drivers/rtc/rtc-mc13783.c

   1 /*
   2  * Real Time Clock driver for Freescale MC13783 PMIC
   3  *
   4  * (C) 2009 Sascha Hauer, Pengutronix
   5  * (C) 2009 Uwe Kleine-Koenig, Pengutronix
   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/mfd/mc13783.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/slab.h>
  17 #include <linux/rtc.h>
  18
  19 #define DRIVER_NAME "mc13783-rtc"
  20
  21 #define MC13783_RTCTOD  20
  22 #define MC13783_RTCTODA 21
  23 #define MC13783_RTCDAY  22
  24 #define MC13783_RTCDAYA 23
  25
  26 struct mc13783_rtc {
  27         struct rtc_device *rtc;
  28         struct mc13783 *mc13783;
  29         int valid;
  30 };
  31
  32 static int mc13783_rtc_irq_enable_unlocked(struct device *dev,
  33                 unsigned int enabled, int irq)
  34 {
  35         struct mc13783_rtc *priv = dev_get_drvdata(dev);
  36         int (*func)(struct mc13783 *mc13783, int irq);
  37
  38         if (!priv->valid)
  39                 return -ENODATA;
  40
  41         func = enabled ? mc13783_irq_unmask : mc13783_irq_mask;
  42         return func(priv->mc13783, irq);
  43 }
  44
  45 static int mc13783_rtc_irq_enable(struct device *dev,
  46                 unsigned int enabled, int irq)
  47 {
  48         struct mc13783_rtc *priv = dev_get_drvdata(dev);
  49         int ret;
  50
  51         mc13783_lock(priv->mc13783);
  52
  53         ret = mc13783_rtc_irq_enable_unlocked(dev, enabled, irq);
  54
  55         mc13783_unlock(priv->mc13783);
  56
  57         return ret;
  58 }
  59
  60 static int mc13783_rtc_read_time(struct device *dev, struct rtc_time *tm)
  61 {
  62         struct mc13783_rtc *priv = dev_get_drvdata(dev);
  63         unsigned int seconds, days1, days2;
  64         unsigned long s1970;
  65         int ret;
  66
  67         mc13783_lock(priv->mc13783);
  68
  69         if (!priv->valid) {
  70                 ret = -ENODATA;
  71                 goto out;
  72         }
  73
  74         ret = mc13783_reg_read(priv->mc13783, MC13783_RTCDAY, &days1);
  75         if (unlikely(ret))
  76                 goto out;
  77
  78         ret = mc13783_reg_read(priv->mc13783, MC13783_RTCTOD, &seconds);
  79         if (unlikely(ret))
  80                 goto out;
  81
  82         ret = mc13783_reg_read(priv->mc13783, MC13783_RTCDAY, &days2);
  83 out:
  84         mc13783_unlock(priv->mc13783);
  85
  86         if (ret)
  87                 return ret;
  88
  89         if (days2 == days1 + 1) {
  90                 if (seconds >= 86400 / 2)
  91                         days2 = days1;
  92                 else
  93                         days1 = days2;
  94         }
  95
  96         if (days1 != days2)
  97                 return -EIO;
  98
  99         s1970 = days1 * 86400 + seconds;
 100
 101         rtc_time_to_tm(s1970, tm);
 102
 103         return rtc_valid_tm(tm);
 104 }
 105
 106 static int mc13783_rtc_set_mmss(struct device *dev, unsigned long secs)
 107 {
 108         struct mc13783_rtc *priv = dev_get_drvdata(dev);
 109         unsigned int seconds, days;
 110         unsigned int alarmseconds;
 111         int ret;
 112
 113         seconds = secs % 86400;
 114         days = secs / 86400;
 115
 116         mc13783_lock(priv->mc13783);
 117
 118         /*
 119          * temporarily invalidate alarm to prevent triggering it when the day is
 120          * already updated while the time isn't yet.
