drivers/rtc/rtc-ds1286.c

   1 /*
   2  * DS1286 Real Time Clock interface for Linux
   3  *
   4  * Copyright (C) 1998, 1999, 2000 Ralf Baechle
   5  * Copyright (C) 2008 Thomas Bogendoerfer
   6  *
   7  * Based on code written by Paul Gortmaker.
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by the
  11  * Free Software Foundation; either version 2 of the License, or (at your
  12  * option) any later version.
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/rtc.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/bcd.h>
  19 #include <linux/rtc/ds1286.h>
  20 #include <linux/io.h>
  21 #include <linux/slab.h>
  22
  23 struct ds1286_priv {
  24         struct rtc_device *rtc;
  25         u32 __iomem *rtcregs;
  26         spinlock_t lock;
  27 };
  28
  29 static inline u8 ds1286_rtc_read(struct ds1286_priv *priv, int reg)
  30 {
  31         return __raw_readl(&priv->rtcregs[reg]) & 0xff;
  32 }
  33
  34 static inline void ds1286_rtc_write(struct ds1286_priv *priv, u8 data, int reg)
  35 {
  36         __raw_writel(data, &priv->rtcregs[reg]);
  37 }
  38
  39
  40 static int ds1286_alarm_irq_enable(struct device *dev, unsigned int enabled)
  41 {
  42         struct ds1286_priv *priv = dev_get_drvdata(dev);
  43         unsigned long flags;
  44         unsigned char val;
  45
  46         /* Allow or mask alarm interrupts */
  47         spin_lock_irqsave(&priv->lock, flags);
  48         val = ds1286_rtc_read(priv, RTC_CMD);
  49         if (enabled)
  50                 val &=  ~RTC_TDM;
  51         else
  52                 val |=  RTC_TDM;
  53         ds1286_rtc_write(priv, val, RTC_CMD);
  54         spin_unlock_irqrestore(&priv->lock, flags);
  55
  56         return 0;
  57 }
  58
  59 #ifdef CONFIG_RTC_INTF_DEV
  60
  61 static int ds1286_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
  62 {
  63         struct ds1286_priv *priv = dev_get_drvdata(dev);
  64         unsigned long flags;
  65         unsigned char val;
  66
  67         switch (cmd) {
  68         case RTC_WIE_OFF:
  69                 /* Mask watchdog int. enab. bit */
  70                 spin_lock_irqsave(&priv->lock, flags);
  71                 val = ds1286_rtc_read(priv, RTC_CMD);
  72                 val |= RTC_WAM;
  73                 ds1286_rtc_write(priv, val, RTC_CMD);
  74                 spin_unlock_irqrestore(&priv->lock, flags);
  75                 break;
  76         case RTC_WIE_ON:
  77                 /* Allow watchdog interrupts.   */
  78                 spin_lock_irqsave(&priv->lock, flags);
  79                 val = ds1286_rtc_read(priv, RTC_CMD);
  80                 val &= ~RTC_WAM;
  81                 ds1286_rtc_write(priv, val, RTC_CMD);
  82                 spin_unlock_irqrestore(&priv->lock, flags);
  83                 break;
  84         default:
  85                 return -ENOIOCTLCMD;
  86         }
  87         return 0;
  88 }
  89
  90 #else
  91 #define ds1286_ioctl    NULL
  92 #endif
  93
  94 #ifdef CONFIG_PROC_FS
  95
  96 static int ds1286_proc(struct device *dev, struct seq_file *seq)
  97 {
  98         struct ds1286_priv *priv = dev_get_drvdata(dev);
  99         unsigned char month, cmd, amode;
 100         const char *s;
 101
 102         month = ds1286_rtc_read(priv, RTC_MONTH);
 103         seq_printf(seq,
 104                    "oscillator\t: %s\n"
 105                    "square_wave\t: %s\n",
 106                    (month & RTC_EOSC) ? "disabled" : "enabled",
 107                    (month & RTC_ESQW) ? "disabled" : "enabled");
 108
 109         amode = ((ds1286_rtc_read(priv, RTC_MINUTES_ALARM) & 0x80) >> 5) |
 110                 ((ds1286_rtc_read(priv, RTC_HOURS_ALARM) & 0x80) >> 6) |
 111                 ((ds1286_rtc_read(priv, RTC_DAY_ALARM) & 0x80) >> 7);
 112         switch (amode) {
 113         case 7:
 114                 s = "each minute";
 115                 break;
 116         case 3:
 117                 s = "minutes match";
 118                 break;
 119         case 1:
 120                 s = "hours and minutes match";
 121                 break;
 122         case 0:
 123                 s = "days, hours and minutes match";
 124                 break;
 125         default:
 126                 s = "invalid";
 127                 break;
 128         }
 129         seq_printf(seq, "alarm_mode\t: %s\n", s);
 130
 131         cmd = ds1286_rtc_read(priv, RTC_CMD);
 132         seq_printf(seq,
 133                    "alarm_enable\t: %s\n"
 134                    "wdog_alarm\t: %s\n"
 135                    "alarm_mask\t: %s\n"
 136                    "wdog_alarm_mask\t: %s\n"
 137                    "interrupt_mode\t: %s\n"
 138                    "INTB_mode\t: %s_active\n"
 139                    "interrupt_pins\t: %s\n",
 140                    (cmd & RTC_TDF) ? "yes" : "no",
 141                    (cmd & RTC_WAF) ? "yes" : "no",
 142                    (cmd & RTC_TDM) ? "disabled" : "enabled",
 143                    (cmd & RTC_WAM) ? "disabled" : "enabled",
 144                    (cmd & RTC_PU_LVL) ? "pulse" : "level",
