drivers/rtc/rtc-tps6586x.c

   1 /*
   2  * rtc-tps6586x.c: RTC driver for TI PMIC TPS6586X
   3  *
   4  * Copyright (c) 2012, NVIDIA Corporation.
   5  *
   6  * Author: Laxman Dewangan <ldewangan@nvidia.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation version 2.
  11  *
  12  * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
  13  * whether express or implied; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20  * 02111-1307, USA
  21  */
  22
  23 #include <linux/device.h>
  24 #include <linux/err.h>
  25 #include <linux/init.h>
  26 #include <linux/kernel.h>
  27 #include <linux/mfd/tps6586x.h>
  28 #include <linux/module.h>
  29 #include <linux/platform_device.h>
  30 #include <linux/pm_runtime.h>
  31 #include <linux/rtc.h>
  32 #include <linux/slab.h>
  33
  34 #define RTC_CTRL                        0xc0
  35 #define POR_RESET_N                     BIT(7)
  36 #define OSC_SRC_SEL                     BIT(6)
  37 #define RTC_ENABLE                      BIT(5)  /* enables alarm */
  38 #define RTC_BUF_ENABLE                  BIT(4)  /* 32 KHz buffer enable */
  39 #define PRE_BYPASS                      BIT(3)  /* 0=1KHz or 1=32KHz updates */
  40 #define CL_SEL_MASK                     (BIT(2)|BIT(1))
  41 #define CL_SEL_POS                      1
  42 #define RTC_ALARM1_HI                   0xc1
  43 #define RTC_COUNT4                      0xc6
  44
  45 /* start a PMU RTC access by reading the register prior to the RTC_COUNT4 */
  46 #define RTC_COUNT4_DUMMYREAD            0xc5
  47
  48 /*only 14-bits width in second*/
  49 #define ALM1_VALID_RANGE_IN_SEC         0x3FFF
  50
  51 #define TPS6586X_RTC_CL_SEL_1_5PF       0x0
  52 #define TPS6586X_RTC_CL_SEL_6_5PF       0x1
  53 #define TPS6586X_RTC_CL_SEL_7_5PF       0x2
  54 #define TPS6586X_RTC_CL_SEL_12_5PF      0x3
  55
  56 struct tps6586x_rtc {
  57         struct device           *dev;
  58         struct rtc_device       *rtc;
  59         int                     irq;
  60         bool                    irq_en;
  61         unsigned long long      epoch_start;
  62 };
  63
  64 static inline struct device *to_tps6586x_dev(struct device *dev)
  65 {
  66         return dev->parent;
  67 }
  68
  69 static int tps6586x_rtc_read_time(struct device *dev, struct rtc_time *tm)
  70 {
  71         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
  72         struct device *tps_dev = to_tps6586x_dev(dev);
  73         unsigned long long ticks = 0;
  74         unsigned long seconds;
  75         u8 buff[6];
  76         int ret;
  77         int i;
  78
  79         ret = tps6586x_reads(tps_dev, RTC_COUNT4_DUMMYREAD, sizeof(buff), buff);
  80         if (ret < 0) {
  81                 dev_err(dev, "read counter failed with err %d\n", ret);
  82                 return ret;
  83         }
  84
  85         for (i = 1; i < sizeof(buff); i++) {
  86                 ticks <<= 8;
  87                 ticks |= buff[i];
  88         }
  89
  90         seconds = ticks >> 10;
  91         seconds += rtc->epoch_start;
  92         rtc_time_to_tm(seconds, tm);
  93         return rtc_valid_tm(tm);
  94 }
  95
  96 static int tps6586x_rtc_set_time(struct device *dev, struct rtc_time *tm)
  97 {
  98         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
  99         struct device *tps_dev = to_tps6586x_dev(dev);
 100         unsigned long long ticks;
 101         unsigned long seconds;
 102         u8 buff[5];
 103         int ret;
 104
 105         rtc_tm_to_time(tm, &seconds);
 106         if (seconds < rtc->epoch_start) {
 107                 dev_err(dev, "requested time unsupported\n");
 108                 return -EINVAL;
 109         }
 110         seconds -= rtc->epoch_start;
 111
 112         ticks = (unsigned long long)seconds << 10;
 113         buff[0] = (ticks >> 32) & 0xff;
 114         buff[1] = (ticks >> 24) & 0xff;
 115         buff[2] = (ticks >> 16) & 0xff;
 116         buff[3] = (ticks >> 8) & 0xff;
 117         buff[4] = ticks & 0xff;
 118
 119         /* Disable RTC before changing time */
 120         ret = tps6586x_clr_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
