drivers/rtc/rtc-ds1511.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * An rtc driver for the Dallas DS1511
   4  *
   5  * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
   6  * Copyright (C) 2007 Andrew Sharp <andy.sharp@lsi.com>
   7  *
   8  * Real time clock driver for the Dallas 1511 chip, which also
   9  * contains a watchdog timer.  There is a tiny amount of code that
  10  * platform code could use to mess with the watchdog device a little
  11  * bit, but not a full watchdog driver.
  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/interrupt.h>
  20 #include <linux/rtc.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/io.h>
  23 #include <linux/module.h>
  24
  25 #define DS1511_SEC              0x0
  26 #define DS1511_MIN              0x1
  27 #define DS1511_HOUR             0x2
  28 #define DS1511_DOW              0x3
  29 #define DS1511_DOM              0x4
  30 #define DS1511_MONTH            0x5
  31 #define DS1511_YEAR             0x6
  32 #define DS1511_CENTURY          0x7
  33 #define DS1511_AM1_SEC          0x8
  34 #define DS1511_AM2_MIN          0x9
  35 #define DS1511_AM3_HOUR         0xa
  36 #define DS1511_AM4_DATE         0xb
  37 #define DS1511_WD_MSEC          0xc
  38 #define DS1511_WD_SEC           0xd
  39 #define DS1511_CONTROL_A        0xe
  40 #define DS1511_CONTROL_B        0xf
  41 #define DS1511_RAMADDR_LSB      0x10
  42 #define DS1511_RAMDATA          0x13
  43
  44 #define DS1511_BLF1     0x80
  45 #define DS1511_BLF2     0x40
  46 #define DS1511_PRS      0x20
  47 #define DS1511_PAB      0x10
  48 #define DS1511_TDF      0x08
  49 #define DS1511_KSF      0x04
  50 #define DS1511_WDF      0x02
  51 #define DS1511_IRQF     0x01
  52 #define DS1511_TE       0x80
  53 #define DS1511_CS       0x40
  54 #define DS1511_BME      0x20
  55 #define DS1511_TPE      0x10
  56 #define DS1511_TIE      0x08
  57 #define DS1511_KIE      0x04
  58 #define DS1511_WDE      0x02
  59 #define DS1511_WDS      0x01
  60 #define DS1511_RAM_MAX  0x100
  61
  62 struct ds1511_data {
  63         struct rtc_device *rtc;
  64         void __iomem *ioaddr;           /* virtual base address */
  65         int irq;
  66         spinlock_t lock;
  67 };
  68
  69 static DEFINE_SPINLOCK(ds1511_lock);
  70
  71 static __iomem char *ds1511_base;
  72 static u32 reg_spacing = 1;
  73
  74 static void rtc_write(uint8_t val, uint32_t reg)
  75 {
  76         writeb(val, ds1511_base + (reg * reg_spacing));
  77 }
  78
  79 static uint8_t rtc_read(uint32_t reg)
  80 {
  81         return readb(ds1511_base + (reg * reg_spacing));
  82 }
  83
  84 static void rtc_disable_update(void)
  85 {
  86         rtc_write((rtc_read(DS1511_CONTROL_B) & ~DS1511_TE), DS1511_CONTROL_B);
  87 }
  88
  89 static void rtc_enable_update(void)
  90 {
  91         rtc_write((rtc_read(DS1511_CONTROL_B) | DS1511_TE), DS1511_CONTROL_B);
  92 }
  93
  94 static int ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
  95 {
  96         u8 mon, day, dow, hrs, min, sec, yrs, cen;
  97         unsigned long flags;
  98
  99         yrs = rtc_tm->tm_year % 100;
 100         cen = 19 + rtc_tm->tm_year / 100;
 101         mon = rtc_tm->tm_mon + 1;   /* tm_mon starts at zero */
 102         day = rtc_tm->tm_mday;
 103         dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */
 104         hrs = rtc_tm->tm_hour;
 105         min = rtc_tm->tm_min;
 106         sec = rtc_tm->tm_sec;
 107
 108         /*
 109          * each register is a different number of valid bits
 110          */
 111         sec = bin2bcd(sec) & 0x7f;
 112         min = bin2bcd(min) & 0x7f;
 113         hrs = bin2bcd(hrs) & 0x3f;
 114         day = bin2bcd(day) & 0x3f;
 115         mon = bin2bcd(mon) & 0x1f;
 116         yrs = bin2bcd(yrs) & 0xff;
 117         cen = bin2bcd(cen) & 0xff;
 118
 119         spin_lock_irqsave(&ds1511_lock, flags);
 120         rtc_disable_update();
 121         rtc_write(cen, DS1511_CENTURY);
 122         rtc_write(yrs, DS1511_YEAR);
 123         rtc_write((rtc_read(DS1511_MONTH) & 0xe0) | mon, DS1511_MONTH);
 124         rtc_write(day, DS1511_DOM);
 125         rtc_write(hrs, DS1511_HOUR);
 126         rtc_write(min, DS1511_MIN);
 127         rtc_write(sec, DS1511_SEC);
 128         rtc_write(dow, DS1511_DOW);
 129         rtc_enable_update();
