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)) + pdata->yy_offset;
  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
  86         tm->tm_wday     = bcd2bin(val & 0x07);
  87         tm->tm_hour     = bcd2bin(M48T59_READ(M48T59_HOUR) & 0x3F);
  88         tm->tm_min      = bcd2bin(M48T59_READ(M48T59_MIN) & 0x7F);
  89         tm->tm_sec      = bcd2bin(M48T59_READ(M48T59_SEC) & 0x7F);
  90
  91         /* Clear the READ bit */
  92         M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL);
  93         spin_unlock_irqrestore(&m48t59->lock, flags);
  94
  95         dev_dbg(dev, "RTC read time %ptR\n", tm);
  96         return 0;
  97 }
  98
  99 static int m48t59_rtc_set_time(struct device *dev, struct rtc_time *tm)
 100 {
 101         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 102         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 103         unsigned long flags;
 104         u8 val = 0;
 105         int year = tm->tm_year - pdata->yy_offset;
 106
 107         dev_dbg(dev, "RTC set time %04d-%02d-%02d %02d/%02d/%02d\n",
 108                 year + 1900, tm->tm_mon, tm->tm_mday,
 109                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 110
 111         if (year < 0)
 112                 return -EINVAL;
 113
 114         spin_lock_irqsave(&m48t59->lock, flags);
 115         /* Issue the WRITE command */
 116         M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
 117
 118         M48T59_WRITE((bin2bcd(tm->tm_sec) & 0x7F), M48T59_SEC);
 119         M48T59_WRITE((bin2bcd(tm->tm_min) & 0x7F), M48T59_MIN);
 120         M48T59_WRITE((bin2bcd(tm->tm_hour) & 0x3F), M48T59_HOUR);
 121         M48T59_WRITE((bin2bcd(tm->tm_mday) & 0x3F), M48T59_MDAY);
 122         /* tm_mon is 0-11 */
 123         M48T59_WRITE((bin2bcd(tm->tm_mon + 1) & 0x1F), M48T59_MONTH);
 124         M48T59_WRITE(bin2bcd(year % 100), M48T59_YEAR);
 125
 126         if (pdata->type == M48T59RTC_TYPE_M48T59 && (year >= 100))
 127                 val = (M48T59_WDAY_CEB | M48T59_WDAY_CB);
 128         val |= (bin2bcd(tm->tm_wday) & 0x07);
 129         M48T59_WRITE(val, M48T59_WDAY);
 130
 131         /* Clear the WRITE bit */
 132         M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
 133         spin_unlock_irqrestore(&m48t59->lock, flags);
 134         return 0;
 135 }
 136
 137 /*
 138  * Read alarm time and date in RTC
 139  */
 140 static int m48t59_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 141 {
 142         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 143         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 144         struct rtc_time *tm = &alrm->time;
 145         unsigned long flags;
 146         u8 val;
 147
 148         /* If no irq, we don't support ALARM */
 149         if (m48t59->irq == NO_IRQ)
 150                 return -EIO;
 151
 152         spin_lock_irqsave(&m48t59->lock, flags);
 153         /* Issue the READ command */
 154         M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);
 155
 156         tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR)) + pdata->yy_offset;
 157         /* tm_mon is 0-11 */
 158         tm->tm_mon = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
 159
 160         val = M48T59_READ(M48T59_WDAY);
 161         if ((val & M48T59_WDAY_CEB) && (val & M48T59_WDAY_CB))
 162                 tm->tm_year += 100;     /* one century */
 163
 164         tm->tm_mday = bcd2bin(M48T59_READ(M48T59_ALARM_DATE));
 165         tm->tm_hour = bcd2bin(M48T59_READ(M48T59_ALARM_HOUR));
 166         tm->tm_min = bcd2bin(M48T59_READ(M48T59_ALARM_MIN));
