/*
   * SuperH On-Chip RTC Support
   *
   * Copyright (C) 2006 - 2009  Paul Mundt
   * Copyright (C) 2006  Jamie Lenehan
   * Copyright (C) 2008  Angelo Castello
   *
   * Based on the old arch/sh/kernel/cpu/rtc.c by:
   *
   *  Copyright (C) 2000  Philipp Rumpf <prumpf@tux.org>
   *  Copyright (C) 1999  Tetsuya Okada & Niibe Yutaka
   *
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   */
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/bcd.h>
  #include <linux/rtc.h>
  #include <linux/init.h>
  #include <linux/platform_device.h>
  #include <linux/seq_file.h>
  #include <linux/interrupt.h>
  #include <linux/spinlock.h>
  #include <linux/io.h>
  #include <linux/log2.h>
  #include <linux/clk.h>
  #include <linux/slab.h>
  #include <asm/rtc.h>
  
  #define DRV_NAME	"sh-rtc"
  #define DRV_VERSION	"0.2.3"
  
  #define RTC_REG(r)	((r) * rtc_reg_size)
  
  #define R64CNT		RTC_REG(0)
  
  #define RSECCNT		RTC_REG(1)	/* RTC sec */
  #define RMINCNT		RTC_REG(2)	/* RTC min */
  #define RHRCNT		RTC_REG(3)	/* RTC hour */
  #define RWKCNT		RTC_REG(4)	/* RTC week */
  #define RDAYCNT		RTC_REG(5)	/* RTC day */
  #define RMONCNT		RTC_REG(6)	/* RTC month */
  #define RYRCNT		RTC_REG(7)	/* RTC year */
  #define RSECAR		RTC_REG(8)	/* ALARM sec */
  #define RMINAR		RTC_REG(9)	/* ALARM min */
  #define RHRAR		RTC_REG(10)	/* ALARM hour */
  #define RWKAR		RTC_REG(11)	/* ALARM week */
  #define RDAYAR		RTC_REG(12)	/* ALARM day */
  #define RMONAR		RTC_REG(13)	/* ALARM month */
  #define RCR1		RTC_REG(14)	/* Control */
  #define RCR2		RTC_REG(15)	/* Control */
  
  /*
   * Note on RYRAR and RCR3: Up until this point most of the register
   * definitions are consistent across all of the available parts. However,
   * the placement of the optional RYRAR and RCR3 (the RYRAR control
   * register used to control RYRCNT/RYRAR compare) varies considerably
   * across various parts, occasionally being mapped in to a completely
   * unrelated address space. For proper RYRAR support a separate resource
   * would have to be handed off, but as this is purely optional in
   * practice, we simply opt not to support it, thereby keeping the code
   * quite a bit more simplified.
   */
  
  /* ALARM Bits - or with BCD encoded value */
  #define AR_ENB		0x80	/* Enable for alarm cmp   */
  
  /* Period Bits */
  #define PF_HP		0x100	/* Enable Half Period to support 8,32,128Hz */
  #define PF_COUNT	0x200	/* Half periodic counter */
  #define PF_OXS		0x400	/* Periodic One x Second */
  #define PF_KOU		0x800	/* Kernel or User periodic request 1=kernel */
  #define PF_MASK		0xf00
  
  /* RCR1 Bits */
  #define RCR1_CF		0x80	/* Carry Flag             */
  #define RCR1_CIE	0x10	/* Carry Interrupt Enable */
  #define RCR1_AIE	0x08	/* Alarm Interrupt Enable */
  #define RCR1_AF		0x01	/* Alarm Flag             */
  
  /* RCR2 Bits */
  #define RCR2_PEF	0x80	/* PEriodic interrupt Flag */
  #define RCR2_PESMASK	0x70	/* Periodic interrupt Set  */
  #define RCR2_RTCEN	0x08	/* ENable RTC              */
  #define RCR2_ADJ	0x04	/* ADJustment (30-second)  */
  #define RCR2_RESET	0x02	/* Reset bit               */
  #define RCR2_START	0x01	/* Start bit               */
  
  struct sh_rtc {
  	void __iomem		*regbase;
  	unsigned long		regsize;
  	struct resource		*res;
  	int			alarm_irq;
  	int			periodic_irq;
  	int			carry_irq;
  	struct clk		*clk;
  	struct rtc_device	*rtc_dev;
  	spinlock_t		lock;
  	unsigned long		capabilities;	/* See asm/rtc.h for cap bits */
  	unsigned short		periodic_freq;
  };
  
  static int __sh_rtc_interrupt(struct sh_rtc *rtc)
  {
  	unsigned int tmp, pending;
  
  	tmp = readb(rtc->regbase + RCR1);
  	pending = tmp & RCR1_CF;
  	tmp &= ~RCR1_CF;
  	writeb(tmp, rtc->regbase + RCR1);
  
