linux/drivers/rtc/rtc-ds1553.c
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   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 "0.2"
  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
  61struct rtc_plat_data {
  62        struct rtc_device *rtc;
  63        void __iomem *ioaddr;
  64        resource_size_t 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
  74static 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
  99static 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
 137static 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
 160static 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
 177static 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
 192static 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 = RTC_IRQF;
 198
 199        /* read and clear interrupt */
 200        if (!(readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF))
 201                return IRQ_NONE;
 202        if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
 203                events |= RTC_UF;
 204        else
 205                events |= RTC_AF;
 206        rtc_update_irq(pdata->rtc, 1, events);
 207        return IRQ_HANDLED;
 208}
 209
 210static int ds1553_rtc_ioctl(struct device *dev, unsigned int cmd,
 211                            unsigned long arg)
 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                return -ENOIOCTLCMD; /* fall back into rtc-dev's emulation */
 218        switch (cmd) {
 219        case RTC_AIE_OFF:
 220                pdata->irqen &= ~RTC_AF;
 221                ds1553_rtc_update_alarm(pdata);
 222                break;
 223        case RTC_AIE_ON:
 224                pdata->irqen |= RTC_AF;
 225                ds1553_rtc_update_alarm(pdata);
 226                break;
 227        case RTC_UIE_OFF:
 228                pdata->irqen &= ~RTC_UF;
 229                ds1553_rtc_update_alarm(pdata);
 230                break;
 231        case RTC_UIE_ON:
 232                pdata->irqen |= RTC_UF;
 233                ds1553_rtc_update_alarm(pdata);
 234                break;
 235        default:
 236                return -ENOIOCTLCMD;
 237        }
 238        return 0;
 239}
 240
 241static const struct rtc_class_ops ds1553_rtc_ops = {
 242        .read_time      = ds1553_rtc_read_time,
 243        .set_time       = ds1553_rtc_set_time,
 244        .read_alarm     = ds1553_rtc_read_alarm,
 245        .set_alarm      = ds1553_rtc_set_alarm,
 246        .ioctl          = ds1553_rtc_ioctl,
 247};
 248
 249static ssize_t ds1553_nvram_read(struct kobject *kobj,
 250                                 struct bin_attribute *bin_attr,
 251                                 char *buf, loff_t pos, size_t size)
 252{
 253        struct platform_device *pdev =
 254                to_platform_device(container_of(kobj, struct device, kobj));
 255        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 256        void __iomem *ioaddr = pdata->ioaddr;
 257        ssize_t count;
 258
 259        for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
 260                *buf++ = readb(ioaddr + pos++);
 261        return count;
 262}
 263
 264static ssize_t ds1553_nvram_write(struct kobject *kobj,
 265                                  struct bin_attribute *bin_attr,
 266                                  char *buf, loff_t pos, size_t size)
 267{
 268        struct platform_device *pdev =
 269                to_platform_device(container_of(kobj, struct device, kobj));
 270        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 271        void __iomem *ioaddr = pdata->ioaddr;
 272        ssize_t count;
 273
 274        for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
 275                writeb(*buf++, ioaddr + pos++);
 276        return count;
 277}
 278
 279static struct bin_attribute ds1553_nvram_attr = {
 280        .attr = {
 281                .name = "nvram",
 282                .mode = S_IRUGO | S_IWUSR,
 283        },
 284        .size = RTC_OFFSET,
 285        .read = ds1553_nvram_read,
 286        .write = ds1553_nvram_write,
 287};
 288
 289static int __devinit ds1553_rtc_probe(struct platform_device *pdev)
 290{
 291        struct rtc_device *rtc;
 292        struct resource *res;
 293        unsigned int cen, sec;
