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