  	/* Users have requested One x Second IRQ */
  	if (pending && rtc->periodic_freq & PF_OXS)
  		rtc_update_irq(rtc->rtc_dev, 1, RTC_UF | RTC_IRQF);
  
  	return pending;
  }
  
  static int __sh_rtc_alarm(struct sh_rtc *rtc)
  {
  	unsigned int tmp, pending;
  
  	tmp = readb(rtc->regbase + RCR1);
  	pending = tmp & RCR1_AF;
  	tmp &= ~(RCR1_AF | RCR1_AIE);
  	writeb(tmp, rtc->regbase + RCR1);
  
  	if (pending)
  		rtc_update_irq(rtc->rtc_dev, 1, RTC_AF | RTC_IRQF);
  
  	return pending;
  }
  
  static int __sh_rtc_periodic(struct sh_rtc *rtc)
  {
  	struct rtc_device *rtc_dev = rtc->rtc_dev;
  	struct rtc_task *irq_task;
  	unsigned int tmp, pending;
  
  	tmp = readb(rtc->regbase + RCR2);
  	pending = tmp & RCR2_PEF;
  	tmp &= ~RCR2_PEF;
  	writeb(tmp, rtc->regbase + RCR2);
  
  	if (!pending)
  		return 0;
  
  	/* Half period enabled than one skipped and the next notified */
  	if ((rtc->periodic_freq & PF_HP) && (rtc->periodic_freq & PF_COUNT))
  		rtc->periodic_freq &= ~PF_COUNT;
  	else {
  		if (rtc->periodic_freq & PF_HP)
  			rtc->periodic_freq |= PF_COUNT;
  		if (rtc->periodic_freq & PF_KOU) {
  			spin_lock(&rtc_dev->irq_task_lock);
  			irq_task = rtc_dev->irq_task;
  			if (irq_task)
  				irq_task->func(irq_task->private_data);
  			spin_unlock(&rtc_dev->irq_task_lock);
  		} else
  			rtc_update_irq(rtc->rtc_dev, 1, RTC_PF | RTC_IRQF);
  	}
  
  	return pending;
  }
  
  static irqreturn_t sh_rtc_interrupt(int irq, void *dev_id)
  {
  	struct sh_rtc *rtc = dev_id;
  	int ret;
  
  	spin_lock(&rtc->lock);
  	ret = __sh_rtc_interrupt(rtc);
  	spin_unlock(&rtc->lock);
  
  	return IRQ_RETVAL(ret);
  }
  
  static irqreturn_t sh_rtc_alarm(int irq, void *dev_id)
  {
  	struct sh_rtc *rtc = dev_id;
  	int ret;
  
  	spin_lock(&rtc->lock);
  	ret = __sh_rtc_alarm(rtc);
  	spin_unlock(&rtc->lock);
  
  	return IRQ_RETVAL(ret);
  }
  
  static irqreturn_t sh_rtc_periodic(int irq, void *dev_id)
  {
  	struct sh_rtc *rtc = dev_id;
  	int ret;
  
  	spin_lock(&rtc->lock);
  	ret = __sh_rtc_periodic(rtc);
  	spin_unlock(&rtc->lock);
  
  	return IRQ_RETVAL(ret);
  }
  
  static irqreturn_t sh_rtc_shared(int irq, void *dev_id)
  {
  	struct sh_rtc *rtc = dev_id;
  	int ret;
  
  	spin_lock(&rtc->lock);
  	ret = __sh_rtc_interrupt(rtc);
  	ret |= __sh_rtc_alarm(rtc);
  	ret |= __sh_rtc_periodic(rtc);
  	spin_unlock(&rtc->lock);
  
  	return IRQ_RETVAL(ret);
  }
  
  static int sh_rtc_irq_set_state(struct device *dev, int enable)
  {
  	struct sh_rtc *rtc = dev_get_drvdata(dev);
  	unsigned int tmp;
  
