drivers/rtc/rtc-palmas.c

   1 /*
   2  * rtc-palmas.c -- Palmas Real Time Clock driver.
   3
   4  * RTC driver for TI Palma series devices like TPS65913,
   5  * TPS65914 power management IC.
   6  *
   7  * Copyright (c) 2012, NVIDIA Corporation.
   8  *
   9  * Author: Laxman Dewangan <ldewangan@nvidia.com>
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License as
  13  * published by the Free Software Foundation version 2.
  14  *
  15  * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
  16  * whether express or implied; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  23  * 02111-1307, USA
  24  */
  25
  26 #include <linux/bcd.h>
  27 #include <linux/errno.h>
  28 #include <linux/init.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/kernel.h>
  31 #include <linux/mfd/palmas.h>
  32 #include <linux/module.h>
  33 #include <linux/of.h>
  34 #include <linux/rtc.h>
  35 #include <linux/types.h>
  36 #include <linux/platform_device.h>
  37 #include <linux/pm.h>
  38
  39 struct palmas_rtc {
  40         struct rtc_device       *rtc;
  41         struct device           *dev;
  42         unsigned int            irq;
  43 };
  44
  45 /* Total number of RTC registers needed to set time*/
  46 #define PALMAS_NUM_TIME_REGS    (PALMAS_YEARS_REG - PALMAS_SECONDS_REG + 1)
  47
  48 /*
  49  * Special bin2bcd mapping to deal with bcd storage of year.
  50  *
  51  *   0-69                -> 0xD0
  52  *  70-99  (1970 - 1999) -> 0xD0 - 0xF9 (correctly rolls to 0x00)
  53  * 100-199 (2000 - 2099) -> 0x00 - 0x99 (does not roll to 0xA0 :-( )
  54  * 200-229 (2100 - 2129) -> 0xA0 - 0xC9 (really for completeness)
  55  * 230-                  -> 0xC9
  56  *
  57  * Confirmed: the only transition that does not work correctly for this rtc
  58  * clock is the transition from 2099 to 2100, it proceeds to 2000. We will
  59  * accept this issue since the clock retains and transitions the year correctly
  60  * in all other conditions.
  61  */
  62 static unsigned char year_bin2bcd(int val)
  63 {
  64         if (val < 70)
  65                 return 0xD0;
  66         if (val < 100)
  67                 return bin2bcd(val - 20) | 0x80; /* KISS leverage of bin2bcd */
  68         if (val >= 230)
  69                 return 0xC9;
  70         if (val >= 200)
  71                 return bin2bcd(val - 180) | 0x80;
  72         return bin2bcd(val - 100);
  73 }
  74
  75 static int year_bcd2bin(unsigned char val)
  76 {
  77         if (val >= 0xD0)
  78                 return bcd2bin(val & 0x7F) + 20;
  79         if (val >= 0xA0)
  80                 return bcd2bin(val & 0x7F) + 180;
  81         return bcd2bin(val) + 100;
  82 }
  83
  84 static int palmas_rtc_read_time(struct device *dev, struct rtc_time *tm)
  85 {
  86         unsigned char rtc_data[PALMAS_NUM_TIME_REGS];
  87         struct palmas *palmas = dev_get_drvdata(dev->parent);
  88         int ret;
  89
  90         /* Copy RTC counting registers to static registers or latches */
  91         ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
  92                 PALMAS_RTC_CTRL_REG_GET_TIME, PALMAS_RTC_CTRL_REG_GET_TIME);
  93         if (ret < 0) {
  94                 dev_err(dev, "RTC CTRL reg update failed, err: %d\n", ret);
  95                 return ret;
  96         }
  97
  98         ret = palmas_bulk_read(palmas, PALMAS_RTC_BASE, PALMAS_SECONDS_REG,
  99                         rtc_data, PALMAS_NUM_TIME_REGS);
 100         if (ret < 0) {
 101                 dev_err(dev, "RTC_SECONDS reg read failed, err = %d\n", ret);
 102                 return ret;
 103         }
 104
 105         tm->tm_sec = bcd2bin(rtc_data[0]);
 106         tm->tm_min = bcd2bin(rtc_data[1]);
 107         tm->tm_hour = bcd2bin(rtc_data[2]);
 108         tm->tm_mday = bcd2bin(rtc_data[3]);
 109         tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
 110         tm->tm_year = year_bcd2bin(rtc_data[5]);
