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 };
  62
  63 static inline struct device *to_tps6586x_dev(struct device *dev)
  64 {
  65         return dev->parent;
  66 }
  67
  68 static int tps6586x_rtc_read_time(struct device *dev, struct rtc_time *tm)
  69 {
  70         struct device *tps_dev = to_tps6586x_dev(dev);
  71         unsigned long long ticks = 0;
  72         time64_t seconds;
  73         u8 buff[6];
  74         int ret;
  75         int i;
  76
  77         ret = tps6586x_reads(tps_dev, RTC_COUNT4_DUMMYREAD, sizeof(buff), buff);
  78         if (ret < 0) {
  79                 dev_err(dev, "read counter failed with err %d\n", ret);
  80                 return ret;
  81         }
  82
  83         for (i = 1; i < sizeof(buff); i++) {
  84                 ticks <<= 8;
  85                 ticks |= buff[i];
  86         }
  87
  88         seconds = ticks >> 10;
  89         rtc_time64_to_tm(seconds, tm);
  90
  91         return 0;
  92 }
  93
  94 static int tps6586x_rtc_set_time(struct device *dev, struct rtc_time *tm)
  95 {
  96         struct device *tps_dev = to_tps6586x_dev(dev);
  97         unsigned long long ticks;
  98         time64_t seconds;
  99         u8 buff[5];
 100         int ret;
 101
 102         seconds = rtc_tm_to_time64(tm);
 103
 104         ticks = (unsigned long long)seconds << 10;
 105         buff[0] = (ticks >> 32) & 0xff;
 106         buff[1] = (ticks >> 24) & 0xff;
 107         buff[2] = (ticks >> 16) & 0xff;
 108         buff[3] = (ticks >> 8) & 0xff;
 109         buff[4] = ticks & 0xff;
 110
 111         /* Disable RTC before changing time */
 112         ret = tps6586x_clr_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
 113         if (ret < 0) {
 114                 dev_err(dev, "failed to clear RTC_ENABLE\n");
 115                 return ret;
 116         }
 117
 118         ret = tps6586x_writes(tps_dev, RTC_COUNT4, sizeof(buff), buff);
 119         if (ret < 0) {
 120                 dev_err(dev, "failed to program new time\n");
 121                 return ret;
 122         }
 123
 124         /* Enable RTC */
 125         ret = tps6586x_set_bits(tps_dev, RTC_CTRL, RTC_ENABLE);
 126         if (ret < 0) {
 127                 dev_err(dev, "failed to set RTC_ENABLE\n");
 128                 return ret;
 129         }
 130         return 0;
 131 }
 132
 133 static int tps6586x_rtc_alarm_irq_enable(struct device *dev,
 134                          unsigned int enabled)
 135 {
 136         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
 137
 138         if (enabled && !rtc->irq_en) {
 139                 enable_irq(rtc->irq);
 140                 rtc->irq_en = true;
 141         } else if (!enabled && rtc->irq_en)  {
 142                 disable_irq(rtc->irq);
 143                 rtc->irq_en = false;
 144         }
 145         return 0;
 146 }
 147
 148 static int tps6586x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 149 {
 150         struct device *tps_dev = to_tps6586x_dev(dev);
 151         time64_t seconds;
 152         unsigned long ticks;
 153         unsigned long rtc_current_time;
 154         unsigned long long rticks = 0;
 155         u8 buff[3];
 156         u8 rbuff[6];
 157         int ret;
 158         int i;
 159
 160         seconds = rtc_tm_to_time64(&alrm->time);
 161
 162         ret = tps6586x_rtc_alarm_irq_enable(dev, alrm->enabled);
 163         if (ret < 0) {
 164                 dev_err(dev, "can't set alarm irq, err %d\n", ret);
 165                 return ret;
 166         }
 167
 168         ret = tps6586x_reads(tps_dev, RTC_COUNT4_DUMMYREAD,
 169                         sizeof(rbuff), rbuff);
 170         if (ret < 0) {
 171                 dev_err(dev, "read counter failed with err %d\n", ret);
 172                 return ret;
 173         }
 174
 175         for (i = 1; i < sizeof(rbuff); i++) {
 176                 rticks <<= 8;
 177                 rticks |= rbuff[i];
 178         }
 179
 180         rtc_current_time = rticks >> 10;
 181         if ((seconds - rtc_current_time) > ALM1_VALID_RANGE_IN_SEC)
 182                 seconds = rtc_current_time - 1;
 183
 184         ticks = (unsigned long long)seconds << 10;
 185         buff[0] = (ticks >> 16) & 0xff;
 186         buff[1] = (ticks >> 8) & 0xff;
 187         buff[2] = ticks & 0xff;
 188
 189         ret = tps6586x_writes(tps_dev, RTC_ALARM1_HI, sizeof(buff), buff);
 190         if (ret)
 191                 dev_err(dev, "programming alarm failed with err %d\n", ret);
 192
 193         return ret;
 194 }
 195
 196 static int tps6586x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 197 {
 198         struct device *tps_dev = to_tps6586x_dev(dev);
 199         unsigned long ticks;
 200         time64_t seconds;
 201         u8 buff[3];
 202         int ret;
 203
