drivers/rtc/rtc-m48t59.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * ST M48T59 RTC driver
   4  *
   5  * Copyright (c) 2007 Wind River Systems, Inc.
   6  *
   7  * Author: Mark Zhan <rongkai.zhan@windriver.com>
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/init.h>
  13 #include <linux/io.h>
  14 #include <linux/device.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/rtc.h>
  17 #include <linux/rtc/m48t59.h>
  18 #include <linux/bcd.h>
  19 #include <linux/slab.h>
  20
  21 #ifndef NO_IRQ
  22 #define NO_IRQ  (-1)
  23 #endif
  24
  25 #define M48T59_READ(reg) (pdata->read_byte(dev, pdata->offset + reg))
  26 #define M48T59_WRITE(val, reg) \
  27         (pdata->write_byte(dev, pdata->offset + reg, val))
  28
  29 #define M48T59_SET_BITS(mask, reg)      \
  30         M48T59_WRITE((M48T59_READ(reg) | (mask)), (reg))
  31 #define M48T59_CLEAR_BITS(mask, reg)    \
  32         M48T59_WRITE((M48T59_READ(reg) & ~(mask)), (reg))
  33
  34 struct m48t59_private {
  35         void __iomem *ioaddr;
  36         int irq;
  37         struct rtc_device *rtc;
  38         spinlock_t lock; /* serialize the NVRAM and RTC access */
  39 };
  40
  41 /*
  42  * This is the generic access method when the chip is memory-mapped
  43  */
  44 static void
  45 m48t59_mem_writeb(struct device *dev, u32 ofs, u8 val)
  46 {
  47         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
  48
  49         writeb(val, m48t59->ioaddr+ofs);
  50 }
  51
  52 static u8
  53 m48t59_mem_readb(struct device *dev, u32 ofs)
  54 {
  55         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
  56
  57         return readb(m48t59->ioaddr+ofs);
  58 }
  59
  60 /*
  61  * NOTE: M48T59 only uses BCD mode
  62  */
  63 static int m48t59_rtc_read_time(struct device *dev, struct rtc_time *tm)
  64 {
  65         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
  66         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
  67         unsigned long flags;
  68         u8 val;
  69
  70         spin_lock_irqsave(&m48t59->lock, flags);
  71         /* Issue the READ command */
  72         M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);
  73
  74         tm->tm_year     = bcd2bin(M48T59_READ(M48T59_YEAR));
  75         /* tm_mon is 0-11 */
  76         tm->tm_mon      = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
  77         tm->tm_mday     = bcd2bin(M48T59_READ(M48T59_MDAY));
  78
  79         val = M48T59_READ(M48T59_WDAY);
  80         if ((pdata->type == M48T59RTC_TYPE_M48T59) &&
  81             (val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB)) {
  82                 dev_dbg(dev, "Century bit is enabled\n");
  83                 tm->tm_year += 100;     /* one century */
  84         }
  85 #ifdef CONFIG_SPARC
  86         /* Sun SPARC machines count years since 1968 */
  87         tm->tm_year += 68;
  88 #endif
  89
  90         tm->tm_wday     = bcd2bin(val & 0x07);
  91         tm->tm_hour     = bcd2bin(M48T59_READ(M48T59_HOUR) & 0x3F);
  92         tm->tm_min      = bcd2bin(M48T59_READ(M48T59_MIN) & 0x7F);
  93         tm->tm_sec      = bcd2bin(M48T59_READ(M48T59_SEC) & 0x7F);
  94
  95         /* Clear the READ bit */
  96         M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL);
  97         spin_unlock_irqrestore(&m48t59->lock, flags);
  98
  99         dev_dbg(dev, "RTC read time %ptR\n", tm);
 100         return 0;
 101 }
 102
 103 static int m48t59_rtc_set_time(struct device *dev, struct rtc_time *tm)
 104 {
 105         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 106         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 107         unsigned long flags;
 108         u8 val = 0;
 109         int year = tm->tm_year;
 110
 111 #ifdef CONFIG_SPARC
 112         /* Sun SPARC machines count years since 1968 */
 113         year -= 68;
 114 #endif
 115
 116         dev_dbg(dev, "RTC set time %04d-%02d-%02d %02d/%02d/%02d\n",
 117                 year + 1900, tm->tm_mon, tm->tm_mday,
 118                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 119
 120         if (year < 0)
 121                 return -EINVAL;
 122
 123         spin_lock_irqsave(&m48t59->lock, flags);
 124         /* Issue the WRITE command */
 125         M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
 126
 127         M48T59_WRITE((bin2bcd(tm->tm_sec) & 0x7F), M48T59_SEC);
 128         M48T59_WRITE((bin2bcd(tm->tm_min) & 0x7F), M48T59_MIN);
 129         M48T59_WRITE((bin2bcd(tm->tm_hour) & 0x3F), M48T59_HOUR);
 130         M48T59_WRITE((bin2bcd(tm->tm_mday) & 0x3F), M48T59_MDAY);
 131         /* tm_mon is 0-11 */
 132         M48T59_WRITE((bin2bcd(tm->tm_mon + 1) & 0x1F), M48T59_MONTH);
