drivers/rtc/rtc-vr41xx.c

   1 /*
   2  *  Driver for NEC VR4100 series Real Time Clock unit.
   3  *
   4  *  Copyright (C) 2003-2008  Yoichi Yuasa <yuasa@linux-mips.org>
   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/io.h>
  24 #include <linux/ioport.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/module.h>
  27 #include <linux/platform_device.h>
  28 #include <linux/rtc.h>
  29 #include <linux/spinlock.h>
  30 #include <linux/types.h>
  31 #include <linux/uaccess.h>
  32 #include <linux/log2.h>
  33
  34 #include <asm/div64.h>
  35
  36 MODULE_AUTHOR("Yoichi Yuasa <yuasa@linux-mips.org>");
  37 MODULE_DESCRIPTION("NEC VR4100 series RTC driver");
  38 MODULE_LICENSE("GPL v2");
  39
  40 /* RTC 1 registers */
  41 #define ETIMELREG               0x00
  42 #define ETIMEMREG               0x02
  43 #define ETIMEHREG               0x04
  44 /* RFU */
  45 #define ECMPLREG                0x08
  46 #define ECMPMREG                0x0a
  47 #define ECMPHREG                0x0c
  48 /* RFU */
  49 #define RTCL1LREG               0x10
  50 #define RTCL1HREG               0x12
  51 #define RTCL1CNTLREG            0x14
  52 #define RTCL1CNTHREG            0x16
  53 #define RTCL2LREG               0x18
  54 #define RTCL2HREG               0x1a
  55 #define RTCL2CNTLREG            0x1c
  56 #define RTCL2CNTHREG            0x1e
  57
  58 /* RTC 2 registers */
  59 #define TCLKLREG                0x00
  60 #define TCLKHREG                0x02
  61 #define TCLKCNTLREG             0x04
  62 #define TCLKCNTHREG             0x06
  63 /* RFU */
  64 #define RTCINTREG               0x1e
  65  #define TCLOCK_INT             0x08
  66  #define RTCLONG2_INT           0x04
  67  #define RTCLONG1_INT           0x02
  68  #define ELAPSEDTIME_INT        0x01
  69
  70 #define RTC_FREQUENCY           32768
  71 #define MAX_PERIODIC_RATE       6553
  72
  73 static void __iomem *rtc1_base;
  74 static void __iomem *rtc2_base;
  75
  76 #define rtc1_read(offset)               readw(rtc1_base + (offset))
  77 #define rtc1_write(offset, value)       writew((value), rtc1_base + (offset))
  78
  79 #define rtc2_read(offset)               readw(rtc2_base + (offset))
  80 #define rtc2_write(offset, value)       writew((value), rtc2_base + (offset))
  81
  82 static unsigned long epoch = 1970;      /* Jan 1 1970 00:00:00 */
  83
  84 static DEFINE_SPINLOCK(rtc_lock);
  85 static char rtc_name[] = "RTC";
  86 static unsigned long periodic_count;
  87 static unsigned int alarm_enabled;
  88 static int aie_irq;
  89 static int pie_irq;
  90
  91 static inline unsigned long read_elapsed_second(void)
  92 {
  93
  94         unsigned long first_low, first_mid, first_high;
  95
  96         unsigned long second_low, second_mid, second_high;
  97
  98         do {
  99                 first_low = rtc1_read(ETIMELREG);
 100                 first_mid = rtc1_read(ETIMEMREG);
 101                 first_high = rtc1_read(ETIMEHREG);
 102                 second_low = rtc1_read(ETIMELREG);
 103                 second_mid = rtc1_read(ETIMEMREG);
 104                 second_high = rtc1_read(ETIMEHREG);
 105         } while (first_low != second_low || first_mid != second_mid ||
 106                  first_high != second_high);
 107
 108         return (first_high << 17) | (first_mid << 1) | (first_low >> 15);
 109 }
 110
 111 static inline void write_elapsed_second(unsigned long sec)
 112 {
 113         spin_lock_irq(&rtc_lock);
 114
 115         rtc1_write(ETIMELREG, (uint16_t)(sec << 15));
 116         rtc1_write(ETIMEMREG, (uint16_t)(sec >> 1));
 117         rtc1_write(ETIMEHREG, (uint16_t)(sec >> 17));
 118
 119         spin_unlock_irq(&rtc_lock);
 120 }
 121
 122 static void vr41xx_rtc_release(struct device *dev)
 123 {
 124
 125         spin_lock_irq(&rtc_lock);
 126
 127         rtc1_write(ECMPLREG, 0);
 128         rtc1_write(ECMPMREG, 0);
 129         rtc1_write(ECMPHREG, 0);
 130         rtc1_write(RTCL1LREG, 0);
 131         rtc1_write(RTCL1HREG, 0);
 132
