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/irq.h>
  27 #include <linux/kernel.h>
  28 #include <linux/mfd/tps6586x.h>
  29 #include <linux/module.h>
  30 #include <linux/platform_device.h>
  31 #include <linux/pm_runtime.h>
  32 #include <linux/rtc.h>
  33 #include <linux/slab.h>
  34
  35 #define RTC_CTRL                        0xc0
  36 #define POR_RESET_N                     BIT(7)
  37 #define OSC_SRC_SEL                     BIT(6)
  38 #define RTC_ENABLE                      BIT(5)  /* enables alarm */
  39 #define RTC_BUF_ENABLE                  BIT(4)  /* 32 KHz buffer enable */
  40 #define PRE_BYPASS                      BIT(3)  /* 0=1KHz or 1=32KHz updates */
  41 #define CL_SEL_MASK                     (BIT(2)|BIT(1))
  42 #define CL_SEL_POS                      1
  43 #define RTC_ALARM1_HI                   0xc1
  44 #define RTC_COUNT4                      0xc6
  45
  46 /* start a PMU RTC access by reading the register prior to the RTC_COUNT4 */
  47 #define RTC_COUNT4_DUMMYREAD            0xc5
  48
  49 /*only 14-bits width in second*/
  50 #define ALM1_VALID_RANGE_IN_SEC         0x3FFF
  51
  52 #define TPS6586X_RTC_CL_SEL_1_5PF       0x0
  53 #define TPS6586X_RTC_CL_SEL_6_5PF       0x1
  54 #define TPS6586X_RTC_CL_SEL_7_5PF       0x2
  55 #define TPS6586X_RTC_CL_SEL_12_5PF      0x3
  56
  57 struct tps6586x_rtc {
  58         struct device           *dev;
  59         struct rtc_device       *rtc;
  60         int                     irq;
  61         bool                    irq_en;
  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 device *tps_dev = to_tps6586x_dev(dev);
  72         unsigned long long ticks = 0;
  73         time64_t seconds;
  74         u8 buff[6];
  75         int ret;
  76         int i;
  77
  78         ret = tps6586x_reads(tps_dev, RTC_COUNT4_DUMMYREAD, sizeof(buff), buff);
  79         if (ret < 0) {
  80                 dev_err(dev, "read counter failed with err %d\n", ret);
  81                 return ret;
  82         }
  83
  84         for (i = 1; i < sizeof(buff); i++) {
  85                 ticks <<= 8;
  86                 ticks |= buff[i];
  87         }
  88
  89         seconds = ticks >> 10;
  90         rtc_time64_to_tm(seconds, tm);
  91
  92         return 0;
  93 }
  94
  95 static int tps6586x_rtc_set_time(struct device *dev, struct rtc_time *tm)
  96 {
  97         struct device *tps_dev = to_tps6586x_dev(dev);
  98         unsigned long long ticks;
  99         time64_t seconds;
 100         u8 buff[5];
 101         int ret;
 102
 103         seconds = rtc_tm_to_time64(tm);
 104
 105         ticks = (unsigned long long)seconds << 10;
 106         buff[0] = (ticks >> 32) & 0xff;
 107         buff[1] = (ticks >> 24) & 0xff;
 108         buff[2] = (ticks >> 16) & 0xff;
 109         buff[3] = (ticks >> 8) & 0xff;
 110         buff[4] = ticks & 0xff;
 111
 112         /* Disable RTC before changing time */
 113         ret = tps6586x_clr_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
 114         if (ret < 0) {
 115                 dev_err(dev, "failed to clear RTC_ENABLE\n");
 116                 return ret;
 117         }
 118
 119         ret = tps6586x_writes(tps_dev, RTC_COUNT4, sizeof(buff), buff);
 120         if (ret < 0) {
 121                 dev_err(dev, "failed to program new time\n");
 122                 return ret;
 123         }
 124
 125         /* Enable RTC */
 126         ret = tps6586x_set_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
 127         if (ret < 0) {
 128                 dev_err(dev, "failed to set RTC_ENABLE\n");
 129                 return ret;
 130         }
 131         return 0;
