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 platform_device *pdev = to_platform_device(dev);
  51         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
  52
  53         writeb(val, m48t59->ioaddr+ofs);
  54 }
  55
  56 static u8
  57 m48t59_mem_readb(struct device *dev, u32 ofs)
  58 {
  59         struct platform_device *pdev = to_platform_device(dev);
  60         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
  61
  62         return readb(m48t59->ioaddr+ofs);
  63 }
  64
  65 /*
  66  * NOTE: M48T59 only uses BCD mode
  67  */
  68 static int m48t59_rtc_read_time(struct device *dev, struct rtc_time *tm)
  69 {
  70         struct platform_device *pdev = to_platform_device(dev);
  71         struct m48t59_plat_data *pdata = pdev->dev.platform_data;
  72         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
  73         unsigned long flags;
  74         u8 val;
  75
  76         spin_lock_irqsave(&m48t59->lock, flags);
  77         /* Issue the READ command */
  78         M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);
  79
  80         tm->tm_year     = bcd2bin(M48T59_READ(M48T59_YEAR));
  81         /* tm_mon is 0-11 */
  82         tm->tm_mon      = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
  83         tm->tm_mday     = bcd2bin(M48T59_READ(M48T59_MDAY));
  84
  85         val = M48T59_READ(M48T59_WDAY);
  86         if ((pdata->type == M48T59RTC_TYPE_M48T59) &&
  87             (val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB)) {
  88                 dev_dbg(dev, "Century bit is enabled\n");
  89                 tm->tm_year += 100;     /* one century */
  90         }
  91 #ifdef CONFIG_SPARC
  92         /* Sun SPARC machines count years since 1968 */
  93         tm->tm_year += 68;
  94 #endif
  95
  96         tm->tm_wday     = bcd2bin(val & 0x07);
  97         tm->tm_hour     = bcd2bin(M48T59_READ(M48T59_HOUR) & 0x3F);
  98         tm->tm_min      = bcd2bin(M48T59_READ(M48T59_MIN) & 0x7F);
  99         tm->tm_sec      = bcd2bin(M48T59_READ(M48T59_SEC) & 0x7F);
 100
 101         /* Clear the READ bit */
 102         M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL);
 103         spin_unlock_irqrestore(&m48t59->lock, flags);
 104
 105         dev_dbg(dev, "RTC read time %04d-%02d-%02d %02d/%02d/%02d\n",
 106                 tm->tm_year + 1900, tm->tm_mon, tm->tm_mday,
 107                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 108         return rtc_valid_tm(tm);
 109 }
 110
 111 static int m48t59_rtc_set_time(struct device *dev, struct rtc_time *tm)
 112 {
 113         struct platform_device *pdev = to_platform_device(dev);
 114         struct m48t59_plat_data *pdata = pdev->dev.platform_data;
 115         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
 116         unsigned long flags;
 117         u8 val = 0;
 118         int year = tm->tm_year;
 119
 120 #ifdef CONFIG_SPARC
 121         /* Sun SPARC machines count years since 1968 */
 122         year -= 68;
 123 #endif
 124
 125         dev_dbg(dev, "RTC set time %04d-%02d-%02d %02d/%02d/%02d\n",
 126                 year + 1900, tm->tm_mon, tm->tm_mday,
 127                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 128
 129         if (year < 0)
 130                 return -EINVAL;
 131
 132         spin_lock_irqsave(&m48t59->lock, flags);
 133         /* Issue the WRITE command */
 134         M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
 135
 136         M48T59_WRITE((bin2bcd(tm->tm_sec) & 0x7F), M48T59_SEC);
 137         M48T59_WRITE((bin2bcd(tm->tm_min) & 0x7F), M48T59_MIN);
 138         M48T59_WRITE((bin2bcd(tm->tm_hour) & 0x3F), M48T59_HOUR);
 139         M48T59_WRITE((bin2bcd(tm->tm_mday) & 0x3F), M48T59_MDAY);
 140         /* tm_mon is 0-11 */
 141         M48T59_WRITE((bin2bcd(tm->tm_mon + 1) & 0x1F), M48T59_MONTH);
 142         M48T59_WRITE(bin2bcd(year % 100), M48T59_YEAR);
