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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * A RTC driver for the Simtek STK17TA84 *5 * By Thomas Hommel <thomas.hommel@ge.com>6 *7 * Based on the DS1553 driver from8 * Atsushi Nemoto <anemo@mba.ocn.ne.jp>9 */10 11#include <linux/bcd.h>12#include <linux/init.h>13#include <linux/kernel.h>14#include <linux/gfp.h>15#include <linux/delay.h>16#include <linux/jiffies.h>17#include <linux/interrupt.h>18#include <linux/rtc.h>19#include <linux/platform_device.h>20#include <linux/io.h>21#include <linux/module.h>22 23#define RTC_REG_SIZE 0x2000024#define RTC_OFFSET 0x1fff025 26#define RTC_FLAGS (RTC_OFFSET + 0)27#define RTC_CENTURY (RTC_OFFSET + 1)28#define RTC_SECONDS_ALARM (RTC_OFFSET + 2)29#define RTC_MINUTES_ALARM (RTC_OFFSET + 3)30#define RTC_HOURS_ALARM (RTC_OFFSET + 4)31#define RTC_DATE_ALARM (RTC_OFFSET + 5)32#define RTC_INTERRUPTS (RTC_OFFSET + 6)33#define RTC_WATCHDOG (RTC_OFFSET + 7)34#define RTC_CALIBRATION (RTC_OFFSET + 8)35#define RTC_SECONDS (RTC_OFFSET + 9)36#define RTC_MINUTES (RTC_OFFSET + 10)37#define RTC_HOURS (RTC_OFFSET + 11)38#define RTC_DAY (RTC_OFFSET + 12)39#define RTC_DATE (RTC_OFFSET + 13)40#define RTC_MONTH (RTC_OFFSET + 14)41#define RTC_YEAR (RTC_OFFSET + 15)42 43#define RTC_SECONDS_MASK 0x7f44#define RTC_DAY_MASK 0x0745#define RTC_CAL_MASK 0x3f46 47/* Bits in the Calibration register */48#define RTC_STOP 0x8049 50/* Bits in the Flags register */51#define RTC_FLAGS_AF 0x4052#define RTC_FLAGS_PF 0x2053#define RTC_WRITE 0x0254#define RTC_READ 0x0155 56/* Bits in the Interrupts register */57#define RTC_INTS_AIE 0x4058 59struct rtc_plat_data {60 struct rtc_device *rtc;61 void __iomem *ioaddr;62 unsigned long last_jiffies;63 int irq;64 unsigned int irqen;65 int alrm_sec;66 int alrm_min;67 int alrm_hour;68 int alrm_mday;69 spinlock_t lock;70};71 72static int stk17ta8_rtc_set_time(struct device *dev, struct rtc_time *tm)73{74 struct rtc_plat_data *pdata = dev_get_drvdata(dev);75 void __iomem *ioaddr = pdata->ioaddr;76 u8 flags;77 78 flags = readb(pdata->ioaddr + RTC_FLAGS);79 writeb(flags | RTC_WRITE, pdata->ioaddr + RTC_FLAGS);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 writeb(bin2bcd((tm->tm_year + 1900) / 100), ioaddr + RTC_CENTURY);89 90 writeb(flags & ~RTC_WRITE, pdata->ioaddr + RTC_FLAGS);91 return 0;92}93 94static int stk17ta8_rtc_read_time(struct device *dev, struct rtc_time *tm)95{96 struct rtc_plat_data *pdata = dev_get_drvdata(dev);97 void __iomem *ioaddr = pdata->ioaddr;98 unsigned int year, month, day, hour, minute, second, week;99 unsigned int century;100 u8 flags;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;106 107 flags = readb(pdata->ioaddr + RTC_FLAGS);108 writeb(flags | RTC_READ, ioaddr + RTC_FLAGS);109 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;110 minute = readb(ioaddr + RTC_MINUTES);111 hour = readb(ioaddr + RTC_HOURS);112 day = readb(ioaddr + RTC_DATE);113 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;114 month = readb(ioaddr + RTC_MONTH);115 year = readb(ioaddr + RTC_YEAR);116 century = readb(ioaddr + RTC_CENTURY);117 writeb(flags & ~RTC_READ, ioaddr + RTC_FLAGS);118 tm->tm_sec = bcd2bin(second);119 