drivers/rtc/rtc-ds1553.c

   1 /*
   2  * An rtc driver for the Dallas DS1553
   3  *
   4  * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/bcd.h>
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/delay.h>
  15 #include <linux/jiffies.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/rtc.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/io.h>
  20
  21 #define DRV_VERSION "0.3"
  22
  23 #define RTC_REG_SIZE            0x2000
  24 #define RTC_OFFSET              0x1ff0
  25
  26 #define RTC_FLAGS               (RTC_OFFSET + 0)
  27 #define RTC_SECONDS_ALARM       (RTC_OFFSET + 2)
  28 #define RTC_MINUTES_ALARM       (RTC_OFFSET + 3)
  29 #define RTC_HOURS_ALARM         (RTC_OFFSET + 4)
  30 #define RTC_DATE_ALARM          (RTC_OFFSET + 5)
  31 #define RTC_INTERRUPTS          (RTC_OFFSET + 6)
  32 #define RTC_WATCHDOG            (RTC_OFFSET + 7)
  33 #define RTC_CONTROL             (RTC_OFFSET + 8)
  34 #define RTC_CENTURY             (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_CENTURY_MASK        0x3f
  44 #define RTC_SECONDS_MASK        0x7f
  45 #define RTC_DAY_MASK            0x07
  46
  47 /* Bits in the Control/Century register */
  48 #define RTC_WRITE               0x80
  49 #define RTC_READ                0x40
  50
  51 /* Bits in the Seconds register */
  52 #define RTC_STOP                0x80
  53
  54 /* Bits in the Flags register */
  55 #define RTC_FLAGS_AF            0x40
  56 #define RTC_FLAGS_BLF           0x10
  57
  58 /* Bits in the Interrupts register */
  59 #define RTC_INTS_AE             0x80
  60
  61 struct rtc_plat_data {
  62         struct rtc_device *rtc;
  63         void __iomem *ioaddr;
  64         unsigned long last_jiffies;
  65         int irq;
  66         unsigned int irqen;
  67         int alrm_sec;
  68         int alrm_min;
  69         int alrm_hour;
  70         int alrm_mday;
  71         spinlock_t lock;
  72 };
  73
  74 static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm)
  75 {
  76         struct platform_device *pdev = to_platform_device(dev);
  77         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
  78         void __iomem *ioaddr = pdata->ioaddr;
  79         u8 century;
  80
  81         century = bin2bcd((tm->tm_year + 1900) / 100);
  82
  83         writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL);
  84
  85         writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
  86         writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
  87         writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
  88         writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
  89         writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
  90         writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
  91         writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
  92
  93         /* RTC_CENTURY and RTC_CONTROL share same register */
  94         writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
  95         writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
  96         return 0;
  97 }
  98
  99 static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm)
 100 {
 101         struct platform_device *pdev = to_platform_device(dev);
 102         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 103         void __iomem *ioaddr = pdata->ioaddr;
 104         unsigned int year, month, day, hour, minute, second, week;
 105         unsigned int century;
 106
 107         /* give enough time to update RTC in case of continuous read */
 108         if (pdata->last_jiffies == jiffies)
 109                 msleep(1);
 110         pdata->last_jiffies = jiffies;
 111         writeb(RTC_READ, ioaddr + RTC_CONTROL);
 112         second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
 113         minute = readb(ioaddr + RTC_MINUTES);
 114         hour = readb(ioaddr + RTC_HOURS);
 115         day = readb(ioaddr + RTC_DATE);
 116         week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
 117         month = readb(ioaddr + RTC_MONTH);
 118         year = readb(ioaddr + RTC_YEAR);
 119         century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
 120         writeb(0, ioaddr + RTC_CONTROL);
 121         tm->tm_sec = bcd2bin(second);
 122         tm->tm_min = bcd2bin(minute);
 123         tm->tm_hour = bcd2bin(hour);
 124         tm->tm_mday = bcd2bin(day);
 125         tm->tm_wday = bcd2bin(week);
 126         tm->tm_mon = bcd2bin(month) - 1;
 127         /* year is 1900 + tm->tm_year */
 128         tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
 129
 130         if (rtc_valid_tm(tm) < 0) {
 131                 dev_err(dev, "retrieved date/time is not valid.\n");
 132                 rtc_time_to_tm(0, tm);
 133         }
 134         return 0;
 135 }
 136
 137 static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata)
 138 {
 139         void __iomem *ioaddr = pdata->ioaddr;
 140         unsigned long flags;
 141
 142         spin_lock_irqsave(&pdata->lock, flags);