 130         spin_unlock_irqrestore(&ds1511_lock, flags);
 131
 132         return 0;
 133 }
 134
 135 static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
 136 {
 137         unsigned int century;
 138         unsigned long flags;
 139
 140         spin_lock_irqsave(&ds1511_lock, flags);
 141         rtc_disable_update();
 142
 143         rtc_tm->tm_sec = rtc_read(DS1511_SEC) & 0x7f;
 144         rtc_tm->tm_min = rtc_read(DS1511_MIN) & 0x7f;
 145         rtc_tm->tm_hour = rtc_read(DS1511_HOUR) & 0x3f;
 146         rtc_tm->tm_mday = rtc_read(DS1511_DOM) & 0x3f;
 147         rtc_tm->tm_wday = rtc_read(DS1511_DOW) & 0x7;
 148         rtc_tm->tm_mon = rtc_read(DS1511_MONTH) & 0x1f;
 149         rtc_tm->tm_year = rtc_read(DS1511_YEAR) & 0x7f;
 150         century = rtc_read(DS1511_CENTURY);
 151
 152         rtc_enable_update();
 153         spin_unlock_irqrestore(&ds1511_lock, flags);
 154
 155         rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
 156         rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
 157         rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
 158         rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
 159         rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday);
 160         rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
 161         rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
 162         century = bcd2bin(century) * 100;
 163
 164         /*
 165          * Account for differences between how the RTC uses the values
 166          * and how they are defined in a struct rtc_time;
 167          */
 168         century += rtc_tm->tm_year;
 169         rtc_tm->tm_year = century - 1900;
 170
 171         rtc_tm->tm_mon--;
 172
 173         return 0;
 174 }
 175
 176 static void ds1511_rtc_alarm_enable(unsigned int enabled)
 177 {
 178         rtc_write(rtc_read(DS1511_CONTROL_B) | (enabled ? DS1511_TIE : 0), DS1511_CONTROL_B);
 179 }
 180
 181 static int ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 182 {
 183         struct ds1511_data *ds1511 = dev_get_drvdata(dev);
 184         unsigned long flags;
 185
 186         spin_lock_irqsave(&ds1511->lock, flags);
 187         rtc_write(bin2bcd(alrm->time.tm_mday) & 0x3f, DS1511_AM4_DATE);
 188         rtc_write(bin2bcd(alrm->time.tm_hour) & 0x3f, DS1511_AM3_HOUR);
 189         rtc_write(bin2bcd(alrm->time.tm_min) & 0x7f, DS1511_AM2_MIN);
 190         rtc_write(bin2bcd(alrm->time.tm_sec) & 0x7f, DS1511_AM1_SEC);
 191         ds1511_rtc_alarm_enable(alrm->enabled);
 192
 193         rtc_read(DS1511_CONTROL_A);     /* clear interrupts */
 194         spin_unlock_irqrestore(&ds1511->lock, flags);
 195
 196         return 0;
 197 }
 198
 199 static int ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 200 {
 201         alrm->time.tm_mday = bcd2bin(rtc_read(DS1511_AM4_DATE) & 0x3f);
 202         alrm->time.tm_hour = bcd2bin(rtc_read(DS1511_AM3_HOUR) & 0x3f);
 203         alrm->time.tm_min = bcd2bin(rtc_read(DS1511_AM2_MIN) & 0x7f);
 204         alrm->time.tm_sec = bcd2bin(rtc_read(DS1511_AM1_SEC) & 0x7f);
 205         alrm->enabled = !!(rtc_read(DS1511_CONTROL_B) & DS1511_TIE);
 206
 207         return 0;
 208 }
 209
 210 static irqreturn_t ds1511_interrupt(int irq, void *dev_id)
 211 {
 212         struct platform_device *pdev = dev_id;
 213         struct ds1511_data *ds1511 = platform_get_drvdata(pdev);
 214         unsigned long events = 0;
 215
 216         spin_lock(&ds1511->lock);
 217         /*
 218          * read and clear interrupt
 219          */
 220         if (rtc_read(DS1511_CONTROL_A) & DS1511_IRQF) {
 221                 events = RTC_IRQF | RTC_AF;
 222                 rtc_update_irq(ds1511->rtc, 1, events);
 223         }
 224         spin_unlock(&ds1511->lock);
 225         return events ? IRQ_HANDLED : IRQ_NONE;
 226 }
 227
 228 static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 229 {
 230         struct ds1511_data *ds1511 = dev_get_drvdata(dev);
 231         unsigned long flags;
 232
 233         spin_lock_irqsave(&ds1511->lock, flags);
 234         ds1511_rtc_alarm_enable(enabled);
 235         spin_unlock_irqrestore(&ds1511->lock, flags);
 236
 237         return 0;
 238 }
 239
 240 static const struct rtc_class_ops ds1511_rtc_ops = {
 241         .read_time              = ds1511_rtc_read_time,
 242         .set_time               = ds1511_rtc_set_time,
