drivers/rtc/rtc-pm8xxx.c

   1 /* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License version 2 and
   5  * only version 2 as published by the Free Software Foundation.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/rtc.h>
  16 #include <linux/pm.h>
  17 #include <linux/slab.h>
  18 #include <linux/spinlock.h>
  19
  20 #include <linux/mfd/pm8xxx/core.h>
  21 #include <linux/mfd/pm8xxx/rtc.h>
  22
  23
  24 /* RTC Register offsets from RTC CTRL REG */
  25 #define PM8XXX_ALARM_CTRL_OFFSET        0x01
  26 #define PM8XXX_RTC_WRITE_OFFSET         0x02
  27 #define PM8XXX_RTC_READ_OFFSET          0x06
  28 #define PM8XXX_ALARM_RW_OFFSET          0x0A
  29
  30 /* RTC_CTRL register bit fields */
  31 #define PM8xxx_RTC_ENABLE               BIT(7)
  32 #define PM8xxx_RTC_ALARM_ENABLE         BIT(1)
  33 #define PM8xxx_RTC_ALARM_CLEAR          BIT(0)
  34
  35 #define NUM_8_BIT_RTC_REGS              0x4
  36
  37 /**
  38  * struct pm8xxx_rtc -  rtc driver internal structure
  39  * @rtc:                rtc device for this driver.
  40  * @rtc_alarm_irq:      rtc alarm irq number.
  41  * @rtc_base:           address of rtc control register.
  42  * @rtc_read_base:      base address of read registers.
  43  * @rtc_write_base:     base address of write registers.
  44  * @alarm_rw_base:      base address of alarm registers.
  45  * @ctrl_reg:           rtc control register.
  46  * @rtc_dev:            device structure.
  47  * @ctrl_reg_lock:      spinlock protecting access to ctrl_reg.
  48  */
  49 struct pm8xxx_rtc {
  50         struct rtc_device *rtc;
  51         int rtc_alarm_irq;
  52         int rtc_base;
  53         int rtc_read_base;
  54         int rtc_write_base;
  55         int alarm_rw_base;
  56         u8  ctrl_reg;
  57         struct device *rtc_dev;
  58         spinlock_t ctrl_reg_lock;
  59 };
  60
  61 /*
  62  * The RTC registers need to be read/written one byte at a time. This is a
  63  * hardware limitation.
  64  */
  65 static int pm8xxx_read_wrapper(struct pm8xxx_rtc *rtc_dd, u8 *rtc_val,
  66                 int base, int count)
  67 {
  68         int i, rc;
  69         struct device *parent = rtc_dd->rtc_dev->parent;
  70
  71         for (i = 0; i < count; i++) {
  72                 rc = pm8xxx_readb(parent, base + i, &rtc_val[i]);
  73                 if (rc < 0) {
  74                         dev_err(rtc_dd->rtc_dev, "PMIC read failed\n");
  75                         return rc;
  76                 }
  77         }
  78
  79         return 0;
  80 }
  81
  82 static int pm8xxx_write_wrapper(struct pm8xxx_rtc *rtc_dd, u8 *rtc_val,
  83                 int base, int count)
  84 {
  85         int i, rc;
  86         struct device *parent = rtc_dd->rtc_dev->parent;
  87
  88         for (i = 0; i < count; i++) {
  89                 rc = pm8xxx_writeb(parent, base + i, rtc_val[i]);
  90                 if (rc < 0) {
  91                         dev_err(rtc_dd->rtc_dev, "PMIC write failed\n");
  92                         return rc;
  93                 }
  94         }
  95
  96         return 0;
  97 }
  98
  99 /*
 100  * Steps to write the RTC registers.
 101  * 1. Disable alarm if enabled.
 102  * 2. Write 0x00 to LSB.
 103  * 3. Write Byte[1], Byte[2], Byte[3] then Byte[0].
 104  * 4. Enable alarm if disabled in step 1.
