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 "0.1"
  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 baseaddr;
  65         unsigned long last_jiffies;
  66         int irq;
  67         unsigned int irqen;
  68         int alrm_sec;
  69         int alrm_min;
  70         int alrm_hour;
  71         int alrm_mday;
  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->rtc->irq_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->rtc->irq_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                                         struct pt_regs *regs)
 194 {
 195         struct platform_device *pdev = dev_id;
 196         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 197         void __iomem *ioaddr = pdata->ioaddr;
 198         unsigned long events = RTC_IRQF;
 199
 200         /* read and clear interrupt */
 201         if (!(readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF))
 202                 return IRQ_NONE;
 203         if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
 204                 events |= RTC_UF;
 205         else
 206                 events |= RTC_AF;
 207         rtc_update_irq(&pdata->rtc->class_dev, 1, events);
 208         return IRQ_HANDLED;
 209 }
 210
 211 static void ds1553_rtc_release(struct device *dev)
 212 {
 213         struct platform_device *pdev = to_platform_device(dev);
 214         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 215
 216         if (pdata->irq >= 0) {
 217                 pdata->irqen = 0;
 218                 ds1553_rtc_update_alarm(pdata);
 219         }
 220 }
 221
 222 static int ds1553_rtc_ioctl(struct device *dev, unsigned int cmd,
 223                             unsigned long arg)
 224 {
 225         struct platform_device *pdev = to_platform_device(dev);
 226         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 227
 228         if (pdata->irq < 0)
 229                 return -ENOIOCTLCMD; /* fall back into rtc-dev's emulation */
 230         switch (cmd) {
 231         case RTC_AIE_OFF:
 232                 pdata->irqen &= ~RTC_AF;
 233                 ds1553_rtc_update_alarm(pdata);
 234                 break;
 235         case RTC_AIE_ON:
 236                 pdata->irqen |= RTC_AF;
 237                 ds1553_rtc_update_alarm(pdata);
 238                 break;
 239         case RTC_UIE_OFF:
 240                 pdata->irqen &= ~RTC_UF;
 241                 ds1553_rtc_update_alarm(pdata);
 242                 break;
 243         case RTC_UIE_ON:
 244                 pdata->irqen |= RTC_UF;
 245                 ds1553_rtc_update_alarm(pdata);
 246                 break;
 247         default:
 248                 return -ENOIOCTLCMD;
 249         }
 250         return 0;
 251 }
 252
 253 static struct rtc_class_ops ds1553_rtc_ops = {
 254         .read_time      = ds1553_rtc_read_time,
 255         .set_time       = ds1553_rtc_set_time,
 256         .read_alarm     = ds1553_rtc_read_alarm,
 257         .set_alarm      = ds1553_rtc_set_alarm,
 258         .release        = ds1553_rtc_release,
 259         .ioctl          = ds1553_rtc_ioctl,
 260 };
 261
 262 static ssize_t ds1553_nvram_read(struct kobject *kobj, char *buf,
 263                                  loff_t pos, size_t size)
 264 {
 265         struct platform_device *pdev =
 266                 to_platform_device(container_of(kobj, struct device, kobj));
 267         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 268         void __iomem *ioaddr = pdata->ioaddr;
 269         ssize_t count;
 270
 271         for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
 272                 *buf++ = readb(ioaddr + pos++);
 273         return count;
 274 }
 275
 276 static ssize_t ds1553_nvram_write(struct kobject *kobj, char *buf,
 277                                   loff_t pos, size_t size)
 278 {
 279         struct platform_device *pdev =
 280                 to_platform_device(container_of(kobj, struct device, kobj));
 281         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 282         void __iomem *ioaddr = pdata->ioaddr;
 283         ssize_t count;
 284
 285         for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
 286                 writeb(*buf++, ioaddr + pos++);
 287         return count;
 288 }
 289
 290 static struct bin_attribute ds1553_nvram_attr = {
 291         .attr = {
 292                 .name = "nvram",
 293                 .mode = S_IRUGO | S_IWUGO,
 294                 .owner = THIS_MODULE,
