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 #include <linux/of.h>
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/rtc.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/pm.h>
  18 #include <linux/regmap.h>
  19 #include <linux/slab.h>
  20 #include <linux/spinlock.h>
  21
  22 /* RTC Register offsets from RTC CTRL REG */
  23 #define PM8XXX_ALARM_CTRL_OFFSET        0x01
  24 #define PM8XXX_RTC_WRITE_OFFSET         0x02
  25 #define PM8XXX_RTC_READ_OFFSET          0x06
  26 #define PM8XXX_ALARM_RW_OFFSET          0x0A
  27
  28 /* RTC_CTRL register bit fields */
  29 #define PM8xxx_RTC_ENABLE               BIT(7)
  30 #define PM8xxx_RTC_ALARM_CLEAR          BIT(0)
  31
  32 #define NUM_8_BIT_RTC_REGS              0x4
  33
  34 /**
  35  * struct pm8xxx_rtc_regs - describe RTC registers per PMIC versions
  36  * @ctrl: base address of control register
  37  * @write: base address of write register
  38  * @read: base address of read register
  39  * @alarm_ctrl: base address of alarm control register
  40  * @alarm_ctrl2: base address of alarm control2 register
  41  * @alarm_rw: base address of alarm read-write register
  42  * @alarm_en: alarm enable mask
  43  */
  44 struct pm8xxx_rtc_regs {
  45         unsigned int ctrl;
  46         unsigned int write;
  47         unsigned int read;
  48         unsigned int alarm_ctrl;
  49         unsigned int alarm_ctrl2;
  50         unsigned int alarm_rw;
  51         unsigned int alarm_en;
  52 };
  53
  54 /**
  55  * struct pm8xxx_rtc -  rtc driver internal structure
  56  * @rtc:                rtc device for this driver.
  57  * @regmap:             regmap used to access RTC registers
  58  * @allow_set_time:     indicates whether writing to the RTC is allowed
  59  * @rtc_alarm_irq:      rtc alarm irq number.
  60  * @ctrl_reg:           rtc control register.
  61  * @rtc_dev:            device structure.
  62  * @ctrl_reg_lock:      spinlock protecting access to ctrl_reg.
  63  */
  64 struct pm8xxx_rtc {
  65         struct rtc_device *rtc;
  66         struct regmap *regmap;
  67         bool allow_set_time;
  68         int rtc_alarm_irq;
  69         const struct pm8xxx_rtc_regs *regs;
  70         struct device *rtc_dev;
  71         spinlock_t ctrl_reg_lock;
  72 };
  73
  74 /*
  75  * Steps to write the RTC registers.
  76  * 1. Disable alarm if enabled.
  77  * 2. Disable rtc if enabled.
  78  * 3. Write 0x00 to LSB.
  79  * 4. Write Byte[1], Byte[2], Byte[3] then Byte[0].
  80  * 5. Enable rtc if disabled in step 2.
  81  * 6. Enable alarm if disabled in step 1.
  82  */
  83 static int pm8xxx_rtc_set_time(struct device *dev, struct rtc_time *tm)
  84 {
  85         int rc, i;
  86         unsigned long secs, irq_flags;
  87         u8 value[NUM_8_BIT_RTC_REGS], alarm_enabled = 0, rtc_disabled = 0;
  88         unsigned int ctrl_reg, rtc_ctrl_reg;
  89         struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
  90         const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
  91
  92         if (!rtc_dd->allow_set_time)
  93                 return -EACCES;
  94
  95         rtc_tm_to_time(tm, &secs);
  96
  97         dev_dbg(dev, "Seconds value to be written to RTC = %lu\n", secs);
  98
  99         for (i = 0; i < NUM_8_BIT_RTC_REGS; i++) {
 100                 value[i] = secs & 0xFF;
 101                 secs >>= 8;
 102         }
 103
 104         spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
 105
 106         rc = regmap_read(rtc_dd->regmap, regs->alarm_ctrl, &ctrl_reg);
 107         if (rc)
 108                 goto rtc_rw_fail;
 109