 111
 112         return ret;
 113 }
 114
 115 static int palmas_rtc_set_time(struct device *dev, struct rtc_time *tm)
 116 {
 117         unsigned char rtc_data[PALMAS_NUM_TIME_REGS];
 118         struct palmas *palmas = dev_get_drvdata(dev->parent);
 119         int ret;
 120
 121         rtc_data[0] = bin2bcd(tm->tm_sec);
 122         rtc_data[1] = bin2bcd(tm->tm_min);
 123         rtc_data[2] = bin2bcd(tm->tm_hour);
 124         rtc_data[3] = bin2bcd(tm->tm_mday);
 125         rtc_data[4] = bin2bcd(tm->tm_mon + 1);
 126         rtc_data[5] = year_bin2bcd(tm->tm_year);
 127
 128         /* Stop RTC while updating the RTC time registers */
 129         ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
 130                 PALMAS_RTC_CTRL_REG_STOP_RTC, 0);
 131         if (ret < 0) {
 132                 dev_err(dev, "RTC stop failed, err = %d\n", ret);
 133                 return ret;
 134         }
 135
 136         ret = palmas_bulk_write(palmas, PALMAS_RTC_BASE, PALMAS_SECONDS_REG,
 137                 rtc_data, PALMAS_NUM_TIME_REGS);
 138         if (ret < 0) {
 139                 dev_err(dev, "RTC_SECONDS reg write failed, err = %d\n", ret);
 140                 return ret;
 141         }
 142
 143         /* Start back RTC */
 144         ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
 145                 PALMAS_RTC_CTRL_REG_STOP_RTC, PALMAS_RTC_CTRL_REG_STOP_RTC);
 146         if (ret < 0)
 147                 dev_err(dev, "RTC start failed, err = %d\n", ret);
 148         return ret;
 149 }
 150
 151 static int palmas_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
 152 {
 153         struct palmas *palmas = dev_get_drvdata(dev->parent);
 154         u8 val;
 155
 156         val = enabled ? PALMAS_RTC_INTERRUPTS_REG_IT_ALARM : 0;
 157         return palmas_write(palmas, PALMAS_RTC_BASE,
 158                 PALMAS_RTC_INTERRUPTS_REG, val);
 159 }
 160
 161 static int palmas_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 162 {
 163         unsigned char alarm_data[PALMAS_NUM_TIME_REGS];
 164         u32 int_val;
 165         struct palmas *palmas = dev_get_drvdata(dev->parent);
 166         int ret;
 167
 168         ret = palmas_bulk_read(palmas, PALMAS_RTC_BASE,
 169                         PALMAS_ALARM_SECONDS_REG,
 170                         alarm_data, PALMAS_NUM_TIME_REGS);
 171         if (ret < 0) {
 172                 dev_err(dev, "RTC_ALARM_SECONDS read failed, err = %d\n", ret);
 173                 return ret;
 174         }
 175
 176         alm->time.tm_sec = bcd2bin(alarm_data[0]);
 177         alm->time.tm_min = bcd2bin(alarm_data[1]);
 178         alm->time.tm_hour = bcd2bin(alarm_data[2]);
 179         alm->time.tm_mday = bcd2bin(alarm_data[3]);
 180         alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1;
 181         alm->time.tm_year = year_bcd2bin(alarm_data[5]);
 182
 183         ret = palmas_read(palmas, PALMAS_RTC_BASE, PALMAS_RTC_INTERRUPTS_REG,
 184                         &int_val);
 185         if (ret < 0) {
 186                 dev_err(dev, "RTC_INTERRUPTS reg read failed, err = %d\n", ret);
 187                 return ret;
 188         }
 189
 190         if (int_val & PALMAS_RTC_INTERRUPTS_REG_IT_ALARM)
 191                 alm->enabled = 1;
 192         return ret;
 193 }
 194
 195 static int palmas_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 196 {
 197         unsigned char alarm_data[PALMAS_NUM_TIME_REGS];
 198         struct palmas *palmas = dev_get_drvdata(dev->parent);
 199         int ret;
 200
 201         ret = palmas_rtc_alarm_irq_enable(dev, 0);
 202         if (ret < 0) {
 203                 dev_err(dev, "Disable RTC alarm failed\n");
 204                 return ret;
 205         }
 206
 207         alarm_data[0] = bin2bcd(alm->time.tm_sec);
 208         alarm_data[1] = bin2bcd(alm->time.tm_min);
 209         alarm_data[2] = bin2bcd(alm->time.tm_hour);
