rtc-sh.c

linux 内核源代码

/*
 * SuperH On-Chip RTC Support
 *
 * Copyright (C) 2006, 2007  Paul Mundt
 * Copyright (C) 2006  Jamie Lenehan
 *
 * Based on the old arch/sh/kernel/cpu/rtc.c by:
 *
 *  Copyright (C) 2000  Philipp Rumpf <[e-mail]>
 *  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 <asm/rtc.h>

#define DRV_NAME	"sh-rtc"
#define DRV_VERSION	"0.1.3"

#ifdef CONFIG_CPU_SH3
#define rtc_reg_size		sizeof(u16)
#define RTC_BIT_INVERTED	0	/* No bug on SH7708, SH7709A */
#define RTC_DEF_CAPABILITIES	0UL
#elif defined(CONFIG_CPU_SH4)
#define rtc_reg_size		sizeof(u32)
#define RTC_BIT_INVERTED	0x40	/* bug on SH7750, SH7750S */
#define RTC_DEF_CAPABILITIES	RTC_CAP_4_DIGIT_YEAR
#endif

#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 */

/* ALARM Bits - or with BCD encoded value */
#define AR_ENB		0x80	/* Enable for alarm cmp   */

/* 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;
	unsigned int alarm_irq, periodic_irq, carry_irq;
	struct rtc_device *rtc_dev;
	spinlock_t lock;
	int rearm_aie;
	unsigned long capabilities;	/* See asm-sh/rtc.h for cap bits */
};

static irqreturn_t sh_rtc_interrupt(int irq, void *dev_id)
{
	struct platform_device *pdev = to_platform_device(dev_id);
	struct sh_rtc *rtc = platform_get_drvdata(pdev);
	unsigned int tmp, events = 0;

	spin_lock(&rtc->lock);

	tmp = readb(rtc->regbase + RCR1);
	tmp &= ~RCR1_CF;

	if (rtc->rearm_aie) {
		if (tmp & RCR1_AF)
			tmp &= ~RCR1_AF;	/* try to clear AF again */
		else {
			tmp |= RCR1_AIE;	/* AF has cleared, rearm IRQ */
			rtc->rearm_aie = 0;
		}
	}

	writeb(tmp, rtc->regbase + RCR1);

	rtc_update_irq(rtc->rtc_dev, 1, events);

	spin_unlock(&rtc->lock);

	return IRQ_HANDLED;
}

static irqreturn_t sh_rtc_alarm(int irq, void *dev_id)
{
	struct platform_device *pdev = to_platform_device(dev_id);
	struct sh_rtc *rtc = platform_get_drvdata(pdev);
	unsigned int tmp, events = 0;

	spin_lock(&rtc->lock);

	tmp = readb(rtc->regbase + RCR1);

	/*
	 * If AF is set then the alarm has triggered. If we clear AF while
	 * the alarm time still matches the RTC time then AF will
	 * immediately be set again, and if AIE is enabled then the alarm
	 * interrupt will immediately be retrigger. So we clear AIE here
	 * and use rtc->rearm_aie so that the carry interrupt will keep
	 * trying to clear AF and once it stays cleared it'll re-enable
	 * AIE.
	 */
	if (tmp & RCR1_AF) {
		events |= RTC_AF | RTC_IRQF;

		tmp &= ~(RCR1_AF|RCR1_AIE);

		writeb(tmp, rtc->regbase + RCR1);

		rtc->rearm_aie = 1;

		rtc_update_irq(rtc->rtc_dev, 1, events);
	}

	spin_unlock(&rtc->lock);
	return IRQ_HANDLED;
}

static irqreturn_t sh_rtc_periodic(int irq, void *dev_id)
{
	struct platform_device *pdev = to_platform_device(dev_id);
	struct sh_rtc *rtc = platform_get_drvdata(pdev);

	spin_lock(&rtc->lock);

	rtc_update_irq(rtc->rtc_dev, 1, RTC_PF | RTC_IRQF);

	spin_unlock(&rtc->lock);

	return IRQ_HANDLED;
}

static inline void sh_rtc_setpie(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 + RCR2);

	if (enable) {
		tmp &= ~RCR2_PESMASK;
		tmp |= RCR2_PEF | (2 << 4);
	} else
		tmp &= ~(RCR2_PESMASK | RCR2_PEF);

	writeb(tmp, rtc->regbase + RCR2);

	spin_unlock_irq(&rtc->lock);
}

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;
		rtc->rearm_aie = 0;
	} else if (rtc->rearm_aie == 0)
		tmp |= RCR1_AIE;

	writeb(tmp, rtc->regbase + RCR1);

	spin_unlock_irq(&rtc->lock);
}

static int sh_rtc_open(struct device *dev)
{
	struct sh_rtc *rtc = dev_get_drvdata(dev);
	unsigned int tmp;
	int ret;

	tmp = readb(rtc->regbase + RCR1);
	tmp &= ~RCR1_CF;
	tmp |= RCR1_CIE;
	writeb(tmp, rtc->regbase + RCR1);

	ret = request_irq(rtc->periodic_irq, sh_rtc_periodic, IRQF_DISABLED,
			  "sh-rtc period", dev);
	if (unlikely(ret)) {
		dev_err(dev, "request period IRQ failed with %d, IRQ %d\n",
			ret, rtc->periodic_irq);
		return ret;
	}

	ret = request_irq(rtc->carry_irq, sh_rtc_interrupt, IRQF_DISABLED,
			  "sh-rtc carry", dev);
	if (unlikely(ret)) {
		dev_err(dev, "request carry IRQ failed with %d, IRQ %d\n",
			ret, rtc->carry_irq);
		free_irq(rtc->periodic_irq, dev);
		goto err_bad_carry;
	}

	ret = request_irq(rtc->alarm_irq, sh_rtc_alarm, IRQF_DISABLED,
			  "sh-rtc alarm", dev);
	if (unlikely(ret)) {
		dev_err(dev, "request alarm IRQ failed with %d, IRQ %d\n",
			ret, rtc->alarm_irq);
		goto err_bad_alarm;
	}

	return 0;

err_bad_alarm:
	free_irq(rtc->carry_irq, dev);
err_bad_carry:
	free_irq(rtc->periodic_irq, dev);

	return ret;
}

static void sh_rtc_release(struct device *dev)
{
	struct sh_rtc *rtc = dev_get_drvdata(dev);

	sh_rtc_setpie(dev, 0);
	sh_rtc_setaie(dev, 0);

	free_irq(rtc->periodic_irq, dev);
	free_irq(rtc->carry_irq, dev);
	free_irq(rtc->alarm_irq, dev);
}

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_PEF) ? "yes" : "no");

	return 0;
}

static int sh_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
	unsigned int ret = -ENOIOCTLCMD;

	switch (cmd) {
	case RTC_PIE_OFF:
	case RTC_PIE_ON:
		sh_rtc_setpie(dev, cmd == RTC_PIE_ON);
		ret = 0;
		break;
	case RTC_AIE_OFF:
	case RTC_AIE_ON:
		sh_rtc_setaie(dev, cmd == RTC_AIE_ON);
		ret = 0;
		break;
	}

	return ret;
}

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);
		}