 105  */
 106 static int pm8xxx_rtc_set_time(struct device *dev, struct rtc_time *tm)
 107 {
 108         int rc, i;
 109         unsigned long secs, irq_flags;
 110         u8 value[NUM_8_BIT_RTC_REGS], reg = 0, alarm_enabled = 0, ctrl_reg;
 111         struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
 112
 113         rtc_tm_to_time(tm, &secs);
 114
 115         for (i = 0; i < NUM_8_BIT_RTC_REGS; i++) {
 116                 value[i] = secs & 0xFF;
 117                 secs >>= 8;
 118         }
 119
 120         dev_dbg(dev, "Seconds value to be written to RTC = %lu\n", secs);
 121
 122         spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
 123         ctrl_reg = rtc_dd->ctrl_reg;
 124
 125         if (ctrl_reg & PM8xxx_RTC_ALARM_ENABLE) {
 126                 alarm_enabled = 1;
 127                 ctrl_reg &= ~PM8xxx_RTC_ALARM_ENABLE;
 128                 rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base,
 129                                 1);
 130                 if (rc < 0) {
 131                         dev_err(dev, "Write to RTC control register "
 132                                                                 "failed\n");
 133                         goto rtc_rw_fail;
 134                 }
 135                 rtc_dd->ctrl_reg = ctrl_reg;
 136         } else
 137                 spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
 138
 139         /* Write 0 to Byte[0] */
 140         reg = 0;
 141         rc = pm8xxx_write_wrapper(rtc_dd, &reg, rtc_dd->rtc_write_base, 1);
 142         if (rc < 0) {
 143                 dev_err(dev, "Write to RTC write data register failed\n");
 144                 goto rtc_rw_fail;
 145         }
 146
 147         /* Write Byte[1], Byte[2], Byte[3] */
 148         rc = pm8xxx_write_wrapper(rtc_dd, value + 1,
 149                                         rtc_dd->rtc_write_base + 1, 3);
 150         if (rc < 0) {
 151                 dev_err(dev, "Write to RTC write data register failed\n");
 152                 goto rtc_rw_fail;
 153         }
 154
 155         /* Write Byte[0] */
 156         rc = pm8xxx_write_wrapper(rtc_dd, value, rtc_dd->rtc_write_base, 1);
 157         if (rc < 0) {
 158                 dev_err(dev, "Write to RTC write data register failed\n");
 159                 goto rtc_rw_fail;
 160         }
 161
 162         if (alarm_enabled) {
 163                 ctrl_reg |= PM8xxx_RTC_ALARM_ENABLE;
 164                 rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base,
 165                                                                         1);
 166                 if (rc < 0) {
 167                         dev_err(dev, "Write to RTC control register "
 168                                                                 "failed\n");
 169                         goto rtc_rw_fail;
 170                 }
 171                 rtc_dd->ctrl_reg = ctrl_reg;
 172         }
 173
 174 rtc_rw_fail:
 175         if (alarm_enabled)
 176                 spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
 177
 178         return rc;
 179 }
 180
 181 static int pm8xxx_rtc_read_time(struct device *dev, struct rtc_time *tm)
 182 {
 183         int rc;
 184         u8 value[NUM_8_BIT_RTC_REGS], reg;
 185         unsigned long secs;
 186         struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
 187
 188         rc = pm8xxx_read_wrapper(rtc_dd, value, rtc_dd->rtc_read_base,
 189                                                         NUM_8_BIT_RTC_REGS);
 190         if (rc < 0) {
 191                 dev_err(dev, "RTC read data register failed\n");
 192                 return rc;
 193         }
 194
 195         /*
 196          * Read the LSB again and check if there has been a carry over.
 197          * If there is, redo the read operation.
