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 #include <linux/module.h>
  22
  23 #define DRV_VERSION "0.3"
  24
  25 #define RTC_REG_SIZE            0x2000
  26 #define RTC_OFFSET              0x1ff0
  27
  28 #define RTC_FLAGS               (RTC_OFFSET + 0)
  29 #define RTC_SECONDS_ALARM       (RTC_OFFSET + 2)
  30 #define RTC_MINUTES_ALARM       (RTC_OFFSET + 3)
  31 #define RTC_HOURS_ALARM         (RTC_OFFSET + 4)
  32 #define RTC_DATE_ALARM          (RTC_OFFSET + 5)
  33 #define RTC_INTERRUPTS          (RTC_OFFSET + 6)
  34 #define RTC_WATCHDOG            (RTC_OFFSET + 7)
  35 #define RTC_CONTROL             (RTC_OFFSET + 8)
  36 #define RTC_CENTURY             (RTC_OFFSET + 8)
  37 #define RTC_SECONDS             (RTC_OFFSET + 9)
  38 #define RTC_MINUTES             (RTC_OFFSET + 10)
  39 #define RTC_HOURS               (RTC_OFFSET + 11)
  40 #define RTC_DAY                 (RTC_OFFSET + 12)
  41 #define RTC_DATE                (RTC_OFFSET + 13)
  42 #define RTC_MONTH               (RTC_OFFSET + 14)
  43 #define RTC_YEAR                (RTC_OFFSET + 15)
  44
  45 #define RTC_CENTURY_MASK        0x3f
  46 #define RTC_SECONDS_MASK        0x7f
  47 #define RTC_DAY_MASK            0x07
  48
  49 /* Bits in the Control/Century register */
  50 #define RTC_WRITE               0x80
  51 #define RTC_READ                0x40
  52
  53 /* Bits in the Seconds register */
  54 #define RTC_STOP                0x80
  55
  56 /* Bits in the Flags register */
  57 #define RTC_FLAGS_AF            0x40
  58 #define RTC_FLAGS_BLF           0x10
  59
  60 /* Bits in the Interrupts register */
  61 #define RTC_INTS_AE             0x80
  62
  63 struct rtc_plat_data {
  64         struct rtc_device *rtc;
  65         void __iomem *ioaddr;
  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         spinlock_t lock;
  74 };
  75
  76 static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm)
  77 {
  78         struct platform_device *pdev = to_platform_device(dev);
  79         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
  80         void __iomem *ioaddr = pdata->ioaddr;
  81         u8 century;
  82
  83         century = bin2bcd((tm->tm_year + 1900) / 100);
  84
  85         writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL);
  86
  87         writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
  88         writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
  89         writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
  90         writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
  91         writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
  92         writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
  93         writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
  94
  95         /* RTC_CENTURY and RTC_CONTROL share same register */
  96         writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
  97         writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
  98         return 0;
  99 }
 100
 101 static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm)
 102 {
 103         struct platform_device *pdev = to_platform_device(dev);
 104         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 105         void __iomem *ioaddr = pdata->ioaddr;
 106         unsigned int year, month, day, hour, minute, second, week;
 107         unsigned int century;
 108
 109         /* give enough time to update RTC in case of continuous read */
 110         if (pdata->last_jiffies == jiffies)
 111                 msleep(1);
 112         pdata->last_jiffies = jiffies;
 113         writeb(RTC_READ, ioaddr + RTC_CONTROL);
 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) & RTC_CENTURY_MASK;
 122         writeb(0, ioaddr + RTC_CONTROL);
 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 ds1553_rtc_update_alarm(struct rtc_plat_data *pdata)
 140 {
 141         void __iomem *ioaddr = pdata->ioaddr;
 142         unsigned long flags;
 143
 144         spin_lock_irqsave(&pdata->lock, flags);
 145         writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
 146                0x80 : bin2bcd(pdata->alrm_mday),
 147                ioaddr + RTC_DATE_ALARM);
 148         writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
 149                0x80 : bin2bcd(pdata->alrm_hour),
 150                ioaddr + RTC_HOURS_ALARM);
 151         writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
 152                0x80 : bin2bcd(pdata->alrm_min),
 153                ioaddr + RTC_MINUTES_ALARM);
 154         writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
 155                0x80 : bin2bcd(pdata->alrm_sec),
 156                ioaddr + RTC_SECONDS_ALARM);
 157         writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS);
 158         readb(ioaddr + RTC_FLAGS);      /* clear interrupts */
 159         spin_unlock_irqrestore(&pdata->lock, flags);
 160 }
 161
 162 static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 163 {
 164         struct platform_device *pdev = to_platform_device(dev);
 165         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 166
 167         if (pdata->irq <= 0)
 168                 return -EINVAL;
 169         pdata->alrm_mday = alrm->time.tm_mday;
 170         pdata->alrm_hour = alrm->time.tm_hour;
 171         pdata->alrm_min = alrm->time.tm_min;
 172         pdata->alrm_sec = alrm->time.tm_sec;
 173         if (alrm->enabled)
 174                 pdata->irqen |= RTC_AF;
 175         ds1553_rtc_update_alarm(pdata);
 176         return 0;
 177 }
 178
 179 static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 180 {
 181         struct platform_device *pdev = to_platform_device(dev);
 182         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 183
 184         if (pdata->irq <= 0)
 185                 return -EINVAL;
 186         alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
 187         alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
 188         alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
 189         alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
 190         alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
 191         return 0;
 192 }
 193
