drivers/rtc/rtc-stk17ta8.c

   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
  25 #define DRV_VERSION "0.1"
  26
  27 #define RTC_REG_SIZE            0x20000
  28 #define RTC_OFFSET              0x1fff0
  29
  30 #define RTC_FLAGS               (RTC_OFFSET + 0)
  31 #define RTC_CENTURY             (RTC_OFFSET + 1)
  32 #define RTC_SECONDS_ALARM       (RTC_OFFSET + 2)
  33 #define RTC_MINUTES_ALARM       (RTC_OFFSET + 3)
  34 #define RTC_HOURS_ALARM         (RTC_OFFSET + 4)
  35 #define RTC_DATE_ALARM          (RTC_OFFSET + 5)
  36 #define RTC_INTERRUPTS          (RTC_OFFSET + 6)
  37 #define RTC_WATCHDOG            (RTC_OFFSET + 7)
  38 #define RTC_CALIBRATION         (RTC_OFFSET + 8)
  39 #define RTC_SECONDS             (RTC_OFFSET + 9)
  40 #define RTC_MINUTES             (RTC_OFFSET + 10)
  41 #define RTC_HOURS               (RTC_OFFSET + 11)
  42 #define RTC_DAY                 (RTC_OFFSET + 12)
  43 #define RTC_DATE                (RTC_OFFSET + 13)
  44 #define RTC_MONTH               (RTC_OFFSET + 14)
  45 #define RTC_YEAR                (RTC_OFFSET + 15)
  46
  47 #define RTC_SECONDS_MASK        0x7f
  48 #define RTC_DAY_MASK            0x07
  49 #define RTC_CAL_MASK            0x3f
  50
  51 /* Bits in the Calibration register */
  52 #define RTC_STOP                0x80
  53
  54 /* Bits in the Flags register */
  55 #define RTC_FLAGS_AF            0x40
  56 #define RTC_FLAGS_PF            0x20
  57 #define RTC_WRITE               0x02
  58 #define RTC_READ                0x01
  59
  60 /* Bits in the Interrupts register */
  61 #define RTC_INTS_AIE            0x40
  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 stk17ta8_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 flags;
  82
  83         flags = readb(pdata->ioaddr + RTC_FLAGS);
  84         writeb(flags | RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
  85
  86         writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
  87         writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
  88         writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
  89         writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
  90         writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
  91         writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
  92         writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
  93         writeb(bin2bcd((tm->tm_year + 1900) / 100), ioaddr + RTC_CENTURY);
  94
  95         writeb(flags & ~RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
  96         return 0;
  97 }
  98
  99 static int stk17ta8_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         u8 flags;
 107
 108         /* give enough time to update RTC in case of continuous read */
 109         if (pdata->last_jiffies == jiffies)
 110                 msleep(1);
 111         pdata->last_jiffies = jiffies;
 112
 113         flags = readb(pdata->ioaddr + RTC_FLAGS);
 114         writeb(flags | RTC_READ, ioaddr + RTC_FLAGS);
 115         second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
 116         minute = readb(ioaddr + RTC_MINUTES);
 117         hour = readb(ioaddr + RTC_HOURS);
 118         day = readb(ioaddr + RTC_DATE);
 119         week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
 120         month = readb(ioaddr + RTC_MONTH);
 121         year = readb(ioaddr + RTC_YEAR);
 122         century = readb(ioaddr + RTC_CENTURY);
 123         writeb(flags & ~RTC_READ, ioaddr + RTC_FLAGS);
 124         tm->tm_sec = bcd2bin(second);
 125         tm->tm_min = bcd2bin(minute);
 126         tm->tm_hour = bcd2bin(hour);
 127         tm->tm_mday = bcd2bin(day);
 128         tm->tm_wday = bcd2bin(week);
 129         tm->tm_mon = bcd2bin(month) - 1;
 130         /* year is 1900 + tm->tm_year */
 131         tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
 132
 133         if (rtc_valid_tm(tm) < 0) {
 134                 dev_err(dev, "retrieved date/time is not valid.\n");
 135                 rtc_time_to_tm(0, tm);
 136         }
 137         return 0;
 138 }
 139
 140 static void stk17ta8_rtc_update_alarm(struct rtc_plat_data *pdata)
 141 {
 142         void __iomem *ioaddr = pdata->ioaddr;
 143         unsigned long irqflags;
 144         u8 flags;
 145
 146         spin_lock_irqsave(&pdata->lock, irqflags);
 147
 148         flags = readb(ioaddr + RTC_FLAGS);
 149         writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
 150
 151         writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
 152                0x80 : bin2bcd(pdata->alrm_mday),
 153                ioaddr + RTC_DATE_ALARM);
 154         writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
