drivers/rtc/rtc-vt8500.c

   1 /*
   2  * drivers/rtc/rtc-vt8500.c
   3  *
   4  *  Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
   5  *
   6  * Based on rtc-pxa.c
   7  *
   8  * This software is licensed under the terms of the GNU General Public
   9  * License version 2, as published by the Free Software Foundation, and
  10  * may be copied, distributed, and modified under those terms.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/module.h>
  19 #include <linux/rtc.h>
  20 #include <linux/init.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/io.h>
  23 #include <linux/bcd.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/slab.h>
  26 #include <linux/of.h>
  27
  28 /*
  29  * Register definitions
  30  */
  31 #define VT8500_RTC_TS           0x00    /* Time set */
  32 #define VT8500_RTC_DS           0x04    /* Date set */
  33 #define VT8500_RTC_AS           0x08    /* Alarm set */
  34 #define VT8500_RTC_CR           0x0c    /* Control */
  35 #define VT8500_RTC_TR           0x10    /* Time read */
  36 #define VT8500_RTC_DR           0x14    /* Date read */
  37 #define VT8500_RTC_WS           0x18    /* Write status */
  38 #define VT8500_RTC_CL           0x20    /* Calibration */
  39 #define VT8500_RTC_IS           0x24    /* Interrupt status */
  40 #define VT8500_RTC_ST           0x28    /* Status */
  41
  42 #define INVALID_TIME_BIT        (1 << 31)
  43
  44 #define DATE_CENTURY_S          19
  45 #define DATE_YEAR_S             11
  46 #define DATE_YEAR_MASK          (0xff << DATE_YEAR_S)
  47 #define DATE_MONTH_S            6
  48 #define DATE_MONTH_MASK         (0x1f << DATE_MONTH_S)
  49 #define DATE_DAY_MASK           0x3f
  50
  51 #define TIME_DOW_S              20
  52 #define TIME_DOW_MASK           (0x07 << TIME_DOW_S)
  53 #define TIME_HOUR_S             14
  54 #define TIME_HOUR_MASK          (0x3f << TIME_HOUR_S)
  55 #define TIME_MIN_S              7
  56 #define TIME_MIN_MASK           (0x7f << TIME_MIN_S)
  57 #define TIME_SEC_MASK           0x7f
  58
  59 #define ALARM_DAY_S             20
  60 #define ALARM_DAY_MASK          (0x3f << ALARM_DAY_S)
  61
  62 #define ALARM_DAY_BIT           (1 << 29)
  63 #define ALARM_HOUR_BIT          (1 << 28)
  64 #define ALARM_MIN_BIT           (1 << 27)
  65 #define ALARM_SEC_BIT           (1 << 26)
  66
  67 #define ALARM_ENABLE_MASK       (ALARM_DAY_BIT \
  68                                 | ALARM_HOUR_BIT \
  69                                 | ALARM_MIN_BIT \
  70                                 | ALARM_SEC_BIT)
  71
  72 #define VT8500_RTC_CR_ENABLE    (1 << 0)        /* Enable RTC */
  73 #define VT8500_RTC_CR_12H       (1 << 1)        /* 12h time format */
  74 #define VT8500_RTC_CR_SM_ENABLE (1 << 2)        /* Enable periodic irqs */
  75 #define VT8500_RTC_CR_SM_SEC    (1 << 3)        /* 0: 1Hz/60, 1: 1Hz */
  76 #define VT8500_RTC_CR_CALIB     (1 << 4)        /* Enable calibration */
  77
  78 #define VT8500_RTC_IS_ALARM     (1 << 0)        /* Alarm interrupt status */
  79
  80 struct vt8500_rtc {
  81         void __iomem            *regbase;
  82         struct resource         *res;
  83         int                     irq_alarm;
  84         struct rtc_device       *rtc;
  85         spinlock_t              lock;           /* Protects this structure */
  86 };
  87
  88 static irqreturn_t vt8500_rtc_irq(int irq, void *dev_id)
  89 {
  90         struct vt8500_rtc *vt8500_rtc = dev_id;
  91         u32 isr;
  92         unsigned long events = 0;
  93
  94         spin_lock(&vt8500_rtc->lock);
  95
  96         /* clear interrupt sources */
  97         isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
  98         writel(isr, vt8500_rtc->regbase + VT8500_RTC_IS);
  99
 100         spin_unlock(&vt8500_rtc->lock);
 101
 102         if (isr & VT8500_RTC_IS_ALARM)
 103                 events |= RTC_AF | RTC_IRQF;
 104
 105         rtc_update_irq(vt8500_rtc->rtc, 1, events);
 106
 107         return IRQ_HANDLED;
 108 }
 109
 110 static int vt8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
 111 {
 112         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 113         u32 date, time;
