drivers/rtc/rtc-vr41xx.c

   1 /*
   2  *  Driver for NEC VR4100 series Real Time Clock unit.
   3  *
   4  *  Copyright (C) 2003-2008  Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20 #include <linux/err.h>
  21 #include <linux/fs.h>
  22 #include <linux/init.h>
  23 #include <linux/ioport.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/module.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/rtc.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/types.h>
  30
  31 #include <asm/div64.h>
  32 #include <asm/io.h>
  33 #include <asm/uaccess.h>
  34
  35 MODULE_AUTHOR("Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>");
  36 MODULE_DESCRIPTION("NEC VR4100 series RTC driver");
  37 MODULE_LICENSE("GPL v2");
  38
  39 /* RTC 1 registers */
  40 #define ETIMELREG               0x00
  41 #define ETIMEMREG               0x02
  42 #define ETIMEHREG               0x04
  43 /* RFU */
  44 #define ECMPLREG                0x08
  45 #define ECMPMREG                0x0a
  46 #define ECMPHREG                0x0c
  47 /* RFU */
  48 #define RTCL1LREG               0x10
  49 #define RTCL1HREG               0x12
  50 #define RTCL1CNTLREG            0x14
  51 #define RTCL1CNTHREG            0x16
  52 #define RTCL2LREG               0x18
  53 #define RTCL2HREG               0x1a
  54 #define RTCL2CNTLREG            0x1c
  55 #define RTCL2CNTHREG            0x1e
  56
  57 /* RTC 2 registers */
  58 #define TCLKLREG                0x00
  59 #define TCLKHREG                0x02
  60 #define TCLKCNTLREG             0x04
  61 #define TCLKCNTHREG             0x06
  62 /* RFU */
  63 #define RTCINTREG               0x1e
  64  #define TCLOCK_INT             0x08
  65  #define RTCLONG2_INT           0x04
  66  #define RTCLONG1_INT           0x02
  67  #define ELAPSEDTIME_INT        0x01
  68
  69 #define RTC_FREQUENCY           32768
  70 #define MAX_PERIODIC_RATE       6553
  71
  72 static void __iomem *rtc1_base;
  73 static void __iomem *rtc2_base;
  74
  75 #define rtc1_read(offset)               readw(rtc1_base + (offset))
  76 #define rtc1_write(offset, value)       writew((value), rtc1_base + (offset))
  77
  78 #define rtc2_read(offset)               readw(rtc2_base + (offset))
  79 #define rtc2_write(offset, value)       writew((value), rtc2_base + (offset))
  80
  81 static unsigned long epoch = 1970;      /* Jan 1 1970 00:00:00 */
  82
  83 static DEFINE_SPINLOCK(rtc_lock);
  84 static char rtc_name[] = "RTC";
  85 static unsigned long periodic_count;
  86 static unsigned int alarm_enabled;
  87 static int aie_irq = -1;
  88 static int pie_irq = -1;
  89
  90 static inline unsigned long read_elapsed_second(void)
  91 {
  92
  93         unsigned long first_low, first_mid, first_high;
  94
  95         unsigned long second_low, second_mid, second_high;
  96
  97         do {
  98                 first_low = rtc1_read(ETIMELREG);
  99                 first_mid = rtc1_read(ETIMEMREG);
 100                 first_high = rtc1_read(ETIMEHREG);
 101                 second_low = rtc1_read(ETIMELREG);
 102                 second_mid = rtc1_read(ETIMEMREG);
 103                 second_high = rtc1_read(ETIMEHREG);
 104         } while (first_low != second_low || first_mid != second_mid ||
 105                  first_high != second_high);
 106
 107         return (first_high << 17) | (first_mid << 1) | (first_low >> 15);
 108 }
 109
 110 static inline void write_elapsed_second(unsigned long sec)
 111 {