  	spin_lock_irq(&rtc->lock);
  
  	tmp = readb(rtc->regbase + RCR2);
  
  	if (enable) {
  		rtc->periodic_freq |= PF_KOU;
  		tmp &= ~RCR2_PEF;	/* Clear PES bit */
  		tmp |= (rtc->periodic_freq & ~PF_HP);	/* Set PES2-0 */
  	} else {
  		rtc->periodic_freq &= ~PF_KOU;
  		tmp &= ~(RCR2_PESMASK | RCR2_PEF);
  	}
  
  	writeb(tmp, rtc->regbase + RCR2);
  
  	spin_unlock_irq(&rtc->lock);
  
  	return 0;
  }
  
  static int sh_rtc_irq_set_freq(struct device *dev, int freq)
  {
  	struct sh_rtc *rtc = dev_get_drvdata(dev);
  	int tmp, ret = 0;
  
  	spin_lock_irq(&rtc->lock);
  	tmp = rtc->periodic_freq & PF_MASK;
  
  	switch (freq) {
  	case 0:
  		rtc->periodic_freq = 0x00;
  		break;
  	case 1:
  		rtc->periodic_freq = 0x60;
  		break;
  	case 2:
  		rtc->periodic_freq = 0x50;
  		break;
  	case 4:
  		rtc->periodic_freq = 0x40;
  		break;
  	case 8:
  		rtc->periodic_freq = 0x30 | PF_HP;
  		break;
  	case 16:
  		rtc->periodic_freq = 0x30;
  		break;
  	case 32:
  		rtc->periodic_freq = 0x20 | PF_HP;
  		break;
  	case 64:
  		rtc->periodic_freq = 0x20;
  		break;
  	case 128:
  		rtc->periodic_freq = 0x10 | PF_HP;
  		break;
  	case 256:
  		rtc->periodic_freq = 0x10;
  		break;
  	default:
  		ret = -ENOTSUPP;
  	}
  
  	if (ret == 0)
  		rtc->periodic_freq |= tmp;
  
  	spin_unlock_irq(&rtc->lock);
  	return ret;
  }
  
  static inline void sh_rtc_setaie(struct device *dev, unsigned int enable)
  {
  	struct sh_rtc *rtc = dev_get_drvdata(dev);
  	unsigned int tmp;
  
  	spin_lock_irq(&rtc->lock);
  
  	tmp = readb(rtc->regbase + RCR1);
  
  	if (enable)
  		tmp |= RCR1_AIE;
  	else
  		tmp &= ~RCR1_AIE;
  
  	writeb(tmp, rtc->regbase + RCR1);
  
  	spin_unlock_irq(&rtc->lock);
  }
  
  static int sh_rtc_proc(struct device *dev, struct seq_file *seq)
  {
  	struct sh_rtc *rtc = dev_get_drvdata(dev);
  	unsigned int tmp;
  
  	tmp = readb(rtc->regbase + RCR1);
  	seq_printf(seq, "carry_IRQ\t: %s
  ", (tmp & RCR1_CIE) ? "yes" : "no");
  
  	tmp = readb(rtc->regbase + RCR2);
  	seq_printf(seq, "periodic_IRQ\t: %s
  ",
  		   (tmp & RCR2_PESMASK) ? "yes" : "no");
  
  	return 0;
  }
  
  static inline void sh_rtc_setcie(struct device *dev, unsigned int enable)
  {
  	struct sh_rtc *rtc = dev_get_drvdata(dev);
  	unsigned int tmp;
  
  	spin_lock_irq(&rtc->lock);
  
  	tmp = readb(rtc->regbase + RCR1);
  
  	if (!enable)
  		tmp &= ~RCR1_CIE;
  	else
  		tmp |= RCR1_CIE;
  
  	writeb(tmp, rtc->regbase + RCR1);
  
  	spin_unlock_irq(&rtc->lock);
  }
  
  static int sh_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
  {
  	sh_rtc_setaie(dev, enabled);
  	return 0;
  }
  
  static int sh_rtc_read_time(struct device *dev, struct rtc_time *tm)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct sh_rtc *rtc = platform_get_drvdata(pdev);
  	unsigned int sec128, sec2, yr, yr100, cf_bit;
  
  	do {
  		unsigned int tmp;
  
