// SPDX-License-Identifier: GPL-2.0-only/* * An rtc driver for the Dallas DS1553 * * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp> */ #include <linux/bcd.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/gfp.h>#include <linux/delay.h>#include <linux/jiffies.h>#include <linux/interrupt.h>#include <linux/rtc.h>#include <linux/platform_device.h>#include <linux/io.h>#include <linux/module.h> #define RTC_REG_SIZE		0x2000#define RTC_OFFSET		0x1ff0 #define RTC_FLAGS		(RTC_OFFSET + 0)#define RTC_SECONDS_ALARM	(RTC_OFFSET + 2)#define RTC_MINUTES_ALARM	(RTC_OFFSET + 3)#define RTC_HOURS_ALARM		(RTC_OFFSET + 4)#define RTC_DATE_ALARM		(RTC_OFFSET + 5)#define RTC_INTERRUPTS		(RTC_OFFSET + 6)#define RTC_WATCHDOG		(RTC_OFFSET + 7)#define RTC_CONTROL		(RTC_OFFSET + 8)#define RTC_CENTURY		(RTC_OFFSET + 8)#define RTC_SECONDS		(RTC_OFFSET + 9)#define RTC_MINUTES		(RTC_OFFSET + 10)#define RTC_HOURS		(RTC_OFFSET + 11)#define RTC_DAY			(RTC_OFFSET + 12)#define RTC_DATE		(RTC_OFFSET + 13)#define RTC_MONTH		(RTC_OFFSET + 14)#define RTC_YEAR		(RTC_OFFSET + 15) #define RTC_CENTURY_MASK	0x3f#define RTC_SECONDS_MASK	0x7f#define RTC_DAY_MASK		0x07 /* Bits in the Control/Century register */#define RTC_WRITE		0x80#define RTC_READ		0x40 /* Bits in the Seconds register */#define RTC_STOP		0x80 /* Bits in the Flags register */#define RTC_FLAGS_AF		0x40#define RTC_FLAGS_BLF		0x10 /* Bits in the Interrupts register */#define RTC_INTS_AE		0x80 struct rtc_plat_data {	struct rtc_device *rtc;	void __iomem *ioaddr;	unsigned long last_jiffies;	int irq;	unsigned int irqen;	int alrm_sec;	int alrm_min;	int alrm_hour;	int alrm_mday;	spinlock_t lock;}; static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm){	struct rtc_plat_data *pdata = dev_get_drvdata(dev);	void __iomem *ioaddr = pdata->ioaddr;	u8 century; 	century = bin2bcd((tm->tm_year + 1900) / 100); 	writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL); 	writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);	writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);	writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);	writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);	writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);	writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);	writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS); 	/* RTC_CENTURY and RTC_CONTROL share same register */	writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);	writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);	return 0;} static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm){	struct rtc_plat_data *pdata = dev_get_drvdata(dev);	void __iomem *ioaddr = pdata->ioaddr;	unsigned int year, month, day, hour, minute, second, week;	unsigned int century; 	/* give enough time to update RTC in case of continuous read */	if (pdata->last_jiffies == jiffies)		msleep(1);	pdata->last_jiffies = jiffies;	writeb(RTC_READ, ioaddr + RTC_CONTROL);	second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;	minute = readb(ioaddr + RTC_MINUTES);	hour = readb(ioaddr + RTC_HOURS);	day = readb(ioaddr + RTC_DATE);	week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;	month = readb(ioaddr + RTC_MONTH);	year = readb(ioaddr + RTC_YEAR);	century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;	writeb(0, ioaddr + RTC_CONTROL);	tm->tm_sec = bcd2bin(second);	tm->tm_min = bcd2bin(minute);	tm->tm_hour = bcd2bin(hour);	tm->tm_mday = bcd2bin(day);	tm->tm_wday = bcd2bin(week);	tm->tm_mon = bcd2bin(month) - 1;	/* year is 1900 + tm->tm_year */	tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900; 	return 0;} static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata){	void __iomem *ioaddr = pdata->ioaddr;	unsigned long flags; 	spin_lock_irqsave(&pdata->lock, flags);	writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?	       0x80 : bin2bcd(pdata->alrm_mday),	       ioaddr + RTC_DATE_ALARM);	writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?	       0x80 : bin2bcd(pdata->alrm_hour),	       ioaddr + RTC_HOURS_ALARM);	writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?	       0x80 : bin2bcd(pdata->alrm_min),	       ioaddr + RTC_MINUTES_ALARM);	writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?	       