_SECONDS_MINUTES, 4, time);
  	if (ret < 0)
  		return ret;
  
  	/* Clear RTC_SET to start the clock */
  	ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
  				WM8350_RTC_SET);
  	return ret;
  }
  
  /*
   * Read alarm time and date in RTC
   */
  static int wm8350_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
  {
  	struct wm8350 *wm8350 = dev_get_drvdata(dev);
  	struct rtc_time *tm = &alrm->time;
  	u16 time[4];
  	int ret;
  
  	ret = wm8350_block_read(wm8350, WM8350_ALARM_SECONDS_MINUTES, 4, time);
  	if (ret < 0)
  		return ret;
  
  	tm->tm_sec = time[0] & WM8350_RTC_ALMSECS_MASK;
  	if (tm->tm_sec == WM8350_RTC_ALMSECS_MASK)
  		tm->tm_sec = -1;
  
  	tm->tm_min = time[0] & WM8350_RTC_ALMMINS_MASK;
  	if (tm->tm_min == WM8350_RTC_ALMMINS_MASK)
  		tm->tm_min = -1;
  	else
  		tm->tm_min >>= WM8350_RTC_ALMMINS_SHIFT;
  
  	tm->tm_hour = time[1] & WM8350_RTC_ALMHRS_MASK;
  	if (tm->tm_hour == WM8350_RTC_ALMHRS_MASK)
  		tm->tm_hour = -1;
  
  	tm->tm_wday = ((time[1] >> WM8350_RTC_ALMDAY_SHIFT) & 0x7) - 1;
  	if (tm->tm_wday > 7)
  		tm->tm_wday = -1;
  
  	tm->tm_mon = time[2] & WM8350_RTC_ALMMTH_MASK;
  	if (tm->tm_mon == WM8350_RTC_ALMMTH_MASK)
  		tm->tm_mon = -1;
  	else
  		tm->tm_mon = (tm->tm_mon >> WM8350_RTC_ALMMTH_SHIFT) - 1;
  
  	tm->tm_mday = (time[2] & WM8350_RTC_ALMDATE_MASK);
  	if (tm->tm_mday == WM8350_RTC_ALMDATE_MASK)
  		tm->tm_mday = -1;
  
  	tm->tm_year = -1;
  
  	alrm->enabled = !(time[3] & WM8350_RTC_ALMSTS);
  
  	return 0;
  }
  
  static int wm8350_rtc_stop_alarm(struct wm8350 *wm8350)
  {
  	int retries = WM8350_SET_ALM_RETRIES;
  	u16 rtc_ctrl;
  	int ret;
  
  	/* Set RTC_SET to stop the clock */
  	ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL,
  			      WM8350_RTC_ALMSET);
  	if (ret < 0)
  		return ret;
  
  	/* Wait until confirmation of stopping */
  	do {
  		rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
  		schedule_timeout_uninterruptible(msecs_to_jiffies(1));
  	} while (retries-- && !(rtc_ctrl & WM8350_RTC_ALMSTS));
  
  	if (!(rtc_ctrl & WM8350_RTC_ALMSTS))
  		return -ETIMEDOUT;
  
  	return 0;
  }
  
  static int wm8350_rtc_start_alarm(struct wm8350 *wm8350)
  {
  	int ret;
  	int retries = WM8350_SET_ALM_RETRIES;
  	u16 rtc_ctrl;
  
  	ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
  				WM8350_RTC_ALMSET);
  	if (ret < 0)
  		return ret;
  
  	/* Wait until confirmation */
  	do {
  		rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
  		schedule_timeout_uninterruptible(msecs_to_jiffies(1));
  	} while (retries-- && rtc_ctrl & WM8350_RTC_ALMSTS);
  
  	if (rtc_ctrl & WM8350_RTC_ALMSTS)
  		return -ETIMEDOUT;
  
  	return 0;
  }
  
  static int wm8350_rtc_alarm_irq_enable(struct device *dev,
  				       unsigned int enabled)
  {
  	struct wm8350 *wm8350 = dev_get_drvdata(dev);
  
  	if (enabled)
  		return wm8350_rtc_start_alarm(wm8350);
  	else
  		return wm8350_rtc_stop_alarm(wm8350);
  }
  