 143
 144         if (pdata->type == M48T59RTC_TYPE_M48T59 && (year / 100))
 145                 val = (M48T59_WDAY_CEB | M48T59_WDAY_CB);
 146         val |= (bin2bcd(tm->tm_wday) & 0x07);
 147         M48T59_WRITE(val, M48T59_WDAY);
 148
 149         /* Clear the WRITE bit */
 150         M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
 151         spin_unlock_irqrestore(&m48t59->lock, flags);
 152         return 0;
 153 }
 154
 155 /*
 156  * Read alarm time and date in RTC
 157  */
 158 static int m48t59_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 159 {
 160         struct platform_device *pdev = to_platform_device(dev);
 161         struct m48t59_plat_data *pdata = pdev->dev.platform_data;
 162         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
 163         struct rtc_time *tm = &alrm->time;
 164         unsigned long flags;
 165         u8 val;
 166
 167         /* If no irq, we don't support ALARM */
 168         if (m48t59->irq == NO_IRQ)
 169                 return -EIO;
 170
 171         spin_lock_irqsave(&m48t59->lock, flags);
 172         /* Issue the READ command */
 173         M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);
 174
 175         tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR));
 176 #ifdef CONFIG_SPARC
 177         /* Sun SPARC machines count years since 1968 */
 178         tm->tm_year += 68;
 179 #endif
 180         /* tm_mon is 0-11 */
 181         tm->tm_mon = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
 182
 183         val = M48T59_READ(M48T59_WDAY);
 184         if ((val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB))
 185                 tm->tm_year += 100;     /* one century */
 186
 187         tm->tm_mday = bcd2bin(M48T59_READ(M48T59_ALARM_DATE));
 188         tm->tm_hour = bcd2bin(M48T59_READ(M48T59_ALARM_HOUR));
 189         tm->tm_min = bcd2bin(M48T59_READ(M48T59_ALARM_MIN));
 190         tm->tm_sec = bcd2bin(M48T59_READ(M48T59_ALARM_SEC));
 191
 192         /* Clear the READ bit */
 193         M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL);
 194         spin_unlock_irqrestore(&m48t59->lock, flags);
 195
 196         dev_dbg(dev, "RTC read alarm time %04d-%02d-%02d %02d/%02d/%02d\n",
 197                 tm->tm_year + 1900, tm->tm_mon, tm->tm_mday,
 198                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 199         return rtc_valid_tm(tm);
 200 }
 201
 202 /*
 203  * Set alarm time and date in RTC
 204  */
 205 static int m48t59_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 206 {
 207         struct platform_device *pdev = to_platform_device(dev);
 208         struct m48t59_plat_data *pdata = pdev->dev.platform_data;
 209         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
 210         struct rtc_time *tm = &alrm->time;
 211         u8 mday, hour, min, sec;
 212         unsigned long flags;
 213         int year = tm->tm_year;
 214
 215 #ifdef CONFIG_SPARC
 216         /* Sun SPARC machines count years since 1968 */
 217         year -= 68;
 218 #endif
 219
 220         /* If no irq, we don't support ALARM */
 221         if (m48t59->irq == NO_IRQ)
 222                 return -EIO;
 223
 224         if (year < 0)
 225                 return -EINVAL;
 226
 227         /*
 228          * 0xff means "always match"
 229          */
 230         mday = tm->tm_mday;
 231         mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 232         if (mday == 0xff)
 233                 mday = M48T59_READ(M48T59_MDAY);
 234
 235         hour = tm->tm_hour;
 236         hour = (hour < 24) ? bin2bcd(hour) : 0x00;
 237
 238         min = tm->tm_min;
 239         min = (min < 60) ? bin2bcd(min) : 0x00;
 240
 241         sec = tm->tm_sec;
 242         sec = (sec < 60) ? bin2bcd(sec) : 0x00;
 243
 244         spin_lock_irqsave(&m48t59->lock, flags);
 245         /* Issue the WRITE command */
