// SPDX-License-Identifier: GPL-2.0-only/* * Dallas DS1216 RTC driver * * Copyright (c) 2007 Thomas Bogendoerfer * */ #include <linux/module.h>#include <linux/rtc.h>#include <linux/platform_device.h>#include <linux/bcd.h>#include <linux/slab.h> struct ds1216_regs {	u8 tsec;	u8 sec;	u8 min;	u8 hour;	u8 wday;	u8 mday;	u8 month;	u8 year;}; #define DS1216_HOUR_1224	(1 << 7)#define DS1216_HOUR_AMPM	(1 << 5) struct ds1216_priv {	struct rtc_device *rtc;	void __iomem *ioaddr;}; static const u8 magic[] = {	0xc5, 0x3a, 0xa3, 0x5c, 0xc5, 0x3a, 0xa3, 0x5c}; /* * Read the 64 bit we'd like to have - It a series * of 64 bits showing up in the LSB of the base register. * */static void ds1216_read(u8 __iomem *ioaddr, u8 *buf){	unsigned char c;	int i, j; 	for (i = 0; i < 8; i++) {		c = 0;		for (j = 0; j < 8; j++)			c |= (readb(ioaddr) & 0x1) << j;		buf[i] = c;	}} static void ds1216_write(u8 __iomem *ioaddr, const u8 *buf){	unsigned char c;	int i, j; 	for (i = 0; i < 8; i++) {		c = buf[i];		for (j = 0; j < 8; j++) {			writeb(c, ioaddr);			c = c >> 1;		}	}} static void ds1216_switch_ds_to_clock(u8 __iomem *ioaddr){	/* Reset magic pointer */	readb(ioaddr);	/* Write 64 bit magic to DS1216 */	ds1216_write(ioaddr, magic);} static int ds1216_rtc_read_time(struct device *dev, struct rtc_time *tm){	struct ds1216_priv *priv = dev_get_drvdata(dev);	struct ds1216_regs regs; 	ds1216_switch_ds_to_clock(priv->ioaddr);	ds1216_read(priv->ioaddr, (u8 *)&regs); 	tm->tm_sec = bcd2bin(regs.sec);	tm->tm_min = bcd2bin(regs.min);	if (regs.hour & DS1216_HOUR_1224) {		/* AM/PM mode */		tm->tm_hour = bcd2bin(regs.hour & 0x1f);		if (regs.hour & DS1216_HOUR_AMPM)			tm->tm_hour += 12;	} else		tm->tm_hour = bcd2bin(regs.hour & 0x3f);	tm->tm_wday = (regs.wday & 7) - 1;	tm->tm_mday = bcd2bin(regs.mday & 0x3f);	tm->tm_mon = bcd2bin(regs.month & 0x1f);	tm->tm_year = bcd2bin(regs.year);	if (tm->tm_year < 70)		tm->tm_year += 100; 	return 0;} static int ds1216_rtc_set_time(struct device *dev, struct rtc_time *tm){	struct ds1216_priv *priv = dev_get_drvdata(dev);	struct ds1216_regs regs; 	ds1216_switch_ds_to_clock(priv->ioaddr);	ds1216_read(priv->ioaddr, (u8 *)&regs); 	regs.tsec = 0; /* clear 0.1 and 0.01 seconds */	regs.sec = bin2bcd(tm->tm_sec);	regs.min = bin2bcd(tm->tm_min);	regs.hour &= DS1216_HOUR_1224;	if (regs.hour && tm->tm_hour > 12) {		regs.hour |= DS1216_HOUR_AMPM;		tm->tm_hour -= 12;	}	regs.hour |= bin2bcd(tm->tm_hour);	regs.wday &= ~7;	regs.wday |= tm->tm_wday;	regs.mday = bin2bcd(tm->tm_mday);	regs.month = bin2bcd(tm->tm_mon);	regs.year = bin2bcd(tm->tm_year % 100); 	ds1216_switch_ds_to_clock(priv->ioaddr);	ds1216_write(priv->ioaddr, (u8 *)&regs);	return 0;} static const struct rtc_class_ops ds1216_rtc_ops = {	.read_time	= ds1216_rtc_read_time,	.set_time	= ds1216_rtc_set_time,}; static int __init ds1216_rtc_probe(struct platform_device *pdev){	struct ds1216_priv *priv;	u8 dummy[8]; 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);	if (!priv)		return -ENOMEM; 	platform_set_drvdata(pdev, priv); 	priv->ioaddr = devm_platform_ioremap_resource(pdev, 0);	if (IS_ERR(priv->ioaddr))		return PTR_ERR(priv->ioaddr); 	priv->rtc = devm_rtc_device_register(&pdev->dev, "ds1216",					&ds1216_rtc_ops, THIS_MODULE);	if (IS_ERR(priv->rtc))		return PTR_ERR(priv->rtc); 	/* dummy read to get clock into a known state */	ds1216_read(priv->ioaddr, dummy);	return 0;} static struct platform_driver ds1216_rtc_platform_driver = {	.driver		= {		.name	= "rtc-ds1216",	},}; module_platform_driver_probe(ds1216_rtc_platform_driver, ds1216_rtc_probe); MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");MODULE_DESCRIPTION("DS1216 RTC driver");MODULE_LICENSE("GPL");MODULE_ALIAS("platform:rtc-ds1216");