tm->tm_min = bcd2bin(minute);120 tm->tm_hour = bcd2bin(hour);121 tm->tm_mday = bcd2bin(day);122 tm->tm_wday = bcd2bin(week);123 tm->tm_mon = bcd2bin(month) - 1;124 /* year is 1900 + tm->tm_year */125 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;126 127 return 0;128}129 130static void stk17ta8_rtc_update_alarm(struct rtc_plat_data *pdata)131{132 void __iomem *ioaddr = pdata->ioaddr;133 unsigned long irqflags;134 u8 flags;135 136 spin_lock_irqsave(&pdata->lock, irqflags);137 138 flags = readb(ioaddr + RTC_FLAGS);139 writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);140 141 writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?142 0x80 : bin2bcd(pdata->alrm_mday),143 ioaddr + RTC_DATE_ALARM);144 writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?145 0x80 : bin2bcd(pdata->alrm_hour),146 ioaddr + RTC_HOURS_ALARM);147 writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?148 0x80 : bin2bcd(pdata->alrm_min),149 ioaddr + RTC_MINUTES_ALARM);150 writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?151 0x80 : bin2bcd(pdata->alrm_sec),152 ioaddr + RTC_SECONDS_ALARM);153 writeb(pdata->irqen ? RTC_INTS_AIE : 0, ioaddr + RTC_INTERRUPTS);154 readb(ioaddr + RTC_FLAGS); /* clear interrupts */155 writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);156 spin_unlock_irqrestore(&pdata->lock, irqflags);157}158 159static int stk17ta8_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)160{161 struct rtc_plat_data *pdata = dev_get_drvdata(dev);162 163 if (pdata->irq <= 0)164 return -EINVAL;165 pdata->alrm_mday = alrm->time.tm_mday;166 pdata->alrm_hour = alrm->time.tm_hour;167 pdata->alrm_min = alrm->time.tm_min;168 pdata->alrm_sec = alrm->time.tm_sec;169 if (alrm->enabled)170 pdata->irqen |= RTC_AF;171 stk17ta8_rtc_update_alarm(pdata);172 return 0;173}174 175static int stk17ta8_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)176{177 struct rtc_plat_data *pdata = dev_get_drvdata(dev);178 179 if (pdata->irq <= 0)180 return -EINVAL;181 alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;182 alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;183 alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;184 alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;185 alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;186 return 0;187}188 189static irqreturn_t stk17ta8_rtc_interrupt(int irq, void *dev_id)190{191 struct platform_device *pdev = dev_id;192 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);193 void __iomem *ioaddr = pdata->ioaddr;194 unsigned long events = 0;195 196 spin_lock(&pdata->lock);197 /* read and clear interrupt */198 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {199 events = RTC_IRQF;200 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)201 events |= RTC_UF;202 else203 events |= RTC_AF;204 rtc_update_irq(pdata->rtc, 1, events);205 }206 spin_unlock(&pdata->lock);207 return events ? IRQ_HANDLED : IRQ_NONE;208}209 210static int stk17ta8_rtc_alarm_irq_enable(struct device *dev,211 unsigned int enabled)212{213 struct rtc_plat_data *pdata = dev_get_drvdata(dev);214 215 if (pdata->irq <= 0)216 return -EINVAL;217 if (enabled)218 pdata->irqen |= RTC_AF;219 