 210         alarm_data[3] = bin2bcd(alm->time.tm_mday);
 211         alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
 212         alarm_data[5] = year_bin2bcd(alm->time.tm_year);
 213
 214         ret = palmas_bulk_write(palmas, PALMAS_RTC_BASE,
 215                 PALMAS_ALARM_SECONDS_REG, alarm_data, PALMAS_NUM_TIME_REGS);
 216         if (ret < 0) {
 217                 dev_err(dev, "ALARM_SECONDS_REG write failed, err = %d\n", ret);
 218                 return ret;
 219         }
 220
 221         if (alm->enabled)
 222                 ret = palmas_rtc_alarm_irq_enable(dev, 1);
 223         return ret;
 224 }
 225
 226 static int palmas_clear_interrupts(struct device *dev)
 227 {
 228         struct palmas *palmas = dev_get_drvdata(dev->parent);
 229         unsigned int rtc_reg;
 230         int ret;
 231
 232         ret = palmas_read(palmas, PALMAS_RTC_BASE, PALMAS_RTC_STATUS_REG,
 233                                 &rtc_reg);
 234         if (ret < 0) {
 235                 dev_err(dev, "RTC_STATUS read failed, err = %d\n", ret);
 236                 return ret;
 237         }
 238
 239         ret = palmas_write(palmas, PALMAS_RTC_BASE, PALMAS_RTC_STATUS_REG,
 240                         rtc_reg);
 241         if (ret < 0) {
 242                 dev_err(dev, "RTC_STATUS write failed, err = %d\n", ret);
 243                 return ret;
 244         }
 245         return 0;
 246 }
 247
 248 static irqreturn_t palmas_rtc_interrupt(int irq, void *context)
 249 {
 250         struct palmas_rtc *palmas_rtc = context;
 251         struct device *dev = palmas_rtc->dev;
 252         int ret;
 253
 254         ret = palmas_clear_interrupts(dev);
 255         if (ret < 0) {
 256                 dev_err(dev, "RTC interrupt clear failed, err = %d\n", ret);
 257                 return IRQ_NONE;
 258         }
 259
 260         rtc_update_irq(palmas_rtc->rtc, 1, RTC_IRQF | RTC_AF);
 261         return IRQ_HANDLED;
 262 }
 263
 264 static struct rtc_class_ops palmas_rtc_ops = {
 265         .read_time      = palmas_rtc_read_time,
 266         .set_time       = palmas_rtc_set_time,
 267         .read_alarm     = palmas_rtc_read_alarm,
 268         .set_alarm      = palmas_rtc_set_alarm,
 269         .alarm_irq_enable = palmas_rtc_alarm_irq_enable,
 270 };
 271
 272 static int palmas_rtc_probe(struct platform_device *pdev)
 273 {
 274         struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
 275         struct palmas_rtc *palmas_rtc = NULL;
 276         int ret;
 277         bool enable_bb_charging = false;
 278         bool high_bb_charging = false;
 279
 280         if (pdev->dev.of_node) {
 281                 enable_bb_charging = of_property_read_bool(pdev->dev.of_node,
 282                                         "ti,backup-battery-chargeable");
 283                 high_bb_charging = of_property_read_bool(pdev->dev.of_node,
 284                                         "ti,backup-battery-charge-high-current");
 285         }
 286
 287         palmas_rtc = devm_kzalloc(&pdev->dev, sizeof(struct palmas_rtc),
 288                         GFP_KERNEL);
 289         if (!palmas_rtc)
 290                 return -ENOMEM;
 291
 292         /* Clear pending interrupts */
 293         ret = palmas_clear_interrupts(&pdev->dev);
 294         if (ret < 0) {
 295                 dev_err(&pdev->dev, "clear RTC int failed, err = %d\n", ret);
 296                 return ret;
 297         }
 298
 299         palmas_rtc->dev = &pdev->dev;
 300         platform_set_drvdata(pdev, palmas_rtc);
 301
 302         if (enable_bb_charging) {
 303                 unsigned reg = PALMAS_BACKUP_BATTERY_CTRL_BBS_BBC_LOW_ICHRG;
 304
 305                 if (high_bb_charging)
 306                         reg = 0;
 307
 308                 ret = palmas_update_bits(palmas, PALMAS_PMU_CONTROL_BASE,
 309                         PALMAS_BACKUP_BATTERY_CTRL,