 110         if (ctrl_reg & regs->alarm_en) {
 111                 alarm_enabled = 1;
 112                 ctrl_reg &= ~regs->alarm_en;
 113                 rc = regmap_write(rtc_dd->regmap, regs->alarm_ctrl, ctrl_reg);
 114                 if (rc) {
 115                         dev_err(dev, "Write to RTC Alarm control register failed\n");
 116                         goto rtc_rw_fail;
 117                 }
 118         }
 119
 120         /* Disable RTC H/w before writing on RTC register */
 121         rc = regmap_read(rtc_dd->regmap, regs->ctrl, &rtc_ctrl_reg);
 122         if (rc)
 123                 goto rtc_rw_fail;
 124
 125         if (rtc_ctrl_reg & PM8xxx_RTC_ENABLE) {
 126                 rtc_disabled = 1;
 127                 rtc_ctrl_reg &= ~PM8xxx_RTC_ENABLE;
 128                 rc = regmap_write(rtc_dd->regmap, regs->ctrl, rtc_ctrl_reg);
 129                 if (rc) {
 130                         dev_err(dev, "Write to RTC control register failed\n");
 131                         goto rtc_rw_fail;
 132                 }
 133         }
 134
 135         /* Write 0 to Byte[0] */
 136         rc = regmap_write(rtc_dd->regmap, regs->write, 0);
 137         if (rc) {
 138                 dev_err(dev, "Write to RTC write data register failed\n");
 139                 goto rtc_rw_fail;
 140         }
 141
 142         /* Write Byte[1], Byte[2], Byte[3] */
 143         rc = regmap_bulk_write(rtc_dd->regmap, regs->write + 1,
 144                                &value[1], sizeof(value) - 1);
 145         if (rc) {
 146                 dev_err(dev, "Write to RTC write data register failed\n");
 147                 goto rtc_rw_fail;
 148         }
 149
 150         /* Write Byte[0] */
 151         rc = regmap_write(rtc_dd->regmap, regs->write, value[0]);
 152         if (rc) {
 153                 dev_err(dev, "Write to RTC write data register failed\n");
 154                 goto rtc_rw_fail;
 155         }
 156
 157         /* Enable RTC H/w after writing on RTC register */
 158         if (rtc_disabled) {
 159                 rtc_ctrl_reg |= PM8xxx_RTC_ENABLE;
 160                 rc = regmap_write(rtc_dd->regmap, regs->ctrl, rtc_ctrl_reg);
 161                 if (rc) {
 162                         dev_err(dev, "Write to RTC control register failed\n");
 163                         goto rtc_rw_fail;
 164                 }
 165         }
 166
 167         if (alarm_enabled) {
 168                 ctrl_reg |= regs->alarm_en;
 169                 rc = regmap_write(rtc_dd->regmap, regs->alarm_ctrl, ctrl_reg);
 170                 if (rc) {
 171                         dev_err(dev, "Write to RTC Alarm control register failed\n");
 172                         goto rtc_rw_fail;
 173                 }
 174         }
 175
 176 rtc_rw_fail:
 177         spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
 178
 179         return rc;
 180 }
 181
 182 static int pm8xxx_rtc_read_time(struct device *dev, struct rtc_time *tm)
 183 {
 184         int rc;
 185         u8 value[NUM_8_BIT_RTC_REGS];
 186         unsigned long secs;
 187         unsigned int reg;
 188         struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
 189         const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
 190
 191         rc = regmap_bulk_read(rtc_dd->regmap, regs->read, value, sizeof(value));
 192         if (rc) {
 193                 dev_err(dev, "RTC read data register failed\n");
 194                 return rc;
 195         }
 196
 197         /*
 198          * Read the LSB again and check if there has been a carry over.
 199          * If there is, redo the read operation.
