drivers/rtc/rtc-m48t59.c

   1 /*
   2  * ST M48T59 RTC driver
   3  *
   4  * Copyright (c) 2007 Wind River Systems, Inc.
   5  *
   6  * Author: Mark Zhan <rongkai.zhan@windriver.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/io.h>
  17 #include <linux/device.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/rtc.h>
  20 #include <linux/rtc/m48t59.h>
  21 #include <linux/bcd.h>
  22 #include <linux/slab.h>
  23
  24 #ifndef NO_IRQ
  25 #define NO_IRQ  (-1)
  26 #endif
  27
  28 #define M48T59_READ(reg) (pdata->read_byte(dev, pdata->offset + reg))
  29 #define M48T59_WRITE(val, reg) \
  30         (pdata->write_byte(dev, pdata->offset + reg, val))
  31
  32 #define M48T59_SET_BITS(mask, reg)      \
  33         M48T59_WRITE((M48T59_READ(reg) | (mask)), (reg))
  34 #define M48T59_CLEAR_BITS(mask, reg)    \
  35         M48T59_WRITE((M48T59_READ(reg) & ~(mask)), (reg))
  36
  37 struct m48t59_private {
  38         void __iomem *ioaddr;
  39         int irq;
  40         struct rtc_device *rtc;
  41         spinlock_t lock; /* serialize the NVRAM and RTC access */
  42 };
  43
  44 /*
  45  * This is the generic access method when the chip is memory-mapped
  46  */
  47 static void
  48 m48t59_mem_writeb(struct device *dev, u32 ofs, u8 val)
  49 {
  50         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
  51
  52         writeb(val, m48t59->ioaddr+ofs);
  53 }
  54
  55 static u8
  56 m48t59_mem_readb(struct device *dev, u32 ofs)
  57 {
  58         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
  59
  60         return readb(m48t59->ioaddr+ofs);
  61 }
  62
  63 /*
  64  * NOTE: M48T59 only uses BCD mode
  65  */
  66 static int m48t59_rtc_read_time(struct device *dev, struct rtc_time *tm)
  67 {
  68         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
  69         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
  70         unsigned long flags;
  71         u8 val;
  72
  73         spin_lock_irqsave(&m48t59->lock, flags);
  74         /* Issue the READ command */
  75         M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);
  76
  77         tm->tm_year     = bcd2bin(M48T59_READ(M48T59_YEAR));
  78         /* tm_mon is 0-11 */
  79         tm->tm_mon      = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
  80         tm->tm_mday     = bcd2bin(M48T59_READ(M48T59_MDAY));
  81
  82         val = M48T59_READ(M48T59_WDAY);
  83         if ((pdata->type == M48T59RTC_TYPE_M48T59) &&
  84             (val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB)) {
  85                 dev_dbg(dev, "Century bit is enabled\n");
  86                 tm->tm_year += 100;     /* one century */
  87         }
  88 #ifdef CONFIG_SPARC
  89         /* Sun SPARC machines count years since 1968 */
  90         tm->tm_year += 68;
  91 #endif
  92
  93         tm->tm_wday     = bcd2bin(val & 0x07);
  94         tm->tm_hour     = bcd2bin(M48T59_READ(M48T59_HOUR) & 0x3F);
  95         tm->tm_min      = bcd2bin(M48T59_READ(M48T59_MIN) & 0x7F);
  96         tm->tm_sec      = bcd2bin(M48T59_READ(M48T59_SEC) & 0x7F);
  97
  98         /* Clear the READ bit */
  99         M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL);
 100         spin_unlock_irqrestore(&m48t59->lock, flags);
 101
 102         dev_dbg(dev, "RTC read time %04d-%02d-%02d %02d/%02d/%02d\n",
 103                 tm->tm_year + 1900, tm->tm_mon, tm->tm_mday,
 104                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 105         return 0;
 106 }
 107
 108 static int m48t59_rtc_set_time(struct device *dev, struct rtc_time *tm)
 109 {
 110         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 111         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 112         unsigned long flags;
 113         u8 val = 0;
 114         int year = tm->tm_year;
 115
 116 #ifdef CONFIG_SPARC
 117         /* Sun SPARC machines count years since 1968 */
 118         year -= 68;
 119 #endif
 120
 121         dev_dbg(dev, "RTC set time %04d-%02d-%02d %02d/%02d/%02d\n",
 122                 year + 1900, tm->tm_mon, tm->tm_mday,
 123                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 124
 125         if (year < 0)
 126                 return -EINVAL;
 127
 128         spin_lock_irqsave(&m48t59->lock, flags);
 129         /* Issue the WRITE command */
 130         M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
 131
 132         M48T59_WRITE((bin2bcd(tm->tm_sec) & 0x7F), M48T59_SEC);
 133         M48T59_WRITE((bin2bcd(tm->tm_min) & 0x7F), M48T59_MIN);
 134         M48T59_WRITE((bin2bcd(tm->tm_hour) & 0x3F), M48T59_HOUR);
 135         M48T59_WRITE((bin2bcd(tm->tm_mday) & 0x3F), M48T59_MDAY);
 136         /* tm_mon is 0-11 */
 137         M48T59_WRITE((bin2bcd(tm->tm_mon + 1) & 0x1F), M48T59_MONTH);
