drivers/rtc/rtc-ds1553.c

   1 /*
   2  * An rtc driver for the Dallas DS1553
   3  *
   4  * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.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 version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/bcd.h>
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/gfp.h>
  15 #include <linux/delay.h>
  16 #include <linux/jiffies.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/rtc.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/io.h>
  21 #include <linux/module.h>
  22
  23 #define RTC_REG_SIZE            0x2000
  24 #define RTC_OFFSET              0x1ff0
  25
  26 #define RTC_FLAGS               (RTC_OFFSET + 0)
  27 #define RTC_SECONDS_ALARM       (RTC_OFFSET + 2)
  28 #define RTC_MINUTES_ALARM       (RTC_OFFSET + 3)
  29 #define RTC_HOURS_ALARM         (RTC_OFFSET + 4)
  30 #define RTC_DATE_ALARM          (RTC_OFFSET + 5)
  31 #define RTC_INTERRUPTS          (RTC_OFFSET + 6)
  32 #define RTC_WATCHDOG            (RTC_OFFSET + 7)
  33 #define RTC_CONTROL             (RTC_OFFSET + 8)
  34 #define RTC_CENTURY             (RTC_OFFSET + 8)
  35 #define RTC_SECONDS             (RTC_OFFSET + 9)
  36 #define RTC_MINUTES             (RTC_OFFSET + 10)
  37 #define RTC_HOURS               (RTC_OFFSET + 11)
  38 #define RTC_DAY                 (RTC_OFFSET + 12)
  39 #define RTC_DATE                (RTC_OFFSET + 13)
  40 #define RTC_MONTH               (RTC_OFFSET + 14)
  41 #define RTC_YEAR                (RTC_OFFSET + 15)
  42
  43 #define RTC_CENTURY_MASK        0x3f
  44 #define RTC_SECONDS_MASK        0x7f
  45 #define RTC_DAY_MASK            0x07
  46
  47 /* Bits in the Control/Century register */
  48 #define RTC_WRITE               0x80
  49 #define RTC_READ                0x40
  50
  51 /* Bits in the Seconds register */
  52 #define RTC_STOP                0x80
  53
  54 /* Bits in the Flags register */
  55 #define RTC_FLAGS_AF            0x40
  56 #define RTC_FLAGS_BLF           0x10
  57
  58 /* Bits in the Interrupts register */
  59 #define RTC_INTS_AE             0x80
  60
  61 struct rtc_plat_data {
  62         struct rtc_device *rtc;
  63         void __iomem *ioaddr;
  64         unsigned long last_jiffies;
  65         int irq;
  66         unsigned int irqen;
  67         int alrm_sec;
  68         int alrm_min;
  69         int alrm_hour;
  70         int alrm_mday;
  71         spinlock_t lock;
  72 };
  73
  74 static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm)
  75 {
  76         struct rtc_plat_data *pdata = dev_get_drvdata(dev);
  77         void __iomem *ioaddr = pdata->ioaddr;
  78         u8 century;
  79
  80         century = bin2bcd((tm->tm_year + 1900) / 100);
  81
  82         writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL);
  83
  84         writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
  85         writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
  86         writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
  87         writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
  88         writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
  89         writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
  90         writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
  91
  92         /* RTC_CENTURY and RTC_CONTROL share same register */
  93         writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
  94         writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
  95         return 0;
  96 }
  97
  98 static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm)
  99 {
 100         struct rtc_plat_data *pdata = dev_get_drvdata(dev);
 101         void __iomem *ioaddr = pdata->ioaddr;
 102         unsigned int year, month, day, hour, minute, second, week;
 103         unsigned int century;
 104
 105         /* give enough time to update RTC in case of continuous read */
 106         if (pdata->last_jiffies == jiffies)
 107                 msleep(1);
 108         pdata->last_jiffies = jiffies;
 109         writeb(RTC_READ, ioaddr + RTC_CONTROL);
 110         second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
 111         minute = readb(ioaddr + RTC_MINUTES);
 112         hour = readb(ioaddr + RTC_HOURS);
 113         day = readb(ioaddr + RTC_DATE);
 114         week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
