linux/drivers/rtc/rtc-stk17ta8.c
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   1/*
   2 * A RTC driver for the Simtek STK17TA8
   3 *
   4 * By Thomas Hommel <thomas.hommel@ge.com>
   5 *
   6 * Based on the DS1553 driver from
   7 * Atsushi Nemoto <anemo@mba.ocn.ne.jp>
   8 *
   9 * This program is free software; you can redistribute it and/or modify
  10 * it under the terms of the GNU General Public License version 2 as
  11 * published by the Free Software Foundation.
  12 */
  13
  14#include <linux/bcd.h>
  15#include <linux/init.h>
  16#include <linux/kernel.h>
  17#include <linux/gfp.h>
  18#include <linux/delay.h>
  19#include <linux/jiffies.h>
  20#include <linux/interrupt.h>
  21#include <linux/rtc.h>
  22#include <linux/platform_device.h>
  23#include <linux/io.h>
  24#include <linux/module.h>
  25
  26#define DRV_VERSION "0.1"
  27
  28#define RTC_REG_SIZE            0x20000
  29#define RTC_OFFSET              0x1fff0
  30
  31#define RTC_FLAGS               (RTC_OFFSET + 0)
  32#define RTC_CENTURY             (RTC_OFFSET + 1)
  33#define RTC_SECONDS_ALARM       (RTC_OFFSET + 2)
  34#define RTC_MINUTES_ALARM       (RTC_OFFSET + 3)
  35#define RTC_HOURS_ALARM         (RTC_OFFSET + 4)
  36#define RTC_DATE_ALARM          (RTC_OFFSET + 5)
  37#define RTC_INTERRUPTS          (RTC_OFFSET + 6)
  38#define RTC_WATCHDOG            (RTC_OFFSET + 7)
  39#define RTC_CALIBRATION         (RTC_OFFSET + 8)
  40#define RTC_SECONDS             (RTC_OFFSET + 9)
  41#define RTC_MINUTES             (RTC_OFFSET + 10)
  42#define RTC_HOURS               (RTC_OFFSET + 11)
  43#define RTC_DAY                 (RTC_OFFSET + 12)
  44#define RTC_DATE                (RTC_OFFSET + 13)
  45#define RTC_MONTH               (RTC_OFFSET + 14)
  46#define RTC_YEAR                (RTC_OFFSET + 15)
  47
  48#define RTC_SECONDS_MASK        0x7f
  49#define RTC_DAY_MASK            0x07
  50#define RTC_CAL_MASK            0x3f
  51
  52/* Bits in the Calibration register */
  53#define RTC_STOP                0x80
  54
  55/* Bits in the Flags register */
  56#define RTC_FLAGS_AF            0x40
  57#define RTC_FLAGS_PF            0x20
  58#define RTC_WRITE               0x02
  59#define RTC_READ                0x01
  60
  61/* Bits in the Interrupts register */
  62#define RTC_INTS_AIE            0x40
  63
  64struct rtc_plat_data {
  65        struct rtc_device *rtc;
  66        void __iomem *ioaddr;
  67        unsigned long last_jiffies;
  68        int irq;
  69        unsigned int irqen;
  70        int alrm_sec;
  71        int alrm_min;
  72        int alrm_hour;
  73        int alrm_mday;
  74        spinlock_t lock;
  75};
  76
  77static int stk17ta8_rtc_set_time(struct device *dev, struct rtc_time *tm)
  78{
  79        struct platform_device *pdev = to_platform_device(dev);
  80        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
  81        void __iomem *ioaddr = pdata->ioaddr;
  82        u8 flags;
  83
  84        flags = readb(pdata->ioaddr + RTC_FLAGS);
  85        writeb(flags | RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
  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        writeb(bin2bcd((tm->tm_year + 1900) / 100), ioaddr + RTC_CENTURY);
  95
  96        writeb(flags & ~RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
  97        return 0;
  98}
  99
 100static int stk17ta8_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        u8 flags;
 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
 114        flags = readb(pdata->ioaddr + RTC_FLAGS);
 115        writeb(flags | RTC_READ, ioaddr + RTC_FLAGS);
 116        second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
 117        minute = readb(ioaddr + RTC_MINUTES);
 118        hour = readb(ioaddr + RTC_HOURS);
 119        day = readb(ioaddr + RTC_DATE);
 120        week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
 121        month = readb(ioaddr + RTC_MONTH);
 122        year = readb(ioaddr + RTC_YEAR);
 123        century = readb(ioaddr + RTC_CENTURY);
 124        writeb(flags & ~RTC_READ, ioaddr + RTC_FLAGS);
 125        tm->tm_sec = bcd2bin(second);
 126        tm->tm_min = bcd2bin(minute);
 127        tm->tm_hour = bcd2bin(hour);
 128        tm->tm_mday = bcd2bin(day);
 129        tm->tm_wday = bcd2bin(week);
 130        tm->tm_mon = bcd2bin(month) - 1;
 131        /* year is 1900 + tm->tm_year */
 132        tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
 133
 134        if (rtc_valid_tm(tm) < 0) {
 135                dev_err(dev, "retrieved date/time is not valid.\n");
 136                rtc_time_to_tm(0, tm);
 137        }
 138        return 0;
 139}
 140
 141static void stk17ta8_rtc_update_alarm(struct rtc_plat_data *pdata)
 142{