 294        struct rtc_plat_data *pdata = NULL;
 295        void __iomem *ioaddr = NULL;
 296        int ret = 0;
 297
 298        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 299        if (!res)
 300                return -ENODEV;
 301        pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
 302        if (!pdata)
 303                return -ENOMEM;
 304        if (!request_mem_region(res->start, RTC_REG_SIZE, pdev->name)) {
 305                ret = -EBUSY;
 306                goto out;
 307        }
 308        pdata->baseaddr = res->start;
 309        ioaddr = ioremap(pdata->baseaddr, RTC_REG_SIZE);
 310        if (!ioaddr) {
 311                ret = -ENOMEM;
 312                goto out;
 313        }
 314        pdata->ioaddr = ioaddr;
 315        pdata->irq = platform_get_irq(pdev, 0);
 316
 317        /* turn RTC on if it was not on */
 318        sec = readb(ioaddr + RTC_SECONDS);
 319        if (sec & RTC_STOP) {
 320                sec &= RTC_SECONDS_MASK;
 321                cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
 322                writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
 323                writeb(sec, ioaddr + RTC_SECONDS);
 324                writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
 325        }
 326        if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF)
 327                dev_warn(&pdev->dev, "voltage-low detected.\n");
 328
 329        if (pdata->irq > 0) {
 330                writeb(0, ioaddr + RTC_INTERRUPTS);
 331                if (request_irq(pdata->irq, ds1553_rtc_interrupt,
 332                                IRQF_DISABLED | IRQF_SHARED,
 333                                pdev->name, pdev) < 0) {
 334                        dev_warn(&pdev->dev, "interrupt not available.\n");
 335                        pdata->irq = 0;
 336                }
 337        }
 338
 339        rtc = rtc_device_register(pdev->name, &pdev->dev,
 340                                  &ds1553_rtc_ops, THIS_MODULE);
 341        if (IS_ERR(rtc)) {
 342                ret = PTR_ERR(rtc);
 343                goto out;
 344        }
 345        pdata->rtc = rtc;
 346        pdata->last_jiffies = jiffies;
 347        platform_set_drvdata(pdev, pdata);
 348        ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
 349        if (ret)
 350                goto out;
 351        return 0;
 352 out:
 353        if (pdata->rtc)
 354                rtc_device_unregister(pdata->rtc);
 355        if (pdata->irq > 0)
 356                free_irq(pdata->irq, pdev);
 357        if (ioaddr)
 358                iounmap(ioaddr);
 359        if (pdata->baseaddr)
 360                release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
 361        kfree(pdata);
 362        return ret;
 363}
 364
 365static int __devexit ds1553_rtc_remove(struct platform_device *pdev)
 366{
 367        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 368
 369        sysfs_remove_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
 370        rtc_device_unregister(pdata->rtc);
 371        if (pdata->irq > 0) {
 372                writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
 373                free_irq(pdata->irq, pdev);
 374        }
 375        iounmap(pdata->ioaddr);
 376        release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
 377        kfree(pdata);
 378        return 0;
 379}
 380
 381/* work with hotplug and coldplug */
 382MODULE_ALIAS("platform:rtc-ds1553");
 383
 384static struct platform_driver ds1553_rtc_driver = {
 385        .probe          = ds1553_rtc_probe,
 386        .remove         = __devexit_p(ds1553_rtc_remove),
 387        .driver         = {
 388                .name   = "rtc-ds1553",
 389                .owner  = THIS_MODULE,
 390        },
 391};
 392
 393static __init int ds1553_init(void)
 394{
 395        return platform_driver_register(&ds1553_rtc_driver);
 396}
 397
 398static __exit void ds1553_exit(void)
 399{
 400        platform_driver_unregister(&ds1553_rtc_driver);
 401}
 402
 403module_init(ds1553_init);
 404module_exit(ds1553_exit);
 405
 406MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
 407MODULE_DESCRIPTION("Dallas DS1553 RTC driver");
 408MODULE_LICENSE("GPL");
 409MODULE_VERSION(DRV_VERSION);
 410