 143         writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
 144                0x80 : bin2bcd(pdata->alrm_mday),
 145                ioaddr + RTC_DATE_ALARM);
 146         writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
 147                0x80 : bin2bcd(pdata->alrm_hour),
 148                ioaddr + RTC_HOURS_ALARM);
 149         writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
 150                0x80 : bin2bcd(pdata->alrm_min),
 151                ioaddr + RTC_MINUTES_ALARM);
 152         writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
 153                0x80 : bin2bcd(pdata->alrm_sec),
 154                ioaddr + RTC_SECONDS_ALARM);
 155         writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS);
 156         readb(ioaddr + RTC_FLAGS);      /* clear interrupts */
 157         spin_unlock_irqrestore(&pdata->lock, flags);
 158 }
 159
 160 static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 161 {
 162         struct platform_device *pdev = to_platform_device(dev);
 163         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 164
 165         if (pdata->irq <= 0)
 166                 return -EINVAL;
 167         pdata->alrm_mday = alrm->time.tm_mday;
 168         pdata->alrm_hour = alrm->time.tm_hour;
 169         pdata->alrm_min = alrm->time.tm_min;
 170         pdata->alrm_sec = alrm->time.tm_sec;
 171         if (alrm->enabled)
 172                 pdata->irqen |= RTC_AF;
 173         ds1553_rtc_update_alarm(pdata);
 174         return 0;
 175 }
 176
 177 static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 178 {
 179         struct platform_device *pdev = to_platform_device(dev);
 180         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 181
 182         if (pdata->irq <= 0)
 183                 return -EINVAL;
 184         alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
 185         alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
 186         alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
 187         alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
 188         alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
 189         return 0;
 190 }
 191
 192 static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id)
 193 {
 194         struct platform_device *pdev = dev_id;
 195         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 196         void __iomem *ioaddr = pdata->ioaddr;
 197         unsigned long events = 0;
 198
 199         spin_lock(&pdata->lock);
 200         /* read and clear interrupt */
 201         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {
 202                 events = RTC_IRQF;
 203                 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
 204                         events |= RTC_UF;
 205                 else
 206                         events |= RTC_AF;
 207                 if (likely(pdata->rtc))
 208                         rtc_update_irq(pdata->rtc, 1, events);
 209         }
 210         spin_unlock(&pdata->lock);
 211         return events ? IRQ_HANDLED : IRQ_NONE;
 212 }
 213
 214 static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 215 {
 216         struct platform_device *pdev = to_platform_device(dev);
 217         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 218
 219         if (pdata->irq <= 0)
 220                 return -EINVAL;
 221         if (enabled)
 222                 pdata->irqen |= RTC_AF;
 223         else
 224                 pdata->irqen &= ~RTC_AF;
 225         ds1553_rtc_update_alarm(pdata);
 226         return 0;
 227 }
 228
 229 static int ds1553_rtc_update_irq_enable(struct device *dev,
 230         unsigned int enabled)
 231 {
 232         struct platform_device *pdev = to_platform_device(dev);
 233         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 234
 235         if (pdata->irq <= 0)
 236                 return -EINVAL;
 237         if (enabled)
 238                 pdata->irqen |= RTC_UF;
 239         else
 240                 pdata->irqen &= ~RTC_UF;
 241         ds1553_rtc_update_alarm(pdata);
 242         return 0;
 243 }
 244
 245 static const struct rtc_class_ops ds1553_rtc_ops = {
 246         .read_time              = ds1553_rtc_read_time,
 247         .set_time               = ds1553_rtc_set_time,
 248         .read_alarm             = ds1553_rtc_read_alarm,
 249         .set_alarm              = ds1553_rtc_set_alarm,
 250         .alarm_irq_enable       = ds1553_rtc_alarm_irq_enable,
 251         .update_irq_enable      = ds1553_rtc_update_irq_enable,
 252 };
 253
 254 static ssize_t ds1553_nvram_read(struct kobject *kobj,
 255                                  struct bin_attribute *bin_attr,
 256                                  char *buf, loff_t pos, size_t size)
 257 {
 258         struct device *dev = container_of(kobj, struct device, kobj);
 259         struct platform_device *pdev = to_platform_device(dev);
 260         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 261         void __iomem *ioaddr = pdata->ioaddr;