 133         M48T59_WRITE(bin2bcd(year % 100), M48T59_YEAR);
 134
 135         if (pdata->type == M48T59RTC_TYPE_M48T59 && (year / 100))
 136                 val = (M48T59_WDAY_CEB | M48T59_WDAY_CB);
 137         val |= (bin2bcd(tm->tm_wday) & 0x07);
 138         M48T59_WRITE(val, M48T59_WDAY);
 139
 140         /* Clear the WRITE bit */
 141         M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
 142         spin_unlock_irqrestore(&m48t59->lock, flags);
 143         return 0;
 144 }
 145
 146 /*
 147  * Read alarm time and date in RTC
 148  */
 149 static int m48t59_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 150 {
 151         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 152         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 153         struct rtc_time *tm = &alrm->time;
 154         unsigned long flags;
 155         u8 val;
 156
 157         /* If no irq, we don't support ALARM */
 158         if (m48t59->irq == NO_IRQ)
 159                 return -EIO;
 160
 161         spin_lock_irqsave(&m48t59->lock, flags);
 162         /* Issue the READ command */
 163         M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);
 164
 165         tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR));
 166 #ifdef CONFIG_SPARC
 167         /* Sun SPARC machines count years since 1968 */
 168         tm->tm_year += 68;
 169 #endif
 170         /* tm_mon is 0-11 */
 171         tm->tm_mon = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
 172
 173         val = M48T59_READ(M48T59_WDAY);
 174         if ((val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB))
 175                 tm->tm_year += 100;     /* one century */
 176
 177         tm->tm_mday = bcd2bin(M48T59_READ(M48T59_ALARM_DATE));
 178         tm->tm_hour = bcd2bin(M48T59_READ(M48T59_ALARM_HOUR));
 179         tm->tm_min = bcd2bin(M48T59_READ(M48T59_ALARM_MIN));
 180         tm->tm_sec = bcd2bin(M48T59_READ(M48T59_ALARM_SEC));
 181
 182         /* Clear the READ bit */
 183         M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL);
 184         spin_unlock_irqrestore(&m48t59->lock, flags);
 185
 186         dev_dbg(dev, "RTC read alarm time %ptR\n", tm);
 187         return rtc_valid_tm(tm);
 188 }
 189
 190 /*
 191  * Set alarm time and date in RTC
 192  */
 193 static int m48t59_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 194 {
 195         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 196         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 197         struct rtc_time *tm = &alrm->time;
 198         u8 mday, hour, min, sec;
 199         unsigned long flags;
 200         int year = tm->tm_year;
 201
 202 #ifdef CONFIG_SPARC
 203         /* Sun SPARC machines count years since 1968 */
 204         year -= 68;
 205 #endif
 206
 207         /* If no irq, we don't support ALARM */
 208         if (m48t59->irq == NO_IRQ)
 209                 return -EIO;
 210
 211         if (year < 0)
 212                 return -EINVAL;
 213
 214         /*
 215          * 0xff means "always match"
 216          */
 217         mday = tm->tm_mday;
 218         mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 219         if (mday == 0xff)
 220                 mday = M48T59_READ(M48T59_MDAY);
 221
 222         hour = tm->tm_hour;
 223         hour = (hour < 24) ? bin2bcd(hour) : 0x00;
 224
 225         min = tm->tm_min;
 226         min = (min < 60) ? bin2bcd(min) : 0x00;
 227
 228         sec = tm->tm_sec;
 229         sec = (sec < 60) ? bin2bcd(sec) : 0x00;
 230
 231         spin_lock_irqsave(&m48t59->lock, flags);
 232         /* Issue the WRITE command */
 233         M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
 234
 235         M48T59_WRITE(mday, M48T59_ALARM_DATE);
 236         M48T59_WRITE(hour, M48T59_ALARM_HOUR);
 237         M48T59_WRITE(min, M48T59_ALARM_MIN);
 238         M48T59_WRITE(sec, M48T59_ALARM_SEC);
 239
 240         /* Clear the WRITE bit */
 241         M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
 242         spin_unlock_irqrestore(&m48t59->lock, flags);
 243
 244         dev_dbg(dev, "RTC set alarm time %04d-%02d-%02d %02d/%02d/%02d\n",
 245                 year + 1900, tm->tm_mon, tm->tm_mday,
 246                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 247         return 0;
 248 }
 249
 250 /*
 251  * Handle commands from user-space
 252  */
 253 static int m48t59_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 254 {
 255         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 256         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 257         unsigned long flags;
 258
 259         spin_lock_irqsave(&m48t59->lock, flags);