 200          */
 201         rc = regmap_read(rtc_dd->regmap, regs->read, &reg);
 202         if (rc < 0) {
 203                 dev_err(dev, "RTC read data register failed\n");
 204                 return rc;
 205         }
 206
 207         if (unlikely(reg < value[0])) {
 208                 rc = regmap_bulk_read(rtc_dd->regmap, regs->read,
 209                                       value, sizeof(value));
 210                 if (rc) {
 211                         dev_err(dev, "RTC read data register failed\n");
 212                         return rc;
 213                 }
 214         }
 215
 216         secs = value[0] | (value[1] << 8) | (value[2] << 16) |
 217                ((unsigned long)value[3] << 24);
 218
 219         rtc_time_to_tm(secs, tm);
 220
 221         dev_dbg(dev, "secs = %lu, h:m:s == %ptRt, y-m-d = %ptRdr\n", secs, tm, tm);
 222
 223         return 0;
 224 }
 225
 226 static int pm8xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 227 {
 228         int rc, i;
 229         u8 value[NUM_8_BIT_RTC_REGS];
 230         unsigned int ctrl_reg;
 231         unsigned long secs, irq_flags;
 232         struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
 233         const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
 234
 235         rtc_tm_to_time(&alarm->time, &secs);
 236
 237         for (i = 0; i < NUM_8_BIT_RTC_REGS; i++) {
 238                 value[i] = secs & 0xFF;
 239                 secs >>= 8;
 240         }
 241
 242         spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
 243
 244         rc = regmap_bulk_write(rtc_dd->regmap, regs->alarm_rw, value,
 245                                sizeof(value));
 246         if (rc) {
 247                 dev_err(dev, "Write to RTC ALARM register failed\n");
 248                 goto rtc_rw_fail;
 249         }
 250
 251         rc = regmap_read(rtc_dd->regmap, regs->alarm_ctrl, &ctrl_reg);
 252         if (rc)
 253                 goto rtc_rw_fail;
 254
 255         if (alarm->enabled)
 256                 ctrl_reg |= regs->alarm_en;
 257         else
 258                 ctrl_reg &= ~regs->alarm_en;
 259
 260         rc = regmap_write(rtc_dd->regmap, regs->alarm_ctrl, ctrl_reg);
 261         if (rc) {
 262                 dev_err(dev, "Write to RTC alarm control register failed\n");
 263                 goto rtc_rw_fail;
 264         }
 265
 266         dev_dbg(dev, "Alarm Set for h:m:s=%ptRt, y-m-d=%ptRdr\n",
 267                 &alarm->time, &alarm->time);
 268 rtc_rw_fail:
 269         spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
 270         return rc;
 271 }
 272
 273 static int pm8xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 274 {
 275         int rc;
 276         u8 value[NUM_8_BIT_RTC_REGS];
 277         unsigned long secs;
 278         struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
 279         const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
 280
 281         rc = regmap_bulk_read(rtc_dd->regmap, regs->alarm_rw, value,
 282                               sizeof(value));
 283         if (rc) {
 284                 dev_err(dev, "RTC alarm time read failed\n");
 285                 return rc;
 286         }
 287
 288         secs = value[0] | (value[1] << 8) | (value[2] << 16) |
 289                ((unsigned long)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:m:s=%ptRt, y-m-d=%ptRdr\n",
 300                 &alarm->time, &alarm->time);
 301
 302         return 0;
 303 }
 304
 305 static int pm8xxx_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
 306 {
 307         int rc;
 308         unsigned long irq_flags;
 309         struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
 310         const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
 311         unsigned int ctrl_reg;
 312
 313         spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
 314
 315         rc = regmap_read(rtc_dd->regmap, regs->alarm_ctrl, &ctrl_reg);
 316         if (rc)
 317                 goto rtc_rw_fail;
 318
 319         if (enable)
 320                 ctrl_reg |= regs->alarm_en;
 321         else
 322                 ctrl_reg &= ~regs->alarm_en;
 323
 324         rc = regmap_write(rtc_dd->regmap, regs->alarm_ctrl, ctrl_reg);
 325         if (rc) {
