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/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
  22 #define DRV_VERSION "0.3"
  23
  24 #define RTC_REG_SIZE            0x2000
  25 #define RTC_OFFSET              0x1ff0
  26
  27 #define RTC_FLAGS               (RTC_OFFSET + 0)
  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_CONTROL             (RTC_OFFSET + 8)
  35 #define RTC_CENTURY             (RTC_OFFSET + 8)
  36 #define RTC_SECONDS             (RTC_OFFSET + 9)
  37 #define RTC_MINUTES             (RTC_OFFSET + 10)
  38 #define RTC_HOURS               (RTC_OFFSET + 11)
  39 #define RTC_DAY                 (RTC_OFFSET + 12)
  40 #define RTC_DATE                (RTC_OFFSET + 13)
  41 #define RTC_MONTH               (RTC_OFFSET + 14)
  42 #define RTC_YEAR                (RTC_OFFSET + 15)
  43
  44 #define RTC_CENTURY_MASK        0x3f
  45 #define RTC_SECONDS_MASK        0x7f
  46 #define RTC_DAY_MASK            0x07
  47
  48 /* Bits in the Control/Century register */
  49 #define RTC_WRITE               0x80
  50 #define RTC_READ                0x40
  51
  52 /* Bits in the Seconds register */
  53 #define RTC_STOP                0x80
  54
  55 /* Bits in the Flags register */
  56 #define RTC_FLAGS_AF            0x40
  57 #define RTC_FLAGS_BLF           0x10
  58
  59 /* Bits in the Interrupts register */
  60 #define RTC_INTS_AE             0x80
  61
  62 struct rtc_plat_data {
  63         struct rtc_device *rtc;
  64         void __iomem *ioaddr;
  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         spinlock_t lock;
  73 };
  74
  75 static int ds1553_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 century;
  81
  82         century = bin2bcd((tm->tm_year + 1900) / 100);
  83
  84         writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL);
  85
  86         writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
  87         writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
  88         writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
  89         writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
  90         writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
  91         writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
  92         writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
  93
  94         /* RTC_CENTURY and RTC_CONTROL share same register */
  95         writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
  96         writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
  97         return 0;
  98 }
  99
 100 static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm)
 101 {
 102         struct platform_device *pdev = to_platform_device(dev);
 103         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 104         void __iomem *ioaddr = pdata->ioaddr;
 105         unsigned int year, month, day, hour, minute, second, week;
 106         unsigned int century;
 107
 108         /* give enough time to update RTC in case of continuous read */
 109         if (pdata->last_jiffies == jiffies)
 110                 msleep(1);
 111         pdata->last_jiffies = jiffies;
 112         writeb(RTC_READ, ioaddr + RTC_CONTROL);
 113         second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
 114         minute = readb(ioaddr + RTC_MINUTES);
 115         hour = readb(ioaddr + RTC_HOURS);
 116         day = readb(ioaddr + RTC_DATE);
 117         week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
 118         month = readb(ioaddr + RTC_MONTH);
 119         year = readb(ioaddr + RTC_YEAR);
 120         century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
 121         writeb(0, ioaddr + RTC_CONTROL);
 122         tm->tm_sec = bcd2bin(second);
 123         tm->tm_min = bcd2bin(minute);
 124         tm->tm_hour = bcd2bin(hour);
 125         tm->tm_mday = bcd2bin(day);
 126         tm->tm_wday = bcd2bin(week);
 127         tm->tm_mon = bcd2bin(month) - 1;
 128         /* year is 1900 + tm->tm_year */
 129         tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
 130
 131         if (rtc_valid_tm(tm) < 0) {
 132                 dev_err(dev, "retrieved date/time is not valid.\n");
 133                 rtc_time_to_tm(0, tm);
 134         }
 135         return 0;
 136 }
 137
 138 static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata)
 139 {
 140         void __iomem *ioaddr = pdata->ioaddr;
 141         unsigned long flags;
 142
 143         spin_lock_irqsave(&pdata->lock, flags);
 144         writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
 145                0x80 : bin2bcd(pdata->alrm_mday),