 194 static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id)
 195 {
 196         struct platform_device *pdev = dev_id;
 197         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 198         void __iomem *ioaddr = pdata->ioaddr;
 199         unsigned long events = 0;
 200
 201         spin_lock(&pdata->lock);
 202         /* read and clear interrupt */
 203         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {
 204                 events = RTC_IRQF;
 205                 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
 206                         events |= RTC_UF;
 207                 else
 208                         events |= RTC_AF;
 209                 if (likely(pdata->rtc))
 210                         rtc_update_irq(pdata->rtc, 1, events);
 211         }
 212         spin_unlock(&pdata->lock);
 213         return events ? IRQ_HANDLED : IRQ_NONE;
 214 }
 215
 216 static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 217 {
 218         struct platform_device *pdev = to_platform_device(dev);
 219         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 220
 221         if (pdata->irq <= 0)
 222                 return -EINVAL;
 223         if (enabled)
 224                 pdata->irqen |= RTC_AF;
 225         else
 226                 pdata->irqen &= ~RTC_AF;
 227         ds1553_rtc_update_alarm(pdata);
 228         return 0;
 229 }
 230
 231 static const struct rtc_class_ops ds1553_rtc_ops = {
 232         .read_time              = ds1553_rtc_read_time,
 233         .set_time               = ds1553_rtc_set_time,
 234         .read_alarm             = ds1553_rtc_read_alarm,
 235         .set_alarm              = ds1553_rtc_set_alarm,
 236         .alarm_irq_enable       = ds1553_rtc_alarm_irq_enable,
 237 };
 238
 239 static ssize_t ds1553_nvram_read(struct file *filp, struct kobject *kobj,
 240                                  struct bin_attribute *bin_attr,
 241                                  char *buf, loff_t pos, size_t size)
 242 {
 243         struct device *dev = container_of(kobj, struct device, kobj);
 244         struct platform_device *pdev = to_platform_device(dev);
 245         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 246         void __iomem *ioaddr = pdata->ioaddr;
 247         ssize_t count;
 248
 249         for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
 250                 *buf++ = readb(ioaddr + pos++);
 251         return count;
 252 }
 253
 254 static ssize_t ds1553_nvram_write(struct file *filp, 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                 writeb(*buf++, ioaddr + pos++);
 266         return count;
 267 }
 268
 269 static struct bin_attribute ds1553_nvram_attr = {
 270         .attr = {
 271                 .name = "nvram",
 272                 .mode = S_IRUGO | S_IWUSR,
 273         },
 274         .size = RTC_OFFSET,
 275         .read = ds1553_nvram_read,
 276         .write = ds1553_nvram_write,
 277 };
 278
 279 static int ds1553_rtc_probe(struct platform_device *pdev)
 280 {
 281         struct rtc_device *rtc;
 282         struct resource *res;
 283         unsigned int cen, sec;
 284         struct rtc_plat_data *pdata;
 285         void __iomem *ioaddr;
 286         int ret = 0;
 287
 288         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 289         if (!res)
 290                 return -ENODEV;
 291         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 292         if (!pdata)
 293                 return -ENOMEM;
 294         if (!devm_request_mem_region(&pdev->dev, res->start, RTC_REG_SIZE,
 295                         pdev->name))
 296                 return -EBUSY;
 297
 298         ioaddr = devm_ioremap(&pdev->dev, res->start, RTC_REG_SIZE);
 299         if (!ioaddr)
 300                 return -ENOMEM;
 301         pdata->ioaddr = ioaddr;
 302         pdata->irq = platform_get_irq(pdev, 0);
 303
 304         /* turn RTC on if it was not on */
 305         sec = readb(ioaddr + RTC_SECONDS);
 306         if (sec & RTC_STOP) {
 307                 sec &= RTC_SECONDS_MASK;
 308                 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
 309                 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
 310                 writeb(sec, ioaddr + RTC_SECONDS);
 311                 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
 312         }
 313         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF)
 314                 dev_warn(&pdev->dev, "voltage-low detected.\n");
 315
 316         spin_lock_init(&pdata->lock);
 317         pdata->last_jiffies = jiffies;
 318         platform_set_drvdata(pdev, pdata);
 319         if (pdata->irq > 0) {
 320                 writeb(0, ioaddr + RTC_INTERRUPTS);
 321                 if (devm_request_irq(&pdev->dev, pdata->irq,
 322                                 ds1553_rtc_interrupt,
 323                                 0, pdev->name, pdev) < 0) {
 324                         dev_warn(&pdev->dev, "interrupt not available.\n");
 325                         pdata->irq = 0;
 326                 }
 327         }
 328
 329         rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 330                                   &ds1553_rtc_ops, THIS_MODULE);
 331         if (IS_ERR(rtc))
 332                 return PTR_ERR(rtc);
 333         pdata->rtc = rtc;
 334
 335         ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
 336
 337         return ret;
 338 }
 339
 340 static int 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         if (pdata->irq > 0)
 346                 writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
 347         return 0;
 348 }
 349
 350 /* work with hotplug and coldplug */
 351 MODULE_ALIAS("platform:rtc-ds1553");
 352
 353 static struct platform_driver ds1553_rtc_driver = {
 354         .probe          = ds1553_rtc_probe,
 355         .remove         = ds1553_rtc_remove,
 356         .driver         = {
 357                 .name   = "rtc-ds1553",
 358                 .owner  = THIS_MODULE,
 359         },
 360 };
 361
 362 module_platform_driver(ds1553_rtc_driver);
 363
 364 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
 365 MODULE_DESCRIPTION("Dallas DS1553 RTC driver");
 366 MODULE_LICENSE("GPL");
 367 MODULE_VERSION(DRV_VERSION);