 132 }
 133
 134 static int tps6586x_rtc_alarm_irq_enable(struct device *dev,
 135                          unsigned int enabled)
 136 {
 137         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
 138
 139         if (enabled && !rtc->irq_en) {
 140                 enable_irq(rtc->irq);
 141                 rtc->irq_en = true;
 142         } else if (!enabled && rtc->irq_en)  {
 143                 disable_irq(rtc->irq);
 144                 rtc->irq_en = false;
 145         }
 146         return 0;
 147 }
 148
 149 static int tps6586x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 150 {
 151         struct device *tps_dev = to_tps6586x_dev(dev);
 152         time64_t seconds;
 153         unsigned long ticks;
 154         unsigned long rtc_current_time;
 155         unsigned long long rticks = 0;
 156         u8 buff[3];
 157         u8 rbuff[6];
 158         int ret;
 159         int i;
 160
 161         seconds = rtc_tm_to_time64(&alrm->time);
 162
 163         ret = tps6586x_rtc_alarm_irq_enable(dev, alrm->enabled);
 164         if (ret < 0) {
 165                 dev_err(dev, "can't set alarm irq, err %d\n", ret);
 166                 return ret;
 167         }
 168
 169         ret = tps6586x_reads(tps_dev, RTC_COUNT4_DUMMYREAD,
 170                         sizeof(rbuff), rbuff);
 171         if (ret < 0) {
 172                 dev_err(dev, "read counter failed with err %d\n", ret);
 173                 return ret;
 174         }
 175
 176         for (i = 1; i < sizeof(rbuff); i++) {
 177                 rticks <<= 8;
 178                 rticks |= rbuff[i];
 179         }
 180
 181         rtc_current_time = rticks >> 10;
 182         if ((seconds - rtc_current_time) > ALM1_VALID_RANGE_IN_SEC)
 183                 seconds = rtc_current_time - 1;
 184
 185         ticks = (unsigned long long)seconds << 10;
 186         buff[0] = (ticks >> 16) & 0xff;
 187         buff[1] = (ticks >> 8) & 0xff;
 188         buff[2] = ticks & 0xff;
 189
 190         ret = tps6586x_writes(tps_dev, RTC_ALARM1_HI, sizeof(buff), buff);
 191         if (ret)
 192                 dev_err(dev, "programming alarm failed with err %d\n", ret);
 193
 194         return ret;
 195 }
 196
 197 static int tps6586x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 198 {
 199         struct device *tps_dev = to_tps6586x_dev(dev);
 200         unsigned long ticks;
 201         time64_t seconds;
 202         u8 buff[3];
 203         int ret;
 204
 205         ret = tps6586x_reads(tps_dev, RTC_ALARM1_HI, sizeof(buff), buff);
 206         if (ret) {
 207                 dev_err(dev, "read RTC_ALARM1_HI failed with err %d\n", ret);
 208                 return ret;
 209         }
 210
 211         ticks = (buff[0] << 16) | (buff[1] << 8) | buff[2];
 212         seconds = ticks >> 10;
 213
 214         rtc_time64_to_tm(seconds, &alrm->time);
 215         return 0;
 216 }
 217
 218 static const struct rtc_class_ops tps6586x_rtc_ops = {
 219         .read_time      = tps6586x_rtc_read_time,
 220         .set_time       = tps6586x_rtc_set_time,
 221         .set_alarm      = tps6586x_rtc_set_alarm,
 222         .read_alarm     = tps6586x_rtc_read_alarm,
 223         .alarm_irq_enable = tps6586x_rtc_alarm_irq_enable,
 224 };
 225
 226 static irqreturn_t tps6586x_rtc_irq(int irq, void *data)
 227 {
 228         struct tps6586x_rtc *rtc = data;
 229
 230         rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
 231         return IRQ_HANDLED;
 232 }
 233
 234 static int tps6586x_rtc_probe(struct platform_device *pdev)
 235 {
 236         struct device *tps_dev = to_tps6586x_dev(&pdev->dev);
 237         struct tps6586x_rtc *rtc;
