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                 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; count < size; count++)
 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; count < size; count++)
 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 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         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 297         if (!pdata)
 298                 return -ENOMEM;
 299
 300         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 301         ioaddr = devm_ioremap_resource(&pdev->dev, res);
 302         if (IS_ERR(ioaddr))
 303                 return PTR_ERR(ioaddr);
 304         pdata->ioaddr = ioaddr;
 305         pdata->irq = platform_get_irq(pdev, 0);
 306
 307         /* turn RTC on if it was not on */
 308         cal = readb(ioaddr + RTC_CALIBRATION);
 309         if (cal & RTC_STOP) {
 310                 cal &= RTC_CAL_MASK;
 311                 flags = readb(ioaddr + RTC_FLAGS);
 312                 writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
 313                 writeb(cal, ioaddr + RTC_CALIBRATION);
 314                 writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
 315         }
 316         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF)
 317                 dev_warn(&pdev->dev, "voltage-low detected.\n");
 318
 319         spin_lock_init(&pdata->lock);
 320         pdata->last_jiffies = jiffies;
 321         platform_set_drvdata(pdev, pdata);
 322         if (pdata->irq > 0) {
 323                 writeb(0, ioaddr + RTC_INTERRUPTS);
 324                 if (devm_request_irq(&pdev->dev, pdata->irq,
 325                                 stk17ta8_rtc_interrupt,
 326                                 IRQF_SHARED,
 327                                 pdev->name, pdev) < 0) {
 328                         dev_warn(&pdev->dev, "interrupt not available.\n");
 329                         pdata->irq = 0;
 330                 }
 331         }
 332
 333         pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 334                                   &stk17ta8_rtc_ops, THIS_MODULE);
 335         if (IS_ERR(pdata->rtc))
 336                 return PTR_ERR(pdata->rtc);
 337
 338         ret = sysfs_create_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
 339
 340         return ret;
 341 }
 342
 343 static int stk17ta8_rtc_remove(struct platform_device *pdev)
 344 {
 345         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 346
 347         sysfs_remove_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
 348         if (pdata->irq > 0)
 349                 writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
 350         return 0;
 351 }
 352
 353 /* work with hotplug and coldplug */
 354 MODULE_ALIAS("platform:stk17ta8");
 355
 356 static struct platform_driver stk17ta8_rtc_driver = {
 357         .probe          = stk17ta8_rtc_probe,
 358         .remove         = stk17ta8_rtc_remove,
 359         .driver         = {
 360                 .name   = "stk17ta8",
 361         },
 362 };
 363
 364 module_platform_driver(stk17ta8_rtc_driver);
 365
 366 MODULE_AUTHOR("Thomas Hommel <thomas.hommel@ge.com>");
 367 MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver");
 368 MODULE_LICENSE("GPL");
 369 MODULE_VERSION(DRV_VERSION);