drivers/rtc/rtc-stk17ta8.c

   1 /*
   2  * A RTC driver for the Simtek STK17TA8
   3  *
   4  * By Thomas Hommel <thomas.hommel@gefanuc.com>
   5  *
   6  * Based on the DS1553 driver from
   7  * Atsushi Nemoto <anemo@mba.ocn.ne.jp>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/bcd.h>
  15 #include <linux/init.h>
  16 #include <linux/kernel.h>
  17 #include <linux/delay.h>
  18 #include <linux/jiffies.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/rtc.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/io.h>
  23
  24 #define DRV_VERSION "0.1"
  25
  26 #define RTC_REG_SIZE            0x20000
  27 #define RTC_OFFSET              0x1fff0
  28
  29 #define RTC_FLAGS               (RTC_OFFSET + 0)
  30 #define RTC_CENTURY             (RTC_OFFSET + 1)
  31 #define RTC_SECONDS_ALARM       (RTC_OFFSET + 2)
  32 #define RTC_MINUTES_ALARM       (RTC_OFFSET + 3)
  33 #define RTC_HOURS_ALARM         (RTC_OFFSET + 4)
  34 #define RTC_DATE_ALARM          (RTC_OFFSET + 5)
  35 #define RTC_INTERRUPTS          (RTC_OFFSET + 6)
  36 #define RTC_WATCHDOG            (RTC_OFFSET + 7)
  37 #define RTC_CALIBRATION         (RTC_OFFSET + 8)
  38 #define RTC_SECONDS             (RTC_OFFSET + 9)
  39 #define RTC_MINUTES             (RTC_OFFSET + 10)
  40 #define RTC_HOURS               (RTC_OFFSET + 11)
  41 #define RTC_DAY                 (RTC_OFFSET + 12)
  42 #define RTC_DATE                (RTC_OFFSET + 13)
  43 #define RTC_MONTH               (RTC_OFFSET + 14)
  44 #define RTC_YEAR                (RTC_OFFSET + 15)
  45
  46 #define RTC_SECONDS_MASK        0x7f
  47 #define RTC_DAY_MASK            0x07
  48 #define RTC_CAL_MASK            0x3f
  49
  50 /* Bits in the Calibration register */
  51 #define RTC_STOP                0x80
  52
  53 /* Bits in the Flags register */
  54 #define RTC_FLAGS_AF            0x40
  55 #define RTC_FLAGS_PF            0x20
  56 #define RTC_WRITE               0x02
  57 #define RTC_READ                0x01
  58
  59 /* Bits in the Interrupts register */
  60 #define RTC_INTS_AIE            0x40
  61
  62 struct rtc_plat_data {
  63         struct rtc_device *rtc;
  64         void __iomem *ioaddr;
  65         unsigned long baseaddr;
  66         unsigned long last_jiffies;
  67         int irq;
  68         unsigned int irqen;
  69         int alrm_sec;
  70         int alrm_min;
  71         int alrm_hour;
  72         int alrm_mday;
  73 };
  74
  75 static int stk17ta8_rtc_set_time(struct device *dev, struct rtc_time *tm)
  76 {
  77         struct platform_device *pdev = to_platform_device(dev);
  78         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
  79         void __iomem *ioaddr = pdata->ioaddr;
  80         u8 flags;
  81
  82         flags = readb(pdata->ioaddr + RTC_FLAGS);
  83         writeb(flags | RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
  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         writeb(BIN2BCD((tm->tm_year + 1900) / 100), ioaddr + RTC_CENTURY);
  93
  94         writeb(flags & ~RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
  95         return 0;
  96 }
  97
  98 static int stk17ta8_rtc_read_time(struct device *dev, struct rtc_time *tm)
  99 {
 100         struct platform_device *pdev = to_platform_device(dev);
 101         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 102         void __iomem *ioaddr = pdata->ioaddr;
 103         unsigned int year, month, day, hour, minute, second, week;
 104         unsigned int century;
 105         u8 flags;
 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
 112         flags = readb(pdata->ioaddr + RTC_FLAGS);
 113         writeb(flags | RTC_READ, ioaddr + RTC_FLAGS);
 114         second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
 115         minute = readb(ioaddr + RTC_MINUTES);
 116         hour = readb(ioaddr + RTC_HOURS);
 117         day = readb(ioaddr + RTC_DATE);
 118         week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
 119         month = readb(ioaddr + RTC_MONTH);
 120         year = readb(ioaddr + RTC_YEAR);
 121         century = readb(ioaddr + RTC_CENTURY);
 122         writeb(flags & ~RTC_READ, ioaddr + RTC_FLAGS);
 123         tm->tm_sec = BCD2BIN(second);
 124         tm->tm_min = BCD2BIN(minute);
 125         tm->tm_hour = BCD2BIN(hour);
 126         tm->tm_mday = BCD2BIN(day);
 127         tm->tm_wday = BCD2BIN(week);
 128         tm->tm_mon = BCD2BIN(month) - 1;
 129         /* year is 1900 + tm->tm_year */
 130         tm->tm_year = BCD2BIN(year) + BCD2BIN(century) * 100 - 1900;
 131
 132         if (rtc_valid_tm(tm) < 0) {
 133                 dev_err(dev, "retrieved date/time is not valid.\n");
 134                 rtc_time_to_tm(0, tm);
 135         }
 136         return 0;
 137 }
 138
 139 static void stk17ta8_rtc_update_alarm(struct rtc_plat_data *pdata)
 140 {
 141         void __iomem *ioaddr = pdata->ioaddr;
 142         unsigned long irqflags;
 143         u8 flags;
 144
 145         spin_lock_irqsave(&pdata->rtc->irq_lock, irqflags);
 146
 147         flags = readb(ioaddr + RTC_FLAGS);
 148         writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