0x80 : bin2bcd(pdata->alrm_sec),	       ioaddr + RTC_SECONDS_ALARM);	writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS);	readb(ioaddr + RTC_FLAGS);	/* clear interrupts */	spin_unlock_irqrestore(&pdata->lock, flags);} static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm){	struct rtc_plat_data *pdata = dev_get_drvdata(dev); 	if (pdata->irq <= 0)		return -EINVAL;	pdata->alrm_mday = alrm->time.tm_mday;	pdata->alrm_hour = alrm->time.tm_hour;	pdata->alrm_min = alrm->time.tm_min;	pdata->alrm_sec = alrm->time.tm_sec;	if (alrm->enabled)		pdata->irqen |= RTC_AF;	ds1553_rtc_update_alarm(pdata);	return 0;} static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm){	struct rtc_plat_data *pdata = dev_get_drvdata(dev); 	if (pdata->irq <= 0)		return -EINVAL;	alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;	alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;	alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;	alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;	alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;	return 0;} static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id){	struct platform_device *pdev = dev_id;	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);	void __iomem *ioaddr = pdata->ioaddr;	unsigned long events = 0; 	spin_lock(&pdata->lock);	/* read and clear interrupt */	if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {		events = RTC_IRQF;		if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)			events |= RTC_UF;		else			events |= RTC_AF;		rtc_update_irq(pdata->rtc, 1, events);	}	spin_unlock(&pdata->lock);	return events ? IRQ_HANDLED : IRQ_NONE;} static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled){	struct rtc_plat_data *pdata = dev_get_drvdata(dev); 	if (pdata->irq <= 0)		return -EINVAL;	if (enabled)		pdata->irqen |= RTC_AF;	else		pdata->irqen &= ~RTC_AF;	ds1553_rtc_update_alarm(pdata);	return 0;} static const struct rtc_class_ops ds1553_rtc_ops = {	.read_time		= ds1553_rtc_read_time,	.set_time		= ds1553_rtc_set_time,	.read_alarm		= ds1553_rtc_read_alarm,	.set_alarm		= ds1553_rtc_set_alarm,	.alarm_irq_enable	= ds1553_rtc_alarm_irq_enable,}; static int ds1553_nvram_read(void *priv, unsigned int pos, void *val,			     size_t bytes){	struct platform_device *pdev = priv;	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);	void __iomem *ioaddr = pdata->ioaddr;	u8 *buf = val; 	for (; bytes; bytes--)		*buf++ = readb(ioaddr + pos++);	return 0;} static int ds1553_nvram_write(void *priv, unsigned int pos, void *val,			      size_t bytes){	struct platform_device *pdev = priv;	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);	void __iomem *ioaddr = pdata->ioaddr;	u8 *buf = val; 	for (; bytes; bytes--)		writeb(*buf++, ioaddr + pos++);	return 0;} static int ds1553_rtc_probe(struct platform_device *pdev){	unsigned int cen, sec;	struct rtc_plat_data *pdata;	void __iomem *ioaddr;	int ret = 0;	struct nvmem_config nvmem_cfg = {		.name = "ds1553_nvram",		.word_size = 1,		.stride = 1,		.size = RTC_OFFSET,		.reg_read = ds1553_nvram_read,		.reg_write = ds1553_nvram_write,		.priv = pdev,	}; 	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);	if (!pdata)		return -ENOMEM; 	ioaddr = devm_platform_ioremap_resource(pdev, 0);	if (IS_ERR(ioaddr))		return PTR_ERR(ioaddr);	pdata->ioaddr = ioaddr;	pdata->irq = platform_get_irq(pdev, 0); 	/* turn RTC on if it was not on */	sec = readb(ioaddr + RTC_SECONDS);	if (sec & RTC_STOP) {		sec &= RTC_SECONDS_MASK;		cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;		writeb(RTC_WRITE, ioaddr + RTC_CONTROL);		writeb(sec, ioaddr + RTC_SECONDS);		writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);	}	if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF)		dev_warn(&pdev->dev, "voltage-low detected.\n"); 	spin_lock_init(&pdata->lock);	pdata->last_jiffies = jiffies;	platform_set_drvdata(pdev, pdata); 	pdata->rtc = devm_rtc_allocate_device(&pdev->dev);	if (IS_ERR(pdata->rtc))		return PTR_ERR(pdata->rtc); 	pdata->rtc->ops = &ds1553_rtc_ops; 	ret = devm_rtc_register_device(pdata->rtc);	if (ret)		return ret; 	if (pdata->irq > 0) {		writeb(0, ioaddr + RTC_INTERRUPTS);		if (devm_request_irq(&pdev->dev, pdata->irq,				ds1553_rtc_interrupt,				0, pdev->name, pdev) < 0) {			dev_warn(&pdev->dev, "interrupt not available.\n");			pdata->irq = 0;		}	} 	devm_rtc_nvmem_register(pdata->rtc, &nvmem_cfg); 	return 0;} /* work with hotplug and coldplug */MODULE_ALIAS("platform:rtc-ds1553"); static struct platform_driver ds1553_rtc_driver = {	.probe		= ds1553_rtc_probe,	.driver		= {		.name	= "rtc-ds1553",	},}; module_platform_driver(ds1553_rtc_driver); MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");MODULE_DESCRIPTION("Dallas DS1553 RTC driver");MODULE_LICENSE("GPL");