 310                         PALMAS_BACKUP_BATTERY_CTRL_BBS_BBC_LOW_ICHRG, reg);
 311                 if (ret < 0) {
 312                         dev_err(&pdev->dev,
 313                                 "BACKUP_BATTERY_CTRL update failed, %d\n", ret);
 314                         return ret;
 315                 }
 316
 317                 ret = palmas_update_bits(palmas, PALMAS_PMU_CONTROL_BASE,
 318                         PALMAS_BACKUP_BATTERY_CTRL,
 319                         PALMAS_BACKUP_BATTERY_CTRL_BB_CHG_EN,
 320                         PALMAS_BACKUP_BATTERY_CTRL_BB_CHG_EN);
 321                 if (ret < 0) {
 322                         dev_err(&pdev->dev,
 323                                 "BACKUP_BATTERY_CTRL update failed, %d\n", ret);
 324                         return ret;
 325                 }
 326         }
 327
 328         /* Start RTC */
 329         ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
 330                         PALMAS_RTC_CTRL_REG_STOP_RTC,
 331                         PALMAS_RTC_CTRL_REG_STOP_RTC);
 332         if (ret < 0) {
 333                 dev_err(&pdev->dev, "RTC_CTRL write failed, err = %d\n", ret);
 334                 return ret;
 335         }
 336
 337         palmas_rtc->irq = platform_get_irq(pdev, 0);
 338
 339         device_init_wakeup(&pdev->dev, 1);
 340         palmas_rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 341                                 &palmas_rtc_ops, THIS_MODULE);
 342         if (IS_ERR(palmas_rtc->rtc)) {
 343                 ret = PTR_ERR(palmas_rtc->rtc);
 344                 dev_err(&pdev->dev, "RTC register failed, err = %d\n", ret);
 345                 return ret;
 346         }
 347
 348         ret = devm_request_threaded_irq(&pdev->dev, palmas_rtc->irq, NULL,
 349                         palmas_rtc_interrupt,
 350                         IRQF_TRIGGER_LOW | IRQF_ONESHOT |
 351                         IRQF_EARLY_RESUME,
 352                         dev_name(&pdev->dev), palmas_rtc);
 353         if (ret < 0) {
 354                 dev_err(&pdev->dev, "IRQ request failed, err = %d\n", ret);
 355                 return ret;
 356         }
 357
 358         return 0;
 359 }
 360
 361 static int palmas_rtc_remove(struct platform_device *pdev)
 362 {
 363         palmas_rtc_alarm_irq_enable(&pdev->dev, 0);
 364         return 0;
 365 }
 366
 367 #ifdef CONFIG_PM_SLEEP
 368 static int palmas_rtc_suspend(struct device *dev)
 369 {
 370         struct palmas_rtc *palmas_rtc = dev_get_drvdata(dev);
 371
 372         if (device_may_wakeup(dev))
 373                 enable_irq_wake(palmas_rtc->irq);
 374         return 0;
 375 }
 376
 377 static int palmas_rtc_resume(struct device *dev)
 378 {
 379         struct palmas_rtc *palmas_rtc = dev_get_drvdata(dev);
 380
 381         if (device_may_wakeup(dev))
 382                 disable_irq_wake(palmas_rtc->irq);
 383         return 0;
 384 }
 385 #endif
 386
 387 static SIMPLE_DEV_PM_OPS(palmas_rtc_pm_ops, palmas_rtc_suspend,
 388                          palmas_rtc_resume);
 389
 390 #ifdef CONFIG_OF
 391 static const struct of_device_id of_palmas_rtc_match[] = {
 392         { .compatible = "ti,palmas-rtc"},
 393         { },
 394 };
 395 MODULE_DEVICE_TABLE(of, of_palmas_rtc_match);
 396 #endif
 397
 398 static struct platform_driver palmas_rtc_driver = {
 399         .probe          = palmas_rtc_probe,
 400         .remove         = palmas_rtc_remove,
 401         .driver         = {
 402                 .name   = "palmas-rtc",
 403                 .pm     = &palmas_rtc_pm_ops,
 404                 .of_match_table = of_match_ptr(of_palmas_rtc_match),
 405         },
 406 };
 407
 408 module_platform_driver(palmas_rtc_driver);
 409
 410 MODULE_ALIAS("platform:palmas_rtc");
 411 MODULE_DESCRIPTION("TI PALMAS series RTC driver");
 412 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
 413 MODULE_LICENSE("GPL v2");