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/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
  63struct 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
  76static 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
 101static 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
 139static 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
 162static 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
 179static 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
 194static 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
 216static 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
 231static 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
 239static 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
 254static 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
 269static 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
 279static 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
 340static 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 */
 351MODULE_ALIAS("platform:rtc-ds1553");
 352
 353static 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
 362module_platform_driver(ds1553_rtc_driver);
 363
 364MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
 365MODULE_DESCRIPTION("Dallas DS1553 RTC driver");
 366MODULE_LICENSE("GPL");
 367MODULE_VERSION(DRV_VERSION);
 368
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