 112         spin_lock_irq(&rtc_lock);
 113
 114         rtc1_write(ETIMELREG, (uint16_t)(sec << 15));
 115         rtc1_write(ETIMEMREG, (uint16_t)(sec >> 1));
 116         rtc1_write(ETIMEHREG, (uint16_t)(sec >> 17));
 117
 118         spin_unlock_irq(&rtc_lock);
 119 }
 120
 121 static void vr41xx_rtc_release(struct device *dev)
 122 {
 123
 124         spin_lock_irq(&rtc_lock);
 125
 126         rtc1_write(ECMPLREG, 0);
 127         rtc1_write(ECMPMREG, 0);
 128         rtc1_write(ECMPHREG, 0);
 129         rtc1_write(RTCL1LREG, 0);
 130         rtc1_write(RTCL1HREG, 0);
 131
 132         spin_unlock_irq(&rtc_lock);
 133
 134         disable_irq(aie_irq);
 135         disable_irq(pie_irq);
 136 }
 137
 138 static int vr41xx_rtc_read_time(struct device *dev, struct rtc_time *time)
 139 {
 140         unsigned long epoch_sec, elapsed_sec;
 141
 142         epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
 143         elapsed_sec = read_elapsed_second();
 144
 145         rtc_time_to_tm(epoch_sec + elapsed_sec, time);
 146
 147         return 0;
 148 }
 149
 150 static int vr41xx_rtc_set_time(struct device *dev, struct rtc_time *time)
 151 {
 152         unsigned long epoch_sec, current_sec;
 153
 154         epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
 155         current_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
 156                              time->tm_hour, time->tm_min, time->tm_sec);
 157
 158         write_elapsed_second(current_sec - epoch_sec);
 159
 160         return 0;
 161 }
 162
 163 static int vr41xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 164 {
 165         unsigned long low, mid, high;
 166         struct rtc_time *time = &wkalrm->time;
 167
 168         spin_lock_irq(&rtc_lock);
 169
 170         low = rtc1_read(ECMPLREG);
 171         mid = rtc1_read(ECMPMREG);
 172         high = rtc1_read(ECMPHREG);
 173         wkalrm->enabled = alarm_enabled;
 174
 175         spin_unlock_irq(&rtc_lock);
 176
 177         rtc_time_to_tm((high << 17) | (mid << 1) | (low >> 15), time);
 178
 179         return 0;
 180 }
 181
 182 static int vr41xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 183 {
 184         unsigned long alarm_sec;
 185         struct rtc_time *time = &wkalrm->time;
 186
 187         alarm_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
 188                            time->tm_hour, time->tm_min, time->tm_sec);
 189
 190         spin_lock_irq(&rtc_lock);
 191
 192         if (alarm_enabled)
 193                 disable_irq(aie_irq);
 194
 195         rtc1_write(ECMPLREG, (uint16_t)(alarm_sec << 15));
 196         rtc1_write(ECMPMREG, (uint16_t)(alarm_sec >> 1));
 197         rtc1_write(ECMPHREG, (uint16_t)(alarm_sec >> 17));
 198
 199         if (wkalrm->enabled)
 200                 enable_irq(aie_irq);
 201
 202         alarm_enabled = wkalrm->enabled;
 203
 204         spin_unlock_irq(&rtc_lock);
 205
 206         return 0;
 207 }
 208
 209 static int vr41xx_rtc_irq_set_freq(struct device *dev, int freq)
 210 {
 211         unsigned long count;
 212
 213         count = RTC_FREQUENCY;
 214         do_div(count, freq);
 215
 216         periodic_count = count;
 217
 218         spin_lock_irq(&rtc_lock);
 219
 220         rtc1_write(RTCL1LREG, count);
 221         rtc1_write(RTCL1HREG, count >> 16);
 222
 223         spin_unlock_irq(&rtc_lock);
 224
 225         return 0;
 226 }
 227
 228 static int vr41xx_rtc_irq_set_state(struct device *dev, int enabled)