 121          */
 122         ret = mc13783_reg_read(priv->mc13783, MC13783_RTCTODA, &alarmseconds);
 123         if (unlikely(ret))
 124                 goto out;
 125
 126         if (alarmseconds < 86400) {
 127                 ret = mc13783_reg_write(priv->mc13783,
 128                                 MC13783_RTCTODA, 0x1ffff);
 129                 if (unlikely(ret))
 130                         goto out;
 131         }
 132
 133         /*
 134          * write seconds=0 to prevent a day switch between writing days
 135          * and seconds below
 136          */
 137         ret = mc13783_reg_write(priv->mc13783, MC13783_RTCTOD, 0);
 138         if (unlikely(ret))
 139                 goto out;
 140
 141         ret = mc13783_reg_write(priv->mc13783, MC13783_RTCDAY, days);
 142         if (unlikely(ret))
 143                 goto out;
 144
 145         ret = mc13783_reg_write(priv->mc13783, MC13783_RTCTOD, seconds);
 146         if (unlikely(ret))
 147                 goto out;
 148
 149         /* restore alarm */
 150         if (alarmseconds < 86400) {
 151                 ret = mc13783_reg_write(priv->mc13783,
 152                                 MC13783_RTCTODA, alarmseconds);
 153                 if (unlikely(ret))
 154                         goto out;
 155         }
 156
 157         ret = mc13783_irq_ack(priv->mc13783, MC13783_IRQ_RTCRST);
 158         if (unlikely(ret))
 159                 goto out;
 160
 161         ret = mc13783_irq_unmask(priv->mc13783, MC13783_IRQ_RTCRST);
 162 out:
 163         priv->valid = !ret;
 164
 165         mc13783_unlock(priv->mc13783);
 166
 167         return ret;
 168 }
 169
 170 static int mc13783_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 171 {
 172         struct mc13783_rtc *priv = dev_get_drvdata(dev);
 173         unsigned seconds, days;
 174         unsigned long s1970;
 175         int enabled, pending;
 176         int ret;
 177
 178         mc13783_lock(priv->mc13783);
 179
 180         ret = mc13783_reg_read(priv->mc13783, MC13783_RTCTODA, &seconds);
 181         if (unlikely(ret))
 182                 goto out;
 183         if (seconds >= 86400) {
 184                 ret = -ENODATA;
 185                 goto out;
 186         }
 187
 188         ret = mc13783_reg_read(priv->mc13783, MC13783_RTCDAY, &days);
 189         if (unlikely(ret))
 190                 goto out;
 191
 192         ret = mc13783_irq_status(priv->mc13783, MC13783_IRQ_TODA,
 193                         &enabled, &pending);
 194
 195 out:
 196         mc13783_unlock(priv->mc13783);
 197
 198         if (ret)
 199                 return ret;
 200
 201         alarm->enabled = enabled;
 202         alarm->pending = pending;
 203
 204         s1970 = days * 86400 + seconds;
 205
 206         rtc_time_to_tm(s1970, &alarm->time);
 207         dev_dbg(dev, "%s: %lu\n", __func__, s1970);
 208
 209         return 0;
 210 }
 211
 212 static int mc13783_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 213 {
 214         struct mc13783_rtc *priv = dev_get_drvdata(dev);
 215         unsigned long s1970;
 216         unsigned seconds, days;
 217         int ret;
 218
 219         mc13783_lock(priv->mc13783);
 220
 221         /* disable alarm to prevent false triggering */
 222         ret = mc13783_reg_write(priv->mc13783, MC13783_RTCTODA, 0x1ffff);
 223         if (unlikely(ret))
 224                 goto out;
 225
 226         ret = mc13783_irq_ack(priv->mc13783, MC13783_IRQ_TODA);
 227         if (unlikely(ret))
 228                 goto out;
 229
 230         ret = rtc_tm_to_time(&alarm->time, &s1970);
 231         if (unlikely(ret))
 232                 goto out;
 233
 234         dev_dbg(dev, "%s: o%2.s %lu\n", __func__, alarm->enabled ? "n" : "ff",
 235                         s1970);
 236
 237         ret = mc13783_rtc_irq_enable_unlocked(dev, alarm->enabled,
 238                         MC13783_IRQ_TODA);
 239         if (unlikely(ret))
 240                 goto out;
 241
 242         seconds = s1970 % 86400;
 243         days = s1970 / 86400;
 244
 245         ret = mc13783_reg_write(priv->mc13783, MC13783_RTCDAYA, days);
 246         if (unlikely(ret))
 247                 goto out;
 248
 249         ret = mc13783_reg_write(priv->mc13783, MC13783_RTCTODA, seconds);
 250
 251 out:
 252         mc13783_unlock(priv->mc13783);
 253
 254         return ret;
 255 }
 256
 257 static irqreturn_t mc13783_rtc_alarm_handler(int irq, void *dev)
 258 {
 259         struct mc13783_rtc *priv = dev;
 260         struct mc13783 *mc13783 = priv->mc13783;
 261
 262         dev_dbg(&priv->rtc->dev, "Alarm\n");
 263
 264         rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_AF);
 265
 266         mc13783_irq_ack(mc13783, irq);
 267
 268         return IRQ_HANDLED;
 269 }
 270
 271 static irqreturn_t mc13783_rtc_update_handler(int irq, void *dev)
 272 {
 273         struct mc13783_rtc *priv = dev;
 274         struct mc13783 *mc13783 = priv->mc13783;
 275
 276         dev_dbg(&priv->rtc->dev, "1HZ\n");