 260         if (enabled)
 261                 M48T59_WRITE(M48T59_INTR_AFE, M48T59_INTR);
 262         else
 263                 M48T59_WRITE(0x00, M48T59_INTR);
 264         spin_unlock_irqrestore(&m48t59->lock, flags);
 265
 266         return 0;
 267 }
 268
 269 static int m48t59_rtc_proc(struct device *dev, struct seq_file *seq)
 270 {
 271         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 272         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 273         unsigned long flags;
 274         u8 val;
 275
 276         spin_lock_irqsave(&m48t59->lock, flags);
 277         val = M48T59_READ(M48T59_FLAGS);
 278         spin_unlock_irqrestore(&m48t59->lock, flags);
 279
 280         seq_printf(seq, "battery\t\t: %s\n",
 281                  (val & M48T59_FLAGS_BF) ? "low" : "normal");
 282         return 0;
 283 }
 284
 285 /*
 286  * IRQ handler for the RTC
 287  */
 288 static irqreturn_t m48t59_rtc_interrupt(int irq, void *dev_id)
 289 {
 290         struct device *dev = (struct device *)dev_id;
 291         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 292         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 293         u8 event;
 294
 295         spin_lock(&m48t59->lock);
 296         event = M48T59_READ(M48T59_FLAGS);
 297         spin_unlock(&m48t59->lock);
 298
 299         if (event & M48T59_FLAGS_AF) {
 300                 rtc_update_irq(m48t59->rtc, 1, (RTC_AF | RTC_IRQF));
 301                 return IRQ_HANDLED;
 302         }
 303
 304         return IRQ_NONE;
 305 }
 306
 307 static const struct rtc_class_ops m48t59_rtc_ops = {
 308         .read_time      = m48t59_rtc_read_time,
 309         .set_time       = m48t59_rtc_set_time,
 310         .read_alarm     = m48t59_rtc_readalarm,
 311         .set_alarm      = m48t59_rtc_setalarm,
 312         .proc           = m48t59_rtc_proc,
 313         .alarm_irq_enable = m48t59_rtc_alarm_irq_enable,
 314 };
 315
 316 static const struct rtc_class_ops m48t02_rtc_ops = {
 317         .read_time      = m48t59_rtc_read_time,
 318         .set_time       = m48t59_rtc_set_time,
 319 };
 320
 321 static int m48t59_nvram_read(void *priv, unsigned int offset, void *val,
 322                              size_t size)
 323 {
 324         struct platform_device *pdev = priv;
 325         struct device *dev = &pdev->dev;
 326         struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
 327         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
 328         ssize_t cnt = 0;
 329         unsigned long flags;
 330         u8 *buf = val;
 331
 332         spin_lock_irqsave(&m48t59->lock, flags);
 333
 334         for (; cnt < size; cnt++)
 335                 *buf++ = M48T59_READ(cnt);
 336
 337         spin_unlock_irqrestore(&m48t59->lock, flags);
 338
 339         return 0;
 340 }
 341
 342 static int m48t59_nvram_write(void *priv, unsigned int offset, void *val,
 343                               size_t size)
 344 {
 345         struct platform_device *pdev = priv;
 346         struct device *dev = &pdev->dev;
 347         struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
 348         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
 349         ssize_t cnt = 0;
 350         unsigned long flags;
 351         u8 *buf = val;
 352
 353         spin_lock_irqsave(&m48t59->lock, flags);
 354
 355         for (; cnt < size; cnt++)
 356                 M48T59_WRITE(*buf++, cnt);
 357
 358         spin_unlock_irqrestore(&m48t59->lock, flags);
 359
 360         return 0;
 361 }
 362
 363 static int m48t59_rtc_probe(struct platform_device *pdev)
 364 {
 365         struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
 366         struct m48t59_private *m48t59 = NULL;
 367         struct resource *res;
 368         int ret = -ENOMEM;
 369         const struct rtc_class_ops *ops;
 370         struct nvmem_config nvmem_cfg = {
 371                 .name = "m48t59-",
 372                 .word_size = 1,
 373                 .stride = 1,
 374                 .reg_read = m48t59_nvram_read,
 375                 .reg_write = m48t59_nvram_write,
 376                 .priv = pdev,
 377         };
 378
 379         /* This chip could be memory-mapped or I/O-mapped */
 380         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 381         if (!res) {
 382                 res = platform_get_resource(pdev, IORESOURCE_IO, 0);
 383                 if (!res)
 384                         return -EINVAL;
 385         }
 386
 387         if (res->flags & IORESOURCE_IO) {
 388                 /* If we are I/O-mapped, the platform should provide
 389                  * the operations accessing chip registers.