else220 pdata->irqen &= ~RTC_AF;221 stk17ta8_rtc_update_alarm(pdata);222 return 0;223}224 225static const struct rtc_class_ops stk17ta8_rtc_ops = {226 .read_time = stk17ta8_rtc_read_time,227 .set_time = stk17ta8_rtc_set_time,228 .read_alarm = stk17ta8_rtc_read_alarm,229 .set_alarm = stk17ta8_rtc_set_alarm,230 .alarm_irq_enable = stk17ta8_rtc_alarm_irq_enable,231};232 233static int stk17ta8_nvram_read(void *priv, unsigned int pos, void *val,234 size_t bytes)235{236 struct rtc_plat_data *pdata = priv;237 void __iomem *ioaddr = pdata->ioaddr;238 u8 *buf = val;239 240 for (; bytes; bytes--)241 *buf++ = readb(ioaddr + pos++);242 return 0;243}244 245static int stk17ta8_nvram_write(void *priv, unsigned int pos, void *val,246 size_t bytes)247{248 struct rtc_plat_data *pdata = priv;249 void __iomem *ioaddr = pdata->ioaddr;250 u8 *buf = val;251 252 for (; bytes; bytes--)253 writeb(*buf++, ioaddr + pos++);254 return 0;255}256 257static int stk17ta8_rtc_probe(struct platform_device *pdev)258{259 unsigned int cal;260 unsigned int flags;261 struct rtc_plat_data *pdata;262 void __iomem *ioaddr;263 int ret = 0;264 struct nvmem_config nvmem_cfg = {265 .name = "stk17ta8_nvram",266 .word_size = 1,267 .stride = 1,268 .size = RTC_OFFSET,269 .reg_read = stk17ta8_nvram_read,270 .reg_write = stk17ta8_nvram_write,271 };272 273 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);274 if (!pdata)275 return -ENOMEM;276 277 ioaddr = devm_platform_ioremap_resource(pdev, 0);278 if (IS_ERR(ioaddr))279 return PTR_ERR(ioaddr);280 pdata->ioaddr = ioaddr;281 pdata->irq = platform_get_irq(pdev, 0);282 283 /* turn RTC on if it was not on */284 cal = readb(ioaddr + RTC_CALIBRATION);285 if (cal & RTC_STOP) {286 cal &= RTC_CAL_MASK;287 flags = readb(ioaddr + RTC_FLAGS);288 writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);289 writeb(cal, ioaddr + RTC_CALIBRATION);290 writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);291 }292 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF)293 dev_warn(&pdev->dev, "voltage-low detected.\n");294 295 spin_lock_init(&pdata->lock);296 pdata->last_jiffies = jiffies;297 platform_set_drvdata(pdev, pdata);298 if (pdata->irq > 0) {299 writeb(0, ioaddr + RTC_INTERRUPTS);300 if (devm_request_irq(&pdev->dev, pdata->irq,301 stk17ta8_rtc_interrupt,302 IRQF_SHARED,303 pdev->name, pdev) < 0) {304 dev_warn(&pdev->dev, "interrupt not available.\n");305 pdata->irq = 0;306 }307 }308 309 pdata->rtc = devm_rtc_allocate_device(&pdev->dev);310 if (IS_ERR(pdata->rtc))311 return PTR_ERR(pdata->rtc);312 313 pdata->rtc->ops = &stk17ta8_rtc_ops;314 315 nvmem_cfg.priv = pdata;316 ret = devm_rtc_nvmem_register(pdata->rtc, &nvmem_cfg);317 if (ret)318 return ret;319 320 return devm_rtc_register_device(pdata->rtc);321}322 323/* work with hotplug and coldplug */324MODULE_ALIAS("platform:stk17ta8");325 326static struct platform_driver stk17ta8_rtc_driver = {327 .probe = stk17ta8_rtc_probe,328 .driver = {329 .name = "stk17ta8",330 },331};332 333module_platform_driver(stk17ta8_rtc_driver);334 335MODULE_AUTHOR("Thomas Hommel <thomas.hommel@ge.com>");336MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver");337MODULE_LICENSE("GPL");338