  		spin_lock_irq(&rtc->lock);
  
  		tmp = readb(rtc->regbase + RCR1);
  		tmp &= ~RCR1_CF; /* Clear CF-bit */
  		tmp |= RCR1_CIE;
  		writeb(tmp, rtc->regbase + RCR1);
  
  		sec128 = readb(rtc->regbase + R64CNT);
  
  		tm->tm_sec	= bcd2bin(readb(rtc->regbase + RSECCNT));
  		tm->tm_min	= bcd2bin(readb(rtc->regbase + RMINCNT));
  		tm->tm_hour	= bcd2bin(readb(rtc->regbase + RHRCNT));
  		tm->tm_wday	= bcd2bin(readb(rtc->regbase + RWKCNT));
  		tm->tm_mday	= bcd2bin(readb(rtc->regbase + RDAYCNT));
  		tm->tm_mon	= bcd2bin(readb(rtc->regbase + RMONCNT)) - 1;
  
  		if (rtc->capabilities & RTC_CAP_4_DIGIT_YEAR) {
  			yr  = readw(rtc->regbase + RYRCNT);
  			yr100 = bcd2bin(yr >> 8);
  			yr &= 0xff;
  		} else {
  			yr  = readb(rtc->regbase + RYRCNT);
  			yr100 = bcd2bin((yr == 0x99) ? 0x19 : 0x20);
  		}
  
  		tm->tm_year = (yr100 * 100 + bcd2bin(yr)) - 1900;
  
  		sec2 = readb(rtc->regbase + R64CNT);
  		cf_bit = readb(rtc->regbase + RCR1) & RCR1_CF;
  
  		spin_unlock_irq(&rtc->lock);
  	} while (cf_bit != 0 || ((sec128 ^ sec2) & RTC_BIT_INVERTED) != 0);
  
  #if RTC_BIT_INVERTED != 0
  	if ((sec128 & RTC_BIT_INVERTED))
  		tm->tm_sec--;
  #endif
  
  	/* only keep the carry interrupt enabled if UIE is on */
  	if (!(rtc->periodic_freq & PF_OXS))
  		sh_rtc_setcie(dev, 0);
  
  	dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
  		"mday=%d, mon=%d, year=%d, wday=%d
  ",
  		__func__,
  		tm->tm_sec, tm->tm_min, tm->tm_hour,
  		tm->tm_mday, tm->tm_mon + 1, tm->tm_year, tm->tm_wday);
  
  	return rtc_valid_tm(tm);
  }
  
  static int sh_rtc_set_time(struct device *dev, struct rtc_time *tm)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct sh_rtc *rtc = platform_get_drvdata(pdev);
  	unsigned int tmp;
  	int year;
  
  	spin_lock_irq(&rtc->lock);
  
  	/* Reset pre-scaler & stop RTC */
  	tmp = readb(rtc->regbase + RCR2);
  	tmp |= RCR2_RESET;
  	tmp &= ~RCR2_START;
  	writeb(tmp, rtc->regbase + RCR2);
  
  	writeb(bin2bcd(tm->tm_sec),  rtc->regbase + RSECCNT);
  	writeb(bin2bcd(tm->tm_min),  rtc->regbase + RMINCNT);
  	writeb(bin2bcd(tm->tm_hour), rtc->regbase + RHRCNT);
  	writeb(bin2bcd(tm->tm_wday), rtc->regbase + RWKCNT);
  	writeb(bin2bcd(tm->tm_mday), rtc->regbase + RDAYCNT);
  	writeb(bin2bcd(tm->tm_mon + 1), rtc->regbase + RMONCNT);
  
  	if (rtc->capabilities & RTC_CAP_4_DIGIT_YEAR) {
  		year = (bin2bcd((tm->tm_year + 1900) / 100) << 8) |
  			bin2bcd(tm->tm_year % 100);
  		writew(year, rtc->regbase + RYRCNT);
  	} else {
  		year = tm->tm_year % 100;
  		writeb(bin2bcd(year), rtc->regbase + RYRCNT);
  	}
  