 138         M48T59_WRITE(bin2bcd(year % 100), M48T59_YEAR);
 139
 140         if (pdata->type == M48T59RTC_TYPE_M48T59 && (year / 100))
 141                 val = (M48T59_WDAY_CEB | M48T59_WDAY_CB);
 142         val |= (bin2bcd(tm->tm_wday) & 0x07);
 143         M48T59_WRITE(val, M48T59_WDAY);
 144
 145         /* Clear the WRITE bit */
 146         M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
 147         spin_unlock_irqrestore(&m48t59->lock, flags);
 148         return 0;
 149 }
 150
 151 /*
 152  * Read alarm time and date in RTC
 153  */
 154 static int m48t59_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 155 {
 156         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 157         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 158         struct rtc_time *tm = &alrm->time;
 159         unsigned long flags;
 160         u8 val;
 161
 162         /* If no irq, we don't support ALARM */
 163         if (m48t59->irq == NO_IRQ)
 164                 return -EIO;
 165
 166         spin_lock_irqsave(&m48t59->lock, flags);
 167         /* Issue the READ command */
 168         M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);
 169
 170         tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR));
 171 #ifdef CONFIG_SPARC
 172         /* Sun SPARC machines count years since 1968 */
 173         tm->tm_year += 68;
 174 #endif
 175         /* tm_mon is 0-11 */
 176         tm->tm_mon = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
 177
 178         val = M48T59_READ(M48T59_WDAY);
 179         if ((val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB))
 180                 tm->tm_year += 100;     /* one century */
 181
 182         tm->tm_mday = bcd2bin(M48T59_READ(M48T59_ALARM_DATE));
 183         tm->tm_hour = bcd2bin(M48T59_READ(M48T59_ALARM_HOUR));
 184         tm->tm_min = bcd2bin(M48T59_READ(M48T59_ALARM_MIN));
 185         tm->tm_sec = bcd2bin(M48T59_READ(M48T59_ALARM_SEC));
 186
 187         /* Clear the READ bit */
 188         M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL);
 189         spin_unlock_irqrestore(&m48t59->lock, flags);
 190
 191         dev_dbg(dev, "RTC read alarm time %04d-%02d-%02d %02d/%02d/%02d\n",
 192                 tm->tm_year + 1900, tm->tm_mon, tm->tm_mday,
 193                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 194         return rtc_valid_tm(tm);
 195 }
 196
 197 /*
 198  * Set alarm time and date in RTC
 199  */
 200 static int m48t59_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 201 {
 202         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 203         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 204         struct rtc_time *tm = &alrm->time;
 205         u8 mday, hour, min, sec;
 206         unsigned long flags;
 207         int year = tm->tm_year;
 208
 209 #ifdef CONFIG_SPARC
 210         /* Sun SPARC machines count years since 1968 */
 211         year -= 68;
 212 #endif
 213
 214         /* If no irq, we don't support ALARM */
 215         if (m48t59->irq == NO_IRQ)
 216                 return -EIO;
 217
 218         if (year < 0)
 219                 return -EINVAL;
 220
 221         /*
 222          * 0xff means "always match"
 223          */
 224         mday = tm->tm_mday;
 225         mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 226         if (mday == 0xff)
 227                 mday = M48T59_READ(M48T59_MDAY);
 228
 229         hour = tm->tm_hour;
 230         hour = (hour < 24) ? bin2bcd(hour) : 0x00;
 231
 232         min = tm->tm_min;
 233         min = (min < 60) ? bin2bcd(min) : 0x00;
 234
 235         sec = tm->tm_sec;
 236         sec = (sec < 60) ? bin2bcd(sec) : 0x00;
 237
 238         spin_lock_irqsave(&m48t59->lock, flags);
 239         /* Issue the WRITE command */
 240         M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
 241
 242         M48T59_WRITE(mday, M48T59_ALARM_DATE);
 243         M48T59_WRITE(hour, M48T59_ALARM_HOUR);
 244         M48T59_WRITE(min, M48T59_ALARM_MIN);
 245         M48T59_WRITE(sec, M48T59_ALARM_SEC);
 246
 247         /* Clear the WRITE bit */
 248         M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
 249         spin_unlock_irqrestore(&m48t59->lock, flags);
 250
 251         dev_dbg(dev, "RTC set alarm time %04d-%02d-%02d %02d/%02d/%02d\n",
 252                 year + 1900, tm->tm_mon, tm->tm_mday,
 253                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 254         return 0;
 255 }
 256
 257 /*
 258  * Handle commands from user-space
 259  */
 260 static int m48t59_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 261 {
 262         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 263         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 264         unsigned long flags;