 121         if (ret < 0) {
 122                 dev_err(dev, "failed to clear RTC_ENABLE\n");
 123                 return ret;
 124         }
 125
 126         ret = tps6586x_writes(tps_dev, RTC_COUNT4, sizeof(buff), buff);
 127         if (ret < 0) {
 128                 dev_err(dev, "failed to program new time\n");
 129                 return ret;
 130         }
 131
 132         /* Enable RTC */
 133         ret = tps6586x_set_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
 134         if (ret < 0) {
 135                 dev_err(dev, "failed to set RTC_ENABLE\n");
 136                 return ret;
 137         }
 138         return 0;
 139 }
 140
 141 static int tps6586x_rtc_alarm_irq_enable(struct device *dev,
 142                          unsigned int enabled)
 143 {
 144         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
 145
 146         if (enabled && !rtc->irq_en) {
 147                 enable_irq(rtc->irq);
 148                 rtc->irq_en = true;
 149         } else if (!enabled && rtc->irq_en)  {
 150                 disable_irq(rtc->irq);
 151                 rtc->irq_en = false;
 152         }
 153         return 0;
 154 }
 155
 156 static int tps6586x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 157 {
 158         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
 159         struct device *tps_dev = to_tps6586x_dev(dev);
 160         unsigned long seconds;
 161         unsigned long ticks;
 162         unsigned long rtc_current_time;
 163         unsigned long long rticks = 0;
 164         u8 buff[3];
 165         u8 rbuff[6];
 166         int ret;
 167         int i;
 168
 169         rtc_tm_to_time(&alrm->time, &seconds);
 170
 171         if (alrm->enabled && (seconds < rtc->epoch_start)) {
 172                 dev_err(dev, "can't set alarm to requested time\n");
 173                 return -EINVAL;
 174         }
 175
 176         ret = tps6586x_rtc_alarm_irq_enable(dev, alrm->enabled);
 177         if (ret < 0) {
 178                 dev_err(dev, "can't set alarm irq, err %d\n", ret);
 179                 return ret;
 180         }
 181
 182         seconds -= rtc->epoch_start;
 183         ret = tps6586x_reads(tps_dev, RTC_COUNT4_DUMMYREAD,
 184                         sizeof(rbuff), rbuff);
 185         if (ret < 0) {
 186                 dev_err(dev, "read counter failed with err %d\n", ret);
 187                 return ret;
 188         }
 189
 190         for (i = 1; i < sizeof(rbuff); i++) {
 191                 rticks <<= 8;
 192                 rticks |= rbuff[i];
 193         }
 194
 195         rtc_current_time = rticks >> 10;
 196         if ((seconds - rtc_current_time) > ALM1_VALID_RANGE_IN_SEC)
 197                 seconds = rtc_current_time - 1;
 198
 199         ticks = (unsigned long long)seconds << 10;
 200         buff[0] = (ticks >> 16) & 0xff;
 201         buff[1] = (ticks >> 8) & 0xff;
 202         buff[2] = ticks & 0xff;
 203
 204         ret = tps6586x_writes(tps_dev, RTC_ALARM1_HI, sizeof(buff), buff);
 205         if (ret)
 206                 dev_err(dev, "programming alarm failed with err %d\n", ret);
 207
 208         return ret;
 209 }
 210
 211 static int tps6586x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 212 {
 213         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
 214         struct device *tps_dev = to_tps6586x_dev(dev);
 215         unsigned long ticks;
 216         unsigned long seconds;
 217         u8 buff[3];
 218         int ret;
 219
 220         ret = tps6586x_reads(tps_dev, RTC_ALARM1_HI, sizeof(buff), buff);
 221         if (ret) {
 222                 dev_err(dev, "read RTC_ALARM1_HI failed with err %d\n", ret);
 223                 return ret;
 224         }
 225
 226         ticks = (buff[0] << 16) | (buff[1] << 8) | buff[2];
 227         seconds = ticks >> 10;
 228         seconds += rtc->epoch_start;
 229
 230         rtc_time_to_tm(seconds, &alrm->time);
 231         return 0;
 232 }
 233
 234 static const struct rtc_class_ops tps6586x_rtc_ops = {
 235         .read_time      = tps6586x_rtc_read_time,
 236         .set_time       = tps6586x_rtc_set_time,
