drivers/rtc/rtc-mc13xxx.c

   1 /*
   2  * Real Time Clock driver for Freescale MC13XXX 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/mc13xxx.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 "mc13xxx-rtc"
  20
  21 #define MC13XXX_RTCTOD  20
  22 #define MC13XXX_RTCTODA 21
  23 #define MC13XXX_RTCDAY  22
  24 #define MC13XXX_RTCDAYA 23
  25
  26 #define SEC_PER_DAY     (24 * 60 * 60)
  27
  28 struct mc13xxx_rtc {
  29         struct rtc_device *rtc;
  30         struct mc13xxx *mc13xxx;
  31         int valid;
  32 };
  33
  34 static int mc13xxx_rtc_irq_enable_unlocked(struct device *dev,
  35                 unsigned int enabled, int irq)
  36 {
  37         struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
  38         int (*func)(struct mc13xxx *mc13xxx, int irq);
  39
  40         if (!priv->valid)
  41                 return -ENODATA;
  42
  43         func = enabled ? mc13xxx_irq_unmask : mc13xxx_irq_mask;
  44         return func(priv->mc13xxx, irq);
  45 }
  46
  47 static int mc13xxx_rtc_alarm_irq_enable(struct device *dev,
  48                                         unsigned int enabled)
  49 {
  50         struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
  51         int ret;
  52
  53         mc13xxx_lock(priv->mc13xxx);
  54
  55         ret = mc13xxx_rtc_irq_enable_unlocked(dev, enabled, MC13XXX_IRQ_TODA);
  56
  57         mc13xxx_unlock(priv->mc13xxx);
  58
  59         return ret;
  60 }
  61
  62 static int mc13xxx_rtc_read_time(struct device *dev, struct rtc_time *tm)
  63 {
  64         struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
  65         unsigned int seconds, days1, days2;
  66
  67         if (!priv->valid)
  68                 return -ENODATA;
  69
  70         do {
  71                 int ret;
  72
  73                 ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days1);
  74                 if (ret)
  75                         return ret;
  76
  77                 ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTOD, &seconds);
  78                 if (ret)
  79                         return ret;
  80
  81                 ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days2);
  82                 if (ret)
  83                         return ret;
  84         } while (days1 != days2);
  85
  86         rtc_time64_to_tm((time64_t)days1 * SEC_PER_DAY + seconds, tm);
  87
  88         return 0;
  89 }
  90
  91 static int mc13xxx_rtc_set_mmss(struct device *dev, time64_t secs)
  92 {
  93         struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
  94         unsigned int seconds, days;
  95         unsigned int alarmseconds;
  96         int ret;
  97
  98         days = div_s64_rem(secs, SEC_PER_DAY, &seconds);
  99
 100         mc13xxx_lock(priv->mc13xxx);
 101
 102         /*
 103          * temporarily invalidate alarm to prevent triggering it when the day is
 104          * already updated while the time isn't yet.
 105          */
 106         ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTODA, &alarmseconds);
 107         if (unlikely(ret))
 108                 goto out;
 109
 110         if (alarmseconds < SEC_PER_DAY) {
 111                 ret = mc13xxx_reg_write(priv->mc13xxx,
 112                                 MC13XXX_RTCTODA, 0x1ffff);
 113                 if (unlikely(ret))
 114                         goto out;
 115         }
 116
 117         /*
 118          * write seconds=0 to prevent a day switch between writing days
 119          * and seconds below
 120          */
 121         ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTOD, 0);
 122         if (unlikely(ret))
 123                 goto out;
 124
 125         ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCDAY, days);
 126         if (unlikely(ret))
 127                 goto out;
 128
 129         ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTOD, seconds);
 130         if (unlikely(ret))
 131                 goto out;
 132
 133         /* restore alarm */
 134         if (alarmseconds < SEC_PER_DAY) {
 135                 ret = mc13xxx_reg_write(priv->mc13xxx,
 136                                 MC13XXX_RTCTODA, alarmseconds);
 137                 if (unlikely(ret))
 138                         goto out;
 139         }
 140
 141         if (!priv->valid) {
 142                 ret = mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_RTCRST);
 143                 if (unlikely(ret))
 144                         goto out;
 145
 146                 ret = mc13xxx_irq_unmask(priv->mc13xxx, MC13XXX_IRQ_RTCRST);
 147         }
 148
 149 out:
 150         priv->valid = !ret;
 151
 152         mc13xxx_unlock(priv->mc13xxx);
 153
 154         return ret;
 155 }
 156
 157 static int mc13xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 158 {
 159         struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
 160         unsigned seconds, days;
 161         time64_t s1970;
 162         int enabled, pending;
 163         int ret;
 164
 165         mc13xxx_lock(priv->mc13xxx);
 166
 167         ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTODA, &seconds);
 168         if (unlikely(ret))
 169                 goto out;
 170         if (seconds >= SEC_PER_DAY) {
 171                 ret = -ENODATA;
 172                 goto out;
 173         }
 174
 175         ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days);
 176         if (unlikely(ret))
 177                 goto out;
 178
 179         ret = mc13xxx_irq_status(priv->mc13xxx, MC13XXX_IRQ_TODA,
 180                         &enabled, &pending);
 181
 182 out:
