drivers/rtc/rtc-mpc5121.c

   1 /*
   2  * Real-time clock driver for MPC5121
   3  *
   4  * Copyright 2007, Domen Puncer <domen.puncer@telargo.com>
   5  * Copyright 2008, Freescale Semiconductor, Inc. All rights reserved.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/rtc.h>
  15 #include <linux/of_device.h>
  16 #include <linux/of_platform.h>
  17 #include <linux/io.h>
  18 #include <linux/slab.h>
  19
  20 struct mpc5121_rtc_regs {
  21         u8 set_time;            /* RTC + 0x00 */
  22         u8 hour_set;            /* RTC + 0x01 */
  23         u8 minute_set;          /* RTC + 0x02 */
  24         u8 second_set;          /* RTC + 0x03 */
  25
  26         u8 set_date;            /* RTC + 0x04 */
  27         u8 month_set;           /* RTC + 0x05 */
  28         u8 weekday_set;         /* RTC + 0x06 */
  29         u8 date_set;            /* RTC + 0x07 */
  30
  31         u8 write_sw;            /* RTC + 0x08 */
  32         u8 sw_set;              /* RTC + 0x09 */
  33         u16 year_set;           /* RTC + 0x0a */
  34
  35         u8 alm_enable;          /* RTC + 0x0c */
  36         u8 alm_hour_set;        /* RTC + 0x0d */
  37         u8 alm_min_set;         /* RTC + 0x0e */
  38         u8 int_enable;          /* RTC + 0x0f */
  39
  40         u8 reserved1;
  41         u8 hour;                /* RTC + 0x11 */
  42         u8 minute;              /* RTC + 0x12 */
  43         u8 second;              /* RTC + 0x13 */
  44
  45         u8 month;               /* RTC + 0x14 */
  46         u8 wday_mday;           /* RTC + 0x15 */
  47         u16 year;               /* RTC + 0x16 */
  48
  49         u8 int_alm;             /* RTC + 0x18 */
  50         u8 int_sw;              /* RTC + 0x19 */
  51         u8 alm_status;          /* RTC + 0x1a */
  52         u8 sw_minute;           /* RTC + 0x1b */
  53
  54         u8 bus_error_1;         /* RTC + 0x1c */
  55         u8 int_day;             /* RTC + 0x1d */
  56         u8 int_min;             /* RTC + 0x1e */
  57         u8 int_sec;             /* RTC + 0x1f */
  58
  59         /*
  60          * target_time:
  61          *      intended to be used for hibernation but hibernation
  62          *      does not work on silicon rev 1.5 so use it for non-volatile
  63          *      storage of offset between the actual_time register and linux
  64          *      time
  65          */
  66         u32 target_time;        /* RTC + 0x20 */
  67         /*
  68          * actual_time:
  69          *      readonly time since VBAT_RTC was last connected
  70          */
  71         u32 actual_time;        /* RTC + 0x24 */
  72         u32 keep_alive;         /* RTC + 0x28 */
  73 };
  74
  75 struct mpc5121_rtc_data {
  76         unsigned irq;
  77         unsigned irq_periodic;
  78         struct mpc5121_rtc_regs __iomem *regs;
  79         struct rtc_device *rtc;
  80         struct rtc_wkalrm wkalarm;
  81 };
  82
  83 /*
  84  * Update second/minute/hour registers.
  85  *
  86  * This is just so alarm will work.
  87  */
  88 static void mpc5121_rtc_update_smh(struct mpc5121_rtc_regs __iomem *regs,
  89                                    struct rtc_time *tm)
  90 {
  91         out_8(&regs->second_set, tm->tm_sec);
  92         out_8(&regs->minute_set, tm->tm_min);
  93         out_8(&regs->hour_set, tm->tm_hour);
  94
  95         /* set time sequence */
  96         out_8(&regs->set_time, 0x1);
  97         out_8(&regs->set_time, 0x3);
  98         out_8(&regs->set_time, 0x1);
  99         out_8(&regs->set_time, 0x0);
 100 }
 101
 102 static int mpc5121_rtc_read_time(struct device *dev, struct rtc_time *tm)
 103 {
 104         struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
 105         struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
 106         unsigned long now;
 107
 108         /*
 109          * linux time is actual_time plus the offset saved in target_time
 110          */
 111         now = in_be32(&regs->actual_time) + in_be32(&regs->target_time);
 112
 113         rtc_time_to_tm(now, tm);
 114
 115         /*
 116          * update second minute hour registers
 117          * so alarms will work
 118          */
 119         mpc5121_rtc_update_smh(regs, tm);
 120
 121         return rtc_valid_tm(tm);
 122 }
 123
 124 static int mpc5121_rtc_set_time(struct device *dev, struct rtc_time *tm)
 125 {
 126         struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
 127         struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
 128         int ret;
 129         unsigned long now;
 130
 131         /*
 132          * The actual_time register is read only so we write the offset
 133          * between it and linux time to the target_time register.
