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 #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
  64 struct 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
  77 static 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
 100 static 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
 141 static 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
 170 static 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
 187 static 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
 202 static 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
 224 static 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
 240 static 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
 248 static 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
 263 static 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
 278 static 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
 288 static int __devinit 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 = rtc_device_register(pdev->name, &pdev->dev,
 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         if (ret)
 346                 rtc_device_unregister(pdata->rtc);
 347         return ret;
 348 }
 349
 350 static int __devexit stk17ta8_rtc_remove(struct platform_device *pdev)
 351 {
 352         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 353
 354         sysfs_remove_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
 355         rtc_device_unregister(pdata->rtc);
 356         if (pdata->irq > 0)
 357                 writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
 358         return 0;
 359 }
 360
 361 /* work with hotplug and coldplug */
 362 MODULE_ALIAS("platform:stk17ta8");
 363
 364 static struct platform_driver stk17ta8_rtc_driver = {
 365         .probe          = stk17ta8_rtc_probe,
 366         .remove         = __devexit_p(stk17ta8_rtc_remove),
 367         .driver         = {
 368                 .name   = "stk17ta8",
 369                 .owner  = THIS_MODULE,
 370         },
 371 };
 372
 373 module_platform_driver(stk17ta8_rtc_driver);
 374
 375 MODULE_AUTHOR("Thomas Hommel <thomas.hommel@ge.com>");
 376 MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver");
 377 MODULE_LICENSE("GPL");
 378 MODULE_VERSION(DRV_VERSION);