  static int wm8350_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
  {
  	struct wm8350 *wm8350 = dev_get_drvdata(dev);
  	struct rtc_time *tm = &alrm->time;
  	u16 time[3];
  	int ret;
  
  	memset(time, 0, sizeof(time));
  
  	if (tm->tm_sec != -1)
  		time[0] |= tm->tm_sec;
  	else
  		time[0] |= WM8350_RTC_ALMSECS_MASK;
  
  	if (tm->tm_min != -1)
  		time[0] |= tm->tm_min << WM8350_RTC_ALMMINS_SHIFT;
  	else
  		time[0] |= WM8350_RTC_ALMMINS_MASK;
  
  	if (tm->tm_hour != -1)
  		time[1] |= tm->tm_hour;
  	else
  		time[1] |= WM8350_RTC_ALMHRS_MASK;
  
  	if (tm->tm_wday != -1)
  		time[1] |= (tm->tm_wday + 1) << WM8350_RTC_ALMDAY_SHIFT;
  	else
  		time[1] |= WM8350_RTC_ALMDAY_MASK;
  
  	if (tm->tm_mday != -1)
  		time[2] |= tm->tm_mday;
  	else
  		time[2] |= WM8350_RTC_ALMDATE_MASK;
  
  	if (tm->tm_mon != -1)
  		time[2] |= (tm->tm_mon + 1) << WM8350_RTC_ALMMTH_SHIFT;
  	else
  		time[2] |= WM8350_RTC_ALMMTH_MASK;
  
  	ret = wm8350_rtc_stop_alarm(wm8350);
  	if (ret < 0)
  		return ret;
  
  	/* Write time to RTC */
  	ret = wm8350_block_write(wm8350, WM8350_ALARM_SECONDS_MINUTES,
  				 3, time);
  	if (ret < 0)
  		return ret;
  
  	if (alrm->enabled)
  		ret = wm8350_rtc_start_alarm(wm8350);
  
  	return ret;
  }
  
  static irqreturn_t wm8350_rtc_alarm_handler(int irq, void *data)
  {
  	struct wm8350 *wm8350 = data;
  	struct rtc_device *rtc = wm8350->rtc.rtc;
  	int ret;
  
  	rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
  
  	/* Make it one shot */
  	ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL,
  			      WM8350_RTC_ALMSET);
  	if (ret != 0) {
  		dev_err(&(wm8350->rtc.pdev->dev),
  			"Failed to disable alarm: %d
  ", ret);
  	}
  
  	return IRQ_HANDLED;
  }
  
  static irqreturn_t wm8350_rtc_update_handler(int irq, void *data)
  {
  	struct wm8350 *wm8350 = data;
  	struct rtc_device *rtc = wm8350->rtc.rtc;
  
  	rtc_update_irq(rtc, 1, RTC_IRQF | RTC_UF);
  
  	return IRQ_HANDLED;
  }
  
  static const struct rtc_class_ops wm8350_rtc_ops = {
  	.read_time = wm8350_rtc_readtime,
  	.set_time = wm8350_rtc_settime,
  	.read_alarm = wm8350_rtc_readalarm,
  	.set_alarm = wm8350_rtc_setalarm,
  	.alarm_irq_enable = wm8350_rtc_alarm_irq_enable,
  };
  
  #ifdef CONFIG_PM_SLEEP
  static int wm8350_rtc_suspend(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct wm8350 *wm8350 = dev_get_drvdata(&pdev->dev);
  	int ret = 0;
  	u16 reg;
  
  	reg = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
  
  	if (device_may_wakeup(&wm8350->rtc.pdev->dev) &&
  	    reg & WM8350_RTC_ALMSTS) {
  		ret = wm8350_rtc_stop_alarm(wm8350);
  		if (ret != 0)
  			dev_err(&pdev->dev, "Failed to stop RTC alarm: %d
  ",
  				ret);
  	}
  
  	return ret;
  }
  
  static int wm8350_rtc_resume(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct wm8350 *wm8350 = dev_get_drvdata(&pdev->dev);
  	int ret;
  
  	if (wm8350->rtc.alarm_enabled) {
  		ret = wm8350_rtc_start_alarm(wm8350);
  		if (ret != 0)
  			dev_err(&pdev->dev,
  				"Failed to restart RTC alarm: %d
  ", ret);
  	}
  