 114
 115         date = readl(vt8500_rtc->regbase + VT8500_RTC_DR);
 116         time = readl(vt8500_rtc->regbase + VT8500_RTC_TR);
 117
 118         tm->tm_sec = bcd2bin(time & TIME_SEC_MASK);
 119         tm->tm_min = bcd2bin((time & TIME_MIN_MASK) >> TIME_MIN_S);
 120         tm->tm_hour = bcd2bin((time & TIME_HOUR_MASK) >> TIME_HOUR_S);
 121         tm->tm_mday = bcd2bin(date & DATE_DAY_MASK);
 122         tm->tm_mon = bcd2bin((date & DATE_MONTH_MASK) >> DATE_MONTH_S) - 1;
 123         tm->tm_year = bcd2bin((date & DATE_YEAR_MASK) >> DATE_YEAR_S)
 124                         + ((date >> DATE_CENTURY_S) & 1 ? 200 : 100);
 125         tm->tm_wday = (time & TIME_DOW_MASK) >> TIME_DOW_S;
 126
 127         return 0;
 128 }
 129
 130 static int vt8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
 131 {
 132         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 133
 134         if (tm->tm_year < 100) {
 135                 dev_warn(dev, "Only years 2000-2199 are supported by the "
 136                               "hardware!\n");
 137                 return -EINVAL;
 138         }
 139
 140         writel((bin2bcd(tm->tm_year % 100) << DATE_YEAR_S)
 141                 | (bin2bcd(tm->tm_mon + 1) << DATE_MONTH_S)
 142                 | (bin2bcd(tm->tm_mday))
 143                 | ((tm->tm_year >= 200) << DATE_CENTURY_S),
 144                 vt8500_rtc->regbase + VT8500_RTC_DS);
 145         writel((bin2bcd(tm->tm_wday) << TIME_DOW_S)
 146                 | (bin2bcd(tm->tm_hour) << TIME_HOUR_S)
 147                 | (bin2bcd(tm->tm_min) << TIME_MIN_S)
 148                 | (bin2bcd(tm->tm_sec)),
 149                 vt8500_rtc->regbase + VT8500_RTC_TS);
 150
 151         return 0;
 152 }
 153
 154 static int vt8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 155 {
 156         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 157         u32 isr, alarm;
 158
 159         alarm = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
 160         isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
 161
 162         alrm->time.tm_mday = bcd2bin((alarm & ALARM_DAY_MASK) >> ALARM_DAY_S);
 163         alrm->time.tm_hour = bcd2bin((alarm & TIME_HOUR_MASK) >> TIME_HOUR_S);
 164         alrm->time.tm_min = bcd2bin((alarm & TIME_MIN_MASK) >> TIME_MIN_S);
 165         alrm->time.tm_sec = bcd2bin((alarm & TIME_SEC_MASK));
 166
 167         alrm->enabled = (alarm & ALARM_ENABLE_MASK) ? 1 : 0;
 168         alrm->pending = (isr & VT8500_RTC_IS_ALARM) ? 1 : 0;
 169
 170         return rtc_valid_tm(&alrm->time);
 171 }
 172
 173 static int vt8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 174 {
 175         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 176
 177         writel((alrm->enabled ? ALARM_ENABLE_MASK : 0)
 178                 | (bin2bcd(alrm->time.tm_mday) << ALARM_DAY_S)
 179                 | (bin2bcd(alrm->time.tm_hour) << TIME_HOUR_S)
 180                 | (bin2bcd(alrm->time.tm_min) << TIME_MIN_S)
 181                 | (bin2bcd(alrm->time.tm_sec)),
 182                 vt8500_rtc->regbase + VT8500_RTC_AS);
 183
 184         return 0;
 185 }
 186
 187 static int vt8500_alarm_irq_enable(struct device *dev, unsigned int enabled)
 188 {
 189         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 190         unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
 191
 192         if (enabled)
 193                 tmp |= ALARM_ENABLE_MASK;
 194         else
 195                 tmp &= ~ALARM_ENABLE_MASK;
 196
 197         writel(tmp, vt8500_rtc->regbase + VT8500_RTC_AS);
 198         return 0;
 199 }
 200
 201 static const struct rtc_class_ops vt8500_rtc_ops = {
 202         .read_time = vt8500_rtc_read_time,
 203         .set_time = vt8500_rtc_set_time,
 204         .read_alarm = vt8500_rtc_read_alarm,
 205         .set_alarm = vt8500_rtc_set_alarm,
 206         .alarm_irq_enable = vt8500_alarm_irq_enable,
 207 };
 208
 209 static int vt8500_rtc_probe(struct platform_device *pdev)
 210 {
 211         struct vt8500_rtc *vt8500_rtc;
 212         int ret;
 213
 214         vt8500_rtc = devm_kzalloc(&pdev->dev,