 149
 150         writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
 151                0x80 : BIN2BCD(pdata->alrm_mday),
 152                ioaddr + RTC_DATE_ALARM);
 153         writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
 154                0x80 : BIN2BCD(pdata->alrm_hour),
 155                ioaddr + RTC_HOURS_ALARM);
 156         writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
 157                0x80 : BIN2BCD(pdata->alrm_min),
 158                ioaddr + RTC_MINUTES_ALARM);
 159         writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
 160                0x80 : BIN2BCD(pdata->alrm_sec),
 161                ioaddr + RTC_SECONDS_ALARM);
 162         writeb(pdata->irqen ? RTC_INTS_AIE : 0, ioaddr + RTC_INTERRUPTS);
 163         readb(ioaddr + RTC_FLAGS);      /* clear interrupts */
 164         writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
 165         spin_unlock_irqrestore(&pdata->rtc->irq_lock, irqflags);
 166 }
 167
 168 static int stk17ta8_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 169 {
 170         struct platform_device *pdev = to_platform_device(dev);
 171         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 172
 173         if (pdata->irq < 0)
 174                 return -EINVAL;
 175         pdata->alrm_mday = alrm->time.tm_mday;
 176         pdata->alrm_hour = alrm->time.tm_hour;
 177         pdata->alrm_min = alrm->time.tm_min;
 178         pdata->alrm_sec = alrm->time.tm_sec;
 179         if (alrm->enabled)
 180                 pdata->irqen |= RTC_AF;
 181         stk17ta8_rtc_update_alarm(pdata);
 182         return 0;
 183 }
 184
 185 static int stk17ta8_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 186 {
 187         struct platform_device *pdev = to_platform_device(dev);
 188         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 189
 190         if (pdata->irq < 0)
 191                 return -EINVAL;
 192         alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
 193         alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
 194         alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
 195         alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
 196         alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
 197         return 0;
 198 }
 199
 200 static irqreturn_t stk17ta8_rtc_interrupt(int irq, void *dev_id)
 201 {
 202         struct platform_device *pdev = dev_id;
 203         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 204         void __iomem *ioaddr = pdata->ioaddr;
 205         unsigned long events = RTC_IRQF;
 206
 207         /* read and clear interrupt */
 208         if (!(readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF))
 209                 return IRQ_NONE;
 210         if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
 211                 events |= RTC_UF;
 212         else
 213                 events |= RTC_AF;
 214         rtc_update_irq(pdata->rtc, 1, events);
 215         return IRQ_HANDLED;
 216 }
 217
 218 static void stk17ta8_rtc_release(struct device *dev)
 219 {
 220         struct platform_device *pdev = to_platform_device(dev);
 221         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 222
 223         if (pdata->irq >= 0) {
 224                 pdata->irqen = 0;
 225                 stk17ta8_rtc_update_alarm(pdata);
 226         }
 227 }
 228
 229 static int stk17ta8_rtc_ioctl(struct device *dev, unsigned int cmd,
 230                             unsigned long arg)
 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 -ENOIOCTLCMD; /* fall back into rtc-dev's emulation */
 237         switch (cmd) {
 238         case RTC_AIE_OFF:
 239                 pdata->irqen &= ~RTC_AF;
 240                 stk17ta8_rtc_update_alarm(pdata);
 241                 break;
 242         case RTC_AIE_ON:
 243                 pdata->irqen |= RTC_AF;
 244                 stk17ta8_rtc_update_alarm(pdata);
 245                 break;
 246         default:
 247                 return -ENOIOCTLCMD;
 248         }
 249         return 0;
 250 }
 251
 252 static const struct rtc_class_ops stk17ta8_rtc_ops = {
 253         .read_time      = stk17ta8_rtc_read_time,
 254         .set_time       = stk17ta8_rtc_set_time,
 255         .read_alarm     = stk17ta8_rtc_read_alarm,
 256         .set_alarm      = stk17ta8_rtc_set_alarm,
 257         .release        = stk17ta8_rtc_release,
 258         .ioctl          = stk17ta8_rtc_ioctl,
 259 };
 260
 261 static ssize_t stk17ta8_nvram_read(struct kobject *kobj,
 262                                  struct bin_attribute *attr, 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 stk17ta8_nvram_write(struct kobject *kobj,
 277                                   struct bin_attribute *attr, char *buf,
 278                                   loff_t pos, size_t size)
 279 {
 280         struct platform_device *pdev =
 281                 to_platform_device(container_of(kobj, struct device, kobj));
 282         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 283         void __iomem *ioaddr = pdata->ioaddr;
 284         ssize_t count;