  	/* Start RTC */
  	tmp = readb(rtc->regbase + RCR2);
  	tmp &= ~RCR2_RESET;
  	tmp |= RCR2_RTCEN | RCR2_START;
  	writeb(tmp, rtc->regbase + RCR2);
  
  	spin_unlock_irq(&rtc->lock);
  
  	return 0;
  }
  
  static inline int sh_rtc_read_alarm_value(struct sh_rtc *rtc, int reg_off)
  {
  	unsigned int byte;
  	int value = 0xff;	/* return 0xff for ignored values */
  
  	byte = readb(rtc->regbase + reg_off);
  	if (byte & AR_ENB) {
  		byte &= ~AR_ENB;	/* strip the enable bit */
  		value = bcd2bin(byte);
  	}
  
  	return value;
  }
  
  static int sh_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct sh_rtc *rtc = platform_get_drvdata(pdev);
  	struct rtc_time *tm = &wkalrm->time;
  
  	spin_lock_irq(&rtc->lock);
  
  	tm->tm_sec	= sh_rtc_read_alarm_value(rtc, RSECAR);
  	tm->tm_min	= sh_rtc_read_alarm_value(rtc, RMINAR);
  	tm->tm_hour	= sh_rtc_read_alarm_value(rtc, RHRAR);
  	tm->tm_wday	= sh_rtc_read_alarm_value(rtc, RWKAR);
  	tm->tm_mday	= sh_rtc_read_alarm_value(rtc, RDAYAR);
  	tm->tm_mon	= sh_rtc_read_alarm_value(rtc, RMONAR);
  	if (tm->tm_mon > 0)
  		tm->tm_mon -= 1; /* RTC is 1-12, tm_mon is 0-11 */
  	tm->tm_year     = 0xffff;
  
  	wkalrm->enabled = (readb(rtc->regbase + RCR1) & RCR1_AIE) ? 1 : 0;
  
  	spin_unlock_irq(&rtc->lock);
  
  	return 0;
  }
  
  static inline void sh_rtc_write_alarm_value(struct sh_rtc *rtc,
  					    int value, int reg_off)
  {
  	/* < 0 for a value that is ignored */
  	if (value < 0)
  		writeb(0, rtc->regbase + reg_off);
  	else
  		writeb(bin2bcd(value) | AR_ENB,  rtc->regbase + reg_off);
  }
  
  static int sh_rtc_check_alarm(struct rtc_time *tm)
  {
  	/*
  	 * The original rtc says anything > 0xc0 is "don't care" or "match
  	 * all" - most users use 0xff but rtc-dev uses -1 for the same thing.
  	 * The original rtc doesn't support years - some things use -1 and
  	 * some 0xffff. We use -1 to make out tests easier.
  	 */
  	if (tm->tm_year == 0xffff)
  		tm->tm_year = -1;
  	if (tm->tm_mon >= 0xff)
  		tm->tm_mon = -1;
  	if (tm->tm_mday >= 0xff)
  		tm->tm_mday = -1;
  	if (tm->tm_wday >= 0xff)
  		tm->tm_wday = -1;
  	if (tm->tm_hour >= 0xff)
  		tm->tm_hour = -1;
  	if (tm->tm_min >= 0xff)
  		tm->tm_min = -1;
  	if (tm->tm_sec >= 0xff)
  		tm->tm_sec = -1;
  
  	if (tm->tm_year > 9999 ||
  		tm->tm_mon >= 12 ||
  		tm->tm_mday == 0 || tm->tm_mday >= 32 ||
  		tm->tm_wday >= 7 ||
  		tm->tm_hour >= 24 ||
  		tm->tm_min >= 60 ||
  		tm->tm_sec >= 60)
  		return -EINVAL;
  
  	return 0;
  }
  
  static int sh_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct sh_rtc *rtc = platform_get_drvdata(pdev);
  	unsigned int rcr1;
  	struct rtc_time *tm = &wkalrm->time;
  	int mon, err;
  
  	err = sh_rtc_check_alarm(tm);
  	if (unlikely(err < 0))
  		return err;
  
  	spin_lock_irq(&rtc->lock);
  
  	/* disable alarm interrupt and clear the alarm flag */
  	rcr1 = readb(rtc->regbase + RCR1);
  	rcr1 &= ~(RCR1_AF | RCR1_AIE);
  	writeb(rcr1, rtc->regbase + RCR1);
  