 265
 266         spin_lock_irqsave(&m48t59->lock, flags);
 267         if (enabled)
 268                 M48T59_WRITE(M48T59_INTR_AFE, M48T59_INTR);
 269         else
 270                 M48T59_WRITE(0x00, M48T59_INTR);
 271         spin_unlock_irqrestore(&m48t59->lock, flags);
 272
 273         return 0;
 274 }
 275
 276 static int m48t59_rtc_proc(struct device *dev, struct seq_file *seq)
 277 {
 278         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 279         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 280         unsigned long flags;
 281         u8 val;
 282
 283         spin_lock_irqsave(&m48t59->lock, flags);
 284         val = M48T59_READ(M48T59_FLAGS);
 285         spin_unlock_irqrestore(&m48t59->lock, flags);
 286
 287         seq_printf(seq, "battery\t\t: %s\n",
 288                  (val & M48T59_FLAGS_BF) ? "low" : "normal");
 289         return 0;
 290 }
 291
 292 /*
 293  * IRQ handler for the RTC
 294  */
 295 static irqreturn_t m48t59_rtc_interrupt(int irq, void *dev_id)
 296 {
 297         struct device *dev = (struct device *)dev_id;
 298         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 299         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 300         u8 event;
 301
 302         spin_lock(&m48t59->lock);
 303         event = M48T59_READ(M48T59_FLAGS);
 304         spin_unlock(&m48t59->lock);
 305
 306         if (event & M48T59_FLAGS_AF) {
 307                 rtc_update_irq(m48t59->rtc, 1, (RTC_AF | RTC_IRQF));
 308                 return IRQ_HANDLED;
 309         }
 310
 311         return IRQ_NONE;
 312 }
 313
 314 static const struct rtc_class_ops m48t59_rtc_ops = {
 315         .read_time      = m48t59_rtc_read_time,
 316         .set_time       = m48t59_rtc_set_time,
 317         .read_alarm     = m48t59_rtc_readalarm,
 318         .set_alarm      = m48t59_rtc_setalarm,
 319         .proc           = m48t59_rtc_proc,
 320         .alarm_irq_enable = m48t59_rtc_alarm_irq_enable,
 321 };
 322
 323 static const struct rtc_class_ops m48t02_rtc_ops = {
 324         .read_time      = m48t59_rtc_read_time,
 325         .set_time       = m48t59_rtc_set_time,
 326 };
 327
 328 static int m48t59_nvram_read(void *priv, unsigned int offset, void *val,
 329                              size_t size)
 330 {
 331         struct platform_device *pdev = priv;
 332         struct device *dev = &pdev->dev;
 333         struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
 334         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
 335         ssize_t cnt = 0;
 336         unsigned long flags;
 337         u8 *buf = val;
 338
 339         spin_lock_irqsave(&m48t59->lock, flags);
 340
 341         for (; cnt < size; cnt++)
 342                 *buf++ = M48T59_READ(cnt);
 343
 344         spin_unlock_irqrestore(&m48t59->lock, flags);
 345
 346         return 0;
 347 }
 348
 349 static int m48t59_nvram_write(void *priv, unsigned int offset, void *val,
 350                               size_t size)
 351 {
 352         struct platform_device *pdev = priv;
 353         struct device *dev = &pdev->dev;
 354         struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
 355         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
 356         ssize_t cnt = 0;
 357         unsigned long flags;
 358         u8 *buf = val;
 359
 360         spin_lock_irqsave(&m48t59->lock, flags);
 361
 362         for (; cnt < size; cnt++)
 363                 M48T59_WRITE(*buf++, cnt);
 364
 365         spin_unlock_irqrestore(&m48t59->lock, flags);
 366
 367         return 0;
 368 }
 369
 370 static int m48t59_rtc_probe(struct platform_device *pdev)
 371 {
 372         struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
 373         struct m48t59_private *m48t59 = NULL;
 374         struct resource *res;
 375         int ret = -ENOMEM;
 376         const struct rtc_class_ops *ops;
 377         struct nvmem_config nvmem_cfg = {
 378                 .name = "m48t59-",
 379                 .word_size = 1,
 380                 .stride = 1,
 381                 .reg_read = m48t59_nvram_read,
 382                 .reg_write = m48t59_nvram_write,
 383                 .priv = pdev,
 384         };
 385
 386         /* This chip could be memory-mapped or I/O-mapped */
 387         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 388         if (!res) {
 389                 res = platform_get_resource(pdev, IORESOURCE_IO, 0);
 390                 if (!res)
 391                         return -EINVAL;
 392         }
 393
 394         if (res->flags & IORESOURCE_IO) {
 395                 /* If we are I/O-mapped, the platform should provide
 396                  * the operations accessing chip registers.