 229 {
 230         if (enabled)
 231                 enable_irq(pie_irq);
 232         else
 233                 disable_irq(pie_irq);
 234
 235         return 0;
 236 }
 237
 238 static int vr41xx_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 239 {
 240         switch (cmd) {
 241         case RTC_AIE_ON:
 242                 spin_lock_irq(&rtc_lock);
 243
 244                 if (!alarm_enabled) {
 245                         enable_irq(aie_irq);
 246                         alarm_enabled = 1;
 247                 }
 248
 249                 spin_unlock_irq(&rtc_lock);
 250                 break;
 251         case RTC_AIE_OFF:
 252                 spin_lock_irq(&rtc_lock);
 253
 254                 if (alarm_enabled) {
 255                         disable_irq(aie_irq);
 256                         alarm_enabled = 0;
 257                 }
 258
 259                 spin_unlock_irq(&rtc_lock);
 260                 break;
 261         case RTC_EPOCH_READ:
 262                 return put_user(epoch, (unsigned long __user *)arg);
 263         case RTC_EPOCH_SET:
 264                 /* Doesn't support before 1900 */
 265                 if (arg < 1900)
 266                         return -EINVAL;
 267                 epoch = arg;
 268                 break;
 269         default:
 270                 return -ENOIOCTLCMD;
 271         }
 272
 273         return 0;
 274 }
 275
 276 static irqreturn_t elapsedtime_interrupt(int irq, void *dev_id)
 277 {
 278         struct platform_device *pdev = (struct platform_device *)dev_id;
 279         struct rtc_device *rtc = platform_get_drvdata(pdev);
 280
 281         rtc2_write(RTCINTREG, ELAPSEDTIME_INT);
 282
 283         rtc_update_irq(rtc, 1, RTC_AF);
 284
 285         return IRQ_HANDLED;
 286 }
 287
 288 static irqreturn_t rtclong1_interrupt(int irq, void *dev_id)
 289 {
 290         struct platform_device *pdev = (struct platform_device *)dev_id;
 291         struct rtc_device *rtc = platform_get_drvdata(pdev);
 292         unsigned long count = periodic_count;
 293
 294         rtc2_write(RTCINTREG, RTCLONG1_INT);
 295
 296         rtc1_write(RTCL1LREG, count);
 297         rtc1_write(RTCL1HREG, count >> 16);
 298
 299         rtc_update_irq(rtc, 1, RTC_PF);
 300
 301         return IRQ_HANDLED;
 302 }
 303
 304 static const struct rtc_class_ops vr41xx_rtc_ops = {
 305         .release        = vr41xx_rtc_release,
 306         .ioctl          = vr41xx_rtc_ioctl,
 307         .read_time      = vr41xx_rtc_read_time,
 308         .set_time       = vr41xx_rtc_set_time,
 309         .read_alarm     = vr41xx_rtc_read_alarm,
 310         .set_alarm      = vr41xx_rtc_set_alarm,
 311         .irq_set_freq   = vr41xx_rtc_irq_set_freq,
 312         .irq_set_state  = vr41xx_rtc_irq_set_state,
 313 };
 314
 315 static int __devinit rtc_probe(struct platform_device *pdev)
 316 {
 317         struct resource *res;
 318         struct rtc_device *rtc;
 319         int retval;
 320
 321         if (pdev->num_resources != 4)
 322                 return -EBUSY;
 323
 324         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 325         if (!res)
 326                 return -EBUSY;
 327
 328         rtc1_base = ioremap(res->start, res->end - res->start + 1);
 329         if (!rtc1_base)
 330                 return -EBUSY;
 331
 332         res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 333         if (!res) {
 334                 retval = -EBUSY;