 133         spin_unlock_irq(&rtc_lock);
 134
 135         disable_irq(aie_irq);
 136         disable_irq(pie_irq);
 137 }
 138
 139 static int vr41xx_rtc_read_time(struct device *dev, struct rtc_time *time)
 140 {
 141         unsigned long epoch_sec, elapsed_sec;
 142
 143         epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
 144         elapsed_sec = read_elapsed_second();
 145
 146         rtc_time_to_tm(epoch_sec + elapsed_sec, time);
 147
 148         return 0;
 149 }
 150
 151 static int vr41xx_rtc_set_time(struct device *dev, struct rtc_time *time)
 152 {
 153         unsigned long epoch_sec, current_sec;
 154
 155         epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
 156         current_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
 157                              time->tm_hour, time->tm_min, time->tm_sec);
 158
 159         write_elapsed_second(current_sec - epoch_sec);
 160
 161         return 0;
 162 }
 163
 164 static int vr41xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 165 {
 166         unsigned long low, mid, high;
 167         struct rtc_time *time = &wkalrm->time;
 168
 169         spin_lock_irq(&rtc_lock);
 170
 171         low = rtc1_read(ECMPLREG);
 172         mid = rtc1_read(ECMPMREG);
 173         high = rtc1_read(ECMPHREG);
 174         wkalrm->enabled = alarm_enabled;
 175
 176         spin_unlock_irq(&rtc_lock);
 177
 178         rtc_time_to_tm((high << 17) | (mid << 1) | (low >> 15), time);
 179
 180         return 0;
 181 }
 182
 183 static int vr41xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 184 {
 185         unsigned long alarm_sec;
 186         struct rtc_time *time = &wkalrm->time;
 187
 188         alarm_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
 189                            time->tm_hour, time->tm_min, time->tm_sec);
 190
 191         spin_lock_irq(&rtc_lock);
 192
 193         if (alarm_enabled)
 194                 disable_irq(aie_irq);
 195
 196         rtc1_write(ECMPLREG, (uint16_t)(alarm_sec << 15));
 197         rtc1_write(ECMPMREG, (uint16_t)(alarm_sec >> 1));
 198         rtc1_write(ECMPHREG, (uint16_t)(alarm_sec >> 17));
 199
 200         if (wkalrm->enabled)
 201                 enable_irq(aie_irq);
 202
 203         alarm_enabled = wkalrm->enabled;
 204
 205         spin_unlock_irq(&rtc_lock);
 206
 207         return 0;
 208 }
 209
 210 static int vr41xx_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 211 {
 212         switch (cmd) {
 213         case RTC_EPOCH_READ:
 214                 return put_user(epoch, (unsigned long __user *)arg);
 215         case RTC_EPOCH_SET:
 216                 /* Doesn't support before 1900 */
 217                 if (arg < 1900)
 218                         return -EINVAL;
 219                 epoch = arg;
 220                 break;
 221         default:
 222                 return -ENOIOCTLCMD;
 223         }
 224
 225         return 0;
 226 }
 227
 228 static int vr41xx_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 229 {
 230         spin_lock_irq(&rtc_lock);
 231         if (enabled) {
 232                 if (!alarm_enabled) {
 233                         enable_irq(aie_irq);
 234                         alarm_enabled = 1;
 235                 }
 236         } else {
 237                 if (alarm_enabled) {
 238                         disable_irq(aie_irq);
 239                         alarm_enabled = 0;
 240                 }
 241         }
 242         spin_unlock_irq(&rtc_lock);
 243         return 0;
 244 }
 245
 246 static irqreturn_t elapsedtime_interrupt(int irq, void *dev_id)
 247 {
 248         struct platform_device *pdev = (struct platform_device *)dev_id;
 249         struct rtc_device *rtc = platform_get_drvdata(pdev);
 250
 251         rtc2_write(RTCINTREG, ELAPSEDTIME_INT);
 252
 253         rtc_update_irq(rtc, 1, RTC_AF);
 254
 255         return IRQ_HANDLED;
 256 }
 257
 258 static irqreturn_t rtclong1_interrupt(int irq, void *dev_id)
 259 {