 243         .read_alarm             = ds1511_rtc_read_alarm,
 244         .set_alarm              = ds1511_rtc_set_alarm,
 245         .alarm_irq_enable       = ds1511_rtc_alarm_irq_enable,
 246 };
 247
 248 static int ds1511_nvram_read(void *priv, unsigned int pos, void *buf,
 249                              size_t size)
 250 {
 251         int i;
 252
 253         rtc_write(pos, DS1511_RAMADDR_LSB);
 254         for (i = 0; i < size; i++)
 255                 *(char *)buf++ = rtc_read(DS1511_RAMDATA);
 256
 257         return 0;
 258 }
 259
 260 static int ds1511_nvram_write(void *priv, unsigned int pos, void *buf,
 261                               size_t size)
 262 {
 263         int i;
 264
 265         rtc_write(pos, DS1511_RAMADDR_LSB);
 266         for (i = 0; i < size; i++)
 267                 rtc_write(*(char *)buf++, DS1511_RAMDATA);
 268
 269         return 0;
 270 }
 271
 272 static int ds1511_rtc_probe(struct platform_device *pdev)
 273 {
 274         struct ds1511_data *ds1511;
 275         int ret = 0;
 276         struct nvmem_config ds1511_nvmem_cfg = {
 277                 .name = "ds1511_nvram",
 278                 .word_size = 1,
 279                 .stride = 1,
 280                 .size = DS1511_RAM_MAX,
 281                 .reg_read = ds1511_nvram_read,
 282                 .reg_write = ds1511_nvram_write,
 283                 .priv = &pdev->dev,
 284         };
 285
 286         ds1511 = devm_kzalloc(&pdev->dev, sizeof(*ds1511), GFP_KERNEL);
 287         if (!ds1511)
 288                 return -ENOMEM;
 289
 290         ds1511_base = devm_platform_ioremap_resource(pdev, 0);
 291         if (IS_ERR(ds1511_base))
 292                 return PTR_ERR(ds1511_base);
 293         ds1511->ioaddr = ds1511_base;
 294         ds1511->irq = platform_get_irq(pdev, 0);
 295
 296         /*
 297          * turn on the clock and the crystal, etc.
 298          */
 299         rtc_write(DS1511_BME, DS1511_CONTROL_B);
 300         rtc_write(0, DS1511_CONTROL_A);
 301         /*
 302          * clear the wdog counter
 303          */
 304         rtc_write(0, DS1511_WD_MSEC);
 305         rtc_write(0, DS1511_WD_SEC);
 306         /*
 307          * start the clock
 308          */
 309         rtc_enable_update();
 310
 311         /*
 312          * check for a dying bat-tree
 313          */
 314         if (rtc_read(DS1511_CONTROL_A) & DS1511_BLF1)
 315                 dev_warn(&pdev->dev, "voltage-low detected.\n");
 316
 317         spin_lock_init(&ds1511->lock);
 318         platform_set_drvdata(pdev, ds1511);
 319
 320         ds1511->rtc = devm_rtc_allocate_device(&pdev->dev);
 321         if (IS_ERR(ds1511->rtc))
 322                 return PTR_ERR(ds1511->rtc);
 323
 324         ds1511->rtc->ops = &ds1511_rtc_ops;
 325         ds1511->rtc->range_max = RTC_TIMESTAMP_END_2099;
 326         ds1511->rtc->alarm_offset_max = 28 * 24 * 60 * 60 - 1;
 327
 328         /*
 329          * if the platform has an interrupt in mind for this device,
 330          * then by all means, set it
 331          */
 332         if (ds1511->irq > 0) {
 333                 rtc_read(DS1511_CONTROL_A);
 334                 if (devm_request_irq(&pdev->dev, ds1511->irq, ds1511_interrupt,
 335                         IRQF_SHARED, pdev->name, pdev) < 0) {
 336
 337                         dev_warn(&pdev->dev, "interrupt not available.\n");
 338                         ds1511->irq = 0;
 339                 }
 340         }
 341
 342         if (ds1511->irq == 0)
 343                 clear_bit(RTC_FEATURE_ALARM, ds1511->rtc->features);
 344
 345         ret = devm_rtc_register_device(ds1511->rtc);
 346         if (ret)
 347                 return ret;
 348
 349         devm_rtc_nvmem_register(ds1511->rtc, &ds1511_nvmem_cfg);
 350
 351         return 0;
 352 }
 353
 354 /* work with hotplug and coldplug */
 355 MODULE_ALIAS("platform:ds1511");
 356
 357 static struct platform_driver ds1511_rtc_driver = {
 358         .probe          = ds1511_rtc_probe,
 359         .driver         = {
 360                 .name   = "ds1511",
 361         },
 362 };
 363
 364 module_platform_driver(ds1511_rtc_driver);
 365
 366 MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>");
 367 MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
 368 MODULE_LICENSE("GPL");