 155                0x80 : bin2bcd(pdata->alrm_hour),
 156                ioaddr + RTC_HOURS_ALARM);
 157         writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
 158                0x80 : bin2bcd(pdata->alrm_min),
 159                ioaddr + RTC_MINUTES_ALARM);
 160         writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
 161                0x80 : bin2bcd(pdata->alrm_sec),
 162                ioaddr + RTC_SECONDS_ALARM);
 163         writeb(pdata->irqen ? RTC_INTS_AIE : 0, ioaddr + RTC_INTERRUPTS);
 164         readb(ioaddr + RTC_FLAGS);      /* clear interrupts */
 165         writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
 166         spin_unlock_irqrestore(&pdata->lock, irqflags);
 167 }
 168
 169 static int stk17ta8_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 170 {
 171         struct platform_device *pdev = to_platform_device(dev);
 172         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 173
 174         if (pdata->irq <= 0)
 175                 return -EINVAL;
 176         pdata->alrm_mday = alrm->time.tm_mday;
 177         pdata->alrm_hour = alrm->time.tm_hour;
 178         pdata->alrm_min = alrm->time.tm_min;
 179         pdata->alrm_sec = alrm->time.tm_sec;
 180         if (alrm->enabled)
 181                 pdata->irqen |= RTC_AF;
 182         stk17ta8_rtc_update_alarm(pdata);
 183         return 0;
 184 }
 185
 186 static int stk17ta8_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 187 {
 188         struct platform_device *pdev = to_platform_device(dev);
 189         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 190
 191         if (pdata->irq <= 0)
 192                 return -EINVAL;
 193         alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
 194         alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
 195         alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
 196         alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
 197         alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
 198         return 0;
 199 }
 200
 201 static irqreturn_t stk17ta8_rtc_interrupt(int irq, void *dev_id)
 202 {
 203         struct platform_device *pdev = dev_id;
 204         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 205         void __iomem *ioaddr = pdata->ioaddr;
 206         unsigned long events = 0;
 207
 208         spin_lock(&pdata->lock);
 209         /* read and clear interrupt */
 210         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {
 211                 events = RTC_IRQF;
 212                 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
 213                         events |= RTC_UF;
 214                 else
 215                         events |= RTC_AF;
 216                 if (likely(pdata->rtc))
 217                         rtc_update_irq(pdata->rtc, 1, events);
 218         }
 219         spin_unlock(&pdata->lock);
 220         return events ? IRQ_HANDLED : IRQ_NONE;
 221 }
 222
 223 static int stk17ta8_rtc_alarm_irq_enable(struct device *dev,
 224         unsigned int enabled)
 225 {
 226         struct platform_device *pdev = to_platform_device(dev);
 227         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 228
 229         if (pdata->irq <= 0)
 230                 return -EINVAL;
 231         if (enabled)
 232                 pdata->irqen |= RTC_AF;
 233         else
 234                 pdata->irqen &= ~RTC_AF;
 235         stk17ta8_rtc_update_alarm(pdata);
 236         return 0;
 237 }
 238
 239 static const struct rtc_class_ops stk17ta8_rtc_ops = {
 240         .read_time              = stk17ta8_rtc_read_time,
 241         .set_time               = stk17ta8_rtc_set_time,
 242         .read_alarm             = stk17ta8_rtc_read_alarm,
 243         .set_alarm              = stk17ta8_rtc_set_alarm,
 244         .alarm_irq_enable       = stk17ta8_rtc_alarm_irq_enable,
 245 };
 246
 247 static ssize_t stk17ta8_nvram_read(struct file *filp, struct kobject *kobj,
 248                                  struct bin_attribute *attr, char *buf,
 249                                  loff_t pos, size_t size)
 250 {
 251         struct device *dev = container_of(kobj, struct device, kobj);
 252         struct platform_device *pdev = to_platform_device(dev);
 253         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 254         void __iomem *ioaddr = pdata->ioaddr;
 255         ssize_t count;
 256
 257         for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
 258                 *buf++ = readb(ioaddr + pos++);
 259         return count;
 260 }
 261
 262 static ssize_t stk17ta8_nvram_write(struct file *filp, struct kobject *kobj,