 183         mc13xxx_unlock(priv->mc13xxx);
 184
 185         if (ret)
 186                 return ret;
 187
 188         alarm->enabled = enabled;
 189         alarm->pending = pending;
 190
 191         s1970 = (time64_t)days * SEC_PER_DAY + seconds;
 192
 193         rtc_time64_to_tm(s1970, &alarm->time);
 194         dev_dbg(dev, "%s: %lld\n", __func__, (long long)s1970);
 195
 196         return 0;
 197 }
 198
 199 static int mc13xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 200 {
 201         struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
 202         time64_t s1970;
 203         u32 seconds, days;
 204         int ret;
 205
 206         mc13xxx_lock(priv->mc13xxx);
 207
 208         /* disable alarm to prevent false triggering */
 209         ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTODA, 0x1ffff);
 210         if (unlikely(ret))
 211                 goto out;
 212
 213         ret = mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_TODA);
 214         if (unlikely(ret))
 215                 goto out;
 216
 217         s1970 = rtc_tm_to_time64(&alarm->time);
 218
 219         dev_dbg(dev, "%s: %s %lld\n", __func__, alarm->enabled ? "on" : "off",
 220                         (long long)s1970);
 221
 222         ret = mc13xxx_rtc_irq_enable_unlocked(dev, alarm->enabled,
 223                         MC13XXX_IRQ_TODA);
 224         if (unlikely(ret))
 225                 goto out;
 226
 227         days = div_s64_rem(s1970, SEC_PER_DAY, &seconds);
 228
 229         ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCDAYA, days);
 230         if (unlikely(ret))
 231                 goto out;
 232
 233         ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTODA, seconds);
 234
 235 out:
 236         mc13xxx_unlock(priv->mc13xxx);
 237
 238         return ret;
 239 }
 240
 241 static irqreturn_t mc13xxx_rtc_alarm_handler(int irq, void *dev)
 242 {
 243         struct mc13xxx_rtc *priv = dev;
 244         struct mc13xxx *mc13xxx = priv->mc13xxx;
 245
 246         rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_AF);
 247
 248         mc13xxx_irq_ack(mc13xxx, irq);
 249
 250         return IRQ_HANDLED;
 251 }
 252
 253 static const struct rtc_class_ops mc13xxx_rtc_ops = {
 254         .read_time = mc13xxx_rtc_read_time,
 255         .set_mmss64 = mc13xxx_rtc_set_mmss,
 256         .read_alarm = mc13xxx_rtc_read_alarm,
 257         .set_alarm = mc13xxx_rtc_set_alarm,
 258         .alarm_irq_enable = mc13xxx_rtc_alarm_irq_enable,
 259 };
 260
 261 static irqreturn_t mc13xxx_rtc_reset_handler(int irq, void *dev)
 262 {
 263         struct mc13xxx_rtc *priv = dev;
 264         struct mc13xxx *mc13xxx = priv->mc13xxx;
 265
 266         priv->valid = 0;
 267
 268         mc13xxx_irq_mask(mc13xxx, irq);
 269
 270         return IRQ_HANDLED;
 271 }
 272
 273 static int __init mc13xxx_rtc_probe(struct platform_device *pdev)
 274 {
 275         int ret;
 276         struct mc13xxx_rtc *priv;
 277         struct mc13xxx *mc13xxx;
 278
 279         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 280         if (!priv)
 281                 return -ENOMEM;
 282
 283         mc13xxx = dev_get_drvdata(pdev->dev.parent);
 284         priv->mc13xxx = mc13xxx;
 285         priv->valid = 1;
 286
 287         platform_set_drvdata(pdev, priv);
 288
 289         mc13xxx_lock(mc13xxx);
 290
 291         mc13xxx_irq_ack(mc13xxx, MC13XXX_IRQ_RTCRST);
 292
 293         ret = mc13xxx_irq_request(mc13xxx, MC13XXX_IRQ_RTCRST,
 294                         mc13xxx_rtc_reset_handler, DRIVER_NAME, priv);
 295         if (ret)
 296                 goto err_irq_request;
 297
 298         ret = mc13xxx_irq_request_nounmask(mc13xxx, MC13XXX_IRQ_TODA,
 299                         mc13xxx_rtc_alarm_handler, DRIVER_NAME, priv);
 300         if (ret)
 301                 goto err_irq_request;
 302
 303         mc13xxx_unlock(mc13xxx);
 304
 305         priv->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 306                                              &mc13xxx_rtc_ops, THIS_MODULE);
 307
 308         return 0;
 309
 310 err_irq_request:
 311         mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_TODA, priv);
 312         mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_RTCRST, priv);
 313
 314         mc13xxx_unlock(mc13xxx);
 315
 316         return ret;
 317 }
 318
 319 static int mc13xxx_rtc_remove(struct platform_device *pdev)
 320 {
 321         struct mc13xxx_rtc *priv = platform_get_drvdata(pdev);
 322
 323         mc13xxx_lock(priv->mc13xxx);
 324
 325         mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TODA, priv);
 326         mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_RTCRST, priv);
 327
 328         mc13xxx_unlock(priv->mc13xxx);
 329
 330         return 0;
 331 }
 332
 333 static const struct platform_device_id mc13xxx_rtc_idtable[] = {
 334         {
 335                 .name = "mc13783-rtc",
 336         }, {
 337                 .name = "mc13892-rtc",
 338         }, {
 339                 .name = "mc34708-rtc",
 340         },
 341         { /* sentinel */ }
 342 };
 343 MODULE_DEVICE_TABLE(platform, mc13xxx_rtc_idtable);
 344
 345 static struct platform_driver mc13xxx_rtc_driver = {
 346         .id_table = mc13xxx_rtc_idtable,
 347         .remove = mc13xxx_rtc_remove,
 348         .driver = {
 349                 .name = DRIVER_NAME,
 350         },
 351 };
 352
 353 module_platform_driver_probe(mc13xxx_rtc_driver, &mc13xxx_rtc_probe);
 354
 355 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
 356 MODULE_DESCRIPTION("RTC driver for Freescale MC13XXX PMIC");
 357 MODULE_LICENSE("GPL v2");