 246         M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
 247
 248         M48T59_WRITE(mday, M48T59_ALARM_DATE);
 249         M48T59_WRITE(hour, M48T59_ALARM_HOUR);
 250         M48T59_WRITE(min, M48T59_ALARM_MIN);
 251         M48T59_WRITE(sec, M48T59_ALARM_SEC);
 252
 253         /* Clear the WRITE bit */
 254         M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
 255         spin_unlock_irqrestore(&m48t59->lock, flags);
 256
 257         dev_dbg(dev, "RTC set alarm time %04d-%02d-%02d %02d/%02d/%02d\n",
 258                 year + 1900, tm->tm_mon, tm->tm_mday,
 259                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 260         return 0;
 261 }
 262
 263 /*
 264  * Handle commands from user-space
 265  */
 266 static int m48t59_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 267 {
 268         struct platform_device *pdev = to_platform_device(dev);
 269         struct m48t59_plat_data *pdata = pdev->dev.platform_data;
 270         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
 271         unsigned long flags;
 272
 273         spin_lock_irqsave(&m48t59->lock, flags);
 274         if (enabled)
 275                 M48T59_WRITE(M48T59_INTR_AFE, M48T59_INTR);
 276         else
 277                 M48T59_WRITE(0x00, M48T59_INTR);
 278         spin_unlock_irqrestore(&m48t59->lock, flags);
 279
 280         return 0;
 281 }
 282
 283 static int m48t59_rtc_proc(struct device *dev, struct seq_file *seq)
 284 {
 285         struct platform_device *pdev = to_platform_device(dev);
 286         struct m48t59_plat_data *pdata = pdev->dev.platform_data;
 287         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
 288         unsigned long flags;
 289         u8 val;
 290
 291         spin_lock_irqsave(&m48t59->lock, flags);
 292         val = M48T59_READ(M48T59_FLAGS);
 293         spin_unlock_irqrestore(&m48t59->lock, flags);
 294
 295         seq_printf(seq, "battery\t\t: %s\n",
 296                  (val & M48T59_FLAGS_BF) ? "low" : "normal");
 297         return 0;
 298 }
 299
 300 /*
 301  * IRQ handler for the RTC
 302  */
 303 static irqreturn_t m48t59_rtc_interrupt(int irq, void *dev_id)
 304 {
 305         struct device *dev = (struct device *)dev_id;
 306         struct platform_device *pdev = to_platform_device(dev);
 307         struct m48t59_plat_data *pdata = pdev->dev.platform_data;
 308         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
 309         u8 event;
 310
 311         spin_lock(&m48t59->lock);
 312         event = M48T59_READ(M48T59_FLAGS);
 313         spin_unlock(&m48t59->lock);
 314
 315         if (event & M48T59_FLAGS_AF) {
 316                 rtc_update_irq(m48t59->rtc, 1, (RTC_AF | RTC_IRQF));
 317                 return IRQ_HANDLED;
 318         }
 319
 320         return IRQ_NONE;
 321 }
 322
 323 static const struct rtc_class_ops m48t59_rtc_ops = {
 324         .read_time      = m48t59_rtc_read_time,
 325         .set_time       = m48t59_rtc_set_time,
 326         .read_alarm     = m48t59_rtc_readalarm,
 327         .set_alarm      = m48t59_rtc_setalarm,
 328         .proc           = m48t59_rtc_proc,
 329         .alarm_irq_enable = m48t59_rtc_alarm_irq_enable,
 330 };
 331
 332 static const struct rtc_class_ops m48t02_rtc_ops = {
 333         .read_time      = m48t59_rtc_read_time,
 334         .set_time       = m48t59_rtc_set_time,
 335 };
 336
 337 static ssize_t m48t59_nvram_read(struct file *filp, struct kobject *kobj,
 338                                 struct bin_attribute *bin_attr,
 339                                 char *buf, loff_t pos, size_t size)
 340 {
 341         struct device *dev = container_of(kobj, struct device, kobj);
 342         struct platform_device *pdev = to_platform_device(dev);
 343         struct m48t59_plat_data *pdata = pdev->dev.platform_data;
 344         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
 345         ssize_t cnt = 0;