 115         month = readb(ioaddr + RTC_MONTH);
 116         year = readb(ioaddr + RTC_YEAR);
 117         century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
 118         writeb(0, ioaddr + RTC_CONTROL);
 119         tm->tm_sec = bcd2bin(second);
 120         tm->tm_min = bcd2bin(minute);
 121         tm->tm_hour = bcd2bin(hour);
 122         tm->tm_mday = bcd2bin(day);
 123         tm->tm_wday = bcd2bin(week);
 124         tm->tm_mon = bcd2bin(month) - 1;
 125         /* year is 1900 + tm->tm_year */
 126         tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
 127
 128         return 0;
 129 }
 130
 131 static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata)
 132 {
 133         void __iomem *ioaddr = pdata->ioaddr;
 134         unsigned long flags;
 135
 136         spin_lock_irqsave(&pdata->lock, flags);
 137         writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
 138                0x80 : bin2bcd(pdata->alrm_mday),
 139                ioaddr + RTC_DATE_ALARM);
 140         writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
 141                0x80 : bin2bcd(pdata->alrm_hour),
 142                ioaddr + RTC_HOURS_ALARM);
 143         writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
 144                0x80 : bin2bcd(pdata->alrm_min),
 145                ioaddr + RTC_MINUTES_ALARM);
 146         writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
 147                0x80 : bin2bcd(pdata->alrm_sec),
 148                ioaddr + RTC_SECONDS_ALARM);
 149         writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS);
 150         readb(ioaddr + RTC_FLAGS);      /* clear interrupts */
 151         spin_unlock_irqrestore(&pdata->lock, flags);
 152 }
 153
 154 static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 155 {
 156         struct rtc_plat_data *pdata = dev_get_drvdata(dev);
 157
 158         if (pdata->irq <= 0)
 159                 return -EINVAL;
 160         pdata->alrm_mday = alrm->time.tm_mday;
 161         pdata->alrm_hour = alrm->time.tm_hour;
 162         pdata->alrm_min = alrm->time.tm_min;
 163         pdata->alrm_sec = alrm->time.tm_sec;
 164         if (alrm->enabled)
 165                 pdata->irqen |= RTC_AF;
 166         ds1553_rtc_update_alarm(pdata);
 167         return 0;
 168 }
 169
 170 static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 171 {
 172         struct rtc_plat_data *pdata = dev_get_drvdata(dev);
 173
 174         if (pdata->irq <= 0)
 175                 return -EINVAL;
 176         alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
 177         alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
 178         alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
 179         alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
 180         alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
 181         return 0;
 182 }
 183
 184 static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id)
 185 {
 186         struct platform_device *pdev = dev_id;
 187         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 188         void __iomem *ioaddr = pdata->ioaddr;
 189         unsigned long events = 0;
 190
 191         spin_lock(&pdata->lock);
 192         /* read and clear interrupt */
 193         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {
 194                 events = RTC_IRQF;
 195                 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
 196                         events |= RTC_UF;
 197                 else
 198                         events |= RTC_AF;
 199                 rtc_update_irq(pdata->rtc, 1, events);
 200         }
 201         spin_unlock(&pdata->lock);
 202         return events ? IRQ_HANDLED : IRQ_NONE;
 203 }
 204
 205 static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 206 {
 207         struct rtc_plat_data *pdata = dev_get_drvdata(dev);
 208
 209         if (pdata->irq <= 0)
 210                 return -EINVAL;
 211         if (enabled)
 212                 pdata->irqen |= RTC_AF;
 213         else
 214                 pdata->irqen &= ~RTC_AF;
 215         ds1553_rtc_update_alarm(pdata);
 216         return 0;
 217 }
 218
 219 static const struct rtc_class_ops ds1553_rtc_ops = {
 220         .read_time              = ds1553_rtc_read_time,
 221         .set_time               = ds1553_rtc_set_time,