 204         ret = tps6586x_reads(tps_dev, RTC_ALARM1_HI, sizeof(buff), buff);
 205         if (ret) {
 206                 dev_err(dev, "read RTC_ALARM1_HI failed with err %d\n", ret);
 207                 return ret;
 208         }
 209
 210         ticks = (buff[0] << 16) | (buff[1] << 8) | buff[2];
 211         seconds = ticks >> 10;
 212
 213         rtc_time64_to_tm(seconds, &alrm->time);
 214         return 0;
 215 }
 216
 217 static const struct rtc_class_ops tps6586x_rtc_ops = {
 218         .read_time      = tps6586x_rtc_read_time,
 219         .set_time       = tps6586x_rtc_set_time,
 220         .set_alarm      = tps6586x_rtc_set_alarm,
 221         .read_alarm     = tps6586x_rtc_read_alarm,
 222         .alarm_irq_enable = tps6586x_rtc_alarm_irq_enable,
 223 };
 224
 225 static irqreturn_t tps6586x_rtc_irq(int irq, void *data)
 226 {
 227         struct tps6586x_rtc *rtc = data;
 228
 229         rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
 230         return IRQ_HANDLED;
 231 }
 232
 233 static int tps6586x_rtc_probe(struct platform_device *pdev)
 234 {
 235         struct device *tps_dev = to_tps6586x_dev(&pdev->dev);
 236         struct tps6586x_rtc *rtc;
 237         int ret;
 238
 239         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 240         if (!rtc)
 241                 return -ENOMEM;
 242
 243         rtc->dev = &pdev->dev;
 244         rtc->irq = platform_get_irq(pdev, 0);
 245
 246         /* 1 kHz tick mode, enable tick counting */
 247         ret = tps6586x_update(tps_dev, RTC_CTRL,
 248                 RTC_ENABLE | OSC_SRC_SEL |
 249                 ((TPS6586X_RTC_CL_SEL_1_5PF << CL_SEL_POS) & CL_SEL_MASK),
 250                 RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
 251         if (ret < 0) {
 252                 dev_err(&pdev->dev, "unable to start counter\n");
 253                 return ret;
 254         }
 255
 256         device_init_wakeup(&pdev->dev, 1);
 257
 258         platform_set_drvdata(pdev, rtc);
 259         rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 260         if (IS_ERR(rtc->rtc)) {
 261                 ret = PTR_ERR(rtc->rtc);
 262                 goto fail_rtc_register;
 263         }
 264
 265         rtc->rtc->ops = &tps6586x_rtc_ops;
 266         rtc->rtc->range_max = (1ULL << 30) - 1; /* 30-bit seconds */
 267         rtc->rtc->start_secs = mktime64(2009, 1, 1, 0, 0, 0);
 268         rtc->rtc->set_start_time = true;
 269
 270         ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
 271                                 tps6586x_rtc_irq,
 272                                 IRQF_ONESHOT,
 273                                 dev_name(&pdev->dev), rtc);
 274         if (ret < 0) {
 275                 dev_err(&pdev->dev, "request IRQ(%d) failed with ret %d\n",
 276                                 rtc->irq, ret);
 277                 goto fail_rtc_register;
 278         }
 279         disable_irq(rtc->irq);
 280
 281         ret = rtc_register_device(rtc->rtc);
 282         if (ret)
 283                 goto fail_rtc_register;
 284
 285         return 0;
 286
 287 fail_rtc_register:
 288         tps6586x_update(tps_dev, RTC_CTRL, 0,
 289                 RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
 290         return ret;
 291 };
 292
 293 static int tps6586x_rtc_remove(struct platform_device *pdev)
 294 {
 295         struct device *tps_dev = to_tps6586x_dev(&pdev->dev);
 296
 297         tps6586x_update(tps_dev, RTC_CTRL, 0,
 298                 RTC_ENABLE | OSC_SRC_SEL | PRE_BYPASS | CL_SEL_MASK);
 299         return 0;
 300 }
 301
 302 #ifdef CONFIG_PM_SLEEP
 303 static int tps6586x_rtc_suspend(struct device *dev)
 304 {
 305         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
 306
 307         if (device_may_wakeup(dev))
 308                 enable_irq_wake(rtc->irq);
 309         return 0;
 310 }
 311
 312 static int tps6586x_rtc_resume(struct device *dev)
 313 {
 314         struct tps6586x_rtc *rtc = dev_get_drvdata(dev);
 315
 316         if (device_may_wakeup(dev))
 317                 disable_irq_wake(rtc->irq);
 318         return 0;
 319 }
 320 #endif
 321
 322 static SIMPLE_DEV_PM_OPS(tps6586x_pm_ops, tps6586x_rtc_suspend,
 323                         tps6586x_rtc_resume);
 324
 325 static struct platform_driver tps6586x_rtc_driver = {
 326         .driver = {
 327                 .name   = "tps6586x-rtc",
 328                 .pm     = &tps6586x_pm_ops,
 329         },
 330         .probe  = tps6586x_rtc_probe,
 331         .remove = tps6586x_rtc_remove,
 332 };
 333 module_platform_driver(tps6586x_rtc_driver);
 334
 335 MODULE_ALIAS("platform:tps6586x-rtc");
 336 MODULE_DESCRIPTION("TI TPS6586x RTC driver");
 337 MODULE_AUTHOR("Laxman dewangan <ldewangan@nvidia.com>");
 338 MODULE_LICENSE("GPL v2");