 167         tm->tm_sec = bcd2bin(M48T59_READ(M48T59_ALARM_SEC));
 168
 169         /* Clear the READ bit */
 170         M48T59_CLEAR_BITS(M48T59_CNTL_READ, M48T59_CNTL);
 171         spin_unlock_irqrestore(&m48t59->lock, flags);
 172
 173         dev_dbg(dev, "RTC read alarm time %ptR\n", tm);
 174         return rtc_valid_tm(tm);
 175 }
 176
 177 /*
 178  * Set alarm time and date in RTC
 179  */
 180 static int m48t59_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 181 {
 182         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 183         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 184         struct rtc_time *tm = &alrm->time;
 185         u8 mday, hour, min, sec;
 186         unsigned long flags;
 187         int year = tm->tm_year - pdata->yy_offset;
 188
 189         /* If no irq, we don't support ALARM */
 190         if (m48t59->irq == NO_IRQ)
 191                 return -EIO;
 192
 193         if (year < 0)
 194                 return -EINVAL;
 195
 196         /*
 197          * 0xff means "always match"
 198          */
 199         mday = tm->tm_mday;
 200         mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 201         if (mday == 0xff)
 202                 mday = M48T59_READ(M48T59_MDAY);
 203
 204         hour = tm->tm_hour;
 205         hour = (hour < 24) ? bin2bcd(hour) : 0x00;
 206
 207         min = tm->tm_min;
 208         min = (min < 60) ? bin2bcd(min) : 0x00;
 209
 210         sec = tm->tm_sec;
 211         sec = (sec < 60) ? bin2bcd(sec) : 0x00;
 212
 213         spin_lock_irqsave(&m48t59->lock, flags);
 214         /* Issue the WRITE command */
 215         M48T59_SET_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
 216
 217         M48T59_WRITE(mday, M48T59_ALARM_DATE);
 218         M48T59_WRITE(hour, M48T59_ALARM_HOUR);
 219         M48T59_WRITE(min, M48T59_ALARM_MIN);
 220         M48T59_WRITE(sec, M48T59_ALARM_SEC);
 221
 222         /* Clear the WRITE bit */
 223         M48T59_CLEAR_BITS(M48T59_CNTL_WRITE, M48T59_CNTL);
 224         spin_unlock_irqrestore(&m48t59->lock, flags);
 225
 226         dev_dbg(dev, "RTC set alarm time %04d-%02d-%02d %02d/%02d/%02d\n",
 227                 year + 1900, tm->tm_mon, tm->tm_mday,
 228                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 229         return 0;
 230 }
 231
 232 /*
 233  * Handle commands from user-space
 234  */
 235 static int m48t59_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 236 {
 237         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 238         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 239         unsigned long flags;
 240
 241         spin_lock_irqsave(&m48t59->lock, flags);
 242         if (enabled)
 243                 M48T59_WRITE(M48T59_INTR_AFE, M48T59_INTR);
 244         else
 245                 M48T59_WRITE(0x00, M48T59_INTR);
 246         spin_unlock_irqrestore(&m48t59->lock, flags);
 247
 248         return 0;
 249 }
 250
 251 static int m48t59_rtc_proc(struct device *dev, struct seq_file *seq)
 252 {
 253         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 254         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 255         unsigned long flags;
 256         u8 val;
 257
 258         spin_lock_irqsave(&m48t59->lock, flags);
 259         val = M48T59_READ(M48T59_FLAGS);
 260         spin_unlock_irqrestore(&m48t59->lock, flags);
 261
 262         seq_printf(seq, "battery\t\t: %s\n",
 263                  (val & M48T59_FLAGS_BF) ? "low" : "normal");
 264         return 0;
 265 }
 266
 267 /*
