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_time_to_tm(days1 * SEC_PER_DAY + seconds, tm);
  87
  88         return rtc_valid_tm(tm);
  89 }
  90
  91 static int mc13xxx_rtc_set_mmss(struct device *dev, unsigned long 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         seconds = secs % SEC_PER_DAY;
  99         days = secs / SEC_PER_DAY;
 100
 101         mc13xxx_lock(priv->mc13xxx);
 102
 103         /*
 104          * temporarily invalidate alarm to prevent triggering it when the day is
 105          * already updated while the time isn't yet.
 106          */
 107         ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTODA, &alarmseconds);
 108         if (unlikely(ret))
 109                 goto out;
 110
 111         if (alarmseconds < SEC_PER_DAY) {
 112                 ret = mc13xxx_reg_write(priv->mc13xxx,
 113                                 MC13XXX_RTCTODA, 0x1ffff);
 114                 if (unlikely(ret))
 115                         goto out;
 116         }
 117
 118         /*
 119          * write seconds=0 to prevent a day switch between writing days
 120          * and seconds below
 121          */
 122         ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTOD, 0);
 123         if (unlikely(ret))
 124                 goto out;
 125
 126         ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCDAY, days);
 127         if (unlikely(ret))
 128                 goto out;
 129
 130         ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTOD, seconds);
 131         if (unlikely(ret))
 132                 goto out;
 133
 134         /* restore alarm */
 135         if (alarmseconds < SEC_PER_DAY) {
 136                 ret = mc13xxx_reg_write(priv->mc13xxx,
 137                                 MC13XXX_RTCTODA, alarmseconds);
 138                 if (unlikely(ret))
 139                         goto out;
 140         }
 141
 142         if (!priv->valid) {
 143                 ret = mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_RTCRST);
 144                 if (unlikely(ret))
 145                         goto out;
 146
 147                 ret = mc13xxx_irq_unmask(priv->mc13xxx, MC13XXX_IRQ_RTCRST);
 148         }
 149
 150 out:
 151         priv->valid = !ret;
 152
 153         mc13xxx_unlock(priv->mc13xxx);
 154
 155         return ret;
 156 }
 157
 158 static int mc13xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 159 {
 160         struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
 161         unsigned seconds, days;
 162         unsigned long s1970;
 163         int enabled, pending;
 164         int ret;
 165
 166         mc13xxx_lock(priv->mc13xxx);
 167
 168         ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTODA, &seconds);
 169         if (unlikely(ret))
 170                 goto out;
 171         if (seconds >= SEC_PER_DAY) {
 172                 ret = -ENODATA;
 173                 goto out;
 174         }
 175
 176         ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days);
 177         if (unlikely(ret))
 178                 goto out;
 179
 180         ret = mc13xxx_irq_status(priv->mc13xxx, MC13XXX_IRQ_TODA,
 181                         &enabled, &pending);
 182
 183 out:
 184         mc13xxx_unlock(priv->mc13xxx);
 185
 186         if (ret)
 187                 return ret;
 188
 189         alarm->enabled = enabled;
 190         alarm->pending = pending;
 191
 192         s1970 = days * SEC_PER_DAY + seconds;
 193
 194         rtc_time_to_tm(s1970, &alarm->time);
 195         dev_dbg(dev, "%s: %lu\n", __func__, s1970);
 196
 197         return 0;
 198 }
 199
 200 static int mc13xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 201 {
 202         struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
 203         unsigned long s1970;
 204         unsigned seconds, days;
 205         int ret;
 206
 207         mc13xxx_lock(priv->mc13xxx);
 208
 209         /* disable alarm to prevent false triggering */
 210         ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTODA, 0x1ffff);
 211         if (unlikely(ret))
 212                 goto out;
 213
 214         ret = mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_TODA);
 215         if (unlikely(ret))
 216                 goto out;
 217
 218         ret = rtc_tm_to_time(&alarm->time, &s1970);
 219         if (unlikely(ret))
 220                 goto out;
 221
 222         dev_dbg(dev, "%s: o%2.s %lu\n", __func__, alarm->enabled ? "n" : "ff",
 223                         s1970);
 224
 225         ret = mc13xxx_rtc_irq_enable_unlocked(dev, alarm->enabled,
 226                         MC13XXX_IRQ_TODA);
 227         if (unlikely(ret))
 228                 goto out;
 229
 230         seconds = s1970 % SEC_PER_DAY;
 231         days = s1970 / SEC_PER_DAY;
 232
