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 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                 rtc_update_irq(pdata->rtc, 1, events);
 208         }
 209         spin_unlock(&pdata->lock);
 210         return events ? IRQ_HANDLED : IRQ_NONE;
 211 }
 212
 213 static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 214 {
 215         struct platform_device *pdev = to_platform_device(dev);
 216         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 217
 218         if (pdata->irq <= 0)
 219                 return -EINVAL;
 220         if (enabled)
 221                 pdata->irqen |= RTC_AF;
 222         else
 223                 pdata->irqen &= ~RTC_AF;
 224         ds1553_rtc_update_alarm(pdata);
 225         return 0;
 226 }
 227
 228 static const struct rtc_class_ops ds1553_rtc_ops = {
 229         .read_time              = ds1553_rtc_read_time,
 230         .set_time               = ds1553_rtc_set_time,
 231         .read_alarm             = ds1553_rtc_read_alarm,
 232         .set_alarm              = ds1553_rtc_set_alarm,
 233         .alarm_irq_enable       = ds1553_rtc_alarm_irq_enable,
 234 };
 235
 236 static ssize_t ds1553_nvram_read(struct file *filp, struct kobject *kobj,
 237                                  struct bin_attribute *bin_attr,
 238                                  char *buf, loff_t pos, size_t size)
 239 {
 240         struct device *dev = container_of(kobj, struct device, kobj);
 241         struct platform_device *pdev = to_platform_device(dev);
 242         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 243         void __iomem *ioaddr = pdata->ioaddr;
 244         ssize_t count;
 245
 246         for (count = 0; count < size; count++)
 247                 *buf++ = readb(ioaddr + pos++);
 248         return count;
 249 }
 250
 251 static ssize_t ds1553_nvram_write(struct file *filp, struct kobject *kobj,
 252                                   struct bin_attribute *bin_attr,
 253                                   char *buf, loff_t pos, size_t size)
 254 {
 255         struct device *dev = container_of(kobj, struct device, kobj);
 256         struct platform_device *pdev = to_platform_device(dev);
 257         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 258         void __iomem *ioaddr = pdata->ioaddr;
 259         ssize_t count;
 260
 261         for (count = 0; count < size; count++)
 262                 writeb(*buf++, ioaddr + pos++);
 263         return count;
 264 }
 265
 266 static struct bin_attribute ds1553_nvram_attr = {
 267         .attr = {
 268                 .name = "nvram",
 269                 .mode = S_IRUGO | S_IWUSR,
 270         },
 271         .size = RTC_OFFSET,
 272         .read = ds1553_nvram_read,
 273         .write = ds1553_nvram_write,
 274 };
 275
 276 static int ds1553_rtc_probe(struct platform_device *pdev)
 277 {
 278         struct resource *res;
 279         unsigned int cen, sec;
 280         struct rtc_plat_data *pdata;
 281         void __iomem *ioaddr;
 282         int ret = 0;
 283
 284         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 285         if (!pdata)
 286                 return -ENOMEM;
 287
 288         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 289         ioaddr = devm_ioremap_resource(&pdev->dev, res);
 290         if (IS_ERR(ioaddr))
 291                 return PTR_ERR(ioaddr);
 292         pdata->ioaddr = ioaddr;
 293         pdata->irq = platform_get_irq(pdev, 0);
 294
 295         /* turn RTC on if it was not on */
 296         sec = readb(ioaddr + RTC_SECONDS);
 297         if (sec & RTC_STOP) {
 298                 sec &= RTC_SECONDS_MASK;
 299                 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
 300                 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
 301                 writeb(sec, ioaddr + RTC_SECONDS);
 302                 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
 303         }
 304         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF)
 305                 dev_warn(&pdev->dev, "voltage-low detected.\n");
 306
 307         spin_lock_init(&pdata->lock);
 308         pdata->last_jiffies = jiffies;
 309         platform_set_drvdata(pdev, pdata);
 310
 311         pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 312                                   &ds1553_rtc_ops, THIS_MODULE);
 313         if (IS_ERR(pdata->rtc))
 314                 return PTR_ERR(pdata->rtc);
 315
 316         if (pdata->irq > 0) {
 317                 writeb(0, ioaddr + RTC_INTERRUPTS);
 318                 if (devm_request_irq(&pdev->dev, pdata->irq,
 319                                 ds1553_rtc_interrupt,
 320                                 0, pdev->name, pdev) < 0) {
 321                         dev_warn(&pdev->dev, "interrupt not available.\n");
 322                         pdata->irq = 0;
 323                 }
 324         }
 325
 326         ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
 327         if (ret)
 328                 dev_err(&pdev->dev, "unable to create sysfs file: %s\n",
 329                         ds1553_nvram_attr.attr.name);
 330
 331         return 0;
 332 }
 333
 334 static int ds1553_rtc_remove(struct platform_device *pdev)
 335 {
 336         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 337
 338         sysfs_remove_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
 339         if (pdata->irq > 0)
 340                 writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
 341         return 0;
 342 }
 343
 344 /* work with hotplug and coldplug */
 345 MODULE_ALIAS("platform:rtc-ds1553");
 346
 347 static struct platform_driver ds1553_rtc_driver = {
 348         .probe          = ds1553_rtc_probe,
 349         .remove         = ds1553_rtc_remove,
 350         .driver         = {
 351                 .name   = "rtc-ds1553",
 352         },
 353 };
 354
 355 module_platform_driver(ds1553_rtc_driver);
 356
 357 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
 358 MODULE_DESCRIPTION("Dallas DS1553 RTC driver");
 359 MODULE_LICENSE("GPL");