drivers/rtc/rtc-ds1286.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * DS1286 Real Time Clock interface for Linux
   4  *
   5  * Copyright (C) 1998, 1999, 2000 Ralf Baechle
   6  * Copyright (C) 2008 Thomas Bogendoerfer
   7  *
   8  * Based on code written by Paul Gortmaker.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/rtc.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/bcd.h>
  15 #include <linux/rtc/ds1286.h>
  16 #include <linux/io.h>
  17 #include <linux/slab.h>
  18
  19 struct ds1286_priv {
  20         struct rtc_device *rtc;
  21         u32 __iomem *rtcregs;
  22         spinlock_t lock;
  23 };
  24
  25 static inline u8 ds1286_rtc_read(struct ds1286_priv *priv, int reg)
  26 {
  27         return __raw_readl(&priv->rtcregs[reg]) & 0xff;
  28 }
  29
  30 static inline void ds1286_rtc_write(struct ds1286_priv *priv, u8 data, int reg)
  31 {
  32         __raw_writel(data, &priv->rtcregs[reg]);
  33 }
  34
  35
  36 static int ds1286_alarm_irq_enable(struct device *dev, unsigned int enabled)
  37 {
  38         struct ds1286_priv *priv = dev_get_drvdata(dev);
  39         unsigned long flags;
  40         unsigned char val;
  41
  42         /* Allow or mask alarm interrupts */
  43         spin_lock_irqsave(&priv->lock, flags);
  44         val = ds1286_rtc_read(priv, RTC_CMD);
  45         if (enabled)
  46                 val &=  ~RTC_TDM;
  47         else
  48                 val |=  RTC_TDM;
  49         ds1286_rtc_write(priv, val, RTC_CMD);
  50         spin_unlock_irqrestore(&priv->lock, flags);
  51
  52         return 0;
  53 }
  54
  55 #ifdef CONFIG_RTC_INTF_DEV
  56
  57 static int ds1286_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
  58 {
  59         struct ds1286_priv *priv = dev_get_drvdata(dev);
  60         unsigned long flags;
  61         unsigned char val;
  62
  63         switch (cmd) {
  64         case RTC_WIE_OFF:
  65                 /* Mask watchdog int. enab. bit */
  66                 spin_lock_irqsave(&priv->lock, flags);
  67                 val = ds1286_rtc_read(priv, RTC_CMD);
  68                 val |= RTC_WAM;
  69                 ds1286_rtc_write(priv, val, RTC_CMD);
  70                 spin_unlock_irqrestore(&priv->lock, flags);
  71                 break;
  72         case RTC_WIE_ON:
  73                 /* Allow watchdog interrupts.   */
  74                 spin_lock_irqsave(&priv->lock, flags);
  75                 val = ds1286_rtc_read(priv, RTC_CMD);
  76                 val &= ~RTC_WAM;
  77                 ds1286_rtc_write(priv, val, RTC_CMD);
  78                 spin_unlock_irqrestore(&priv->lock, flags);
  79                 break;
  80         default:
  81                 return -ENOIOCTLCMD;
  82         }
  83         return 0;
  84 }
  85
  86 #else
  87 #define ds1286_ioctl    NULL
  88 #endif
  89
  90 #ifdef CONFIG_PROC_FS
  91
  92 static int ds1286_proc(struct device *dev, struct seq_file *seq)
  93 {
  94         struct ds1286_priv *priv = dev_get_drvdata(dev);
  95         unsigned char month, cmd, amode;
  96         const char *s;
  97
  98         month = ds1286_rtc_read(priv, RTC_MONTH);
  99         seq_printf(seq,
 100                    "oscillator\t: %s\n"
 101                    "square_wave\t: %s\n",
 102                    (month & RTC_EOSC) ? "disabled" : "enabled",
 103                    (month & RTC_ESQW) ? "disabled" : "enabled");
 104
 105         amode = ((ds1286_rtc_read(priv, RTC_MINUTES_ALARM) & 0x80) >> 5) |
 106                 ((ds1286_rtc_read(priv, RTC_HOURS_ALARM) & 0x80) >> 6) |
 107                 ((ds1286_rtc_read(priv, RTC_DAY_ALARM) & 0x80) >> 7);
 108         switch (amode) {
 109         case 7:
 110                 s = "each minute";
 111                 break;
 112         case 3:
 113                 s = "minutes match";
 114                 break;
 115         case 1:
 116                 s = "hours and minutes match";
 117                 break;
 118         case 0:
 119                 s = "days, hours and minutes match";
 120                 break;
 121         default:
 122                 s = "invalid";
 123                 break;
 124         }
 125         seq_printf(seq, "alarm_mode\t: %s\n", s);
 126
 127         cmd = ds1286_rtc_read(priv, RTC_CMD);
 128         seq_printf(seq,
 129                    "alarm_enable\t: %s\n"
 130                    "wdog_alarm\t: %s\n"
 131                    "alarm_mask\t: %s\n"
 132                    "wdog_alarm_mask\t: %s\n"
 133                    "interrupt_mode\t: %s\n"
 134                    "INTB_mode\t: %s_active\n"
 135                    "interrupt_pins\t: %s\n",
 136                    (cmd & RTC_TDF) ? "yes" : "no",
 137                    (cmd & RTC_WAF) ? "yes" : "no",
 138                    (cmd & RTC_TDM) ? "disabled" : "enabled",
 139                    (cmd & RTC_WAM) ? "disabled" : "enabled",
 140                    (cmd & RTC_PU_LVL) ? "pulse" : "level",
 141                    (cmd & RTC_IBH_LO) ? "low" : "high",
 142                    (cmd & RTC_IPSW) ? "unswapped" : "swapped");
 143         return 0;
 144 }
 145
 146 #else
 147 #define ds1286_proc     NULL
 148 #endif
 149
 150 static int ds1286_read_time(struct device *dev, struct rtc_time *tm)
 151 {
 152         struct ds1286_priv *priv = dev_get_drvdata(dev);
 153         unsigned char save_control;
 154         unsigned long flags;
 155         unsigned long uip_watchdog = jiffies;
 156
 157         /*
 158          * read RTC once any update in progress is done. The update
 159          * can take just over 2ms. We wait 10 to 20ms. There is no need to
 160          * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
 161          * If you need to know *exactly* when a second has started, enable
 162          * periodic update complete interrupts, (via ioctl) and then
 163          * immediately read /dev/rtc which will block until you get the IRQ.