 268  * IRQ handler for the RTC
 269  */
 270 static irqreturn_t m48t59_rtc_interrupt(int irq, void *dev_id)
 271 {
 272         struct device *dev = (struct device *)dev_id;
 273         struct m48t59_plat_data *pdata = dev_get_platdata(dev);
 274         struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 275         u8 event;
 276
 277         spin_lock(&m48t59->lock);
 278         event = M48T59_READ(M48T59_FLAGS);
 279         spin_unlock(&m48t59->lock);
 280
 281         if (event & M48T59_FLAGS_AF) {
 282                 rtc_update_irq(m48t59->rtc, 1, (RTC_AF | RTC_IRQF));
 283                 return IRQ_HANDLED;
 284         }
 285
 286         return IRQ_NONE;
 287 }
 288
 289 static const struct rtc_class_ops m48t59_rtc_ops = {
 290         .read_time      = m48t59_rtc_read_time,
 291         .set_time       = m48t59_rtc_set_time,
 292         .read_alarm     = m48t59_rtc_readalarm,
 293         .set_alarm      = m48t59_rtc_setalarm,
 294         .proc           = m48t59_rtc_proc,
 295         .alarm_irq_enable = m48t59_rtc_alarm_irq_enable,
 296 };
 297
 298 static int m48t59_nvram_read(void *priv, unsigned int offset, void *val,
 299                              size_t size)
 300 {
 301         struct platform_device *pdev = priv;
 302         struct device *dev = &pdev->dev;
 303         struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
 304         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
 305         ssize_t cnt = 0;
 306         unsigned long flags;
 307         u8 *buf = val;
 308
 309         spin_lock_irqsave(&m48t59->lock, flags);
 310
 311         for (; cnt < size; cnt++)
 312                 *buf++ = M48T59_READ(cnt);
 313
 314         spin_unlock_irqrestore(&m48t59->lock, flags);
 315
 316         return 0;
 317 }
 318
 319 static int m48t59_nvram_write(void *priv, unsigned int offset, void *val,
 320                               size_t size)
 321 {
 322         struct platform_device *pdev = priv;
 323         struct device *dev = &pdev->dev;
 324         struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
 325         struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
 326         ssize_t cnt = 0;
 327         unsigned long flags;
 328         u8 *buf = val;
 329
 330         spin_lock_irqsave(&m48t59->lock, flags);
 331
 332         for (; cnt < size; cnt++)
 333                 M48T59_WRITE(*buf++, cnt);
 334
 335         spin_unlock_irqrestore(&m48t59->lock, flags);
 336
 337         return 0;
 338 }
 339
 340 static int m48t59_rtc_probe(struct platform_device *pdev)
 341 {
 342         struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
 343         struct m48t59_private *m48t59 = NULL;
 344         struct resource *res;
 345         int ret = -ENOMEM;
 346         struct nvmem_config nvmem_cfg = {
 347                 .name = "m48t59-",
 348                 .word_size = 1,
 349                 .stride = 1,
 350                 .reg_read = m48t59_nvram_read,
 351                 .reg_write = m48t59_nvram_write,
 352                 .priv = pdev,
 353         };
 354
 355         /* This chip could be memory-mapped or I/O-mapped */
 356         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 357         if (!res) {
 358                 res = platform_get_resource(pdev, IORESOURCE_IO, 0);
 359                 if (!res)
 360                         return -EINVAL;
 361         }
 362
 363         if (res->flags & IORESOURCE_IO) {
 364                 /* If we are I/O-mapped, the platform should provide
 365                  * the operations accessing chip registers.