 146                ioaddr + RTC_DATE_ALARM);
 147         writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
 148                0x80 : bin2bcd(pdata->alrm_hour),
 149                ioaddr + RTC_HOURS_ALARM);
 150         writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
 151                0x80 : bin2bcd(pdata->alrm_min),
 152                ioaddr + RTC_MINUTES_ALARM);
 153         writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
 154                0x80 : bin2bcd(pdata->alrm_sec),
 155                ioaddr + RTC_SECONDS_ALARM);
 156         writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS);
 157         readb(ioaddr + RTC_FLAGS);      /* clear interrupts */
 158         spin_unlock_irqrestore(&pdata->lock, flags);
 159 }
 160
 161 static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 162 {
 163         struct platform_device *pdev = to_platform_device(dev);
 164         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 165
 166         if (pdata->irq <= 0)
 167                 return -EINVAL;
 168         pdata->alrm_mday = alrm->time.tm_mday;
 169         pdata->alrm_hour = alrm->time.tm_hour;
 170         pdata->alrm_min = alrm->time.tm_min;
 171         pdata->alrm_sec = alrm->time.tm_sec;
 172         if (alrm->enabled)
 173                 pdata->irqen |= RTC_AF;
 174         ds1553_rtc_update_alarm(pdata);
 175         return 0;
 176 }
 177
 178 static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 179 {
 180         struct platform_device *pdev = to_platform_device(dev);
 181         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 182
 183         if (pdata->irq <= 0)
 184                 return -EINVAL;
 185         alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
 186         alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
 187         alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
 188         alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
 189         alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
 190         return 0;
 191 }
 192
 193 static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id)
 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 = 0;
 199
 200         spin_lock(&pdata->lock);
 201         /* read and clear interrupt */
 202         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {
 203                 events = RTC_IRQF;
 204                 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
 205                         events |= RTC_UF;
 206                 else
 207                         events |= RTC_AF;
 208                 if (likely(pdata->rtc))
 209                         rtc_update_irq(pdata->rtc, 1, events);
 210         }
 211         spin_unlock(&pdata->lock);
 212         return events ? IRQ_HANDLED : IRQ_NONE;
 213 }
 214
 215 static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 216 {
 217         struct platform_device *pdev = to_platform_device(dev);
 218         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 219
 220         if (pdata->irq <= 0)
 221                 return -EINVAL;
 222         if (enabled)
 223                 pdata->irqen |= RTC_AF;
 224         else
 225                 pdata->irqen &= ~RTC_AF;
 226         ds1553_rtc_update_alarm(pdata);
 227         return 0;
 228 }
 229
 230 static const struct rtc_class_ops ds1553_rtc_ops = {
 231         .read_time              = ds1553_rtc_read_time,
 232         .set_time               = ds1553_rtc_set_time,
 233         .read_alarm             = ds1553_rtc_read_alarm,
 234         .set_alarm              = ds1553_rtc_set_alarm,
 235         .alarm_irq_enable       = ds1553_rtc_alarm_irq_enable,
 236 };
 237
 238 static ssize_t ds1553_nvram_read(struct file *filp, struct kobject *kobj,
 239                                  struct bin_attribute *bin_attr,
 240                                  char *buf, loff_t pos, size_t size)
 241 {
 242         struct device *dev = container_of(kobj, struct device, kobj);
 243         struct platform_device *pdev = to_platform_device(dev);
 244         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 245         void __iomem *ioaddr = pdata->ioaddr;
 246         ssize_t count;
 247
 248         for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
 249                 *buf++ = readb(ioaddr + pos++);
 250         return count;
 251 }
 252
 253 static ssize_t ds1553_nvram_write(struct file *filp, struct kobject *kobj,
 254                                   struct bin_attribute *bin_attr,
 255                                   char *buf, loff_t pos, size_t size)
 256 {
