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/ds1286.h>
  20 #include <linux/io.h>
  21 #include <linux/slab.h>
  22
  23 #define DRV_VERSION             "1.0"
  24
  25 struct ds1286_priv {
  26         struct rtc_device *rtc;
  27         u32 __iomem *rtcregs;
  28         spinlock_t lock;
  29 };
  30
  31 static inline u8 ds1286_rtc_read(struct ds1286_priv *priv, int reg)
  32 {
  33         return __raw_readl(&priv->rtcregs[reg]) & 0xff;
  34 }
  35
  36 static inline void ds1286_rtc_write(struct ds1286_priv *priv, u8 data, int reg)
  37 {
  38         __raw_writel(data, &priv->rtcregs[reg]);
  39 }
  40
  41
  42 static int ds1286_alarm_irq_enable(struct device *dev, unsigned int enabled)
  43 {
  44         struct ds1286_priv *priv = dev_get_drvdata(dev);
  45         unsigned long flags;
  46         unsigned char val;
  47
  48         /* Allow or mask alarm interrupts */
  49         spin_lock_irqsave(&priv->lock, flags);
  50         val = ds1286_rtc_read(priv, RTC_CMD);
  51         if (enabled)
  52                 val &=  ~RTC_TDM;
  53         else
  54                 val |=  RTC_TDM;
  55         ds1286_rtc_write(priv, val, RTC_CMD);
  56         spin_unlock_irqrestore(&priv->lock, flags);
  57
  58         return 0;
  59 }
  60
  61 #ifdef CONFIG_RTC_INTF_DEV
  62
  63 static int ds1286_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
  64 {
  65         struct ds1286_priv *priv = dev_get_drvdata(dev);
  66         unsigned long flags;
  67         unsigned char val;
  68
  69         switch (cmd) {
  70         case RTC_WIE_OFF:
  71                 /* Mask watchdog int. enab. bit */
  72                 spin_lock_irqsave(&priv->lock, flags);
  73                 val = ds1286_rtc_read(priv, RTC_CMD);
  74                 val |= RTC_WAM;
  75                 ds1286_rtc_write(priv, val, RTC_CMD);
  76                 spin_unlock_irqrestore(&priv->lock, flags);
  77                 break;
  78         case RTC_WIE_ON:
  79                 /* Allow watchdog interrupts.   */
  80                 spin_lock_irqsave(&priv->lock, flags);
  81                 val = ds1286_rtc_read(priv, RTC_CMD);
  82                 val &= ~RTC_WAM;
  83                 ds1286_rtc_write(priv, val, RTC_CMD);
  84                 spin_unlock_irqrestore(&priv->lock, flags);
  85                 break;
  86         default:
  87                 return -ENOIOCTLCMD;
  88         }
  89         return 0;
  90 }
  91
  92 #else
  93 #define ds1286_ioctl    NULL
  94 #endif
  95
  96 #ifdef CONFIG_PROC_FS
  97
  98 static int ds1286_proc(struct device *dev, struct seq_file *seq)
  99 {
 100         struct ds1286_priv *priv = dev_get_drvdata(dev);
 101         unsigned char month, cmd, amode;
 102         const char *s;
 103
 104         month = ds1286_rtc_read(priv, RTC_MONTH);
 105         seq_printf(seq,
 106                    "oscillator\t: %s\n"
 107                    "square_wave\t: %s\n",
 108                    (month & RTC_EOSC) ? "disabled" : "enabled",
 109                    (month & RTC_ESQW) ? "disabled" : "enabled");
 110
 111         amode = ((ds1286_rtc_read(priv, RTC_MINUTES_ALARM) & 0x80) >> 5) |
 112                 ((ds1286_rtc_read(priv, RTC_HOURS_ALARM) & 0x80) >> 6) |
 113                 ((ds1286_rtc_read(priv, RTC_DAY_ALARM) & 0x80) >> 7);
 114         switch (amode) {
 115         case 7:
 116                 s = "each minute";
 117                 break;
 118         case 3:
 119                 s = "minutes match";
 120                 break;
 121         case 1:
 122                 s = "hours and minutes match";
 123                 break;
 124         case 0:
 125                 s = "days, hours and minutes match";
 126                 break;
 127         default:
 128                 s = "invalid";
 129                 break;
 130         }
 131         seq_printf(seq, "alarm_mode\t: %s\n", s);
 132
 133         cmd = ds1286_rtc_read(priv, RTC_CMD);
 134         seq_printf(seq,
 135                    "alarm_enable\t: %s\n"
 136                    "wdog_alarm\t: %s\n"
 137                    "alarm_mask\t: %s\n"
 138                    "wdog_alarm_mask\t: %s\n"
 139                    "interrupt_mode\t: %s\n"
 140                    "INTB_mode\t: %s_active\n"
 141                    "interrupt_pins\t: %s\n",
 142                    (cmd & RTC_TDF) ? "yes" : "no",
 143                    (cmd & RTC_WAF) ? "yes" : "no",
 144                    (cmd & RTC_TDM) ? "disabled" : "enabled",
 145                    (cmd & RTC_WAM) ? "disabled" : "enabled",
 146                    (cmd & RTC_PU_LVL) ? "pulse" : "level",
 147                    (cmd & RTC_IBH_LO) ? "low" : "high",
 148                    (cmd & RTC_IPSW) ? "unswapped" : "swapped");
 149         return 0;
 150 }
 151
 152 #else
 153 #define ds1286_proc     NULL
 154 #endif
 155
 156 static int ds1286_read_time(struct device *dev, struct rtc_time *tm)
 157 {
 158         struct ds1286_priv *priv = dev_get_drvdata(dev);
 159         unsigned char save_control;
 160         unsigned long flags;
 161         unsigned long uip_watchdog = jiffies;
 162
 163         /*
 164          * read RTC once any update in progress is done. The update
 165          * can take just over 2ms. We wait 10 to 20ms. There is no need to
 166          * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
 167          * If you need to know *exactly* when a second has started, enable
 168          * periodic update complete interrupts, (via ioctl) and then
 169          * immediately read /dev/rtc which will block until you get the IRQ.
