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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * An rtc driver for the Dallas DS15534 *5 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>6 */7 8#include <linux/bcd.h>9#include <linux/init.h>10#include <linux/kernel.h>11#include <linux/gfp.h>12#include <linux/delay.h>13#include <linux/jiffies.h>14#include <linux/interrupt.h>15#include <linux/rtc.h>16#include <linux/platform_device.h>17#include <linux/io.h>18#include <linux/module.h>19 20#define RTC_REG_SIZE 0x200021#define RTC_OFFSET 0x1ff022 23#define RTC_FLAGS (RTC_OFFSET + 0)24#define RTC_SECONDS_ALARM (RTC_OFFSET + 2)25#define RTC_MINUTES_ALARM (RTC_OFFSET + 3)26#define RTC_HOURS_ALARM (RTC_OFFSET + 4)27#define RTC_DATE_ALARM (RTC_OFFSET + 5)28#define RTC_INTERRUPTS (RTC_OFFSET + 6)29#define RTC_WATCHDOG (RTC_OFFSET + 7)30#define RTC_CONTROL (RTC_OFFSET + 8)31#define RTC_CENTURY (RTC_OFFSET + 8)32#define RTC_SECONDS (RTC_OFFSET + 9)33#define RTC_MINUTES (RTC_OFFSET + 10)34#define RTC_HOURS (RTC_OFFSET + 11)35#define RTC_DAY (RTC_OFFSET + 12)36#define RTC_DATE (RTC_OFFSET + 13)37#define RTC_MONTH (RTC_OFFSET + 14)38#define RTC_YEAR (RTC_OFFSET + 15)39 40#define RTC_CENTURY_MASK 0x3f41#define RTC_SECONDS_MASK 0x7f42#define RTC_DAY_MASK 0x0743 44/* Bits in the Control/Century register */45#define RTC_WRITE 0x8046#define RTC_READ 0x4047 48/* Bits in the Seconds register */49#define RTC_STOP 0x8050 51/* Bits in the Flags register */52#define RTC_FLAGS_AF 0x4053#define RTC_FLAGS_BLF 0x1054 55/* Bits in the Interrupts register */56#define RTC_INTS_AE 0x8057 58struct rtc_plat_data {59 struct rtc_device *rtc;60 void __iomem *ioaddr;61 unsigned long last_jiffies;62 int irq;63 unsigned int irqen;64 int alrm_sec;65 int alrm_min;66 int alrm_hour;67 int alrm_mday;68 spinlock_t lock;69};70 71static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm)72{73 struct rtc_plat_data *pdata = dev_get_drvdata(dev);74 void __iomem *ioaddr = pdata->ioaddr;75 u8 century;76 77 century = bin2bcd((tm->tm_year + 1900) / 100);78 79 writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL);80 81 writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);82 writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);83 writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);84 writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);85 writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);86 writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);87 writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);88 89 /* RTC_CENTURY and RTC_CONTROL share same register */90 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);91 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);92 return 0;93}94 95static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm)96{97 struct rtc_plat_data *pdata = dev_get_drvdata(dev);98 void __iomem *ioaddr = pdata->ioaddr;99 unsigned int year, month, day, hour, minute, second, week;100 unsigned int century;101 102 /* give enough time to update RTC in case of continuous read */103 if (pdata->last_jiffies == jiffies)104 msleep(1);105 pdata->last_jiffies = jiffies;106 writeb(RTC_READ, ioaddr + RTC_CONTROL);107 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;108 minute = readb(ioaddr + RTC_MINUTES);109 hour = readb(ioaddr + RTC_HOURS);110 day = readb(ioaddr + RTC_DATE);111 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;112 month = readb(ioaddr + RTC_MONTH);113 year = readb(ioaddr + RTC_YEAR);114 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;115 writeb(0, ioaddr + RTC_CONTROL);116 tm->tm_sec = bcd2bin(second);117 tm->tm_min = bcd2bin(minute);118 tm->tm_hour = bcd2bin(hour);119 tm->tm_mday = bcd2bin(day);120 tm->tm_wday = bcd2bin(week);121 tm->tm_mon = bcd2bin(month) - 1;122 /* year is 1900 + tm->tm_year */123 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;124 125 return 0;126}127 128static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata)129{130 void __iomem *ioaddr = pdata->ioaddr;131 unsigned long flags;132 133 spin_lock_irqsave(&pdata->lock, flags);134 writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?135 0x80 : bin2bcd(pdata->alrm_mday),136 ioaddr + RTC_DATE_ALARM);137 writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?138 0x80 : bin2bcd(pdata->alrm_hour),139 ioaddr + RTC_HOURS_ALARM);140 writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?141 0x80 : bin2bcd(pdata->alrm_min),142 ioaddr + RTC_MINUTES_ALARM);143 writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?144 0x80 : bin2bcd(pdata->alrm_sec),145 ioaddr + RTC_SECONDS_ALARM);146 writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS);147 readb(ioaddr + RTC_FLAGS); /* clear interrupts */148 spin_unlock_irqrestore(&pdata->lock, flags);149}150 151static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)152{153 struct rtc_plat_data *pdata = dev_get_drvdata(dev);154 155 if (pdata->irq <= 0)156 return -EINVAL;157 pdata->alrm_mday = alrm->time.tm_mday;158 pdata->alrm_hour = alrm->time.tm_hour;159 pdata->alrm_min = alrm->time.tm_min;160 pdata->alrm_sec = alrm->time.tm_sec;161 if (alrm->enabled)162 pdata->irqen |= RTC_AF;163 ds1553_rtc_update_alarm(pdata);164 return 0;165}166 167static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)168{169 struct rtc_plat_data *pdata = dev_get_drvdata(dev);170 171 if (pdata->irq <= 0)172 return -EINVAL;173 alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;174 alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;175 alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;176 alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;177 alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;178 return 0;179}180 181static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id)182{183 struct platform_device *pdev = dev_id;184 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);185 void __iomem *ioaddr = pdata->ioaddr;186 unsigned long events = 0;187 188 spin_lock(&pdata->lock);189 /* read and clear interrupt */190 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {191 events = RTC_IRQF;192 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)193 events |= RTC_UF;194 else195 events |= RTC_AF;196 rtc_update_irq(pdata->rtc, 1, events);197 }198 spin_unlock(&pdata->lock);199 return events ? IRQ_HANDLED : IRQ_NONE;200}201 202static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)203{204 struct rtc_plat_data *pdata = dev_get_drvdata(dev);205 206 if (pdata->irq <= 0)207 return -EINVAL;208 if (enabled)209 pdata->irqen |= RTC_AF;210 else211 pdata->irqen &= ~RTC_AF;212 ds1553_rtc_update_alarm(pdata);213 return 0;214}215 216static const struct rtc_class_ops ds1553_rtc_ops = {217 .read_time = ds1553_rtc_read_time,218 .set_time = ds1553_rtc_set_time,219 .read_alarm = ds1553_rtc_read_alarm,220 .set_alarm = ds1553_rtc_set_alarm,221 .alarm_irq_enable = ds1553_rtc_alarm_irq_enable,222};223 224static int ds1553_nvram_read(void *priv, unsigned int pos, void *val,225 size_t bytes)226{227 struct platform_device *pdev = priv;228 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);229 void __iomem *ioaddr = pdata->ioaddr;230 u8 *buf = val;231 232 for (; bytes; bytes--)233 *buf++ = readb(ioaddr + pos++);234 return 0;235}236 237static int ds1553_nvram_write(void *priv, unsigned int pos, void *val,238 size_t bytes)239{240 struct platform_device *pdev = priv;241 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);242 void __iomem *ioaddr = pdata->ioaddr;243 u8 *buf = val;244 245 for (; bytes; bytes--)246 writeb(*buf++, ioaddr + pos++);247 return 0;248}249 250static int ds1553_rtc_probe(struct platform_device *pdev)251{252 unsigned int cen, sec;253 struct rtc_plat_data *pdata;254 void __iomem *ioaddr;255 int ret = 0;256 struct nvmem_config nvmem_cfg = {257 .name = "ds1553_nvram",258 .word_size = 1,259 .stride = 1,260 .size = RTC_OFFSET,261 .reg_read = ds1553_nvram_read,262 .reg_write = ds1553_nvram_write,263 .priv = pdev,264 };265 266 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);267 if (!pdata)268 return -ENOMEM;269 270 ioaddr = devm_platform_ioremap_resource(pdev, 0);271 if (IS_ERR(ioaddr))272 return PTR_ERR(ioaddr);273 pdata->ioaddr = ioaddr;274 pdata->irq = platform_get_irq(pdev, 0);275 276 /* turn RTC on if it was not on */277 sec = readb(ioaddr + RTC_SECONDS);278 if (sec & RTC_STOP) {279 sec &= RTC_SECONDS_MASK;280 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;281 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);282 writeb(sec, ioaddr + RTC_SECONDS);283 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);284 }285 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF)286 dev_warn(&pdev->dev, "voltage-low detected.\n");287 288 spin_lock_init(&pdata->lock);289 pdata->last_jiffies = jiffies;290 platform_set_drvdata(pdev, pdata);291 292 pdata->rtc = devm_rtc_allocate_device(&pdev->dev);293 if (IS_ERR(pdata->rtc))294 return PTR_ERR(pdata->rtc);295 296 pdata->rtc->ops = &ds1553_rtc_ops;297 298 ret = devm_rtc_register_device(pdata->rtc);299 if (ret)300 return ret;301 302 if (pdata->irq > 0) {303 writeb(0, ioaddr + RTC_INTERRUPTS);304 if (devm_request_irq(&pdev->dev, pdata->irq,305 ds1553_rtc_interrupt,306 0, pdev->name, pdev) < 0) {307 dev_warn(&pdev->dev, "interrupt not available.\n");308 pdata->irq = 0;309 }310 }311 312 devm_rtc_nvmem_register(pdata->rtc, &nvmem_cfg);313 314 return 0;315}316 317/* work with hotplug and coldplug */318MODULE_ALIAS("platform:rtc-ds1553");319 320static struct platform_driver ds1553_rtc_driver = {321 .probe = ds1553_rtc_probe,322 .driver = {323 .name = "rtc-ds1553",324 },325};326 327module_platform_driver(ds1553_rtc_driver);328 329MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");330MODULE_DESCRIPTION("Dallas DS1553 RTC driver");331MODULE_LICENSE("GPL");332