 335                 goto err_rtc1_iounmap;
 336         }
 337
 338         rtc2_base = ioremap(res->start, res->end - res->start + 1);
 339         if (!rtc2_base) {
 340                 retval = -EBUSY;
 341                 goto err_rtc1_iounmap;
 342         }
 343
 344         rtc = rtc_device_register(rtc_name, &pdev->dev, &vr41xx_rtc_ops, THIS_MODULE);
 345         if (IS_ERR(rtc)) {
 346                 retval = PTR_ERR(rtc);
 347                 goto err_iounmap_all;
 348         }
 349
 350         rtc->max_user_freq = MAX_PERIODIC_RATE;
 351
 352         spin_lock_irq(&rtc_lock);
 353
 354         rtc1_write(ECMPLREG, 0);
 355         rtc1_write(ECMPMREG, 0);
 356         rtc1_write(ECMPHREG, 0);
 357         rtc1_write(RTCL1LREG, 0);
 358         rtc1_write(RTCL1HREG, 0);
 359
 360         spin_unlock_irq(&rtc_lock);
 361
 362         aie_irq = platform_get_irq(pdev, 0);
 363         if (aie_irq < 0 || aie_irq >= NR_IRQS) {
 364                 retval = -EBUSY;
 365                 goto err_device_unregister;
 366         }
 367
 368         retval = request_irq(aie_irq, elapsedtime_interrupt, IRQF_DISABLED,
 369                              "elapsed_time", pdev);
 370         if (retval < 0)
 371                 goto err_device_unregister;
 372
 373         pie_irq = platform_get_irq(pdev, 1);
 374         if (pie_irq < 0 || pie_irq >= NR_IRQS)
 375                 goto err_free_irq;
 376
 377         retval = request_irq(pie_irq, rtclong1_interrupt, IRQF_DISABLED,
 378                              "rtclong1", pdev);
 379         if (retval < 0)
 380                 goto err_free_irq;
 381
 382         platform_set_drvdata(pdev, rtc);
 383
 384         disable_irq(aie_irq);
 385         disable_irq(pie_irq);
 386
 387         printk(KERN_INFO "rtc: Real Time Clock of NEC VR4100 series\n");
 388
 389         return 0;
 390
 391 err_free_irq:
 392         free_irq(aie_irq, pdev);
 393
 394 err_device_unregister:
 395         rtc_device_unregister(rtc);
 396
 397 err_iounmap_all:
 398         iounmap(rtc2_base);
 399         rtc2_base = NULL;
 400
 401 err_rtc1_iounmap:
 402         iounmap(rtc1_base);
 403         rtc1_base = NULL;
 404
 405         return retval;
 406 }
 407
 408 static int __devexit rtc_remove(struct platform_device *pdev)
 409 {
 410         struct rtc_device *rtc;
 411
 412         rtc = platform_get_drvdata(pdev);
 413         if (rtc)
 414                 rtc_device_unregister(rtc);
 415
 416         platform_set_drvdata(pdev, NULL);
 417
 418         free_irq(aie_irq, pdev);
 419         free_irq(pie_irq, pdev);
 420         if (rtc1_base)
 421                 iounmap(rtc1_base);
 422         if (rtc2_base)
 423                 iounmap(rtc2_base);
 424
 425         return 0;
 426 }
 427
 428 /* work with hotplug and coldplug */
 429 MODULE_ALIAS("platform:RTC");
 430
 431 static struct platform_driver rtc_platform_driver = {
 432         .probe          = rtc_probe,
 433         .remove         = __devexit_p(rtc_remove),
 434         .driver         = {
 435                 .name   = rtc_name,
 436                 .owner  = THIS_MODULE,
 437         },
 438 };
 439
 440 static int __init vr41xx_rtc_init(void)
 441 {
 442         return platform_driver_register(&rtc_platform_driver);
 443 }
 444
 445 static void __exit vr41xx_rtc_exit(void)
 446 {
 447         platform_driver_unregister(&rtc_platform_driver);
 448 }
 449
 450 module_init(vr41xx_rtc_init);
 451 module_exit(vr41xx_rtc_exit);