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/mod_devicetable.h>
  17 #include <linux/slab.h>
  18 #include <linux/rtc.h>
  19
  20 #define DRIVER_NAME "mc13xxx-rtc"
  21
  22 #define MC13XXX_RTCTOD  20
  23 #define MC13XXX_RTCTODA 21
  24 #define MC13XXX_RTCDAY  22
  25 #define MC13XXX_RTCDAYA 23
  26
  27 #define SEC_PER_DAY     (24 * 60 * 60)
  28
  29 struct mc13xxx_rtc {
  30         struct rtc_device *rtc;
  31         struct mc13xxx *mc13xxx;
  32         int valid;
  33 };
  34
  35 static int mc13xxx_rtc_irq_enable_unlocked(struct device *dev,
  36                 unsigned int enabled, int irq)
  37 {
  38         struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
  39         int (*func)(struct mc13xxx *mc13xxx, int irq);
  40
  41         if (!priv->valid)
  42                 return -ENODATA;
  43
  44         func = enabled ? mc13xxx_irq_unmask : mc13xxx_irq_mask;
  45         return func(priv->mc13xxx, irq);
  46 }
  47
  48 static int mc13xxx_rtc_alarm_irq_enable(struct device *dev,
  49                                         unsigned int enabled)
  50 {
  51         struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
  52         int ret;
  53
  54         mc13xxx_lock(priv->mc13xxx);
  55
  56         ret = mc13xxx_rtc_irq_enable_unlocked(dev, enabled, MC13XXX_IRQ_TODA);
  57
  58         mc13xxx_unlock(priv->mc13xxx);
  59
  60         return ret;
  61 }
  62
  63 static int mc13xxx_rtc_read_time(struct device *dev, struct rtc_time *tm)
  64 {
  65         struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
  66         unsigned int seconds, days1, days2;
  67
  68         if (!priv->valid)
  69                 return -ENODATA;
  70
  71         do {
  72                 int ret;
  73
  74                 ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days1);
  75                 if (ret)
  76                         return ret;
  77
  78                 ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTOD, &seconds);
  79                 if (ret)
  80                         return ret;
  81
  82                 ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days2);
  83                 if (ret)
  84                         return ret;
  85         } while (days1 != days2);
  86
  87         rtc_time64_to_tm((time64_t)days1 * SEC_PER_DAY + seconds, tm);
  88
  89         return 0;
  90 }
  91
  92 static int mc13xxx_rtc_set_mmss(struct device *dev, time64_t secs)
  93 {
  94         struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
  95         unsigned int seconds, days;
  96         unsigned int alarmseconds;
  97         int ret;
  98
  99         days = div_s64_rem(secs, SEC_PER_DAY, &seconds);
 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         time64_t 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 = (time64_t)days * SEC_PER_DAY + seconds;
 193
 194         rtc_time64_to_tm(s1970, &alarm->time);
 195         dev_dbg(dev, "%s: %lld\n", __func__, (long long)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         time64_t s1970;
 204         u32 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         s1970 = rtc_tm_to_time64(&alarm->time);
 219
 220         dev_dbg(dev, "%s: %s %lld\n", __func__, alarm->enabled ? "on" : "off",
 221                         (long long)s1970);
 222
 223         ret = mc13xxx_rtc_irq_enable_unlocked(dev, alarm->enabled,
 224                         MC13XXX_IRQ_TODA);
 225         if (unlikely(ret))
 226                 goto out;
 227
 228         days = div_s64_rem(s1970, SEC_PER_DAY, &seconds);
 229
 230         ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCDAYA, days);
 231         if (unlikely(ret))
 232                 goto out;
 233
 234         ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTODA, seconds);
 235
 236 out:
 237         mc13xxx_unlock(priv->mc13xxx);