 390                  */
 391                 if (!pdata || !pdata->write_byte || !pdata->read_byte)
 392                         return -EINVAL;
 393         } else if (res->flags & IORESOURCE_MEM) {
 394                 /* we are memory-mapped */
 395                 if (!pdata) {
 396                         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata),
 397                                                 GFP_KERNEL);
 398                         if (!pdata)
 399                                 return -ENOMEM;
 400                         /* Ensure we only kmalloc platform data once */
 401                         pdev->dev.platform_data = pdata;
 402                 }
 403                 if (!pdata->type)
 404                         pdata->type = M48T59RTC_TYPE_M48T59;
 405
 406                 /* Try to use the generic memory read/write ops */
 407                 if (!pdata->write_byte)
 408                         pdata->write_byte = m48t59_mem_writeb;
 409                 if (!pdata->read_byte)
 410                         pdata->read_byte = m48t59_mem_readb;
 411         }
 412
 413         m48t59 = devm_kzalloc(&pdev->dev, sizeof(*m48t59), GFP_KERNEL);
 414         if (!m48t59)
 415                 return -ENOMEM;
 416
 417         m48t59->ioaddr = pdata->ioaddr;
 418
 419         if (!m48t59->ioaddr) {
 420                 /* ioaddr not mapped externally */
 421                 m48t59->ioaddr = devm_ioremap(&pdev->dev, res->start,
 422                                                 resource_size(res));
 423                 if (!m48t59->ioaddr)
 424                         return ret;
 425         }
 426
 427         /* Try to get irq number. We also can work in
 428          * the mode without IRQ.
 429          */
 430         m48t59->irq = platform_get_irq(pdev, 0);
 431         if (m48t59->irq <= 0)
 432                 m48t59->irq = NO_IRQ;
 433
 434         if (m48t59->irq != NO_IRQ) {
 435                 ret = devm_request_irq(&pdev->dev, m48t59->irq,
 436                                 m48t59_rtc_interrupt, IRQF_SHARED,
 437                                 "rtc-m48t59", &pdev->dev);
 438                 if (ret)
 439                         return ret;
 440         }
 441         switch (pdata->type) {
 442         case M48T59RTC_TYPE_M48T59:
 443                 ops = &m48t59_rtc_ops;
 444                 pdata->offset = 0x1ff0;
 445                 break;
 446         case M48T59RTC_TYPE_M48T02:
 447                 ops = &m48t02_rtc_ops;
 448                 pdata->offset = 0x7f0;
 449                 break;
 450         case M48T59RTC_TYPE_M48T08:
 451                 ops = &m48t02_rtc_ops;
 452                 pdata->offset = 0x1ff0;
 453                 break;
 454         default:
 455                 dev_err(&pdev->dev, "Unknown RTC type\n");
 456                 return -ENODEV;
 457         }
 458
 459         spin_lock_init(&m48t59->lock);
 460         platform_set_drvdata(pdev, m48t59);
 461
 462         m48t59->rtc = devm_rtc_allocate_device(&pdev->dev);
 463         if (IS_ERR(m48t59->rtc))
 464                 return PTR_ERR(m48t59->rtc);
 465
 466         m48t59->rtc->ops = ops;
 467
 468         nvmem_cfg.size = pdata->offset;
 469         ret = devm_rtc_nvmem_register(m48t59->rtc, &nvmem_cfg);
 470         if (ret)
 471                 return ret;
 472
 473         ret = devm_rtc_register_device(m48t59->rtc);
 474         if (ret)
 475                 return ret;
 476
 477         return 0;
 478 }
 479
 480 /* work with hotplug and coldplug */
 481 MODULE_ALIAS("platform:rtc-m48t59");
 482
 483 static struct platform_driver m48t59_rtc_driver = {
 484         .driver         = {
 485                 .name   = "rtc-m48t59",
 486         },
 487         .probe          = m48t59_rtc_probe,
 488 };
 489
 490 module_platform_driver(m48t59_rtc_driver);
 491
 492 MODULE_AUTHOR("Mark Zhan <rongkai.zhan@windriver.com>");
 493 MODULE_DESCRIPTION("M48T59/M48T02/M48T08 RTC driver");
 494 MODULE_LICENSE("GPL");