 143        void __iomem *ioaddr = pdata->ioaddr;
 144        unsigned long irqflags;
 145        u8 flags;
 146
 147        spin_lock_irqsave(&pdata->lock, irqflags);
 148
 149        flags = readb(ioaddr + RTC_FLAGS);
 150        writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
 151
 152        writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
 153               0x80 : bin2bcd(pdata->alrm_mday),
 154               ioaddr + RTC_DATE_ALARM);
 155        writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
 156               0x80 : bin2bcd(pdata->alrm_hour),
 157               ioaddr + RTC_HOURS_ALARM);
 158        writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
 159               0x80 : bin2bcd(pdata->alrm_min),
 160               ioaddr + RTC_MINUTES_ALARM);
 161        writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
 162               0x80 : bin2bcd(pdata->alrm_sec),
 163               ioaddr + RTC_SECONDS_ALARM);
 164        writeb(pdata->irqen ? RTC_INTS_AIE : 0, ioaddr + RTC_INTERRUPTS);
 165        readb(ioaddr + RTC_FLAGS);      /* clear interrupts */
 166        writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
 167        spin_unlock_irqrestore(&pdata->lock, irqflags);
 168}
 169
 170static int stk17ta8_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 171{
 172        struct platform_device *pdev = to_platform_device(dev);
 173        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 174
 175        if (pdata->irq <= 0)
 176                return -EINVAL;
 177        pdata->alrm_mday = alrm->time.tm_mday;
 178        pdata->alrm_hour = alrm->time.tm_hour;
 179        pdata->alrm_min = alrm->time.tm_min;
 180        pdata->alrm_sec = alrm->time.tm_sec;
 181        if (alrm->enabled)
 182                pdata->irqen |= RTC_AF;
 183        stk17ta8_rtc_update_alarm(pdata);
 184        return 0;
 185}
 186
 187static int stk17ta8_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 188{
 189        struct platform_device *pdev = to_platform_device(dev);
 190        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 191
 192        if (pdata->irq <= 0)
 193                return -EINVAL;
 194        alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
 195        alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
 196        alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
 197        alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
 198        alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
 199        return 0;
 200}
 201
 202static irqreturn_t stk17ta8_rtc_interrupt(int irq, void *dev_id)
 203{
 204        struct platform_device *pdev = dev_id;
 205        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 206        void __iomem *ioaddr = pdata->ioaddr;
 207        unsigned long events = 0;
 208
 209        spin_lock(&pdata->lock);
 210        /* read and clear interrupt */
 211        if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {
 212                events = RTC_IRQF;
 213                if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
 214                        events |= RTC_UF;
 215                else
 216                        events |= RTC_AF;
 217                if (likely(pdata->rtc))
 218                        rtc_update_irq(pdata->rtc, 1, events);
 219        }
 220        spin_unlock(&pdata->lock);
 221        return events ? IRQ_HANDLED : IRQ_NONE;
 222}
 223
 224static int stk17ta8_rtc_alarm_irq_enable(struct device *dev,
 225        unsigned int enabled)
 226{
 227        struct platform_device *pdev = to_platform_device(dev);
 228        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 229
 230        if (pdata->irq <= 0)
 231                return -EINVAL;
 232        if (enabled)
 233                pdata->irqen |= RTC_AF;
 234        else
 235                pdata->irqen &= ~RTC_AF;
 236        stk17ta8_rtc_update_alarm(pdata);
 237        return 0;
 238}
 239
 240static const struct rtc_class_ops stk17ta8_rtc_ops = {
 241        .read_time              = stk17ta8_rtc_read_time,
 242        .set_time               = stk17ta8_rtc_set_time,
 243        .read_alarm             = stk17ta8_rtc_read_alarm,
 244        .set_alarm              = stk17ta8_rtc_set_alarm,
 245        .alarm_irq_enable       = stk17ta8_rtc_alarm_irq_enable,
 246};
 247
 248static ssize_t stk17ta8_nvram_read(struct file *filp, struct kobject *kobj,
 249                                 struct bin_attribute *attr, char *buf,
 250                                 loff_t pos, size_t size)
 251{
 252        struct device *dev = container_of(kobj, struct device, kobj);
 253        struct platform_device *pdev = to_platform_device(dev);