 277
 278         rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_UF);
 279
 280         mc13783_irq_ack(mc13783, irq);
 281
 282         return IRQ_HANDLED;
 283 }
 284
 285 static int mc13783_rtc_update_irq_enable(struct device *dev,
 286                 unsigned int enabled)
 287 {
 288         return mc13783_rtc_irq_enable(dev, enabled, MC13783_IRQ_1HZ);
 289 }
 290
 291 static int mc13783_rtc_alarm_irq_enable(struct device *dev,
 292                 unsigned int enabled)
 293 {
 294         return mc13783_rtc_irq_enable(dev, enabled, MC13783_IRQ_TODA);
 295 }
 296
 297 static const struct rtc_class_ops mc13783_rtc_ops = {
 298         .read_time = mc13783_rtc_read_time,
 299         .set_mmss = mc13783_rtc_set_mmss,
 300         .read_alarm = mc13783_rtc_read_alarm,
 301         .set_alarm = mc13783_rtc_set_alarm,
 302         .alarm_irq_enable = mc13783_rtc_alarm_irq_enable,
 303         .update_irq_enable = mc13783_rtc_update_irq_enable,
 304 };
 305
 306 static irqreturn_t mc13783_rtc_reset_handler(int irq, void *dev)
 307 {
 308         struct mc13783_rtc *priv = dev;
 309         struct mc13783 *mc13783 = priv->mc13783;
 310
 311         dev_dbg(&priv->rtc->dev, "RTCRST\n");
 312         priv->valid = 0;
 313
 314         mc13783_irq_mask(mc13783, irq);
 315
 316         return IRQ_HANDLED;
 317 }
 318
 319 static int __devinit mc13783_rtc_probe(struct platform_device *pdev)
 320 {
 321         int ret;
 322         struct mc13783_rtc *priv;
 323         struct mc13783 *mc13783;
 324         int rtcrst_pending;
 325
 326         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 327         if (!priv)
 328                 return -ENOMEM;
 329
 330         mc13783 = dev_get_drvdata(pdev->dev.parent);
 331         priv->mc13783 = mc13783;
 332
 333         platform_set_drvdata(pdev, priv);
 334
 335         mc13783_lock(mc13783);
 336
 337         ret = mc13783_irq_request(mc13783, MC13783_IRQ_RTCRST,
 338                         mc13783_rtc_reset_handler, DRIVER_NAME, priv);
 339         if (ret)
 340                 goto err_reset_irq_request;
 341
 342         ret = mc13783_irq_status(mc13783, MC13783_IRQ_RTCRST,
 343                         NULL, &rtcrst_pending);
 344         if (ret)
 345                 goto err_reset_irq_status;
 346
 347         priv->valid = !rtcrst_pending;
 348
 349         ret = mc13783_irq_request_nounmask(mc13783, MC13783_IRQ_1HZ,
 350                         mc13783_rtc_update_handler, DRIVER_NAME, priv);
 351         if (ret)
 352                 goto err_update_irq_request;
 353
 354         ret = mc13783_irq_request_nounmask(mc13783, MC13783_IRQ_TODA,
 355                         mc13783_rtc_alarm_handler, DRIVER_NAME, priv);
 356         if (ret)
 357                 goto err_alarm_irq_request;
 358
 359         priv->rtc = rtc_device_register(pdev->name,
 360                         &pdev->dev, &mc13783_rtc_ops, THIS_MODULE);
 361         if (IS_ERR(priv->rtc)) {
 362                 ret = PTR_ERR(priv->rtc);
 363
 364                 mc13783_irq_free(mc13783, MC13783_IRQ_TODA, priv);
 365 err_alarm_irq_request:
 366
 367                 mc13783_irq_free(mc13783, MC13783_IRQ_1HZ, priv);
 368 err_update_irq_request:
 369
 370 err_reset_irq_status:
 371
 372                 mc13783_irq_free(mc13783, MC13783_IRQ_RTCRST, priv);
 373 err_reset_irq_request:
 374
 375                 platform_set_drvdata(pdev, NULL);
 376                 kfree(priv);
 377         }
 378
 379         mc13783_unlock(mc13783);
 380
 381         return ret;
 382 }
 383
 384 static int __devexit mc13783_rtc_remove(struct platform_device *pdev)
 385 {
 386         struct mc13783_rtc *priv = platform_get_drvdata(pdev);
 387
 388         mc13783_lock(priv->mc13783);
 389
 390         rtc_device_unregister(priv->rtc);
 391
 392         mc13783_irq_free(priv->mc13783, MC13783_IRQ_TODA, priv);
 393         mc13783_irq_free(priv->mc13783, MC13783_IRQ_1HZ, priv);
 394         mc13783_irq_free(priv->mc13783, MC13783_IRQ_RTCRST, priv);
 395
 396         mc13783_unlock(priv->mc13783);
 397
 398         platform_set_drvdata(pdev, NULL);
 399
 400         kfree(priv);
 401
 402         return 0;
 403 }
 404
 405 static struct platform_driver mc13783_rtc_driver = {
 406         .remove = __devexit_p(mc13783_rtc_remove),
 407         .driver = {
 408                 .name = DRIVER_NAME,
 409                 .owner = THIS_MODULE,
 410         },
 411 };
 412
 413 static int __init mc13783_rtc_init(void)
 414 {
 415         return platform_driver_probe(&mc13783_rtc_driver, &mc13783_rtc_probe);
 416 }
 417 module_init(mc13783_rtc_init);
 418
 419 static void __exit mc13783_rtc_exit(void)
 420 {
 421         platform_driver_unregister(&mc13783_rtc_driver);
 422 }
 423 module_exit(mc13783_rtc_exit);
 424
 425 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
 426 MODULE_DESCRIPTION("RTC driver for Freescale MC13783 PMIC");
 427 MODULE_LICENSE("GPL v2");
 428 MODULE_ALIAS("platform:" DRIVER_NAME);