 346         unsigned long flags;
 347
 348         for (; size > 0 && pos < pdata->offset; cnt++, size--) {
 349                 spin_lock_irqsave(&m48t59->lock, flags);
 350                 *buf++ = M48T59_READ(cnt);
 351                 spin_unlock_irqrestore(&m48t59->lock, flags);
 352         }
 353
 354         return cnt;
 355 }
 356
 357 static ssize_t m48t59_nvram_write(struct file *filp, struct kobject *kobj,
 358                                 struct bin_attribute *bin_attr,
 359                                 char *buf, loff_t pos, size_t size)
 360 {
 361         struct device *dev = container_of(kobj, struct device, kobj);
 362         struct platform_device *pdev = to_platform_device(dev);
 363         struct m48t59_plat_data *pdata = pdev->dev.platform_data;
 364         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
 365         ssize_t cnt = 0;
 366         unsigned long flags;
 367
 368         for (; size > 0 && pos < pdata->offset; cnt++, size--) {
 369                 spin_lock_irqsave(&m48t59->lock, flags);
 370                 M48T59_WRITE(*buf++, cnt);
 371                 spin_unlock_irqrestore(&m48t59->lock, flags);
 372         }
 373
 374         return cnt;
 375 }
 376
 377 static struct bin_attribute m48t59_nvram_attr = {
 378         .attr = {
 379                 .name = "nvram",
 380                 .mode = S_IRUGO | S_IWUSR,
 381         },
 382         .read = m48t59_nvram_read,
 383         .write = m48t59_nvram_write,
 384 };
 385
 386 static int m48t59_rtc_probe(struct platform_device *pdev)
 387 {
 388         struct m48t59_plat_data *pdata = pdev->dev.platform_data;
 389         struct m48t59_private *m48t59 = NULL;
 390         struct resource *res;
 391         int ret = -ENOMEM;
 392         char *name;
 393         const struct rtc_class_ops *ops;
 394
 395         /* This chip could be memory-mapped or I/O-mapped */
 396         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 397         if (!res) {
 398                 res = platform_get_resource(pdev, IORESOURCE_IO, 0);
 399                 if (!res)
 400                         return -EINVAL;
 401         }
 402
 403         if (res->flags & IORESOURCE_IO) {
 404                 /* If we are I/O-mapped, the platform should provide
 405                  * the operations accessing chip registers.
 406                  */
 407                 if (!pdata || !pdata->write_byte || !pdata->read_byte)
 408                         return -EINVAL;
 409         } else if (res->flags & IORESOURCE_MEM) {
 410                 /* we are memory-mapped */
 411                 if (!pdata) {
 412                         pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
 413                         if (!pdata)
 414                                 return -ENOMEM;
 415                         /* Ensure we only kmalloc platform data once */
 416                         pdev->dev.platform_data = pdata;
 417                 }
 418                 if (!pdata->type)
 419                         pdata->type = M48T59RTC_TYPE_M48T59;
 420
 421                 /* Try to use the generic memory read/write ops */
 422                 if (!pdata->write_byte)
 423                         pdata->write_byte = m48t59_mem_writeb;
 424                 if (!pdata->read_byte)
 425                         pdata->read_byte = m48t59_mem_readb;
 426         }
 427
 428         m48t59 = kzalloc(sizeof(*m48t59), GFP_KERNEL);
 429         if (!m48t59)
 430                 return -ENOMEM;
 431
 432         m48t59->ioaddr = pdata->ioaddr;
 433
 434         if (!m48t59->ioaddr) {
 435                 /* ioaddr not mapped externally */
 436                 m48t59->ioaddr = ioremap(res->start, resource_size(res));
 437                 if (!m48t59->ioaddr)
 438                         goto out;
 439         }
 440
 441         /* Try to get irq number. We also can work in
 442          * the mode without IRQ.