 170          * Once the read clears, read the RTC time (again via ioctl). Easy.
 171          */
 172
 173         if (ds1286_rtc_read(priv, RTC_CMD) & RTC_TE)
 174                 while (time_before(jiffies, uip_watchdog + 2*HZ/100))
 175                         barrier();
 176
 177         /*
 178          * Only the values that we read from the RTC are set. We leave
 179          * tm_wday, tm_yday and tm_isdst untouched. Even though the
 180          * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
 181          * by the RTC when initially set to a non-zero value.
 182          */
 183         spin_lock_irqsave(&priv->lock, flags);
 184         save_control = ds1286_rtc_read(priv, RTC_CMD);
 185         ds1286_rtc_write(priv, (save_control|RTC_TE), RTC_CMD);
 186
 187         tm->tm_sec = ds1286_rtc_read(priv, RTC_SECONDS);
 188         tm->tm_min = ds1286_rtc_read(priv, RTC_MINUTES);
 189         tm->tm_hour = ds1286_rtc_read(priv, RTC_HOURS) & 0x3f;
 190         tm->tm_mday = ds1286_rtc_read(priv, RTC_DATE);
 191         tm->tm_mon = ds1286_rtc_read(priv, RTC_MONTH) & 0x1f;
 192         tm->tm_year = ds1286_rtc_read(priv, RTC_YEAR);
 193
 194         ds1286_rtc_write(priv, save_control, RTC_CMD);
 195         spin_unlock_irqrestore(&priv->lock, flags);
 196
 197         tm->tm_sec = bcd2bin(tm->tm_sec);
 198         tm->tm_min = bcd2bin(tm->tm_min);
 199         tm->tm_hour = bcd2bin(tm->tm_hour);
 200         tm->tm_mday = bcd2bin(tm->tm_mday);
 201         tm->tm_mon = bcd2bin(tm->tm_mon);
 202         tm->tm_year = bcd2bin(tm->tm_year);
 203
 204         /*
 205          * Account for differences between how the RTC uses the values
 206          * and how they are defined in a struct rtc_time;
 207          */
 208         if (tm->tm_year < 45)
 209                 tm->tm_year += 30;
 210         tm->tm_year += 40;
 211         if (tm->tm_year < 70)
 212                 tm->tm_year += 100;
 213
 214         tm->tm_mon--;
 215
 216         return rtc_valid_tm(tm);
 217 }
 218
 219 static int ds1286_set_time(struct device *dev, struct rtc_time *tm)
 220 {
 221         struct ds1286_priv *priv = dev_get_drvdata(dev);
 222         unsigned char mon, day, hrs, min, sec;
 223         unsigned char save_control;
 224         unsigned int yrs;
 225         unsigned long flags;
 226
 227         yrs = tm->tm_year + 1900;
 228         mon = tm->tm_mon + 1;   /* tm_mon starts at zero */
 229         day = tm->tm_mday;
 230         hrs = tm->tm_hour;
 231         min = tm->tm_min;
 232         sec = tm->tm_sec;
 233
 234         if (yrs < 1970)
 235                 return -EINVAL;
 236
 237         yrs -= 1940;
 238         if (yrs > 255)    /* They are unsigned */
 239                 return -EINVAL;
 240
 241         if (yrs >= 100)
 242                 yrs -= 100;
 243
 244         sec = bin2bcd(sec);
 245         min = bin2bcd(min);
 246         hrs = bin2bcd(hrs);
 247         day = bin2bcd(day);
 248         mon = bin2bcd(mon);
 249         yrs = bin2bcd(yrs);
 250
 251         spin_lock_irqsave(&priv->lock, flags);
 252         save_control = ds1286_rtc_read(priv, RTC_CMD);
 253         ds1286_rtc_write(priv, (save_control|RTC_TE), RTC_CMD);
 254
 255         ds1286_rtc_write(priv, yrs, RTC_YEAR);
 256         ds1286_rtc_write(priv, mon, RTC_MONTH);
 257         ds1286_rtc_write(priv, day, RTC_DATE);
 258         ds1286_rtc_write(priv, hrs, RTC_HOURS);
 259         ds1286_rtc_write(priv, min, RTC_MINUTES);
 260         ds1286_rtc_write(priv, sec, RTC_SECONDS);
 261         ds1286_rtc_write(priv, 0, RTC_HUNDREDTH_SECOND);
 262
 263         ds1286_rtc_write(priv, save_control, RTC_CMD);
 264         spin_unlock_irqrestore(&priv->lock, flags);
 265         return 0;
 266 }
 267
 268 static int ds1286_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 269 {
 270         struct ds1286_priv *priv = dev_get_drvdata(dev);
 271         unsigned long flags;
 272
 273         /*
 274          * Only the values that we read from the RTC are set. That
 275          * means only tm_wday, tm_hour, tm_min.
