Initial import

1 files changed, 798 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-sh.c b/drivers/rtc/rtc-sh.c
new file mode 100644
index 000000000..2b81dd4ba
--- /dev/null
+++ b/drivers/rtc/rtc-sh.c
@@ -0,0 +1,798 @@
+/*
+ * 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\n", (tmp & RCR1_CIE) ? "yes" : "no");
+
+	tmp = readb(rtc->regbase + RCR2);
+	seq_printf(seq, "periodic_IRQ\t: %s\n",
+		   (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\n",
+		__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\n");
+		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\n");
+		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\n", 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\n",
+				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\n",
+				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\n",
+				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,
+		.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);