 326                 dev_err(dev, "Write to RTC control register failed\n");
 327                 goto rtc_rw_fail;
 328         }
 329
 330 rtc_rw_fail:
 331         spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
 332         return rc;
 333 }
 334
 335 static const struct rtc_class_ops pm8xxx_rtc_ops = {
 336         .read_time      = pm8xxx_rtc_read_time,
 337         .set_time       = pm8xxx_rtc_set_time,
 338         .set_alarm      = pm8xxx_rtc_set_alarm,
 339         .read_alarm     = pm8xxx_rtc_read_alarm,
 340         .alarm_irq_enable = pm8xxx_rtc_alarm_irq_enable,
 341 };
 342
 343 static irqreturn_t pm8xxx_alarm_trigger(int irq, void *dev_id)
 344 {
 345         struct pm8xxx_rtc *rtc_dd = dev_id;
 346         const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
 347         unsigned int ctrl_reg;
 348         int rc;
 349         unsigned long irq_flags;
 350
 351         rtc_update_irq(rtc_dd->rtc, 1, RTC_IRQF | RTC_AF);
 352
 353         spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
 354
 355         /* Clear the alarm enable bit */
 356         rc = regmap_read(rtc_dd->regmap, regs->alarm_ctrl, &ctrl_reg);
 357         if (rc) {
 358                 spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
 359                 goto rtc_alarm_handled;
 360         }
 361
 362         ctrl_reg &= ~regs->alarm_en;
 363
 364         rc = regmap_write(rtc_dd->regmap, regs->alarm_ctrl, ctrl_reg);
 365         if (rc) {
 366                 spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
 367                 dev_err(rtc_dd->rtc_dev,
 368                         "Write to alarm control register failed\n");
 369                 goto rtc_alarm_handled;
 370         }
 371
 372         spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
 373
 374         /* Clear RTC alarm register */
 375         rc = regmap_read(rtc_dd->regmap, regs->alarm_ctrl2, &ctrl_reg);
 376         if (rc) {
 377                 dev_err(rtc_dd->rtc_dev,
 378                         "RTC Alarm control2 register read failed\n");
 379                 goto rtc_alarm_handled;
 380         }
 381
 382         ctrl_reg |= PM8xxx_RTC_ALARM_CLEAR;
 383         rc = regmap_write(rtc_dd->regmap, regs->alarm_ctrl2, ctrl_reg);
 384         if (rc)
 385                 dev_err(rtc_dd->rtc_dev,
 386                         "Write to RTC Alarm control2 register failed\n");
 387
 388 rtc_alarm_handled:
 389         return IRQ_HANDLED;
 390 }
 391
 392 static int pm8xxx_rtc_enable(struct pm8xxx_rtc *rtc_dd)
 393 {
 394         const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
 395         unsigned int ctrl_reg;
 396         int rc;
 397
 398         /* Check if the RTC is on, else turn it on */
 399         rc = regmap_read(rtc_dd->regmap, regs->ctrl, &ctrl_reg);
 400         if (rc)
 401                 return rc;
 402
 403         if (!(ctrl_reg & PM8xxx_RTC_ENABLE)) {
 404                 ctrl_reg |= PM8xxx_RTC_ENABLE;
 405                 rc = regmap_write(rtc_dd->regmap, regs->ctrl, ctrl_reg);
 406                 if (rc)
 407                         return rc;
 408         }
 409
 410         return 0;
 411 }
 412
 413 static const struct pm8xxx_rtc_regs pm8921_regs = {
 414         .ctrl           = 0x11d,
 415         .write          = 0x11f,
 416         .read           = 0x123,
 417         .alarm_rw       = 0x127,
 418         .alarm_ctrl     = 0x11d,
 419         .alarm_ctrl2    = 0x11e,
 420         .alarm_en       = BIT(1),
 421 };
 422
 423 static const struct pm8xxx_rtc_regs pm8058_regs = {
 424         .ctrl           = 0x1e8,
 425         .write          = 0x1ea,
 426         .read           = 0x1ee,
 427         .alarm_rw       = 0x1f2,
 428         .alarm_ctrl     = 0x1e8,
 429         .alarm_ctrl2    = 0x1e9,
 430         .alarm_en       = BIT(1),
 431 };
 432
 433 static const struct pm8xxx_rtc_regs pm8941_regs = {
 434         .ctrl           = 0x6046,
 435         .write          = 0x6040,
 436         .read           = 0x6048,
 437         .alarm_rw       = 0x6140,
 438         .alarm_ctrl     = 0x6146,
 439         .alarm_ctrl2    = 0x6148,
 440         .alarm_en       = BIT(7),
 441 };
 442
 443 /*
 444  * Hardcoded RTC bases until IORESOURCE_REG mapping is figured out
 445  */