 198          */
 199         rc = pm8xxx_read_wrapper(rtc_dd, &reg, rtc_dd->rtc_read_base, 1);
 200         if (rc < 0) {
 201                 dev_err(dev, "RTC read data register failed\n");
 202                 return rc;
 203         }
 204
 205         if (unlikely(reg < value[0])) {
 206                 rc = pm8xxx_read_wrapper(rtc_dd, value,
 207                                 rtc_dd->rtc_read_base, NUM_8_BIT_RTC_REGS);
 208                 if (rc < 0) {
 209                         dev_err(dev, "RTC read data register failed\n");
 210                         return rc;
 211                 }
 212         }
 213
 214         secs = value[0] | (value[1] << 8) | (value[2] << 16) | (value[3] << 24);
 215
 216         rtc_time_to_tm(secs, tm);
 217
 218         rc = rtc_valid_tm(tm);
 219         if (rc < 0) {
 220                 dev_err(dev, "Invalid time read from RTC\n");
 221                 return rc;
 222         }
 223
 224         dev_dbg(dev, "secs = %lu, h:m:s == %d:%d:%d, d/m/y = %d/%d/%d\n",
 225                                 secs, tm->tm_hour, tm->tm_min, tm->tm_sec,
 226                                 tm->tm_mday, tm->tm_mon, tm->tm_year);
 227
 228         return 0;
 229 }
 230
 231 static int pm8xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 232 {
 233         int rc, i;
 234         u8 value[NUM_8_BIT_RTC_REGS], ctrl_reg;
 235         unsigned long secs, irq_flags;
 236         struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
 237
 238         rtc_tm_to_time(&alarm->time, &secs);
 239
 240         for (i = 0; i < NUM_8_BIT_RTC_REGS; i++) {
 241                 value[i] = secs & 0xFF;
 242                 secs >>= 8;
 243         }
 244
 245         spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
 246
 247         rc = pm8xxx_write_wrapper(rtc_dd, value, rtc_dd->alarm_rw_base,
 248                                                         NUM_8_BIT_RTC_REGS);
 249         if (rc < 0) {
 250                 dev_err(dev, "Write to RTC ALARM register failed\n");
 251                 goto rtc_rw_fail;
 252         }
 253
 254         ctrl_reg = rtc_dd->ctrl_reg;
 255         ctrl_reg = alarm->enabled ? (ctrl_reg | PM8xxx_RTC_ALARM_ENABLE) :
 256                                         (ctrl_reg & ~PM8xxx_RTC_ALARM_ENABLE);
 257
 258         rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, 1);
 259         if (rc < 0) {
 260                 dev_err(dev, "Write to RTC control register failed\n");
 261                 goto rtc_rw_fail;
 262         }
 263
 264         rtc_dd->ctrl_reg = ctrl_reg;
 265
 266         dev_dbg(dev, "Alarm Set for h:r:s=%d:%d:%d, d/m/y=%d/%d/%d\n",
 267                                 alarm->time.tm_hour, alarm->time.tm_min,
 268                                 alarm->time.tm_sec, alarm->time.tm_mday,
 269                                 alarm->time.tm_mon, alarm->time.tm_year);
 270 rtc_rw_fail:
 271         spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
 272         return rc;
 273 }
 274
 275 static int pm8xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 276 {
 277         int rc;
 278         u8 value[NUM_8_BIT_RTC_REGS];
 279         unsigned long secs;
 280         struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
 281
 282         rc = pm8xxx_read_wrapper(rtc_dd, value, rtc_dd->alarm_rw_base,
 283                         NUM_8_BIT_RTC_REGS);
 284         if (rc < 0) {
 285                 dev_err(dev, "RTC alarm time read failed\n");
 286                 return rc;
 287         }
 288
 289         secs = value[0] | (value[1] << 8) | (value[2] << 16) | (value[3] << 24);
 290
 291         rtc_time_to_tm(secs, &alarm->time);
 292
 293         rc = rtc_valid_tm(&alarm->time);
 294         if (rc < 0) {
 295                 dev_err(dev, "Invalid alarm time read from RTC\n");
 296                 return rc;
 297         }
 298
 299         dev_dbg(dev, "Alarm set for - h:r:s=%d:%d:%d, d/m/y=%d/%d/%d\n",
 300                                 alarm->time.tm_hour, alarm->time.tm_min,
 301                                 alarm->time.tm_sec, alarm->time.tm_mday,
 302                                 alarm->time.tm_mon, alarm->time.tm_year);
 303
 304         return 0;
 305 }
 306
 307 static int pm8xxx_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
 308 {
 309         int rc;
 310         unsigned long irq_flags;
 311         struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