 443          */
 444         m48t59->irq = platform_get_irq(pdev, 0);
 445         if (m48t59->irq <= 0)
 446                 m48t59->irq = NO_IRQ;
 447
 448         if (m48t59->irq != NO_IRQ) {
 449                 ret = request_irq(m48t59->irq, m48t59_rtc_interrupt,
 450                         IRQF_SHARED, "rtc-m48t59", &pdev->dev);
 451                 if (ret)
 452                         goto out;
 453         }
 454         switch (pdata->type) {
 455         case M48T59RTC_TYPE_M48T59:
 456                 name = "m48t59";
 457                 ops = &m48t59_rtc_ops;
 458                 pdata->offset = 0x1ff0;
 459                 break;
 460         case M48T59RTC_TYPE_M48T02:
 461                 name = "m48t02";
 462                 ops = &m48t02_rtc_ops;
 463                 pdata->offset = 0x7f0;
 464                 break;
 465         case M48T59RTC_TYPE_M48T08:
 466                 name = "m48t08";
 467                 ops = &m48t02_rtc_ops;
 468                 pdata->offset = 0x1ff0;
 469                 break;
 470         default:
 471                 dev_err(&pdev->dev, "Unknown RTC type\n");
 472                 ret = -ENODEV;
 473                 goto out;
 474         }
 475
 476         spin_lock_init(&m48t59->lock);
 477         platform_set_drvdata(pdev, m48t59);
 478
 479         m48t59->rtc = rtc_device_register(name, &pdev->dev, ops, THIS_MODULE);
 480         if (IS_ERR(m48t59->rtc)) {
 481                 ret = PTR_ERR(m48t59->rtc);
 482                 goto out;
 483         }
 484
 485         m48t59_nvram_attr.size = pdata->offset;
 486
 487         ret = sysfs_create_bin_file(&pdev->dev.kobj, &m48t59_nvram_attr);
 488         if (ret) {
 489                 rtc_device_unregister(m48t59->rtc);
 490                 goto out;
 491         }
 492
 493         return 0;
 494
 495 out:
 496         if (m48t59->irq != NO_IRQ)
 497                 free_irq(m48t59->irq, &pdev->dev);
 498         if (m48t59->ioaddr)
 499                 iounmap(m48t59->ioaddr);
 500                 kfree(m48t59);
 501         return ret;
 502 }
 503
 504 static int m48t59_rtc_remove(struct platform_device *pdev)
 505 {
 506         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
 507         struct m48t59_plat_data *pdata = pdev->dev.platform_data;
 508
 509         sysfs_remove_bin_file(&pdev->dev.kobj, &m48t59_nvram_attr);
 510         if (!IS_ERR(m48t59->rtc))
 511                 rtc_device_unregister(m48t59->rtc);
 512         if (m48t59->ioaddr && !pdata->ioaddr)
 513                 iounmap(m48t59->ioaddr);
 514         if (m48t59->irq != NO_IRQ)
 515                 free_irq(m48t59->irq, &pdev->dev);
 516         platform_set_drvdata(pdev, NULL);
 517         kfree(m48t59);
 518         return 0;
 519 }
 520
 521 /* work with hotplug and coldplug */
 522 MODULE_ALIAS("platform:rtc-m48t59");
 523
 524 static struct platform_driver m48t59_rtc_driver = {
 525         .driver         = {
 526                 .name   = "rtc-m48t59",
 527                 .owner  = THIS_MODULE,
 528         },
 529         .probe          = m48t59_rtc_probe,
 530         .remove         = m48t59_rtc_remove,
 531 };
 532
 533 module_platform_driver(m48t59_rtc_driver);
 534
 535 MODULE_AUTHOR("Mark Zhan <rongkai.zhan@windriver.com>");
 536 MODULE_DESCRIPTION("M48T59/M48T02/M48T08 RTC driver");
 537 MODULE_LICENSE("GPL");