 397                  */
 398                 if (!pdata || !pdata->write_byte || !pdata->read_byte)
 399                         return -EINVAL;
 400         } else if (res->flags & IORESOURCE_MEM) {
 401                 /* we are memory-mapped */
 402                 if (!pdata) {
 403                         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata),
 404                                                 GFP_KERNEL);
 405                         if (!pdata)
 406                                 return -ENOMEM;
 407                         /* Ensure we only kmalloc platform data once */
 408                         pdev->dev.platform_data = pdata;
 409                 }
 410                 if (!pdata->type)
 411                         pdata->type = M48T59RTC_TYPE_M48T59;
 412
 413                 /* Try to use the generic memory read/write ops */
 414                 if (!pdata->write_byte)
 415                         pdata->write_byte = m48t59_mem_writeb;
 416                 if (!pdata->read_byte)
 417                         pdata->read_byte = m48t59_mem_readb;
 418         }
 419
 420         m48t59 = devm_kzalloc(&pdev->dev, sizeof(*m48t59), GFP_KERNEL);
 421         if (!m48t59)
 422                 return -ENOMEM;
 423
 424         m48t59->ioaddr = pdata->ioaddr;
 425
 426         if (!m48t59->ioaddr) {
 427                 /* ioaddr not mapped externally */
 428                 m48t59->ioaddr = devm_ioremap(&pdev->dev, res->start,
 429                                                 resource_size(res));
 430                 if (!m48t59->ioaddr)
 431                         return ret;
 432         }
 433
 434         /* Try to get irq number. We also can work in
 435          * the mode without IRQ.
 436          */
 437         m48t59->irq = platform_get_irq(pdev, 0);
 438         if (m48t59->irq <= 0)
 439                 m48t59->irq = NO_IRQ;
 440
 441         if (m48t59->irq != NO_IRQ) {
 442                 ret = devm_request_irq(&pdev->dev, m48t59->irq,
 443                                 m48t59_rtc_interrupt, IRQF_SHARED,
 444                                 "rtc-m48t59", &pdev->dev);
 445                 if (ret)
 446                         return ret;
 447         }
 448         switch (pdata->type) {
 449         case M48T59RTC_TYPE_M48T59:
 450                 ops = &m48t59_rtc_ops;
 451                 pdata->offset = 0x1ff0;
 452                 break;
 453         case M48T59RTC_TYPE_M48T02:
 454                 ops = &m48t02_rtc_ops;
 455                 pdata->offset = 0x7f0;
 456                 break;
 457         case M48T59RTC_TYPE_M48T08:
 458                 ops = &m48t02_rtc_ops;
 459                 pdata->offset = 0x1ff0;
 460                 break;
 461         default:
 462                 dev_err(&pdev->dev, "Unknown RTC type\n");
 463                 return -ENODEV;
 464         }
 465
 466         spin_lock_init(&m48t59->lock);
 467         platform_set_drvdata(pdev, m48t59);
 468
 469         m48t59->rtc = devm_rtc_allocate_device(&pdev->dev);
 470         if (IS_ERR(m48t59->rtc))
 471                 return PTR_ERR(m48t59->rtc);
 472
 473         m48t59->rtc->nvram_old_abi = true;
 474         m48t59->rtc->ops = ops;
 475
 476         nvmem_cfg.size = pdata->offset;
 477         ret = rtc_nvmem_register(m48t59->rtc, &nvmem_cfg);
 478         if (ret)
 479                 return ret;
 480
 481         ret = rtc_register_device(m48t59->rtc);
 482         if (ret)
 483                 return ret;
 484
 485         return 0;
 486 }
 487
 488 /* work with hotplug and coldplug */
 489 MODULE_ALIAS("platform:rtc-m48t59");
 490
 491 static struct platform_driver m48t59_rtc_driver = {
 492         .driver         = {
 493                 .name   = "rtc-m48t59",
 494         },
 495         .probe          = m48t59_rtc_probe,
 496 };
 497
 498 module_platform_driver(m48t59_rtc_driver);
 499
 500 MODULE_AUTHOR("Mark Zhan <rongkai.zhan@windriver.com>");
 501 MODULE_DESCRIPTION("M48T59/M48T02/M48T08 RTC driver");
 502 MODULE_LICENSE("GPL");