  	return 0;
  }
  #endif
  
  static int wm8350_rtc_probe(struct platform_device *pdev)
  {
  	struct wm8350 *wm8350 = platform_get_drvdata(pdev);
  	struct wm8350_rtc *wm_rtc = &wm8350->rtc;
  	int ret = 0;
  	u16 timectl, power5;
  
  	timectl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
  	if (timectl & WM8350_RTC_BCD) {
  		dev_err(&pdev->dev, "RTC BCD mode not supported
  ");
  		return -EINVAL;
  	}
  	if (timectl & WM8350_RTC_12HR) {
  		dev_err(&pdev->dev, "RTC 12 hour mode not supported
  ");
  		return -EINVAL;
  	}
  
  	/* enable the RTC if it's not already enabled */
  	power5 = wm8350_reg_read(wm8350, WM8350_POWER_MGMT_5);
  	if (!(power5 &  WM8350_RTC_TICK_ENA)) {
  		dev_info(wm8350->dev, "Starting RTC
  ");
  
  		wm8350_reg_unlock(wm8350);
  
  		ret = wm8350_set_bits(wm8350, WM8350_POWER_MGMT_5,
  				      WM8350_RTC_TICK_ENA);
  		if (ret < 0) {
  			dev_err(&pdev->dev, "failed to enable RTC: %d
  ", ret);
  			return ret;
  		}
  
  		wm8350_reg_lock(wm8350);
  	}
  
  	if (timectl & WM8350_RTC_STS) {
  		int retries;
  
  		ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
  					WM8350_RTC_SET);
  		if (ret < 0) {
  			dev_err(&pdev->dev, "failed to start: %d
  ", ret);
  			return ret;
  		}
  
  		retries = WM8350_SET_TIME_RETRIES;
  		do {
  			timectl = wm8350_reg_read(wm8350,
  						  WM8350_RTC_TIME_CONTROL);
  		} while (timectl & WM8350_RTC_STS && --retries);
  
  		if (retries == 0) {
  			dev_err(&pdev->dev, "failed to start: timeout
  ");
  			return -ENODEV;
  		}
  	}
  
  	device_init_wakeup(&pdev->dev, 1);
  
  	wm_rtc->rtc = devm_rtc_device_register(&pdev->dev, "wm8350",
  					&wm8350_rtc_ops, THIS_MODULE);
  	if (IS_ERR(wm_rtc->rtc)) {
  		ret = PTR_ERR(wm_rtc->rtc);
  		dev_err(&pdev->dev, "failed to register RTC: %d
  ", ret);
  		return ret;
  	}
  
  	wm8350_register_irq(wm8350, WM8350_IRQ_RTC_SEC,
  			    wm8350_rtc_update_handler, 0,
  			    "RTC Seconds", wm8350);
  	wm8350_mask_irq(wm8350, WM8350_IRQ_RTC_SEC);
  
  	wm8350_register_irq(wm8350, WM8350_IRQ_RTC_ALM,
  			    wm8350_rtc_alarm_handler, 0,
  			    "RTC Alarm", wm8350);
  
  	return 0;
  }
  
  static int wm8350_rtc_remove(struct platform_device *pdev)
  {
  	struct wm8350 *wm8350 = platform_get_drvdata(pdev);
  
  	wm8350_free_irq(wm8350, WM8350_IRQ_RTC_SEC, wm8350);
  	wm8350_free_irq(wm8350, WM8350_IRQ_RTC_ALM, wm8350);
  
  	return 0;
  }
  
  static SIMPLE_DEV_PM_OPS(wm8350_rtc_pm_ops, wm8350_rtc_suspend,
  			wm8350_rtc_resume);
  
  static struct platform_driver wm8350_rtc_driver = {
  	.probe = wm8350_rtc_probe,
  	.remove = wm8350_rtc_remove,
  	.driver = {
  		.name = "wm8350-rtc",
  		.pm = &wm8350_rtc_pm_ops,
  	},
  };
  
  module_platform_driver(wm8350_rtc_driver);
  
  MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
  MODULE_DESCRIPTION("RTC driver for the WM8350");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:wm8350-rtc");