 366                  */
 367                 if (!pdata || !pdata->write_byte || !pdata->read_byte)
 368                         return -EINVAL;
 369         } else if (res->flags & IORESOURCE_MEM) {
 370                 /* we are memory-mapped */
 371                 if (!pdata) {
 372                         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata),
 373                                                 GFP_KERNEL);
 374                         if (!pdata)
 375                                 return -ENOMEM;
 376                         /* Ensure we only kmalloc platform data once */
 377                         pdev->dev.platform_data = pdata;
 378                 }
 379                 if (!pdata->type)
 380                         pdata->type = M48T59RTC_TYPE_M48T59;
 381
 382                 /* Try to use the generic memory read/write ops */
 383                 if (!pdata->write_byte)
 384                         pdata->write_byte = m48t59_mem_writeb;
 385                 if (!pdata->read_byte)
 386                         pdata->read_byte = m48t59_mem_readb;
 387         }
 388
 389         m48t59 = devm_kzalloc(&pdev->dev, sizeof(*m48t59), GFP_KERNEL);
 390         if (!m48t59)
 391                 return -ENOMEM;
 392
 393         m48t59->ioaddr = pdata->ioaddr;
 394
 395         if (!m48t59->ioaddr) {
 396                 /* ioaddr not mapped externally */
 397                 m48t59->ioaddr = devm_ioremap(&pdev->dev, res->start,
 398                                                 resource_size(res));
 399                 if (!m48t59->ioaddr)
 400                         return ret;
 401         }
 402
 403         /* Try to get irq number. We also can work in
 404          * the mode without IRQ.
 405          */
 406         m48t59->irq = platform_get_irq_optional(pdev, 0);
 407         if (m48t59->irq <= 0)
 408                 m48t59->irq = NO_IRQ;
 409
 410         if (m48t59->irq != NO_IRQ) {
 411                 ret = devm_request_irq(&pdev->dev, m48t59->irq,
 412                                 m48t59_rtc_interrupt, IRQF_SHARED,
 413                                 "rtc-m48t59", &pdev->dev);
 414                 if (ret)
 415                         return ret;
 416         }
 417
 418         m48t59->rtc = devm_rtc_allocate_device(&pdev->dev);
 419         if (IS_ERR(m48t59->rtc))
 420                 return PTR_ERR(m48t59->rtc);
 421
 422         switch (pdata->type) {
 423         case M48T59RTC_TYPE_M48T59:
 424                 pdata->offset = 0x1ff0;
 425                 break;
 426         case M48T59RTC_TYPE_M48T02:
 427                 clear_bit(RTC_FEATURE_ALARM, m48t59->rtc->features);
 428                 pdata->offset = 0x7f0;
 429                 break;
 430         case M48T59RTC_TYPE_M48T08:
 431                 clear_bit(RTC_FEATURE_ALARM, m48t59->rtc->features);
 432                 pdata->offset = 0x1ff0;
 433                 break;
 434         default:
 435                 dev_err(&pdev->dev, "Unknown RTC type\n");
 436                 return -ENODEV;
 437         }
 438
 439         spin_lock_init(&m48t59->lock);
 440         platform_set_drvdata(pdev, m48t59);
 441
 442         m48t59->rtc->ops = &m48t59_rtc_ops;
 443         m48t59->rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
 444         m48t59->rtc->range_max = RTC_TIMESTAMP_END_2099;
 445
 446         nvmem_cfg.size = pdata->offset;
 447         ret = devm_rtc_nvmem_register(m48t59->rtc, &nvmem_cfg);
 448         if (ret)
 449                 return ret;
 450
 451         ret = devm_rtc_register_device(m48t59->rtc);
 452         if (ret)
 453                 return ret;
 454
 455         return 0;
 456 }
 457
 458 /* work with hotplug and coldplug */
 459 MODULE_ALIAS("platform:rtc-m48t59");
 460
 461 static struct platform_driver m48t59_rtc_driver = {
 462         .driver         = {
 463                 .name   = "rtc-m48t59",
 464         },
 465         .probe          = m48t59_rtc_probe,
 466 };
 467
 468 module_platform_driver(m48t59_rtc_driver);
 469
 470 MODULE_AUTHOR("Mark Zhan <rongkai.zhan@windriver.com>");
 471 MODULE_DESCRIPTION("M48T59/M48T02/M48T08 RTC driver");
 472 MODULE_LICENSE("GPL");