 237         .set_alarm      = tps6586x_rtc_set_alarm,
 238         .read_alarm     = tps6586x_rtc_read_alarm,
 239         .alarm_irq_enable = tps6586x_rtc_alarm_irq_enable,
 240 };
 241
 242 static irqreturn_t tps6586x_rtc_irq(int irq, void *data)
 243 {
 244         struct tps6586x_rtc *rtc = data;
 245
 246         rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
 247         return IRQ_HANDLED;
 248 }
 249
 250 static int tps6586x_rtc_probe(struct platform_device *pdev)
 251 {
 252         struct device *tps_dev = to_tps6586x_dev(&pdev->dev);
 253         struct tps6586x_rtc *rtc;
 254         int ret;
 255
 256         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 257         if (!rtc)
 258                 return -ENOMEM;
 259
 260         rtc->dev = &pdev->dev;
 261         rtc->irq = platform_get_irq(pdev, 0);
 262
 263         /* Set epoch start as 00:00:00:01:01:2009 */
 264         rtc->epoch_start = mktime(2009, 1, 1, 0, 0, 0);
 265
 266         /* 1 kHz tick mode, enable tick counting */
 267         ret = tps6586x_update(tps_dev, RTC_CTRL,
 268                 RTC_ENABLE | OSC_SRC_SEL |
 269                 ((TPS6586X_RTC_CL_SEL_1_5PF << CL_SEL_POS) & CL_SEL_MASK),
 270                 RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
 271         if (ret < 0) {
 272                 dev_err(&pdev->dev, "unable to start counter\n");
 273                 return ret;
 274         }
 275
 276         device_init_wakeup(&pdev->dev, 1);
 277
 278         platform_set_drvdata(pdev, rtc);
 279         rtc->rtc = devm_rtc_device_register(&pdev->dev, dev_name(&pdev->dev),
 280                                        &tps6586x_rtc_ops, THIS_MODULE);
 281         if (IS_ERR(rtc->rtc)) {
 282                 ret = PTR_ERR(rtc->rtc);
 283                 dev_err(&pdev->dev, "RTC device register: ret %d\n", ret);
 284                 goto fail_rtc_register;
 285         }
 286
 287         ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
 288                                 tps6586x_rtc_irq,
 289                                 IRQF_ONESHOT | IRQF_EARLY_RESUME,
 290                                 dev_name(&pdev->dev), rtc);
 291         if (ret < 0) {
 292                 dev_err(&pdev->dev, "request IRQ(%d) failed with ret %d\n",
 293                                 rtc->irq, ret);
 294                 goto fail_rtc_register;
 295         }
 296         disable_irq(rtc->irq);
 297         return 0;
 298
 299 fail_rtc_register:
 300         tps6586x_update(tps_dev, RTC_CTRL, 0,
 301                 RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
 302         return ret;
 303 };
 304
 305 static int tps6586x_rtc_remove(struct platform_device *pdev)
 306 {
 307         struct device *tps_dev = to_tps6586x_dev(&pdev->dev);
 308
 309         tps6586x_update(tps_dev, RTC_CTRL, 0,
 310                 RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
 311         return 0;
 312 }
 313
 314 #ifdef CONFIG_PM_SLEEP
 315 static int tps6586x_rtc_suspend(struct device *dev)
 316 {
 317         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
 318
 319         if (device_may_wakeup(dev))
 320                 enable_irq_wake(rtc->irq);
 321         return 0;
 322 }
 323
 324 static int tps6586x_rtc_resume(struct device *dev)
 325 {
 326         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
 327
 328         if (device_may_wakeup(dev))
 329                 disable_irq_wake(rtc->irq);
 330         return 0;
 331 }
 332 #endif
 333
 334 static SIMPLE_DEV_PM_OPS(tps6586x_pm_ops, tps6586x_rtc_suspend,
 335                         tps6586x_rtc_resume);
 336
 337 static struct platform_driver tps6586x_rtc_driver = {
 338         .driver = {
 339                 .name   = "tps6586x-rtc",
 340                 .pm     = &tps6586x_pm_ops,
 341         },
 342         .probe  = tps6586x_rtc_probe,
 343         .remove = tps6586x_rtc_remove,
 344 };
 345 module_platform_driver(tps6586x_rtc_driver);
 346
 347 MODULE_ALIAS("platform:rtc-tps6586x");
 348 MODULE_DESCRIPTION("TI TPS6586x RTC driver");
 349 MODULE_AUTHOR("Laxman dewangan <ldewangan@nvidia.com>");
 350 MODULE_LICENSE("GPL v2");