 215                            sizeof(struct vt8500_rtc), GFP_KERNEL);
 216         if (!vt8500_rtc)
 217                 return -ENOMEM;
 218
 219         spin_lock_init(&vt8500_rtc->lock);
 220         platform_set_drvdata(pdev, vt8500_rtc);
 221
 222         vt8500_rtc->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 223         if (!vt8500_rtc->res) {
 224                 dev_err(&pdev->dev, "No I/O memory resource defined\n");
 225                 return -ENXIO;
 226         }
 227
 228         vt8500_rtc->irq_alarm = platform_get_irq(pdev, 0);
 229         if (vt8500_rtc->irq_alarm < 0) {
 230                 dev_err(&pdev->dev, "No alarm IRQ resource defined\n");
 231                 return -ENXIO;
 232         }
 233
 234         vt8500_rtc->res = request_mem_region(vt8500_rtc->res->start,
 235                                              resource_size(vt8500_rtc->res),
 236                                              "vt8500-rtc");
 237         if (vt8500_rtc->res == NULL) {
 238                 dev_err(&pdev->dev, "failed to request I/O memory\n");
 239                 return -EBUSY;
 240         }
 241
 242         vt8500_rtc->regbase = ioremap(vt8500_rtc->res->start,
 243                                       resource_size(vt8500_rtc->res));
 244         if (!vt8500_rtc->regbase) {
 245                 dev_err(&pdev->dev, "Unable to map RTC I/O memory\n");
 246                 ret = -EBUSY;
 247                 goto err_release;
 248         }
 249
 250         /* Enable RTC and set it to 24-hour mode */
 251         writel(VT8500_RTC_CR_ENABLE,
 252                vt8500_rtc->regbase + VT8500_RTC_CR);
 253
 254         vt8500_rtc->rtc = rtc_device_register("vt8500-rtc", &pdev->dev,
 255                                               &vt8500_rtc_ops, THIS_MODULE);
 256         if (IS_ERR(vt8500_rtc->rtc)) {
 257                 ret = PTR_ERR(vt8500_rtc->rtc);
 258                 dev_err(&pdev->dev,
 259                         "Failed to register RTC device -> %d\n", ret);
 260                 goto err_unmap;
 261         }
 262
 263         ret = request_irq(vt8500_rtc->irq_alarm, vt8500_rtc_irq, 0,
 264                           "rtc alarm", vt8500_rtc);
 265         if (ret < 0) {
 266                 dev_err(&pdev->dev, "can't get irq %i, err %d\n",
 267                         vt8500_rtc->irq_alarm, ret);
 268                 goto err_unreg;
 269         }
 270
 271         return 0;
 272
 273 err_unreg:
 274         rtc_device_unregister(vt8500_rtc->rtc);
 275 err_unmap:
 276         iounmap(vt8500_rtc->regbase);
 277 err_release:
 278         release_mem_region(vt8500_rtc->res->start,
 279                            resource_size(vt8500_rtc->res));
 280         return ret;
 281 }
 282
 283 static int vt8500_rtc_remove(struct platform_device *pdev)
 284 {
 285         struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);
 286
 287         free_irq(vt8500_rtc->irq_alarm, vt8500_rtc);
 288
 289         rtc_device_unregister(vt8500_rtc->rtc);
 290
 291         /* Disable alarm matching */
 292         writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);
 293         iounmap(vt8500_rtc->regbase);
 294         release_mem_region(vt8500_rtc->res->start,
 295                            resource_size(vt8500_rtc->res));
 296
 297         platform_set_drvdata(pdev, NULL);
 298
 299         return 0;
 300 }
 301
 302 static const struct of_device_id wmt_dt_ids[] = {
 303         { .compatible = "via,vt8500-rtc", },
 304         {}
 305 };
 306
 307 static struct platform_driver vt8500_rtc_driver = {
 308         .probe          = vt8500_rtc_probe,
 309         .remove         = vt8500_rtc_remove,
 310         .driver         = {
 311                 .name   = "vt8500-rtc",
 312                 .owner  = THIS_MODULE,
 313                 .of_match_table = of_match_ptr(wmt_dt_ids),
 314         },
 315 };
 316
 317 module_platform_driver(vt8500_rtc_driver);
 318
 319 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
 320 MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
 321 MODULE_LICENSE("GPL v2");
 322 MODULE_ALIAS("platform:vt8500-rtc");