 222         .read_alarm             = ds1553_rtc_read_alarm,
 223         .set_alarm              = ds1553_rtc_set_alarm,
 224         .alarm_irq_enable       = ds1553_rtc_alarm_irq_enable,
 225 };
 226
 227 static int ds1553_nvram_read(void *priv, unsigned int pos, void *val,
 228                              size_t bytes)
 229 {
 230         struct platform_device *pdev = priv;
 231         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 232         void __iomem *ioaddr = pdata->ioaddr;
 233         u8 *buf = val;
 234
 235         for (; bytes; bytes--)
 236                 *buf++ = readb(ioaddr + pos++);
 237         return 0;
 238 }
 239
 240 static int ds1553_nvram_write(void *priv, unsigned int pos, void *val,
 241                               size_t bytes)
 242 {
 243         struct platform_device *pdev = priv;
 244         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 245         void __iomem *ioaddr = pdata->ioaddr;
 246         u8 *buf = val;
 247
 248         for (; bytes; bytes--)
 249                 writeb(*buf++, ioaddr + pos++);
 250         return 0;
 251 }
 252
 253 static int ds1553_rtc_probe(struct platform_device *pdev)
 254 {
 255         struct resource *res;
 256         unsigned int cen, sec;
 257         struct rtc_plat_data *pdata;
 258         void __iomem *ioaddr;
 259         int ret = 0;
 260         struct nvmem_config nvmem_cfg = {
 261                 .name = "ds1553_nvram",
 262                 .word_size = 1,
 263                 .stride = 1,
 264                 .size = RTC_OFFSET,
 265                 .reg_read = ds1553_nvram_read,
 266                 .reg_write = ds1553_nvram_write,
 267                 .priv = pdev,
 268         };
 269
 270         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 271         if (!pdata)
 272                 return -ENOMEM;
 273
 274         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 275         ioaddr = devm_ioremap_resource(&pdev->dev, res);
 276         if (IS_ERR(ioaddr))
 277                 return PTR_ERR(ioaddr);
 278         pdata->ioaddr = ioaddr;
 279         pdata->irq = platform_get_irq(pdev, 0);
 280
 281         /* turn RTC on if it was not on */
 282         sec = readb(ioaddr + RTC_SECONDS);
 283         if (sec & RTC_STOP) {
 284                 sec &= RTC_SECONDS_MASK;
 285                 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
 286                 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
 287                 writeb(sec, ioaddr + RTC_SECONDS);
 288                 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
 289         }
 290         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF)
 291                 dev_warn(&pdev->dev, "voltage-low detected.\n");
 292
 293         spin_lock_init(&pdata->lock);
 294         pdata->last_jiffies = jiffies;
 295         platform_set_drvdata(pdev, pdata);
 296
 297         pdata->rtc = devm_rtc_allocate_device(&pdev->dev);
 298         if (IS_ERR(pdata->rtc))
 299                 return PTR_ERR(pdata->rtc);
 300
 301         pdata->rtc->ops = &ds1553_rtc_ops;
 302         pdata->rtc->nvram_old_abi = true;
 303
 304         ret = rtc_register_device(pdata->rtc);
 305         if (ret)
 306                 return ret;
 307
 308         if (pdata->irq > 0) {
 309                 writeb(0, ioaddr + RTC_INTERRUPTS);
 310                 if (devm_request_irq(&pdev->dev, pdata->irq,
 311                                 ds1553_rtc_interrupt,
 312                                 0, pdev->name, pdev) < 0) {
 313                         dev_warn(&pdev->dev, "interrupt not available.\n");
 314                         pdata->irq = 0;
 315                 }
 316         }
 317
 318         if (rtc_nvmem_register(pdata->rtc, &nvmem_cfg))
 319                 dev_err(&pdev->dev, "unable to register nvmem\n");
 320
 321         return 0;
 322 }
 323
 324 /* work with hotplug and coldplug */
 325 MODULE_ALIAS("platform:rtc-ds1553");
 326
 327 static struct platform_driver ds1553_rtc_driver = {
 328         .probe          = ds1553_rtc_probe,
 329         .driver         = {
 330                 .name   = "rtc-ds1553",
 331         },
 332 };
 333
 334 module_platform_driver(ds1553_rtc_driver);
 335
 336 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
 337 MODULE_DESCRIPTION("Dallas DS1553 RTC driver");
 338 MODULE_LICENSE("GPL");