 164          * Once the read clears, read the RTC time (again via ioctl). Easy.
 165          */
 166
 167         if (ds1286_rtc_read(priv, RTC_CMD) & RTC_TE)
 168                 while (time_before(jiffies, uip_watchdog + 2*HZ/100))
 169                         barrier();
 170
 171         /*
 172          * Only the values that we read from the RTC are set. We leave
 173          * tm_wday, tm_yday and tm_isdst untouched. Even though the
 174          * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
 175          * by the RTC when initially set to a non-zero value.
 176          */
 177         spin_lock_irqsave(&priv->lock, flags);
 178         save_control = ds1286_rtc_read(priv, RTC_CMD);
 179         ds1286_rtc_write(priv, (save_control|RTC_TE), RTC_CMD);
 180
 181         tm->tm_sec = ds1286_rtc_read(priv, RTC_SECONDS);
 182         tm->tm_min = ds1286_rtc_read(priv, RTC_MINUTES);
 183         tm->tm_hour = ds1286_rtc_read(priv, RTC_HOURS) & 0x3f;
 184         tm->tm_mday = ds1286_rtc_read(priv, RTC_DATE);
 185         tm->tm_mon = ds1286_rtc_read(priv, RTC_MONTH) & 0x1f;
 186         tm->tm_year = ds1286_rtc_read(priv, RTC_YEAR);
 187
 188         ds1286_rtc_write(priv, save_control, RTC_CMD);
 189         spin_unlock_irqrestore(&priv->lock, flags);
 190
 191         tm->tm_sec = bcd2bin(tm->tm_sec);
 192         tm->tm_min = bcd2bin(tm->tm_min);
 193         tm->tm_hour = bcd2bin(tm->tm_hour);
 194         tm->tm_mday = bcd2bin(tm->tm_mday);
 195         tm->tm_mon = bcd2bin(tm->tm_mon);
 196         tm->tm_year = bcd2bin(tm->tm_year);
 197
 198         /*
 199          * Account for differences between how the RTC uses the values
 200          * and how they are defined in a struct rtc_time;
 201          */
 202         if (tm->tm_year < 45)
 203                 tm->tm_year += 30;
 204         tm->tm_year += 40;
 205         if (tm->tm_year < 70)
 206                 tm->tm_year += 100;
 207
 208         tm->tm_mon--;
 209
 210         return 0;
 211 }
 212
 213 static int ds1286_set_time(struct device *dev, struct rtc_time *tm)
 214 {
 215         struct ds1286_priv *priv = dev_get_drvdata(dev);
 216         unsigned char mon, day, hrs, min, sec;
 217         unsigned char save_control;
 218         unsigned int yrs;
 219         unsigned long flags;
 220
 221         yrs = tm->tm_year + 1900;
 222         mon = tm->tm_mon + 1;   /* tm_mon starts at zero */
 223         day = tm->tm_mday;
 224         hrs = tm->tm_hour;
 225         min = tm->tm_min;
 226         sec = tm->tm_sec;
 227
 228         if (yrs < 1970)
 229                 return -EINVAL;
 230
 231         yrs -= 1940;
 232         if (yrs > 255)    /* They are unsigned */
 233                 return -EINVAL;
 234
 235         if (yrs >= 100)
 236                 yrs -= 100;
 237
 238         sec = bin2bcd(sec);
 239         min = bin2bcd(min);
 240         hrs = bin2bcd(hrs);
 241         day = bin2bcd(day);
 242         mon = bin2bcd(mon);
 243         yrs = bin2bcd(yrs);
 244
 245         spin_lock_irqsave(&priv->lock, flags);
 246         save_control = ds1286_rtc_read(priv, RTC_CMD);
 247         ds1286_rtc_write(priv, (save_control|RTC_TE), RTC_CMD);
 248
 249         ds1286_rtc_write(priv, yrs, RTC_YEAR);
 250         ds1286_rtc_write(priv, mon, RTC_MONTH);
 251         ds1286_rtc_write(priv, day, RTC_DATE);
 252         ds1286_rtc_write(priv, hrs, RTC_HOURS);
 253         ds1286_rtc_write(priv, min, RTC_MINUTES);
 254         ds1286_rtc_write(priv, sec, RTC_SECONDS);
 255         ds1286_rtc_write(priv, 0, RTC_HUNDREDTH_SECOND);
 256
 257         ds1286_rtc_write(priv, save_control, RTC_CMD);
 258         spin_unlock_irqrestore(&priv->lock, flags);
 259         return 0;
 260 }
 261
 262 static int ds1286_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 263 {
 264         struct ds1286_priv *priv = dev_get_drvdata(dev);
 265         unsigned long flags;
 266
 267         /*
 268          * Only the values that we read from the RTC are set. That
 269          * means only tm_wday, tm_hour, tm_min.