 262         ssize_t count;
 263
 264         for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
 265                 *buf++ = readb(ioaddr + pos++);
 266         return count;
 267 }
 268
 269 static ssize_t ds1553_nvram_write(struct kobject *kobj,
 270                                   struct bin_attribute *bin_attr,
 271                                   char *buf, loff_t pos, size_t size)
 272 {
 273         struct device *dev = container_of(kobj, struct device, kobj);
 274         struct platform_device *pdev = to_platform_device(dev);
 275         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 276         void __iomem *ioaddr = pdata->ioaddr;
 277         ssize_t count;
 278
 279         for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
 280                 writeb(*buf++, ioaddr + pos++);
 281         return count;
 282 }
 283
 284 static struct bin_attribute ds1553_nvram_attr = {
 285         .attr = {
 286                 .name = "nvram",
 287                 .mode = S_IRUGO | S_IWUSR,
 288         },
 289         .size = RTC_OFFSET,
 290         .read = ds1553_nvram_read,
 291         .write = ds1553_nvram_write,
 292 };
 293
 294 static int __devinit ds1553_rtc_probe(struct platform_device *pdev)
 295 {
 296         struct rtc_device *rtc;
 297         struct resource *res;
 298         unsigned int cen, sec;
 299         struct rtc_plat_data *pdata;
 300         void __iomem *ioaddr;
 301         int ret = 0;
 302
 303         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 304         if (!res)
 305                 return -ENODEV;
 306         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 307         if (!pdata)
 308                 return -ENOMEM;
 309         if (!devm_request_mem_region(&pdev->dev, res->start, RTC_REG_SIZE,
 310                         pdev->name))
 311                 return -EBUSY;
 312
 313         ioaddr = devm_ioremap(&pdev->dev, res->start, RTC_REG_SIZE);
 314         if (!ioaddr)
 315                 return -ENOMEM;
 316         pdata->ioaddr = ioaddr;
 317         pdata->irq = platform_get_irq(pdev, 0);
 318
 319         /* turn RTC on if it was not on */
 320         sec = readb(ioaddr + RTC_SECONDS);
 321         if (sec & RTC_STOP) {
 322                 sec &= RTC_SECONDS_MASK;
 323                 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
 324                 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
 325                 writeb(sec, ioaddr + RTC_SECONDS);
 326                 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
 327         }
 328         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF)
 329                 dev_warn(&pdev->dev, "voltage-low detected.\n");
 330
 331         spin_lock_init(&pdata->lock);
 332         pdata->last_jiffies = jiffies;
 333         platform_set_drvdata(pdev, pdata);
 334         if (pdata->irq > 0) {
 335                 writeb(0, ioaddr + RTC_INTERRUPTS);
 336                 if (devm_request_irq(&pdev->dev, pdata->irq,
 337                                 ds1553_rtc_interrupt,
 338                                 IRQF_DISABLED, pdev->name, pdev) < 0) {
 339                         dev_warn(&pdev->dev, "interrupt not available.\n");
 340                         pdata->irq = 0;
 341                 }
 342         }
 343
 344         rtc = rtc_device_register(pdev->name, &pdev->dev,
 345                                   &ds1553_rtc_ops, THIS_MODULE);
 346         if (IS_ERR(rtc))
 347                 return PTR_ERR(rtc);
 348         pdata->rtc = rtc;
 349
 350         ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
 351         if (ret)
 352                 rtc_device_unregister(rtc);
 353         return ret;
 354 }
 355
 356 static int __devexit ds1553_rtc_remove(struct platform_device *pdev)
 357 {
 358         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 359
 360         sysfs_remove_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
 361         rtc_device_unregister(pdata->rtc);
 362         if (pdata->irq > 0)
 363                 writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
 364         return 0;
 365 }
 366
 367 /* work with hotplug and coldplug */
 368 MODULE_ALIAS("platform:rtc-ds1553");
 369
 370 static struct platform_driver ds1553_rtc_driver = {
 371         .probe          = ds1553_rtc_probe,
 372         .remove         = __devexit_p(ds1553_rtc_remove),
 373         .driver         = {
 374                 .name   = "rtc-ds1553",
 375                 .owner  = THIS_MODULE,
 376         },
 377 };
 378
 379 static __init int ds1553_init(void)
 380 {
 381         return platform_driver_register(&ds1553_rtc_driver);
 382 }
 383
 384 static __exit void ds1553_exit(void)
 385 {
 386         platform_driver_unregister(&ds1553_rtc_driver);
 387 }
 388
 389 module_init(ds1553_init);
 390 module_exit(ds1553_exit);
 391
 392 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
 393 MODULE_DESCRIPTION("Dallas DS1553 RTC driver");
 394 MODULE_LICENSE("GPL");
 395 MODULE_VERSION(DRV_VERSION);