kernel/drivers/rtc/rtc-tps80031.c

   1 /*
   2  * rtc-tps80031.c -- TI TPS80031/TPS80032 RTC driver
   3  *
   4  * RTC driver for TI TPS80031/TPS80032 Fully Integrated
   5  * Power Management with Power Path and Battery Charger
   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/device.h>
  28 #include <linux/err.h>
  29 #include <linux/init.h>
  30 #include <linux/kernel.h>
  31 #include <linux/module.h>
  32 #include <linux/mfd/tps80031.h>
  33 #include <linux/platform_device.h>
  34 #include <linux/pm.h>
  35 #include <linux/rtc.h>
  36 #include <linux/slab.h>
  37
  38 #define ENABLE_ALARM_INT                        0x08
  39 #define ALARM_INT_STATUS                        0x40
  40
  41 /**
  42  * Setting bit to 1 in STOP_RTC will run the RTC and
  43  * setting this bit to 0 will freeze RTC.
  44  */
  45 #define STOP_RTC                                0x1
  46
  47 /* Power on reset Values of RTC registers */
  48 #define TPS80031_RTC_POR_YEAR                   0
  49 #define TPS80031_RTC_POR_MONTH                  1
  50 #define TPS80031_RTC_POR_DAY                    1
  51
  52 /* Numbers of registers for time and alarms */
  53 #define TPS80031_RTC_TIME_NUM_REGS              7
  54 #define TPS80031_RTC_ALARM_NUM_REGS             6
  55
  56 /**
  57  * PMU RTC have only 2 nibbles to store year information, so using an
  58  * offset of 100 to set the base year as 2000 for our driver.
  59  */
  60 #define RTC_YEAR_OFFSET 100
  61
  62 struct tps80031_rtc {
  63         struct rtc_device       *rtc;
  64         int                     irq;
  65 };
  66
  67 static int tps80031_rtc_read_time(struct device *dev, struct rtc_time *tm)
  68 {
  69         u8 buff[TPS80031_RTC_TIME_NUM_REGS];
  70         int ret;
  71
  72         ret = tps80031_reads(dev->parent, TPS80031_SLAVE_ID1,
  73                         TPS80031_SECONDS_REG, TPS80031_RTC_TIME_NUM_REGS, buff);
  74         if (ret < 0) {
  75                 dev_err(dev, "reading RTC_SECONDS_REG failed, err = %d\n", ret);
  76                 return ret;
  77         }
  78
  79         tm->tm_sec = bcd2bin(buff[0]);
  80         tm->tm_min = bcd2bin(buff[1]);
  81         tm->tm_hour = bcd2bin(buff[2]);
  82         tm->tm_mday = bcd2bin(buff[3]);
  83         tm->tm_mon = bcd2bin(buff[4]) - 1;
  84         tm->tm_year = bcd2bin(buff[5]) + RTC_YEAR_OFFSET;
  85         tm->tm_wday = bcd2bin(buff[6]);
  86         return 0;
  87 }
  88
  89 static int tps80031_rtc_set_time(struct device *dev, struct rtc_time *tm)
  90 {
  91         u8 buff[7];
  92         int ret;
  93
  94         buff[0] = bin2bcd(tm->tm_sec);
  95         buff[1] = bin2bcd(tm->tm_min);
  96         buff[2] = bin2bcd(tm->tm_hour);
  97         buff[3] = bin2bcd(tm->tm_mday);
  98         buff[4] = bin2bcd(tm->tm_mon + 1);
  99         buff[5] = bin2bcd(tm->tm_year % RTC_YEAR_OFFSET);
 100         buff[6] = bin2bcd(tm->tm_wday);
 101
 102         /* Stop RTC while updating the RTC time registers */
 103         ret = tps80031_clr_bits(dev->parent, TPS80031_SLAVE_ID1,
 104                                 TPS80031_RTC_CTRL_REG, STOP_RTC);
 105         if (ret < 0) {
 106                 dev_err(dev->parent, "Stop RTC failed, err = %d\n", ret);
 107                 return ret;
 108         }
 109
 110         ret = tps80031_writes(dev->parent, TPS80031_SLAVE_ID1,
 111                         TPS80031_SECONDS_REG,