 270          */
 271         spin_lock_irqsave(&priv->lock, flags);
 272         alm->time.tm_min = ds1286_rtc_read(priv, RTC_MINUTES_ALARM) & 0x7f;
 273         alm->time.tm_hour = ds1286_rtc_read(priv, RTC_HOURS_ALARM)  & 0x1f;
 274         alm->time.tm_wday = ds1286_rtc_read(priv, RTC_DAY_ALARM)    & 0x07;
 275         ds1286_rtc_read(priv, RTC_CMD);
 276         spin_unlock_irqrestore(&priv->lock, flags);
 277
 278         alm->time.tm_min = bcd2bin(alm->time.tm_min);
 279         alm->time.tm_hour = bcd2bin(alm->time.tm_hour);
 280         alm->time.tm_sec = 0;
 281         return 0;
 282 }
 283
 284 static int ds1286_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 285 {
 286         struct ds1286_priv *priv = dev_get_drvdata(dev);
 287         unsigned char hrs, min, sec;
 288
 289         hrs = alm->time.tm_hour;
 290         min = alm->time.tm_min;
 291         sec = alm->time.tm_sec;
 292
 293         if (hrs >= 24)
 294                 hrs = 0xff;
 295
 296         if (min >= 60)
 297                 min = 0xff;
 298
 299         if (sec != 0)
 300                 return -EINVAL;
 301
 302         min = bin2bcd(min);
 303         hrs = bin2bcd(hrs);
 304
 305         spin_lock(&priv->lock);
 306         ds1286_rtc_write(priv, hrs, RTC_HOURS_ALARM);
 307         ds1286_rtc_write(priv, min, RTC_MINUTES_ALARM);
 308         spin_unlock(&priv->lock);
 309
 310         return 0;
 311 }
 312
 313 static const struct rtc_class_ops ds1286_ops = {
 314         .ioctl          = ds1286_ioctl,
 315         .proc           = ds1286_proc,
 316         .read_time      = ds1286_read_time,
 317         .set_time       = ds1286_set_time,
 318         .read_alarm     = ds1286_read_alarm,
 319         .set_alarm      = ds1286_set_alarm,
 320         .alarm_irq_enable = ds1286_alarm_irq_enable,
 321 };
 322
 323 static int ds1286_probe(struct platform_device *pdev)
 324 {
 325         struct rtc_device *rtc;
 326         struct ds1286_priv *priv;
 327
 328         priv = devm_kzalloc(&pdev->dev, sizeof(struct ds1286_priv), GFP_KERNEL);
 329         if (!priv)
 330                 return -ENOMEM;
 331
 332         priv->rtcregs = devm_platform_ioremap_resource(pdev, 0);
 333         if (IS_ERR(priv->rtcregs))
 334                 return PTR_ERR(priv->rtcregs);
 335
 336         spin_lock_init(&priv->lock);
 337         platform_set_drvdata(pdev, priv);
 338         rtc = devm_rtc_device_register(&pdev->dev, "ds1286", &ds1286_ops,
 339                                         THIS_MODULE);
 340         if (IS_ERR(rtc))
 341                 return PTR_ERR(rtc);
 342         priv->rtc = rtc;
 343         return 0;
 344 }
 345
 346 static struct platform_driver ds1286_platform_driver = {
 347         .driver         = {
 348                 .name   = "rtc-ds1286",
 349         },
 350         .probe          = ds1286_probe,
 351 };
 352
 353 module_platform_driver(ds1286_platform_driver);
 354
 355 MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
 356 MODULE_DESCRIPTION("DS1286 RTC driver");
 357 MODULE_LICENSE("GPL");
 358 MODULE_ALIAS("platform:rtc-ds1286");