 238         int ret;
 239
 240         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 241         if (!rtc)
 242                 return -ENOMEM;
 243
 244         rtc->dev = &pdev->dev;
 245         rtc->irq = platform_get_irq(pdev, 0);
 246
 247         /* 1 kHz tick mode, enable tick counting */
 248         ret = tps6586x_update(tps_dev, RTC_CTRL,
 249                 RTC_ENABLE | OSC_SRC_SEL |
 250                 ((TPS6586X_RTC_CL_SEL_1_5PF << CL_SEL_POS) & CL_SEL_MASK),
 251                 RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
 252         if (ret < 0) {
 253                 dev_err(&pdev->dev, "unable to start counter\n");
 254                 return ret;
 255         }
 256
 257         device_init_wakeup(&pdev->dev, 1);
 258
 259         platform_set_drvdata(pdev, rtc);
 260         rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 261         if (IS_ERR(rtc->rtc)) {
 262                 ret = PTR_ERR(rtc->rtc);
 263                 goto fail_rtc_register;
 264         }
 265
 266         rtc->rtc->ops = &tps6586x_rtc_ops;
 267         rtc->rtc->range_max = (1ULL << 30) - 1; /* 30-bit seconds */
 268         rtc->rtc->start_secs = mktime64(2009, 1, 1, 0, 0, 0);
 269         rtc->rtc->set_start_time = true;
 270
 271         irq_set_status_flags(rtc->irq, IRQ_NOAUTOEN);
 272
 273         ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
 274                                 tps6586x_rtc_irq,
 275                                 IRQF_ONESHOT,
 276                                 dev_name(&pdev->dev), rtc);
 277         if (ret < 0) {
 278                 dev_err(&pdev->dev, "request IRQ(%d) failed with ret %d\n",
 279                                 rtc->irq, ret);
 280                 goto fail_rtc_register;
 281         }
 282
 283         ret = devm_rtc_register_device(rtc->rtc);
 284         if (ret)
 285                 goto fail_rtc_register;
 286
 287         return 0;
 288
 289 fail_rtc_register:
 290         tps6586x_update(tps_dev, RTC_CTRL, 0,
 291                 RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
 292         return ret;
 293 };
 294
 295 static int tps6586x_rtc_remove(struct platform_device *pdev)
 296 {
 297         struct device *tps_dev = to_tps6586x_dev(&pdev->dev);
 298
 299         tps6586x_update(tps_dev, RTC_CTRL, 0,
 300                 RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
 301         return 0;
 302 }
 303
 304 #ifdef CONFIG_PM_SLEEP
 305 static int tps6586x_rtc_suspend(struct device *dev)
 306 {
 307         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
 308
 309         if (device_may_wakeup(dev))
 310                 enable_irq_wake(rtc->irq);
 311         return 0;
 312 }
 313
 314 static int tps6586x_rtc_resume(struct device *dev)
 315 {
 316         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
 317
 318         if (device_may_wakeup(dev))
 319                 disable_irq_wake(rtc->irq);
 320         return 0;
 321 }
 322 #endif
 323
 324 static SIMPLE_DEV_PM_OPS(tps6586x_pm_ops, tps6586x_rtc_suspend,
 325                         tps6586x_rtc_resume);
 326
 327 static struct platform_driver tps6586x_rtc_driver = {
 328         .driver = {
 329                 .name   = "tps6586x-rtc",
 330                 .pm     = &tps6586x_pm_ops,
 331         },
 332         .probe  = tps6586x_rtc_probe,
 333         .remove = tps6586x_rtc_remove,
 334 };
 335 module_platform_driver(tps6586x_rtc_driver);
 336
 337 MODULE_ALIAS("platform:tps6586x-rtc");
 338 MODULE_DESCRIPTION("TI TPS6586x RTC driver");
 339 MODULE_AUTHOR("Laxman dewangan <ldewangan@nvidia.com>");
 340 MODULE_LICENSE("GPL v2");