 260         struct platform_device *pdev = (struct platform_device *)dev_id;
 261         struct rtc_device *rtc = platform_get_drvdata(pdev);
 262         unsigned long count = periodic_count;
 263
 264         rtc2_write(RTCINTREG, RTCLONG1_INT);
 265
 266         rtc1_write(RTCL1LREG, count);
 267         rtc1_write(RTCL1HREG, count >> 16);
 268
 269         rtc_update_irq(rtc, 1, RTC_PF);
 270
 271         return IRQ_HANDLED;
 272 }
 273
 274 static const struct rtc_class_ops vr41xx_rtc_ops = {
 275         .release                = vr41xx_rtc_release,
 276         .ioctl                  = vr41xx_rtc_ioctl,
 277         .read_time              = vr41xx_rtc_read_time,
 278         .set_time               = vr41xx_rtc_set_time,
 279         .read_alarm             = vr41xx_rtc_read_alarm,
 280         .set_alarm              = vr41xx_rtc_set_alarm,
 281         .alarm_irq_enable       = vr41xx_rtc_alarm_irq_enable,
 282 };
 283
 284 static int rtc_probe(struct platform_device *pdev)
 285 {
 286         struct resource *res;
 287         struct rtc_device *rtc;
 288         int retval;
 289
 290         if (pdev->num_resources != 4)
 291                 return -EBUSY;
 292
 293         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 294         if (!res)
 295                 return -EBUSY;
 296
 297         rtc1_base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
 298         if (!rtc1_base)
 299                 return -EBUSY;
 300
 301         res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 302         if (!res) {
 303                 retval = -EBUSY;
 304                 goto err_rtc1_iounmap;
 305         }
 306
 307         rtc2_base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
 308         if (!rtc2_base) {
 309                 retval = -EBUSY;
 310                 goto err_rtc1_iounmap;
 311         }
 312
 313         rtc = devm_rtc_device_register(&pdev->dev, rtc_name, &vr41xx_rtc_ops,
 314                                         THIS_MODULE);
 315         if (IS_ERR(rtc)) {
 316                 retval = PTR_ERR(rtc);
 317                 goto err_iounmap_all;
 318         }
 319
 320         rtc->max_user_freq = MAX_PERIODIC_RATE;
 321
 322         spin_lock_irq(&rtc_lock);
 323
 324         rtc1_write(ECMPLREG, 0);
 325         rtc1_write(ECMPMREG, 0);
 326         rtc1_write(ECMPHREG, 0);
 327         rtc1_write(RTCL1LREG, 0);
 328         rtc1_write(RTCL1HREG, 0);
 329
 330         spin_unlock_irq(&rtc_lock);
 331
 332         aie_irq = platform_get_irq(pdev, 0);
 333         if (aie_irq <= 0) {
 334                 retval = -EBUSY;
 335                 goto err_iounmap_all;
 336         }
 337
 338         retval = devm_request_irq(&pdev->dev, aie_irq, elapsedtime_interrupt, 0,
 339                                 "elapsed_time", pdev);
 340         if (retval < 0)
 341                 goto err_iounmap_all;
 342
 343         pie_irq = platform_get_irq(pdev, 1);
 344         if (pie_irq <= 0) {
 345                 retval = -EBUSY;
 346                 goto err_iounmap_all;
 347         }
 348
 349         retval = devm_request_irq(&pdev->dev, pie_irq, rtclong1_interrupt, 0,
 350                                 "rtclong1", pdev);
 351         if (retval < 0)
 352                 goto err_iounmap_all;
 353
 354         platform_set_drvdata(pdev, rtc);
 355
 356         disable_irq(aie_irq);
 357         disable_irq(pie_irq);
 358
 359         dev_info(&pdev->dev, "Real Time Clock of NEC VR4100 series\n");
 360
 361         return 0;
 362
 363 err_iounmap_all:
 364         rtc2_base = NULL;
 365
 366 err_rtc1_iounmap:
 367         rtc1_base = NULL;
 368
 369         return retval;
 370 }
 371
 372 /* work with hotplug and coldplug */
 373 MODULE_ALIAS("platform:RTC");
 374
 375 static struct platform_driver rtc_platform_driver = {
 376         .probe          = rtc_probe,
 377         .driver         = {
 378                 .name   = rtc_name,
 379         },
 380 };
 381
 382 module_platform_driver(rtc_platform_driver);