 112                         TPS80031_RTC_TIME_NUM_REGS, buff);
 113         if (ret < 0) {
 114                 dev_err(dev, "writing RTC_SECONDS_REG failed, err %d\n", ret);
 115                 return ret;
 116         }
 117
 118         ret = tps80031_set_bits(dev->parent, TPS80031_SLAVE_ID1,
 119                                 TPS80031_RTC_CTRL_REG, STOP_RTC);
 120         if (ret < 0)
 121                 dev_err(dev->parent, "Start RTC failed, err = %d\n", ret);
 122         return ret;
 123 }
 124
 125 static int tps80031_rtc_alarm_irq_enable(struct device *dev,
 126                                          unsigned int enable)
 127 {
 128         int ret;
 129
 130         if (enable)
 131                 ret = tps80031_set_bits(dev->parent, TPS80031_SLAVE_ID1,
 132                                 TPS80031_RTC_INTERRUPTS_REG, ENABLE_ALARM_INT);
 133         else
 134                 ret = tps80031_clr_bits(dev->parent, TPS80031_SLAVE_ID1,
 135                                 TPS80031_RTC_INTERRUPTS_REG, ENABLE_ALARM_INT);
 136         if (ret < 0) {
 137                 dev_err(dev, "Update on RTC_INT failed, err = %d\n", ret);
 138                 return ret;
 139         }
 140         return 0;
 141 }
 142
 143 static int tps80031_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 144 {
 145         u8 buff[TPS80031_RTC_ALARM_NUM_REGS];
 146         int ret;
 147
 148         buff[0] = bin2bcd(alrm->time.tm_sec);
 149         buff[1] = bin2bcd(alrm->time.tm_min);
 150         buff[2] = bin2bcd(alrm->time.tm_hour);
 151         buff[3] = bin2bcd(alrm->time.tm_mday);
 152         buff[4] = bin2bcd(alrm->time.tm_mon + 1);
 153         buff[5] = bin2bcd(alrm->time.tm_year % RTC_YEAR_OFFSET);
 154         ret = tps80031_writes(dev->parent, TPS80031_SLAVE_ID1,
 155                         TPS80031_ALARM_SECONDS_REG,
 156                         TPS80031_RTC_ALARM_NUM_REGS, buff);
 157         if (ret < 0) {
 158                 dev_err(dev, "Writing RTC_ALARM failed, err %d\n", ret);
 159                 return ret;
 160         }
 161         return tps80031_rtc_alarm_irq_enable(dev, alrm->enabled);
 162 }
 163
 164 static int tps80031_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 165 {
 166         u8 buff[6];
 167         int ret;
 168
 169         ret = tps80031_reads(dev->parent, TPS80031_SLAVE_ID1,
 170                         TPS80031_ALARM_SECONDS_REG,
 171                         TPS80031_RTC_ALARM_NUM_REGS, buff);
 172         if (ret < 0) {
 173                 dev_err(dev->parent,
 174                         "reading RTC_ALARM failed, err = %d\n", ret);
 175                 return ret;
 176         }
 177
 178         alrm->time.tm_sec = bcd2bin(buff[0]);
 179         alrm->time.tm_min = bcd2bin(buff[1]);
 180         alrm->time.tm_hour = bcd2bin(buff[2]);
 181         alrm->time.tm_mday = bcd2bin(buff[3]);
 182         alrm->time.tm_mon = bcd2bin(buff[4]) - 1;
 183         alrm->time.tm_year = bcd2bin(buff[5]) + RTC_YEAR_OFFSET;
 184         return 0;
 185 }
 186
 187 static int clear_alarm_int_status(struct device *dev, struct tps80031_rtc *rtc)
 188 {
 189         int ret;
 190         u8 buf;
 191
 192         /**
 193          * As per datasheet, A dummy read of this  RTC_STATUS_REG register
 194          * is necessary before each I2C read in order to update the status
 195          * register value.