 276          */
 277         spin_lock_irqsave(&priv->lock, flags);
 278         alm->time.tm_min = ds1286_rtc_read(priv, RTC_MINUTES_ALARM) & 0x7f;
 279         alm->time.tm_hour = ds1286_rtc_read(priv, RTC_HOURS_ALARM)  & 0x1f;
 280         alm->time.tm_wday = ds1286_rtc_read(priv, RTC_DAY_ALARM)    & 0x07;
 281         ds1286_rtc_read(priv, RTC_CMD);
 282         spin_unlock_irqrestore(&priv->lock, flags);
 283
 284         alm->time.tm_min = bcd2bin(alm->time.tm_min);
 285         alm->time.tm_hour = bcd2bin(alm->time.tm_hour);
 286         alm->time.tm_sec = 0;
 287         return 0;
 288 }
 289
 290 static int ds1286_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 291 {
 292         struct ds1286_priv *priv = dev_get_drvdata(dev);
 293         unsigned char hrs, min, sec;
 294
 295         hrs = alm->time.tm_hour;
 296         min = alm->time.tm_min;
 297         sec = alm->time.tm_sec;
 298
 299         if (hrs >= 24)
 300                 hrs = 0xff;
 301
 302         if (min >= 60)
 303                 min = 0xff;
 304
 305         if (sec != 0)
 306                 return -EINVAL;
 307
 308         min = bin2bcd(min);
 309         hrs = bin2bcd(hrs);
 310
 311         spin_lock(&priv->lock);
 312         ds1286_rtc_write(priv, hrs, RTC_HOURS_ALARM);
 313         ds1286_rtc_write(priv, min, RTC_MINUTES_ALARM);
 314         spin_unlock(&priv->lock);
 315
 316         return 0;
 317 }
 318
 319 static const struct rtc_class_ops ds1286_ops = {
 320         .ioctl          = ds1286_ioctl,
 321         .proc           = ds1286_proc,
 322         .read_time      = ds1286_read_time,
 323         .set_time       = ds1286_set_time,
 324         .read_alarm     = ds1286_read_alarm,
 325         .set_alarm      = ds1286_set_alarm,
 326         .alarm_irq_enable = ds1286_alarm_irq_enable,
 327 };
 328
 329 static int ds1286_probe(struct platform_device *pdev)
 330 {
 331         struct rtc_device *rtc;
 332         struct resource *res;
 333         struct ds1286_priv *priv;
 334
 335         priv = devm_kzalloc(&pdev->dev, sizeof(struct ds1286_priv), GFP_KERNEL);
 336         if (!priv)
 337                 return -ENOMEM;
 338
 339         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 340         priv->rtcregs = devm_ioremap_resource(&pdev->dev, res);
 341         if (IS_ERR(priv->rtcregs))
 342                 return PTR_ERR(priv->rtcregs);
 343
 344         spin_lock_init(&priv->lock);
 345         platform_set_drvdata(pdev, priv);
 346         rtc = devm_rtc_device_register(&pdev->dev, "ds1286", &ds1286_ops,
 347                                         THIS_MODULE);
 348         if (IS_ERR(rtc))
 349                 return PTR_ERR(rtc);
 350         priv->rtc = rtc;
 351         return 0;
 352 }
 353
 354 static struct platform_driver ds1286_platform_driver = {
 355         .driver         = {
 356                 .name   = "rtc-ds1286",
 357         },
 358         .probe          = ds1286_probe,
 359 };
 360
 361 module_platform_driver(ds1286_platform_driver);
 362
 363 MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
 364 MODULE_DESCRIPTION("DS1286 RTC driver");
 365 MODULE_LICENSE("GPL");
 366 MODULE_VERSION(DRV_VERSION);
 367 MODULE_ALIAS("platform:rtc-ds1286");