 145                    (cmd & RTC_IBH_LO) ? "low" : "high",
 146                    (cmd & RTC_IPSW) ? "unswapped" : "swapped");
 147         return 0;
 148 }
 149
 150 #else
 151 #define ds1286_proc     NULL
 152 #endif
 153
 154 static int ds1286_read_time(struct device *dev, struct rtc_time *tm)
 155 {
 156         struct ds1286_priv *priv = dev_get_drvdata(dev);
 157         unsigned char save_control;
 158         unsigned long flags;
 159         unsigned long uip_watchdog = jiffies;
 160
 161         /*
 162          * read RTC once any update in progress is done. The update
 163          * can take just over 2ms. We wait 10 to 20ms. There is no need to
 164          * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
 165          * If you need to know *exactly* when a second has started, enable
 166          * periodic update complete interrupts, (via ioctl) and then
 167          * immediately read /dev/rtc which will block until you get the IRQ.
 168          * Once the read clears, read the RTC time (again via ioctl). Easy.
 169          */
 170
 171         if (ds1286_rtc_read(priv, RTC_CMD) & RTC_TE)
 172                 while (time_before(jiffies, uip_watchdog + 2*HZ/100))
 173                         barrier();
 174
 175         /*
 176          * Only the values that we read from the RTC are set. We leave
 177          * tm_wday, tm_yday and tm_isdst untouched. Even though the
 178          * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
 179          * by the RTC when initially set to a non-zero value.
 180          */
 181         spin_lock_irqsave(&priv->lock, flags);
 182         save_control = ds1286_rtc_read(priv, RTC_CMD);
 183         ds1286_rtc_write(priv, (save_control|RTC_TE), RTC_CMD);
 184
 185         tm->tm_sec = ds1286_rtc_read(priv, RTC_SECONDS);
 186         tm->tm_min = ds1286_rtc_read(priv, RTC_MINUTES);
 187         tm->tm_hour = ds1286_rtc_read(priv, RTC_HOURS) & 0x3f;
 188         tm->tm_mday = ds1286_rtc_read(priv, RTC_DATE);
 189         tm->tm_mon = ds1286_rtc_read(priv, RTC_MONTH) & 0x1f;
 190         tm->tm_year = ds1286_rtc_read(priv, RTC_YEAR);
 191
 192         ds1286_rtc_write(priv, save_control, RTC_CMD);
 193         spin_unlock_irqrestore(&priv->lock, flags);
 194
 195         tm->tm_sec = bcd2bin(tm->tm_sec);
 196         tm->tm_min = bcd2bin(tm->tm_min);
 197         tm->tm_hour = bcd2bin(tm->tm_hour);
 198         tm->tm_mday = bcd2bin(tm->tm_mday);
 199         tm->tm_mon = bcd2bin(tm->tm_mon);
 200         tm->tm_year = bcd2bin(tm->tm_year);
 201
 202         /*
 203          * Account for differences between how the RTC uses the values
 204          * and how they are defined in a struct rtc_time;
 205          */
 206         if (tm->tm_year < 45)
 207                 tm->tm_year += 30;
 208         tm->tm_year += 40;
 209         if (tm->tm_year < 70)
 210                 tm->tm_year += 100;
 211
 212         tm->tm_mon--;
 213
 214         return rtc_valid_tm(tm);
 215 }
 216
 217 static int ds1286_set_time(struct device *dev, struct rtc_time *tm)
 218 {
 219         struct ds1286_priv *priv = dev_get_drvdata(dev);
 220         unsigned char mon, day, hrs, min, sec;
 221         unsigned char save_control;
 222         unsigned int yrs;
 223         unsigned long flags;
 224
 225         yrs = tm->tm_year + 1900;
 226         mon = tm->tm_mon + 1;   /* tm_mon starts at zero */
 227         day = tm->tm_mday;
 228         hrs = tm->tm_hour;
 229         min = tm->tm_min;
 230         sec = tm->tm_sec;
 231
 232         if (yrs < 1970)
 233                 return -EINVAL;
 234
 235         yrs -= 1940;
 236         if (yrs > 255)    /* They are unsigned */
 237                 return -EINVAL;
 238
 239         if (yrs >= 100)
 240                 yrs -= 100;
 241
 242         sec = bin2bcd(sec);
 243         min = bin2bcd(min);
 244         hrs = bin2bcd(hrs);
 245         day = bin2bcd(day);
 246         mon = bin2bcd(mon);
 247         yrs = bin2bcd(yrs);
 248
 249         spin_lock_irqsave(&priv->lock, flags);
 250         save_control = ds1286_rtc_read(priv, RTC_CMD);
 251         ds1286_rtc_write(priv, (save_control|RTC_TE), RTC_CMD);
 252
 253         ds1286_rtc_write(priv, yrs, RTC_YEAR);
 254         ds1286_rtc_write(priv, mon, RTC_MONTH);
 255         ds1286_rtc_write(priv, day, RTC_DATE);
 256         ds1286_rtc_write(priv, hrs, RTC_HOURS);
 257         ds1286_rtc_write(priv, min, RTC_MINUTES);
 258         ds1286_rtc_write(priv, sec, RTC_SECONDS);
 259         ds1286_rtc_write(priv, 0, RTC_HUNDREDTH_SECOND);
 260
 261         ds1286_rtc_write(priv, save_control, RTC_CMD);
 262         spin_unlock_irqrestore(&priv->lock, flags);
 263         return 0;
 264 }
 265
 266 static int ds1286_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 267 {
 268         struct ds1286_priv *priv = dev_get_drvdata(dev);
 269         unsigned long flags;
 270
 271         /*
 272          * Only the values that we read from the RTC are set. That
 273          * means only tm_wday, tm_hour, tm_min.