 238
 239         return ret;
 240 }
 241
 242 static irqreturn_t mc13xxx_rtc_alarm_handler(int irq, void *dev)
 243 {
 244         struct mc13xxx_rtc *priv = dev;
 245         struct mc13xxx *mc13xxx = priv->mc13xxx;
 246
 247         rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_AF);
 248
 249         mc13xxx_irq_ack(mc13xxx, irq);
 250
 251         return IRQ_HANDLED;
 252 }
 253
 254 static const struct rtc_class_ops mc13xxx_rtc_ops = {
 255         .read_time = mc13xxx_rtc_read_time,
 256         .set_mmss64 = mc13xxx_rtc_set_mmss,
 257         .read_alarm = mc13xxx_rtc_read_alarm,
 258         .set_alarm = mc13xxx_rtc_set_alarm,
 259         .alarm_irq_enable = mc13xxx_rtc_alarm_irq_enable,
 260 };
 261
 262 static irqreturn_t mc13xxx_rtc_reset_handler(int irq, void *dev)
 263 {
 264         struct mc13xxx_rtc *priv = dev;
 265         struct mc13xxx *mc13xxx = priv->mc13xxx;
 266
 267         priv->valid = 0;
 268
 269         mc13xxx_irq_mask(mc13xxx, irq);
 270
 271         return IRQ_HANDLED;
 272 }
 273
 274 static int __init mc13xxx_rtc_probe(struct platform_device *pdev)
 275 {
 276         int ret;
 277         struct mc13xxx_rtc *priv;
 278         struct mc13xxx *mc13xxx;
 279
 280         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 281         if (!priv)
 282                 return -ENOMEM;
 283
 284         mc13xxx = dev_get_drvdata(pdev->dev.parent);
 285         priv->mc13xxx = mc13xxx;
 286         priv->valid = 1;
 287
 288         platform_set_drvdata(pdev, priv);
 289
 290         mc13xxx_lock(mc13xxx);
 291
 292         mc13xxx_irq_ack(mc13xxx, MC13XXX_IRQ_RTCRST);
 293
 294         ret = mc13xxx_irq_request(mc13xxx, MC13XXX_IRQ_RTCRST,
 295                         mc13xxx_rtc_reset_handler, DRIVER_NAME, priv);
 296         if (ret)
 297                 goto err_irq_request;
 298
 299         ret = mc13xxx_irq_request_nounmask(mc13xxx, MC13XXX_IRQ_TODA,
 300                         mc13xxx_rtc_alarm_handler, DRIVER_NAME, priv);
 301         if (ret)
 302                 goto err_irq_request;
 303
 304         mc13xxx_unlock(mc13xxx);
 305
 306         priv->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 307                                              &mc13xxx_rtc_ops, THIS_MODULE);
 308
 309         return 0;
 310
 311 err_irq_request:
 312         mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_TODA, priv);
 313         mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_RTCRST, priv);
 314
 315         mc13xxx_unlock(mc13xxx);
 316
 317         return ret;
 318 }
 319
 320 static int mc13xxx_rtc_remove(struct platform_device *pdev)
 321 {
 322         struct mc13xxx_rtc *priv = platform_get_drvdata(pdev);
 323
 324         mc13xxx_lock(priv->mc13xxx);
 325
 326         mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TODA, priv);
 327         mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_RTCRST, priv);
 328
 329         mc13xxx_unlock(priv->mc13xxx);
 330
 331         return 0;
 332 }
 333
 334 static const struct platform_device_id mc13xxx_rtc_idtable[] = {
 335         {
 336                 .name = "mc13783-rtc",
 337         }, {
 338                 .name = "mc13892-rtc",
 339         }, {
 340                 .name = "mc34708-rtc",
 341         },
 342         { /* sentinel */ }
 343 };
 344 MODULE_DEVICE_TABLE(platform, mc13xxx_rtc_idtable);
 345
 346 static struct platform_driver mc13xxx_rtc_driver = {
 347         .id_table = mc13xxx_rtc_idtable,
 348         .remove = mc13xxx_rtc_remove,
 349         .driver = {
 350                 .name = DRIVER_NAME,
 351         },
 352 };
 353
 354 module_platform_driver_probe(mc13xxx_rtc_driver, &mc13xxx_rtc_probe);
 355
 356 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
 357 MODULE_DESCRIPTION("RTC driver for Freescale MC13XXX PMIC");
 358 MODULE_LICENSE("GPL v2");