 134          */
 135         ret = rtc_tm_to_time(tm, &now);
 136         if (ret == 0)
 137                 out_be32(&regs->target_time, now - in_be32(&regs->actual_time));
 138
 139         /*
 140          * update second minute hour registers
 141          * so alarms will work
 142          */
 143         mpc5121_rtc_update_smh(regs, tm);
 144
 145         return 0;
 146 }
 147
 148 static int mpc5121_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 149 {
 150         struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
 151         struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
 152
 153         *alarm = rtc->wkalarm;
 154
 155         alarm->pending = in_8(&regs->alm_status);
 156
 157         return 0;
 158 }
 159
 160 static int mpc5121_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 161 {
 162         struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
 163         struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
 164
 165         /*
 166          * the alarm has no seconds so deal with it
 167          */
 168         if (alarm->time.tm_sec) {
 169                 alarm->time.tm_sec = 0;
 170                 alarm->time.tm_min++;
 171                 if (alarm->time.tm_min >= 60) {
 172                         alarm->time.tm_min = 0;
 173                         alarm->time.tm_hour++;
 174                         if (alarm->time.tm_hour >= 24)
 175                                 alarm->time.tm_hour = 0;
 176                 }
 177         }
 178
 179         alarm->time.tm_mday = -1;
 180         alarm->time.tm_mon = -1;
 181         alarm->time.tm_year = -1;
 182
 183         out_8(&regs->alm_min_set, alarm->time.tm_min);
 184         out_8(&regs->alm_hour_set, alarm->time.tm_hour);
 185
 186         out_8(&regs->alm_enable, alarm->enabled);
 187
 188         rtc->wkalarm = *alarm;
 189         return 0;
 190 }
 191
 192 static irqreturn_t mpc5121_rtc_handler(int irq, void *dev)
 193 {
 194         struct mpc5121_rtc_data *rtc = dev_get_drvdata((struct device *)dev);
 195         struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
 196
 197         if (in_8(&regs->int_alm)) {
 198                 /* acknowledge and clear status */
 199                 out_8(&regs->int_alm, 1);
 200                 out_8(&regs->alm_status, 1);
 201
 202                 rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
 203                 return IRQ_HANDLED;
 204         }
 205
 206         return IRQ_NONE;
 207 }
 208
 209 static irqreturn_t mpc5121_rtc_handler_upd(int irq, void *dev)
 210 {
 211         struct mpc5121_rtc_data *rtc = dev_get_drvdata((struct device *)dev);
 212         struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
 213
 214         if (in_8(&regs->int_sec) && (in_8(&regs->int_enable) & 0x1)) {
 215                 /* acknowledge */
 216                 out_8(&regs->int_sec, 1);
 217
 218                 rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_UF);
 219                 return IRQ_HANDLED;
 220         }
 221
 222         return IRQ_NONE;
 223 }
 224
 225 static int mpc5121_rtc_alarm_irq_enable(struct device *dev,
 226                                         unsigned int enabled)
 227 {
 228         struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
 229         struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
 230         int val;
 231
 232         if (enabled)
 233                 val = 1;
 234         else
 235                 val = 0;
 236
 237         out_8(&regs->alm_enable, val);
 238         rtc->wkalarm.enabled = val;
 239
 240         return 0;
 241 }
 242
 243 static int mpc5121_rtc_update_irq_enable(struct device *dev,
 244                                          unsigned int enabled)
 245 {
 246         struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
 247         struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
 248         int val;
 249
 250         val = in_8(&regs->int_enable);
 251
 252         if (enabled)
 253                 val = (val & ~0x8) | 0x1;
 254         else
 255                 val &= ~0x1;
 256
 257         out_8(&regs->int_enable, val);
 258
 259         return 0;
 260 }
 261
 262 static const struct rtc_class_ops mpc5121_rtc_ops = {
 263         .read_time = mpc5121_rtc_read_time,
 264         .set_time = mpc5121_rtc_set_time,
 265         .read_alarm = mpc5121_rtc_read_alarm,
 266         .set_alarm = mpc5121_rtc_set_alarm,