 274          */
 275         spin_lock_irqsave(&priv->lock, flags);
 276         alm->time.tm_min = ds1286_rtc_read(priv, RTC_MINUTES_ALARM) & 0x7f;
 277         alm->time.tm_hour = ds1286_rtc_read(priv, RTC_HOURS_ALARM)  & 0x1f;
 278         alm->time.tm_wday = ds1286_rtc_read(priv, RTC_DAY_ALARM)    & 0x07;
 279         ds1286_rtc_read(priv, RTC_CMD);
 280         spin_unlock_irqrestore(&priv->lock, flags);
 281
 282         alm->time.tm_min = bcd2bin(alm->time.tm_min);
 283         alm->time.tm_hour = bcd2bin(alm->time.tm_hour);
 284         alm->time.tm_sec = 0;
 285         return 0;
 286 }
 287
 288 static int ds1286_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 289 {
 290         struct ds1286_priv *priv = dev_get_drvdata(dev);
 291         unsigned char hrs, min, sec;
 292
 293         hrs = alm->time.tm_hour;
 294         min = alm->time.tm_min;
 295         sec = alm->time.tm_sec;
 296
 297         if (hrs >= 24)
 298                 hrs = 0xff;
 299
 300         if (min >= 60)
 301                 min = 0xff;
 302
 303         if (sec != 0)
 304                 return -EINVAL;
 305
 306         min = bin2bcd(min);
 307         hrs = bin2bcd(hrs);
 308
 309         spin_lock(&priv->lock);
 310         ds1286_rtc_write(priv, hrs, RTC_HOURS_ALARM);
 311         ds1286_rtc_write(priv, min, RTC_MINUTES_ALARM);
 312         spin_unlock(&priv->lock);
 313
 314         return 0;
 315 }
 316
 317 static const struct rtc_class_ops ds1286_ops = {
 318         .ioctl          = ds1286_ioctl,
 319         .proc           = ds1286_proc,
 320         .read_time      = ds1286_read_time,
 321         .set_time       = ds1286_set_time,
 322         .read_alarm     = ds1286_read_alarm,
 323         .set_alarm      = ds1286_set_alarm,
 324         .alarm_irq_enable = ds1286_alarm_irq_enable,
 325 };
 326
 327 static int ds1286_probe(struct platform_device *pdev)
 328 {
 329         struct rtc_device *rtc;
 330         struct resource *res;
 331         struct ds1286_priv *priv;
 332
 333         priv = devm_kzalloc(&pdev->dev, sizeof(struct ds1286_priv), GFP_KERNEL);
 334         if (!priv)
 335                 return -ENOMEM;
 336
 337         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 338         priv->rtcregs = devm_ioremap_resource(&pdev->dev, res);
 339         if (IS_ERR(priv->rtcregs))
 340                 return PTR_ERR(priv->rtcregs);
 341
 342         spin_lock_init(&priv->lock);
 343         platform_set_drvdata(pdev, priv);
 344         rtc = devm_rtc_device_register(&pdev->dev, "ds1286", &ds1286_ops,
 345                                         THIS_MODULE);
 346         if (IS_ERR(rtc))
 347                 return PTR_ERR(rtc);
 348         priv->rtc = rtc;
 349         return 0;
 350 }
 351
 352 static struct platform_driver ds1286_platform_driver = {
 353         .driver         = {
 354                 .name   = "rtc-ds1286",
 355         },
 356         .probe          = ds1286_probe,
 357 };
 358
 359 module_platform_driver(ds1286_platform_driver);
 360
 361 MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
 362 MODULE_DESCRIPTION("DS1286 RTC driver");
 363 MODULE_LICENSE("GPL");
 364 MODULE_ALIAS("platform:rtc-ds1286");