 285
 286         for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
 287                 writeb(*buf++, ioaddr + pos++);
 288         return count;
 289 }
 290
 291 static struct bin_attribute stk17ta8_nvram_attr = {
 292         .attr = {
 293                 .name = "nvram",
 294                 .mode = S_IRUGO | S_IWUSR,
 295                 .owner = THIS_MODULE,
 296         },
 297         .size = RTC_OFFSET,
 298         .read = stk17ta8_nvram_read,
 299         .write = stk17ta8_nvram_write,
 300 };
 301
 302 static int __init stk17ta8_rtc_probe(struct platform_device *pdev)
 303 {
 304         struct rtc_device *rtc;
 305         struct resource *res;
 306         unsigned int cal;
 307         unsigned int flags;
 308         struct rtc_plat_data *pdata;
 309         void __iomem *ioaddr = NULL;
 310         int ret = 0;
 311
 312         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 313         if (!res)
 314                 return -ENODEV;
 315
 316         pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
 317         if (!pdata)
 318                 return -ENOMEM;
 319         pdata->irq = -1;
 320         if (!request_mem_region(res->start, RTC_REG_SIZE, pdev->name)) {
 321                 ret = -EBUSY;
 322                 goto out;
 323         }
 324         pdata->baseaddr = res->start;
 325         ioaddr = ioremap(pdata->baseaddr, RTC_REG_SIZE);
 326         if (!ioaddr) {
 327                 ret = -ENOMEM;
 328                 goto out;
 329         }
 330         pdata->ioaddr = ioaddr;
 331         pdata->irq = platform_get_irq(pdev, 0);
 332
 333         /* turn RTC on if it was not on */
 334         cal = readb(ioaddr + RTC_CALIBRATION);
 335         if (cal & RTC_STOP) {
 336                 cal &= RTC_CAL_MASK;
 337                 flags = readb(ioaddr + RTC_FLAGS);
 338                 writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
 339                 writeb(cal, ioaddr + RTC_CALIBRATION);
 340                 writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
 341         }
 342         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF)
 343                 dev_warn(&pdev->dev, "voltage-low detected.\n");
 344
 345         if (pdata->irq >= 0) {
 346                 writeb(0, ioaddr + RTC_INTERRUPTS);
 347                 if (request_irq(pdata->irq, stk17ta8_rtc_interrupt,
 348                                 IRQF_DISABLED | IRQF_SHARED,
 349                                 pdev->name, pdev) < 0) {
 350                         dev_warn(&pdev->dev, "interrupt not available.\n");
 351                         pdata->irq = -1;
 352                 }
 353         }
 354
 355         rtc = rtc_device_register(pdev->name, &pdev->dev,
 356                                   &stk17ta8_rtc_ops, THIS_MODULE);
 357         if (IS_ERR(rtc)) {
 358                 ret = PTR_ERR(rtc);
 359                 goto out;
 360         }
 361         pdata->rtc = rtc;
 362         pdata->last_jiffies = jiffies;
 363         platform_set_drvdata(pdev, pdata);
 364         ret = sysfs_create_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
 365         if (ret)
 366                 goto out;
 367         return 0;
 368  out:
 369         if (pdata->rtc)
 370                 rtc_device_unregister(pdata->rtc);
 371         if (pdata->irq >= 0)
 372                 free_irq(pdata->irq, pdev);
 373         if (ioaddr)
 374                 iounmap(ioaddr);
 375         if (pdata->baseaddr)
 376                 release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
 377         kfree(pdata);
 378         return ret;
 379 }
 380
 381 static int __devexit stk17ta8_rtc_remove(struct platform_device *pdev)
 382 {
 383         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 384
 385         sysfs_remove_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
 386         rtc_device_unregister(pdata->rtc);
 387         if (pdata->irq >= 0) {
 388                 writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
 389                 free_irq(pdata->irq, pdev);
 390         }
 391         iounmap(pdata->ioaddr);
 392         release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
 393         kfree(pdata);
 394         return 0;
 395 }
 396
 397 static struct platform_driver stk17ta8_rtc_driver = {
 398         .probe          = stk17ta8_rtc_probe,
 399         .remove         = __devexit_p(stk17ta8_rtc_remove),
 400         .driver         = {
 401                 .name   = "stk17ta8",
 402                 .owner  = THIS_MODULE,
 403         },
 404 };
 405
 406 static __init int stk17ta8_init(void)
 407 {
 408         return platform_driver_register(&stk17ta8_rtc_driver);
 409 }
 410
 411 static __exit void stk17ta8_exit(void)
 412 {
 413         return platform_driver_unregister(&stk17ta8_rtc_driver);
 414 }
 415
 416 module_init(stk17ta8_init);
 417 module_exit(stk17ta8_exit);
 418
 419 MODULE_AUTHOR("Thomas Hommel <thomas.hommel@gefanuc.com>");
 420 MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver");
 421 MODULE_LICENSE("GPL");
 422 MODULE_VERSION(DRV_VERSION);