 267         .alarm_irq_enable = mpc5121_rtc_alarm_irq_enable,
 268         .update_irq_enable = mpc5121_rtc_update_irq_enable,
 269 };
 270
 271 static int __devinit mpc5121_rtc_probe(struct of_device *op,
 272                                         const struct of_device_id *match)
 273 {
 274         struct mpc5121_rtc_data *rtc;
 275         int err = 0;
 276         u32 ka;
 277
 278         rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
 279         if (!rtc)
 280                 return -ENOMEM;
 281
 282         rtc->regs = of_iomap(op->dev.of_node, 0);
 283         if (!rtc->regs) {
 284                 dev_err(&op->dev, "%s: couldn't map io space\n", __func__);
 285                 err = -ENOSYS;
 286                 goto out_free;
 287         }
 288
 289         device_init_wakeup(&op->dev, 1);
 290
 291         dev_set_drvdata(&op->dev, rtc);
 292
 293         rtc->irq = irq_of_parse_and_map(op->dev.of_node, 1);
 294         err = request_irq(rtc->irq, mpc5121_rtc_handler, IRQF_DISABLED,
 295                                                 "mpc5121-rtc", &op->dev);
 296         if (err) {
 297                 dev_err(&op->dev, "%s: could not request irq: %i\n",
 298                                                         __func__, rtc->irq);
 299                 goto out_dispose;
 300         }
 301
 302         rtc->irq_periodic = irq_of_parse_and_map(op->dev.of_node, 0);
 303         err = request_irq(rtc->irq_periodic, mpc5121_rtc_handler_upd,
 304                                 IRQF_DISABLED, "mpc5121-rtc_upd", &op->dev);
 305         if (err) {
 306                 dev_err(&op->dev, "%s: could not request irq: %i\n",
 307                                                 __func__, rtc->irq_periodic);
 308                 goto out_dispose2;
 309         }
 310
 311         ka = in_be32(&rtc->regs->keep_alive);
 312         if (ka & 0x02) {
 313                 dev_warn(&op->dev,
 314                         "mpc5121-rtc: Battery or oscillator failure!\n");
 315                 out_be32(&rtc->regs->keep_alive, ka);
 316         }
 317
 318         rtc->rtc = rtc_device_register("mpc5121-rtc", &op->dev,
 319                                         &mpc5121_rtc_ops, THIS_MODULE);
 320         if (IS_ERR(rtc->rtc)) {
 321                 err = PTR_ERR(rtc->rtc);
 322                 goto out_free_irq;
 323         }
 324
 325         return 0;
 326
 327 out_free_irq:
 328         free_irq(rtc->irq_periodic, &op->dev);
 329 out_dispose2:
 330         irq_dispose_mapping(rtc->irq_periodic);
 331         free_irq(rtc->irq, &op->dev);
 332 out_dispose:
 333         irq_dispose_mapping(rtc->irq);
 334         iounmap(rtc->regs);
 335 out_free:
 336         kfree(rtc);
 337
 338         return err;
 339 }
 340
 341 static int __devexit mpc5121_rtc_remove(struct of_device *op)
 342 {
 343         struct mpc5121_rtc_data *rtc = dev_get_drvdata(&op->dev);
 344         struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
 345
 346         /* disable interrupt, so there are no nasty surprises */
 347         out_8(&regs->alm_enable, 0);
 348         out_8(&regs->int_enable, in_8(&regs->int_enable) & ~0x1);
 349
 350         rtc_device_unregister(rtc->rtc);
 351         iounmap(rtc->regs);
 352         free_irq(rtc->irq, &op->dev);
 353         free_irq(rtc->irq_periodic, &op->dev);
 354         irq_dispose_mapping(rtc->irq);
 355         irq_dispose_mapping(rtc->irq_periodic);
 356         dev_set_drvdata(&op->dev, NULL);
 357         kfree(rtc);
 358
 359         return 0;
 360 }
 361
 362 static struct of_device_id mpc5121_rtc_match[] __devinitdata = {
 363         { .compatible = "fsl,mpc5121-rtc", },
 364         {},
 365 };
 366
 367 static struct of_platform_driver mpc5121_rtc_driver = {
 368         .driver = {
 369                 .name = "mpc5121-rtc",
 370                 .owner = THIS_MODULE,
 371                 .of_match_table = mpc5121_rtc_match,
 372         },
 373         .probe = mpc5121_rtc_probe,
 374         .remove = __devexit_p(mpc5121_rtc_remove),
 375 };
 376
 377 static int __init mpc5121_rtc_init(void)
 378 {
 379         return of_register_platform_driver(&mpc5121_rtc_driver);
 380 }
 381 module_init(mpc5121_rtc_init);
 382
 383 static void __exit mpc5121_rtc_exit(void)
 384 {
 385         of_unregister_platform_driver(&mpc5121_rtc_driver);
 386 }
 387 module_exit(mpc5121_rtc_exit);
 388
 389 MODULE_LICENSE("GPL");
 390 MODULE_AUTHOR("John Rigby <jcrigby@gmail.com>");