  	/* set alarm time */
  	sh_rtc_write_alarm_value(rtc, tm->tm_sec,  RSECAR);
  	sh_rtc_write_alarm_value(rtc, tm->tm_min,  RMINAR);
  	sh_rtc_write_alarm_value(rtc, tm->tm_hour, RHRAR);
  	sh_rtc_write_alarm_value(rtc, tm->tm_wday, RWKAR);
  	sh_rtc_write_alarm_value(rtc, tm->tm_mday, RDAYAR);
  	mon = tm->tm_mon;
  	if (mon >= 0)
  		mon += 1;
  	sh_rtc_write_alarm_value(rtc, mon, RMONAR);
  
  	if (wkalrm->enabled) {
  		rcr1 |= RCR1_AIE;
  		writeb(rcr1, rtc->regbase + RCR1);
  	}
  
  	spin_unlock_irq(&rtc->lock);
  
  	return 0;
  }
  
  static struct rtc_class_ops sh_rtc_ops = {
  	.read_time	= sh_rtc_read_time,
  	.set_time	= sh_rtc_set_time,
  	.read_alarm	= sh_rtc_read_alarm,
  	.set_alarm	= sh_rtc_set_alarm,
  	.proc		= sh_rtc_proc,
  	.alarm_irq_enable = sh_rtc_alarm_irq_enable,
  };
  
  static int __init sh_rtc_probe(struct platform_device *pdev)
  {
  	struct sh_rtc *rtc;
  	struct resource *res;
  	struct rtc_time r;
  	char clk_name[6];
  	int clk_id, ret;
  
  	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
  	if (unlikely(!rtc))
  		return -ENOMEM;
  
  	spin_lock_init(&rtc->lock);
  
  	/* get periodic/carry/alarm irqs */
  	ret = platform_get_irq(pdev, 0);
  	if (unlikely(ret <= 0)) {
  		dev_err(&pdev->dev, "No IRQ resource
  ");
  		return -ENOENT;
  	}
  
  	rtc->periodic_irq = ret;
  	rtc->carry_irq = platform_get_irq(pdev, 1);
  	rtc->alarm_irq = platform_get_irq(pdev, 2);
  
  	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
  	if (unlikely(res == NULL)) {
  		dev_err(&pdev->dev, "No IO resource
  ");
  		return -ENOENT;
  	}
  
  	rtc->regsize = resource_size(res);
  
  	rtc->res = devm_request_mem_region(&pdev->dev, res->start,
  					rtc->regsize, pdev->name);
  	if (unlikely(!rtc->res))
  		return -EBUSY;
  
  	rtc->regbase = devm_ioremap_nocache(&pdev->dev, rtc->res->start,
  					rtc->regsize);
  	if (unlikely(!rtc->regbase))
  		return -EINVAL;
  
  	clk_id = pdev->id;
  	/* With a single device, the clock id is still "rtc0" */
  	if (clk_id < 0)
  		clk_id = 0;
  
  	snprintf(clk_name, sizeof(clk_name), "rtc%d", clk_id);
  
  	rtc->clk = devm_clk_get(&pdev->dev, clk_name);
  	if (IS_ERR(rtc->clk)) {
  		/*
  		 * No error handling for rtc->clk intentionally, not all
  		 * platforms will have a unique clock for the RTC, and
  		 * the clk API can handle the struct clk pointer being
  		 * NULL.
  		 */
  		rtc->clk = NULL;
  	}
  
  	clk_enable(rtc->clk);
  
  	rtc->capabilities = RTC_DEF_CAPABILITIES;
  	if (dev_get_platdata(&pdev->dev)) {
  		struct sh_rtc_platform_info *pinfo =
  			dev_get_platdata(&pdev->dev);
  
  		/*
  		 * Some CPUs have special capabilities in addition to the
  		 * default set. Add those in here.
  		 */
  		rtc->capabilities |= pinfo->capabilities;
  	}
  
  	if (rtc->carry_irq <= 0) {
  		/* register shared periodic/carry/alarm irq */
  		ret = devm_request_irq(&pdev->dev, rtc->periodic_irq,
  				sh_rtc_shared, 0, "sh-rtc", rtc);
  		if (unlikely(ret)) {
  			dev_err(&pdev->dev,
  				"request IRQ failed with %d, IRQ %d
  ", ret,
  				rtc->periodic_irq);
  			goto err_unmap;
  		}
  	} else {
  		/* register periodic/carry/alarm irqs */
  		ret = devm_request_irq(&pdev->dev, rtc->periodic_irq,
  				sh_rtc_periodic, 0, "sh-rtc period", rtc);
  		if (unlikely(ret)) {
  			dev_err(&pdev->dev,
  				"request period IRQ failed with %d, IRQ %d
  ",
  				ret, rtc->periodic_irq);
  			goto err_unmap;
  		}
  