 263                                   struct bin_attribute *attr, char *buf,
 264                                   loff_t pos, size_t size)
 265 {
 266         struct device *dev = container_of(kobj, struct device, kobj);
 267         struct platform_device *pdev = to_platform_device(dev);
 268         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 269         void __iomem *ioaddr = pdata->ioaddr;
 270         ssize_t count;
 271
 272         for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
 273                 writeb(*buf++, ioaddr + pos++);
 274         return count;
 275 }
 276
 277 static struct bin_attribute stk17ta8_nvram_attr = {
 278         .attr = {
 279                 .name = "nvram",
 280                 .mode = S_IRUGO | S_IWUSR,
 281         },
 282         .size = RTC_OFFSET,
 283         .read = stk17ta8_nvram_read,
 284         .write = stk17ta8_nvram_write,
 285 };
 286
 287 static int __devinit stk17ta8_rtc_probe(struct platform_device *pdev)
 288 {
 289         struct resource *res;
 290         unsigned int cal;
 291         unsigned int flags;
 292         struct rtc_plat_data *pdata;
 293         void __iomem *ioaddr;
 294         int ret = 0;
 295
 296         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 297         if (!res)
 298                 return -ENODEV;
 299
 300         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 301         if (!pdata)
 302                 return -ENOMEM;
 303         if (!devm_request_mem_region(&pdev->dev, res->start, RTC_REG_SIZE,
 304                         pdev->name))
 305                 return -EBUSY;
 306         ioaddr = devm_ioremap(&pdev->dev, res->start, RTC_REG_SIZE);
 307         if (!ioaddr)
 308                 return -ENOMEM;
 309         pdata->ioaddr = ioaddr;
 310         pdata->irq = platform_get_irq(pdev, 0);
 311
 312         /* turn RTC on if it was not on */
 313         cal = readb(ioaddr + RTC_CALIBRATION);
 314         if (cal & RTC_STOP) {
 315                 cal &= RTC_CAL_MASK;
 316                 flags = readb(ioaddr + RTC_FLAGS);
 317                 writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
 318                 writeb(cal, ioaddr + RTC_CALIBRATION);
 319                 writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
 320         }
 321         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF)
 322                 dev_warn(&pdev->dev, "voltage-low detected.\n");
 323
 324         spin_lock_init(&pdata->lock);
 325         pdata->last_jiffies = jiffies;
 326         platform_set_drvdata(pdev, pdata);
 327         if (pdata->irq > 0) {
 328                 writeb(0, ioaddr + RTC_INTERRUPTS);
 329                 if (devm_request_irq(&pdev->dev, pdata->irq,
 330                                 stk17ta8_rtc_interrupt,
 331                                 IRQF_DISABLED | IRQF_SHARED,
 332                                 pdev->name, pdev) < 0) {
 333                         dev_warn(&pdev->dev, "interrupt not available.\n");
 334                         pdata->irq = 0;
 335                 }
 336         }
 337
 338         pdata->rtc = rtc_device_register(pdev->name, &pdev->dev,
 339                                   &stk17ta8_rtc_ops, THIS_MODULE);
 340         if (IS_ERR(pdata->rtc))
 341                 return PTR_ERR(pdata->rtc);
 342
 343         ret = sysfs_create_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
 344         if (ret)
 345                 rtc_device_unregister(pdata->rtc);
 346         return ret;
 347 }
 348
 349 static int __devexit 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         rtc_device_unregister(pdata->rtc);
 355         if (pdata->irq > 0)
 356                 writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
 357         return 0;
 358 }
 359
 360 /* work with hotplug and coldplug */
 361 MODULE_ALIAS("platform:stk17ta8");
 362
 363 static struct platform_driver stk17ta8_rtc_driver = {
 364         .probe          = stk17ta8_rtc_probe,
 365         .remove         = __devexit_p(stk17ta8_rtc_remove),
 366         .driver         = {
 367                 .name   = "stk17ta8",
 368                 .owner  = THIS_MODULE,
 369         },
 370 };
 371
 372 static __init int stk17ta8_init(void)
 373 {
 374         return platform_driver_register(&stk17ta8_rtc_driver);
 375 }
 376
 377 static __exit void stk17ta8_exit(void)
 378 {
 379         platform_driver_unregister(&stk17ta8_rtc_driver);
 380 }
 381
 382 module_init(stk17ta8_init);
 383 module_exit(stk17ta8_exit);
 384
 385 MODULE_AUTHOR("Thomas Hommel <thomas.hommel@ge.com>");
 386 MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver");
 387 MODULE_LICENSE("GPL");
 388 MODULE_VERSION(DRV_VERSION);