 295         },
 296         .size = RTC_OFFSET,
 297         .read = ds1553_nvram_read,
 298         .write = ds1553_nvram_write,
 299 };
 300
 301 static int __init ds1553_rtc_probe(struct platform_device *pdev)
 302 {
 303         struct rtc_device *rtc;
 304         struct resource *res;
 305         unsigned int cen, sec;
 306         struct rtc_plat_data *pdata = NULL;
 307         void __iomem *ioaddr = NULL;
 308         int ret = 0;
 309
 310         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 311         if (!res)
 312                 return -ENODEV;
 313         pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
 314         if (!pdata)
 315                 return -ENOMEM;
 316         pdata->irq = -1;
 317         if (!request_mem_region(res->start, RTC_REG_SIZE, pdev->name)) {
 318                 ret = -EBUSY;
 319                 goto out;
 320         }
 321         pdata->baseaddr = res->start;
 322         ioaddr = ioremap(pdata->baseaddr, RTC_REG_SIZE);
 323         if (!ioaddr) {
 324                 ret = -ENOMEM;
 325                 goto out;
 326         }
 327         pdata->ioaddr = ioaddr;
 328         pdata->irq = platform_get_irq(pdev, 0);
 329
 330         /* turn RTC on if it was not on */
 331         sec = readb(ioaddr + RTC_SECONDS);
 332         if (sec & RTC_STOP) {
 333                 sec &= RTC_SECONDS_MASK;
 334                 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
 335                 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
 336                 writeb(sec, ioaddr + RTC_SECONDS);
 337                 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
 338         }
 339         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF)
 340                 dev_warn(&pdev->dev, "voltage-low detected.\n");
 341
 342         if (pdata->irq >= 0) {
 343                 writeb(0, ioaddr + RTC_INTERRUPTS);
 344                 if (request_irq(pdata->irq, ds1553_rtc_interrupt, IRQF_SHARED,
 345                                 pdev->name, pdev) < 0) {
 346                         dev_warn(&pdev->dev, "interrupt not available.\n");
 347                         pdata->irq = -1;
 348                 }
 349         }
 350
 351         rtc = rtc_device_register(pdev->name, &pdev->dev,
 352                                   &ds1553_rtc_ops, THIS_MODULE);
 353         if (IS_ERR(rtc)) {
 354                 ret = PTR_ERR(rtc);
 355                 goto out;
 356         }
 357         pdata->rtc = rtc;
 358         pdata->last_jiffies = jiffies;
 359         platform_set_drvdata(pdev, pdata);
 360         sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
 361         return 0;
 362  out:
 363         if (pdata->irq >= 0)
 364                 free_irq(pdata->irq, pdev);
 365         if (ioaddr)
 366                 iounmap(ioaddr);
 367         if (pdata->baseaddr)
 368                 release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
 369         kfree(pdata);
 370         return ret;
 371 }
 372
 373 static int __devexit ds1553_rtc_remove(struct platform_device *pdev)
 374 {
 375         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 376
 377         sysfs_remove_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
 378         rtc_device_unregister(pdata->rtc);
 379         if (pdata->irq >= 0) {
 380                 writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
 381                 free_irq(pdata->irq, pdev);
 382         }
 383         iounmap(pdata->ioaddr);
 384         release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
 385         kfree(pdata);
 386         return 0;
 387 }
 388
 389 static struct platform_driver ds1553_rtc_driver = {
 390         .probe          = ds1553_rtc_probe,
 391         .remove         = __devexit_p(ds1553_rtc_remove),
 392         .driver         = {
 393                 .name   = "ds1553",
 394                 .owner  = THIS_MODULE,
 395         },
 396 };
 397
 398 static __init int ds1553_init(void)
 399 {
 400         return platform_driver_register(&ds1553_rtc_driver);
 401 }
 402
 403 static __exit void ds1553_exit(void)
 404 {
 405         return platform_driver_unregister(&ds1553_rtc_driver);
 406 }
 407
 408 module_init(ds1553_init);
 409 module_exit(ds1553_exit);
 410
 411 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
 412 MODULE_DESCRIPTION("Dallas DS1553 RTC driver");
 413 MODULE_LICENSE("GPL");
 414 MODULE_VERSION(DRV_VERSION);