 312         u8 ctrl_reg;
 313
 314         spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
 315         ctrl_reg = rtc_dd->ctrl_reg;
 316         ctrl_reg = (enable) ? (ctrl_reg | PM8xxx_RTC_ALARM_ENABLE) :
 317                                 (ctrl_reg & ~PM8xxx_RTC_ALARM_ENABLE);
 318
 319         rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, 1);
 320         if (rc < 0) {
 321                 dev_err(dev, "Write to RTC control register failed\n");
 322                 goto rtc_rw_fail;
 323         }
 324
 325         rtc_dd->ctrl_reg = ctrl_reg;
 326
 327 rtc_rw_fail:
 328         spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
 329         return rc;
 330 }
 331
 332 static struct rtc_class_ops pm8xxx_rtc_ops = {
 333         .read_time      = pm8xxx_rtc_read_time,
 334         .set_alarm      = pm8xxx_rtc_set_alarm,
 335         .read_alarm     = pm8xxx_rtc_read_alarm,
 336         .alarm_irq_enable = pm8xxx_rtc_alarm_irq_enable,
 337 };
 338
 339 static irqreturn_t pm8xxx_alarm_trigger(int irq, void *dev_id)
 340 {
 341         struct pm8xxx_rtc *rtc_dd = dev_id;
 342         u8 ctrl_reg;
 343         int rc;
 344         unsigned long irq_flags;
 345
 346         rtc_update_irq(rtc_dd->rtc, 1, RTC_IRQF | RTC_AF);
 347
 348         spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
 349
 350         /* Clear the alarm enable bit */
 351         ctrl_reg = rtc_dd->ctrl_reg;
 352         ctrl_reg &= ~PM8xxx_RTC_ALARM_ENABLE;
 353
 354         rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, 1);
 355         if (rc < 0) {
 356                 spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
 357                 dev_err(rtc_dd->rtc_dev, "Write to RTC control register "
 358                                                                 "failed\n");
 359                 goto rtc_alarm_handled;
 360         }
 361
 362         rtc_dd->ctrl_reg = ctrl_reg;
 363         spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
 364
 365         /* Clear RTC alarm register */
 366         rc = pm8xxx_read_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base +
 367                                                 PM8XXX_ALARM_CTRL_OFFSET, 1);
 368         if (rc < 0) {
 369                 dev_err(rtc_dd->rtc_dev, "RTC Alarm control register read "
 370                                                                 "failed\n");
 371                 goto rtc_alarm_handled;
 372         }
 373
 374         ctrl_reg &= ~PM8xxx_RTC_ALARM_CLEAR;
 375         rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base +
 376                                                 PM8XXX_ALARM_CTRL_OFFSET, 1);
 377         if (rc < 0)
 378                 dev_err(rtc_dd->rtc_dev, "Write to RTC Alarm control register"
 379                                                                 " failed\n");
 380
 381 rtc_alarm_handled:
 382         return IRQ_HANDLED;
 383 }
 384
 385 static int pm8xxx_rtc_probe(struct platform_device *pdev)
 386 {
 387         int rc;
 388         u8 ctrl_reg;
 389         bool rtc_write_enable = false;
 390         struct pm8xxx_rtc *rtc_dd;
 391         struct resource *rtc_resource;
 392         const struct pm8xxx_rtc_platform_data *pdata =
 393                                                 dev_get_platdata(&pdev->dev);
 394
 395         if (pdata != NULL)
 396                 rtc_write_enable = pdata->rtc_write_enable;
 397
 398         rtc_dd = kzalloc(sizeof(*rtc_dd), GFP_KERNEL);
 399         if (rtc_dd == NULL) {
 400                 dev_err(&pdev->dev, "Unable to allocate memory!\n");
 401                 return -ENOMEM;
 402         }
 403
 404         /* Initialise spinlock to protect RTC control register */
 405         spin_lock_init(&rtc_dd->ctrl_reg_lock);
 406
 407         rtc_dd->rtc_alarm_irq = platform_get_irq(pdev, 0);
 408         if (rtc_dd->rtc_alarm_irq < 0) {
 409                 dev_err(&pdev->dev, "Alarm IRQ resource absent!\n");
 410                 rc = -ENXIO;
 411                 goto fail_rtc_enable;
 412         }
 413
 414         rtc_resource = platform_get_resource_byname(pdev, IORESOURCE_IO,
 415                                                         "pmic_rtc_base");
 416         if (!(rtc_resource && rtc_resource->start)) {
 417                 dev_err(&pdev->dev, "RTC IO resource absent!\n");
 418                 rc = -ENXIO;
 419                 goto fail_rtc_enable;
 420         }