 446 static const struct of_device_id pm8xxx_id_table[] = {
 447         { .compatible = "qcom,pm8921-rtc", .data = &pm8921_regs },
 448         { .compatible = "qcom,pm8018-rtc", .data = &pm8921_regs },
 449         { .compatible = "qcom,pm8058-rtc", .data = &pm8058_regs },
 450         { .compatible = "qcom,pm8941-rtc", .data = &pm8941_regs },
 451         { },
 452 };
 453 MODULE_DEVICE_TABLE(of, pm8xxx_id_table);
 454
 455 static int pm8xxx_rtc_probe(struct platform_device *pdev)
 456 {
 457         int rc;
 458         struct pm8xxx_rtc *rtc_dd;
 459         const struct of_device_id *match;
 460
 461         match = of_match_node(pm8xxx_id_table, pdev->dev.of_node);
 462         if (!match)
 463                 return -ENXIO;
 464
 465         rtc_dd = devm_kzalloc(&pdev->dev, sizeof(*rtc_dd), GFP_KERNEL);
 466         if (rtc_dd == NULL)
 467                 return -ENOMEM;
 468
 469         /* Initialise spinlock to protect RTC control register */
 470         spin_lock_init(&rtc_dd->ctrl_reg_lock);
 471
 472         rtc_dd->regmap = dev_get_regmap(pdev->dev.parent, NULL);
 473         if (!rtc_dd->regmap) {
 474                 dev_err(&pdev->dev, "Parent regmap unavailable.\n");
 475                 return -ENXIO;
 476         }
 477
 478         rtc_dd->rtc_alarm_irq = platform_get_irq(pdev, 0);
 479         if (rtc_dd->rtc_alarm_irq < 0) {
 480                 dev_err(&pdev->dev, "Alarm IRQ resource absent!\n");
 481                 return -ENXIO;
 482         }
 483
 484         rtc_dd->allow_set_time = of_property_read_bool(pdev->dev.of_node,
 485                                                       "allow-set-time");
 486
 487         rtc_dd->regs = match->data;
 488         rtc_dd->rtc_dev = &pdev->dev;
 489
 490         rc = pm8xxx_rtc_enable(rtc_dd);
 491         if (rc)
 492                 return rc;
 493
 494         platform_set_drvdata(pdev, rtc_dd);
 495
 496         device_init_wakeup(&pdev->dev, 1);
 497
 498         /* Register the RTC device */
 499         rtc_dd->rtc = devm_rtc_device_register(&pdev->dev, "pm8xxx_rtc",
 500                                                &pm8xxx_rtc_ops, THIS_MODULE);
 501         if (IS_ERR(rtc_dd->rtc)) {
 502                 dev_err(&pdev->dev, "%s: RTC registration failed (%ld)\n",
 503                         __func__, PTR_ERR(rtc_dd->rtc));
 504                 return PTR_ERR(rtc_dd->rtc);
 505         }
 506
 507         /* Request the alarm IRQ */
 508         rc = devm_request_any_context_irq(&pdev->dev, rtc_dd->rtc_alarm_irq,
 509                                           pm8xxx_alarm_trigger,
 510                                           IRQF_TRIGGER_RISING,
 511                                           "pm8xxx_rtc_alarm", rtc_dd);
 512         if (rc < 0) {
 513                 dev_err(&pdev->dev, "Request IRQ failed (%d)\n", rc);
 514                 return rc;
 515         }
 516
 517         dev_dbg(&pdev->dev, "Probe success !!\n");
 518
 519         return 0;
 520 }
 521
 522 #ifdef CONFIG_PM_SLEEP
 523 static int pm8xxx_rtc_resume(struct device *dev)
 524 {
 525         struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
 526
 527         if (device_may_wakeup(dev))
 528                 disable_irq_wake(rtc_dd->rtc_alarm_irq);
 529
 530         return 0;
 531 }
 532
 533 static int pm8xxx_rtc_suspend(struct device *dev)
 534 {
 535         struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
 536
 537         if (device_may_wakeup(dev))
 538                 enable_irq_wake(rtc_dd->rtc_alarm_irq);
 539
 540         return 0;
 541 }
 542 #endif
 543
 544 static SIMPLE_DEV_PM_OPS(pm8xxx_rtc_pm_ops,
 545                          pm8xxx_rtc_suspend,
 546                          pm8xxx_rtc_resume);
 547
 548 static struct platform_driver pm8xxx_rtc_driver = {
 549         .probe          = pm8xxx_rtc_probe,
 550         .driver = {
 551                 .name           = "rtc-pm8xxx",
 552                 .pm             = &pm8xxx_rtc_pm_ops,
 553                 .of_match_table = pm8xxx_id_table,
 554         },
 555 };
 556
 557 module_platform_driver(pm8xxx_rtc_driver);
 558
 559 MODULE_ALIAS("platform:rtc-pm8xxx");
 560 MODULE_DESCRIPTION("PMIC8xxx RTC driver");
 561 MODULE_LICENSE("GPL v2");
 562 MODULE_AUTHOR("Anirudh Ghayal <aghayal@codeaurora.org>");