 257         struct device *dev = container_of(kobj, struct device, kobj);
 258         struct platform_device *pdev = to_platform_device(dev);
 259         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 260         void __iomem *ioaddr = pdata->ioaddr;
 261         ssize_t count;
 262
 263         for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
 264                 writeb(*buf++, ioaddr + pos++);
 265         return count;
 266 }
 267
 268 static struct bin_attribute ds1553_nvram_attr = {
 269         .attr = {
 270                 .name = "nvram",
 271                 .mode = S_IRUGO | S_IWUSR,
 272         },
 273         .size = RTC_OFFSET,
 274         .read = ds1553_nvram_read,
 275         .write = ds1553_nvram_write,
 276 };
 277
 278 static int __devinit ds1553_rtc_probe(struct platform_device *pdev)
 279 {
 280         struct rtc_device *rtc;
 281         struct resource *res;
 282         unsigned int cen, sec;
 283         struct rtc_plat_data *pdata;
 284         void __iomem *ioaddr;
 285         int ret = 0;
 286
 287         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 288         if (!res)
 289                 return -ENODEV;
 290         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 291         if (!pdata)
 292                 return -ENOMEM;
 293         if (!devm_request_mem_region(&pdev->dev, res->start, RTC_REG_SIZE,
 294                         pdev->name))
 295                 return -EBUSY;
 296
 297         ioaddr = devm_ioremap(&pdev->dev, res->start, RTC_REG_SIZE);
 298         if (!ioaddr)
 299                 return -ENOMEM;
 300         pdata->ioaddr = ioaddr;
 301         pdata->irq = platform_get_irq(pdev, 0);
 302
 303         /* turn RTC on if it was not on */
 304         sec = readb(ioaddr + RTC_SECONDS);
 305         if (sec & RTC_STOP) {
 306                 sec &= RTC_SECONDS_MASK;
 307                 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
 308                 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
 309                 writeb(sec, ioaddr + RTC_SECONDS);
 310                 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
 311         }
 312         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF)
 313                 dev_warn(&pdev->dev, "voltage-low detected.\n");
 314
 315         spin_lock_init(&pdata->lock);
 316         pdata->last_jiffies = jiffies;
 317         platform_set_drvdata(pdev, pdata);
 318         if (pdata->irq > 0) {
 319                 writeb(0, ioaddr + RTC_INTERRUPTS);
 320                 if (devm_request_irq(&pdev->dev, pdata->irq,
 321                                 ds1553_rtc_interrupt,
 322                                 IRQF_DISABLED, pdev->name, pdev) < 0) {
 323                         dev_warn(&pdev->dev, "interrupt not available.\n");
 324                         pdata->irq = 0;
 325                 }
 326         }
 327
 328         rtc = rtc_device_register(pdev->name, &pdev->dev,
 329                                   &ds1553_rtc_ops, THIS_MODULE);
 330         if (IS_ERR(rtc))
 331                 return PTR_ERR(rtc);
 332         pdata->rtc = rtc;
 333
 334         ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
 335         if (ret)
 336                 rtc_device_unregister(rtc);
 337         return ret;
 338 }
 339
 340 static int __devexit ds1553_rtc_remove(struct platform_device *pdev)
 341 {
 342         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 343
 344         sysfs_remove_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
 345         rtc_device_unregister(pdata->rtc);
 346         if (pdata->irq > 0)
 347                 writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
 348         return 0;
 349 }
 350
 351 /* work with hotplug and coldplug */
 352 MODULE_ALIAS("platform:rtc-ds1553");
 353
 354 static struct platform_driver ds1553_rtc_driver = {
 355         .probe          = ds1553_rtc_probe,
 356         .remove         = __devexit_p(ds1553_rtc_remove),
 357         .driver         = {
 358                 .name   = "rtc-ds1553",
 359                 .owner  = THIS_MODULE,
 360         },
 361 };
 362
 363 static __init int ds1553_init(void)
 364 {
 365         return platform_driver_register(&ds1553_rtc_driver);
 366 }
 367
 368 static __exit void ds1553_exit(void)
 369 {
 370         platform_driver_unregister(&ds1553_rtc_driver);
 371 }
 372
 373 module_init(ds1553_init);
 374 module_exit(ds1553_exit);
 375
 376 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
 377 MODULE_DESCRIPTION("Dallas DS1553 RTC driver");
 378 MODULE_LICENSE("GPL");
 379 MODULE_VERSION(DRV_VERSION);