  		ret = devm_request_irq(&pdev->dev, rtc->carry_irq,
  				sh_rtc_interrupt, 0, "sh-rtc carry", rtc);
  		if (unlikely(ret)) {
  			dev_err(&pdev->dev,
  				"request carry IRQ failed with %d, IRQ %d
  ",
  				ret, rtc->carry_irq);
  			goto err_unmap;
  		}
  
  		ret = devm_request_irq(&pdev->dev, rtc->alarm_irq,
  				sh_rtc_alarm, 0, "sh-rtc alarm", rtc);
  		if (unlikely(ret)) {
  			dev_err(&pdev->dev,
  				"request alarm IRQ failed with %d, IRQ %d
  ",
  				ret, rtc->alarm_irq);
  			goto err_unmap;
  		}
  	}
  
  	platform_set_drvdata(pdev, rtc);
  
  	/* everything disabled by default */
  	sh_rtc_irq_set_freq(&pdev->dev, 0);
  	sh_rtc_irq_set_state(&pdev->dev, 0);
  	sh_rtc_setaie(&pdev->dev, 0);
  	sh_rtc_setcie(&pdev->dev, 0);
  
  	rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, "sh",
  					   &sh_rtc_ops, THIS_MODULE);
  	if (IS_ERR(rtc->rtc_dev)) {
  		ret = PTR_ERR(rtc->rtc_dev);
  		goto err_unmap;
  	}
  
  	rtc->rtc_dev->max_user_freq = 256;
  
  	/* reset rtc to epoch 0 if time is invalid */
  	if (rtc_read_time(rtc->rtc_dev, &r) < 0) {
  		rtc_time_to_tm(0, &r);
  		rtc_set_time(rtc->rtc_dev, &r);
  	}
  
  	device_init_wakeup(&pdev->dev, 1);
  	return 0;
  
  err_unmap:
  	clk_disable(rtc->clk);
  
  	return ret;
  }
  
  static int __exit sh_rtc_remove(struct platform_device *pdev)
  {
  	struct sh_rtc *rtc = platform_get_drvdata(pdev);
  
  	sh_rtc_irq_set_state(&pdev->dev, 0);
  
  	sh_rtc_setaie(&pdev->dev, 0);
  	sh_rtc_setcie(&pdev->dev, 0);
  
  	clk_disable(rtc->clk);
  
  	return 0;
  }
  
  static void sh_rtc_set_irq_wake(struct device *dev, int enabled)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct sh_rtc *rtc = platform_get_drvdata(pdev);
  
  	irq_set_irq_wake(rtc->periodic_irq, enabled);
  
  	if (rtc->carry_irq > 0) {
  		irq_set_irq_wake(rtc->carry_irq, enabled);
  		irq_set_irq_wake(rtc->alarm_irq, enabled);
  	}
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int sh_rtc_suspend(struct device *dev)
  {
  	if (device_may_wakeup(dev))
  		sh_rtc_set_irq_wake(dev, 1);
  
  	return 0;
  }
  
  static int sh_rtc_resume(struct device *dev)
  {
  	if (device_may_wakeup(dev))
  		sh_rtc_set_irq_wake(dev, 0);
  
  	return 0;
  }
  #endif
  
  static SIMPLE_DEV_PM_OPS(sh_rtc_pm_ops, sh_rtc_suspend, sh_rtc_resume);
  
  static struct platform_driver sh_rtc_platform_driver = {
  	.driver		= {
  		.name	= DRV_NAME,
  		.owner	= THIS_MODULE,
  		.pm	= &sh_rtc_pm_ops,
  	},
  	.remove		= __exit_p(sh_rtc_remove),
  };
  
  module_platform_driver_probe(sh_rtc_platform_driver, sh_rtc_probe);
  
  MODULE_DESCRIPTION("SuperH on-chip RTC driver");
  MODULE_VERSION(DRV_VERSION);
  MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>, "
  	      "Jamie Lenehan <lenehan@twibble.org>, "
  	      "Angelo Castello <angelo.castello@st.com>");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:" DRV_NAME);