 254        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 255        void __iomem *ioaddr = pdata->ioaddr;
 256        ssize_t count;
 257
 258        for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
 259                *buf++ = readb(ioaddr + pos++);
 260        return count;
 261}
 262
 263static ssize_t stk17ta8_nvram_write(struct file *filp, struct kobject *kobj,
 264                                  struct bin_attribute *attr, char *buf,
 265                                  loff_t pos, size_t size)
 266{
 267        struct device *dev = container_of(kobj, struct device, kobj);
 268        struct platform_device *pdev = to_platform_device(dev);
 269        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 270        void __iomem *ioaddr = pdata->ioaddr;
 271        ssize_t count;
 272
 273        for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
 274                writeb(*buf++, ioaddr + pos++);
 275        return count;
 276}
 277
 278static struct bin_attribute stk17ta8_nvram_attr = {
 279        .attr = {
 280                .name = "nvram",
 281                .mode = S_IRUGO | S_IWUSR,
 282        },
 283        .size = RTC_OFFSET,
 284        .read = stk17ta8_nvram_read,
 285        .write = stk17ta8_nvram_write,
 286};
 287
 288static int stk17ta8_rtc_probe(struct platform_device *pdev)
 289{
 290        struct resource *res;
 291        unsigned int cal;
 292        unsigned int flags;
 293        struct rtc_plat_data *pdata;
 294        void __iomem *ioaddr;
 295        int ret = 0;
 296
 297        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 298        if (!res)
 299                return -ENODEV;
 300
 301        pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 302        if (!pdata)
 303                return -ENOMEM;
 304        if (!devm_request_mem_region(&pdev->dev, res->start, RTC_REG_SIZE,
 305                        pdev->name))
 306                return -EBUSY;
 307        ioaddr = devm_ioremap(&pdev->dev, res->start, RTC_REG_SIZE);
 308        if (!ioaddr)
 309                return -ENOMEM;
 310        pdata->ioaddr = ioaddr;
 311        pdata->irq = platform_get_irq(pdev, 0);
 312
 313        /* turn RTC on if it was not on */
 314        cal = readb(ioaddr + RTC_CALIBRATION);
 315        if (cal & RTC_STOP) {
 316                cal &= RTC_CAL_MASK;
 317                flags = readb(ioaddr + RTC_FLAGS);
 318                writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
 319                writeb(cal, ioaddr + RTC_CALIBRATION);
 320                writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
 321        }
 322        if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF)
 323                dev_warn(&pdev->dev, "voltage-low detected.\n");
 324
 325        spin_lock_init(&pdata->lock);
 326        pdata->last_jiffies = jiffies;
 327        platform_set_drvdata(pdev, pdata);
 328        if (pdata->irq > 0) {
 329                writeb(0, ioaddr + RTC_INTERRUPTS);
 330                if (devm_request_irq(&pdev->dev, pdata->irq,
 331                                stk17ta8_rtc_interrupt,
 332                                IRQF_SHARED,
 333                                pdev->name, pdev) < 0) {
 334                        dev_warn(&pdev->dev, "interrupt not available.\n");
 335                        pdata->irq = 0;
 336                }
 337        }
 338
 339        pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 340                                  &stk17ta8_rtc_ops, THIS_MODULE);
 341        if (IS_ERR(pdata->rtc))
 342                return PTR_ERR(pdata->rtc);
 343
 344        ret = sysfs_create_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
 345
 346        return ret;
 347}
 348
 349static int stk17ta8_rtc_remove(struct platform_device *pdev)
 350{
 351        struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 352
 353        sysfs_remove_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
 354        if (pdata->irq > 0)
 355                writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
 356        return 0;
 357}
 358
 359/* work with hotplug and coldplug */
 360MODULE_ALIAS("platform:stk17ta8");
 361
 362static struct platform_driver stk17ta8_rtc_driver = {
 363        .probe          = stk17ta8_rtc_probe,
 364        .remove         = stk17ta8_rtc_remove,
 365        .driver         = {
 366                .name   = "stk17ta8",
 367                .owner  = THIS_MODULE,
 368        },
 369};
 370
 371module_platform_driver(stk17ta8_rtc_driver);
 372
 373MODULE_AUTHOR("Thomas Hommel <thomas.hommel@ge.com>");
 374MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver");
 375MODULE_LICENSE("GPL");
 376MODULE_VERSION(DRV_VERSION);
 377
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