 196          */
 197         ret = tps80031_read(dev->parent, TPS80031_SLAVE_ID1,
 198                                 TPS80031_RTC_STATUS_REG, &buf);
 199         if (ret < 0) {
 200                 dev_err(dev, "reading RTC_STATUS failed. err = %d\n", ret);
 201                 return ret;
 202         }
 203
 204         /* clear Alarm status bits.*/
 205         ret = tps80031_set_bits(dev->parent, TPS80031_SLAVE_ID1,
 206                         TPS80031_RTC_STATUS_REG, ALARM_INT_STATUS);
 207         if (ret < 0) {
 208                 dev_err(dev, "clear Alarm INT failed, err = %d\n", ret);
 209                 return ret;
 210         }
 211         return 0;
 212 }
 213
 214 static irqreturn_t tps80031_rtc_irq(int irq, void *data)
 215 {
 216         struct device *dev = data;
 217         struct tps80031_rtc *rtc = dev_get_drvdata(dev);
 218         int ret;
 219
 220         ret = clear_alarm_int_status(dev, rtc);
 221         if (ret < 0)
 222                 return ret;
 223
 224         rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
 225         return IRQ_HANDLED;
 226 }
 227
 228 static const struct rtc_class_ops tps80031_rtc_ops = {
 229         .read_time = tps80031_rtc_read_time,
 230         .set_time = tps80031_rtc_set_time,
 231         .set_alarm = tps80031_rtc_set_alarm,
 232         .read_alarm = tps80031_rtc_read_alarm,
 233         .alarm_irq_enable = tps80031_rtc_alarm_irq_enable,
 234 };
 235
 236 static int tps80031_rtc_probe(struct platform_device *pdev)
 237 {
 238         struct tps80031_rtc *rtc;
 239         struct rtc_time tm;
 240         int ret;
 241
 242         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 243         if (!rtc)
 244                 return -ENOMEM;
 245
 246         rtc->irq = platform_get_irq(pdev, 0);
 247         platform_set_drvdata(pdev, rtc);
 248
 249         /* Start RTC */
 250         ret = tps80031_set_bits(pdev->dev.parent, TPS80031_SLAVE_ID1,
 251                         TPS80031_RTC_CTRL_REG, STOP_RTC);
 252         if (ret < 0) {
 253                 dev_err(&pdev->dev, "failed to start RTC. err = %d\n", ret);
 254                 return ret;
 255         }
 256
 257         /* If RTC have POR values, set time 01:01:2000 */
 258         tps80031_rtc_read_time(&pdev->dev, &tm);
 259         if ((tm.tm_year == RTC_YEAR_OFFSET + TPS80031_RTC_POR_YEAR) &&
 260                 (tm.tm_mon == (TPS80031_RTC_POR_MONTH - 1)) &&
 261                 (tm.tm_mday == TPS80031_RTC_POR_DAY)) {
 262                 tm.tm_year = 2000;
 263                 tm.tm_mday = 1;
 264                 tm.tm_mon = 1;
 265                 ret = tps80031_rtc_set_time(&pdev->dev, &tm);
 266                 if (ret < 0) {
 267                         dev_err(&pdev->dev,
 268                                 "RTC set time failed, err = %d\n", ret);
 269                         return ret;
 270                 }
 271         }
 272
 273         /* Clear alarm intretupt status if it is there */
 274         ret = clear_alarm_int_status(&pdev->dev, rtc);
 275         if (ret < 0) {
 276                 dev_err(&pdev->dev, "Clear alarm int failed, err = %d\n", ret);
 277                 return ret;
 278         }
 279
 280         rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 281                                &tps80031_rtc_ops, THIS_MODULE);
 282         if (IS_ERR(rtc->rtc)) {
 283                 ret = PTR_ERR(rtc->rtc);
 284                 dev_err(&pdev->dev, "RTC registration failed, err %d\n", ret);
 285                 return ret;
 286         }
 287
 288         ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
 289                         tps80031_rtc_irq,
 290                         IRQF_ONESHOT | IRQF_EARLY_RESUME,
 291                         dev_name(&pdev->dev), rtc);
 292         if (ret < 0) {
 293                 dev_err(&pdev->dev, "request IRQ:%d failed, err = %d\n",
 294                          rtc->irq, ret);
 295                 return ret;
 296         }
 297         device_set_wakeup_capable(&pdev->dev, 1);
 298         return 0;
 299 }
 300
 301 #ifdef CONFIG_PM_SLEEP
 302 static int tps80031_rtc_suspend(struct device *dev)
 303 {
 304         struct tps80031_rtc *rtc = dev_get_drvdata(dev);
 305
 306         if (device_may_wakeup(dev))
 307                 enable_irq_wake(rtc->irq);
 308         return 0;
 309 }
 310
 311 static int tps80031_rtc_resume(struct device *dev)
 312 {
 313         struct tps80031_rtc *rtc = dev_get_drvdata(dev);
 314
 315         if (device_may_wakeup(dev))
 316                 disable_irq_wake(rtc->irq);
 317         return 0;
 318 };
 319 #endif
 320
 321 static SIMPLE_DEV_PM_OPS(tps80031_pm_ops, tps80031_rtc_suspend,
 322                         tps80031_rtc_resume);
 323
 324 static struct platform_driver tps80031_rtc_driver = {
 325         .driver = {
 326                 .name   = "tps80031-rtc",
 327                 .pm     = &tps80031_pm_ops,
 328         },
 329         .probe  = tps80031_rtc_probe,
 330 };
 331
 332 module_platform_driver(tps80031_rtc_driver);
 333
 334 MODULE_ALIAS("platform:tps80031-rtc");
 335 MODULE_DESCRIPTION("TI TPS80031/TPS80032 RTC driver");
 336 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
 337 MODULE_LICENSE("GPL v2");