 233         ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCDAYA, days);
 234         if (unlikely(ret))
 235                 goto out;
 236
 237         ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTODA, seconds);
 238
 239 out:
 240         mc13xxx_unlock(priv->mc13xxx);
 241
 242         return ret;
 243 }
 244
 245 static irqreturn_t mc13xxx_rtc_alarm_handler(int irq, void *dev)
 246 {
 247         struct mc13xxx_rtc *priv = dev;
 248         struct mc13xxx *mc13xxx = priv->mc13xxx;
 249
 250         rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_AF);
 251
 252         mc13xxx_irq_ack(mc13xxx, irq);
 253
 254         return IRQ_HANDLED;
 255 }
 256
 257 static irqreturn_t mc13xxx_rtc_update_handler(int irq, void *dev)
 258 {
 259         struct mc13xxx_rtc *priv = dev;
 260         struct mc13xxx *mc13xxx = priv->mc13xxx;
 261
 262         rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_UF);
 263
 264         mc13xxx_irq_ack(mc13xxx, irq);
 265
 266         return IRQ_HANDLED;
 267 }
 268
 269 static const struct rtc_class_ops mc13xxx_rtc_ops = {
 270         .read_time = mc13xxx_rtc_read_time,
 271         .set_mmss = mc13xxx_rtc_set_mmss,
 272         .read_alarm = mc13xxx_rtc_read_alarm,
 273         .set_alarm = mc13xxx_rtc_set_alarm,
 274         .alarm_irq_enable = mc13xxx_rtc_alarm_irq_enable,
 275 };
 276
 277 static irqreturn_t mc13xxx_rtc_reset_handler(int irq, void *dev)
 278 {
 279         struct mc13xxx_rtc *priv = dev;
 280         struct mc13xxx *mc13xxx = priv->mc13xxx;
 281
 282         priv->valid = 0;
 283
 284         mc13xxx_irq_mask(mc13xxx, irq);
 285
 286         return IRQ_HANDLED;
 287 }
 288
 289 static int __init mc13xxx_rtc_probe(struct platform_device *pdev)
 290 {
 291         int ret;
 292         struct mc13xxx_rtc *priv;
 293         struct mc13xxx *mc13xxx;
 294
 295         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 296         if (!priv)
 297                 return -ENOMEM;
 298
 299         mc13xxx = dev_get_drvdata(pdev->dev.parent);
 300         priv->mc13xxx = mc13xxx;
 301         priv->valid = 1;
 302
 303         platform_set_drvdata(pdev, priv);
 304
 305         mc13xxx_lock(mc13xxx);
 306
 307         mc13xxx_irq_ack(mc13xxx, MC13XXX_IRQ_RTCRST);
 308
 309         ret = mc13xxx_irq_request(mc13xxx, MC13XXX_IRQ_RTCRST,
 310                         mc13xxx_rtc_reset_handler, DRIVER_NAME, priv);
 311         if (ret)
 312                 goto err_irq_request;
 313
 314         ret = mc13xxx_irq_request(mc13xxx, MC13XXX_IRQ_1HZ,
 315                         mc13xxx_rtc_update_handler, DRIVER_NAME, priv);
 316         if (ret)
 317                 goto err_irq_request;
 318
 319         ret = mc13xxx_irq_request_nounmask(mc13xxx, MC13XXX_IRQ_TODA,
 320                         mc13xxx_rtc_alarm_handler, DRIVER_NAME, priv);
 321         if (ret)
 322                 goto err_irq_request;
 323
 324         mc13xxx_unlock(mc13xxx);
 325
 326         priv->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 327                                              &mc13xxx_rtc_ops, THIS_MODULE);
 328
 329         return 0;
 330
 331 err_irq_request:
 332         mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_TODA, priv);
 333         mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_1HZ, priv);
 334         mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_RTCRST, priv);
 335
 336         mc13xxx_unlock(mc13xxx);
 337
 338         return ret;
 339 }
 340
 341 static int mc13xxx_rtc_remove(struct platform_device *pdev)
 342 {
 343         struct mc13xxx_rtc *priv = platform_get_drvdata(pdev);
 344
 345         mc13xxx_lock(priv->mc13xxx);
 346
 347         mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TODA, priv);
 348         mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_1HZ, priv);
 349         mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_RTCRST, priv);
 350
 351         mc13xxx_unlock(priv->mc13xxx);
 352
 353         return 0;
 354 }
 355
 356 static const struct platform_device_id mc13xxx_rtc_idtable[] = {
 357         {
 358                 .name = "mc13783-rtc",
 359         }, {
 360                 .name = "mc13892-rtc",
 361         }, {
 362                 .name = "mc34708-rtc",
 363         },
 364         { /* sentinel */ }
 365 };
 366 MODULE_DEVICE_TABLE(platform, mc13xxx_rtc_idtable);
 367
 368 static struct platform_driver mc13xxx_rtc_driver = {
 369         .id_table = mc13xxx_rtc_idtable,
 370         .remove = mc13xxx_rtc_remove,
 371         .driver = {
 372                 .name = DRIVER_NAME,
 373         },
 374 };
 375
 376 module_platform_driver_probe(mc13xxx_rtc_driver, &mc13xxx_rtc_probe);
 377
 378 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
 379 MODULE_DESCRIPTION("RTC driver for Freescale MC13XXX PMIC");
 380 MODULE_LICENSE("GPL v2");