 421
 422         rtc_dd->rtc_base = rtc_resource->start;
 423
 424         /* Setup RTC register addresses */
 425         rtc_dd->rtc_write_base = rtc_dd->rtc_base + PM8XXX_RTC_WRITE_OFFSET;
 426         rtc_dd->rtc_read_base = rtc_dd->rtc_base + PM8XXX_RTC_READ_OFFSET;
 427         rtc_dd->alarm_rw_base = rtc_dd->rtc_base + PM8XXX_ALARM_RW_OFFSET;
 428
 429         rtc_dd->rtc_dev = &pdev->dev;
 430
 431         /* Check if the RTC is on, else turn it on */
 432         rc = pm8xxx_read_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base, 1);
 433         if (rc < 0) {
 434                 dev_err(&pdev->dev, "RTC control register read failed!\n");
 435                 goto fail_rtc_enable;
 436         }
 437
 438         if (!(ctrl_reg & PM8xxx_RTC_ENABLE)) {
 439                 ctrl_reg |= PM8xxx_RTC_ENABLE;
 440                 rc = pm8xxx_write_wrapper(rtc_dd, &ctrl_reg, rtc_dd->rtc_base,
 441                                                                         1);
 442                 if (rc < 0) {
 443                         dev_err(&pdev->dev, "Write to RTC control register "
 444                                                                 "failed\n");
 445                         goto fail_rtc_enable;
 446                 }
 447         }
 448
 449         rtc_dd->ctrl_reg = ctrl_reg;
 450         if (rtc_write_enable == true)
 451                 pm8xxx_rtc_ops.set_time = pm8xxx_rtc_set_time;
 452
 453         platform_set_drvdata(pdev, rtc_dd);
 454
 455         /* Register the RTC device */
 456         rtc_dd->rtc = rtc_device_register("pm8xxx_rtc", &pdev->dev,
 457                                 &pm8xxx_rtc_ops, THIS_MODULE);
 458         if (IS_ERR(rtc_dd->rtc)) {
 459                 dev_err(&pdev->dev, "%s: RTC registration failed (%ld)\n",
 460                                         __func__, PTR_ERR(rtc_dd->rtc));
 461                 rc = PTR_ERR(rtc_dd->rtc);
 462                 goto fail_rtc_enable;
 463         }
 464
 465         /* Request the alarm IRQ */
 466         rc = request_any_context_irq(rtc_dd->rtc_alarm_irq,
 467                                  pm8xxx_alarm_trigger, IRQF_TRIGGER_RISING,
 468                                  "pm8xxx_rtc_alarm", rtc_dd);
 469         if (rc < 0) {
 470                 dev_err(&pdev->dev, "Request IRQ failed (%d)\n", rc);
 471                 goto fail_req_irq;
 472         }
 473
 474         device_init_wakeup(&pdev->dev, 1);
 475
 476         dev_dbg(&pdev->dev, "Probe success !!\n");
 477
 478         return 0;
 479
 480 fail_req_irq:
 481         rtc_device_unregister(rtc_dd->rtc);
 482 fail_rtc_enable:
 483         platform_set_drvdata(pdev, NULL);
 484         kfree(rtc_dd);
 485         return rc;
 486 }
 487
 488 static int pm8xxx_rtc_remove(struct platform_device *pdev)
 489 {
 490         struct pm8xxx_rtc *rtc_dd = platform_get_drvdata(pdev);
 491
 492         device_init_wakeup(&pdev->dev, 0);
 493         free_irq(rtc_dd->rtc_alarm_irq, rtc_dd);
 494         rtc_device_unregister(rtc_dd->rtc);
 495         platform_set_drvdata(pdev, NULL);
 496         kfree(rtc_dd);
 497
 498         return 0;
 499 }
 500
 501 #ifdef CONFIG_PM_SLEEP
 502 static int pm8xxx_rtc_resume(struct device *dev)
 503 {
 504         struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
 505
 506         if (device_may_wakeup(dev))
 507                 disable_irq_wake(rtc_dd->rtc_alarm_irq);
 508
 509         return 0;
 510 }
 511
 512 static int pm8xxx_rtc_suspend(struct device *dev)
 513 {
 514         struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
 515
 516         if (device_may_wakeup(dev))
 517                 enable_irq_wake(rtc_dd->rtc_alarm_irq);
 518
 519         return 0;
 520 }
 521 #endif
 522
 523 static SIMPLE_DEV_PM_OPS(pm8xxx_rtc_pm_ops, pm8xxx_rtc_suspend, pm8xxx_rtc_resume);
 524
 525 static struct platform_driver pm8xxx_rtc_driver = {
 526         .probe          = pm8xxx_rtc_probe,
 527         .remove         = pm8xxx_rtc_remove,
 528         .driver = {
 529                 .name   = PM8XXX_RTC_DEV_NAME,
 530                 .owner  = THIS_MODULE,
 531                 .pm     = &pm8xxx_rtc_pm_ops,
 532         },
 533 };
 534
 535 module_platform_driver(pm8xxx_rtc_driver);
 536
 537 MODULE_ALIAS("platform:rtc-pm8xxx");
 538 MODULE_DESCRIPTION("PMIC8xxx RTC driver");
 539 MODULE_LICENSE("GPL v2");
 540 MODULE_AUTHOR("Anirudh Ghayal <aghayal@codeaurora.org>");