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
  27 /*
  28  * Register definitions
  29  */
  30 #define VT8500_RTC_TS           0x00    /* Time set */
  31 #define VT8500_RTC_DS           0x04    /* Date set */
  32 #define VT8500_RTC_AS           0x08    /* Alarm set */
  33 #define VT8500_RTC_CR           0x0c    /* Control */
  34 #define VT8500_RTC_TR           0x10    /* Time read */
  35 #define VT8500_RTC_DR           0x14    /* Date read */
  36 #define VT8500_RTC_WS           0x18    /* Write status */
  37 #define VT8500_RTC_CL           0x20    /* Calibration */
  38 #define VT8500_RTC_IS           0x24    /* Interrupt status */
  39 #define VT8500_RTC_ST           0x28    /* Status */
  40
  41 #define INVALID_TIME_BIT        (1 << 31)
  42
  43 #define DATE_CENTURY_S          19
  44 #define DATE_YEAR_S             11
  45 #define DATE_YEAR_MASK          (0xff << DATE_YEAR_S)
  46 #define DATE_MONTH_S            6
  47 #define DATE_MONTH_MASK         (0x1f << DATE_MONTH_S)
  48 #define DATE_DAY_MASK           0x3f
  49
  50 #define TIME_DOW_S              20
  51 #define TIME_DOW_MASK           (0x07 << TIME_DOW_S)
  52 #define TIME_HOUR_S             14
  53 #define TIME_HOUR_MASK          (0x3f << TIME_HOUR_S)
  54 #define TIME_MIN_S              7
  55 #define TIME_MIN_MASK           (0x7f << TIME_MIN_S)
  56 #define TIME_SEC_MASK           0x7f
  57
  58 #define ALARM_DAY_S             20
  59 #define ALARM_DAY_MASK          (0x3f << ALARM_DAY_S)
  60
  61 #define ALARM_DAY_BIT           (1 << 29)
  62 #define ALARM_HOUR_BIT          (1 << 28)
  63 #define ALARM_MIN_BIT           (1 << 27)
  64 #define ALARM_SEC_BIT           (1 << 26)
  65
  66 #define ALARM_ENABLE_MASK       (ALARM_DAY_BIT \
  67                                 | ALARM_HOUR_BIT \
  68                                 | ALARM_MIN_BIT \
  69                                 | ALARM_SEC_BIT)
  70
  71 #define VT8500_RTC_CR_ENABLE    (1 << 0)        /* Enable RTC */
  72 #define VT8500_RTC_CR_24H       (1 << 1)        /* 24h time format */
  73 #define VT8500_RTC_CR_SM_ENABLE (1 << 2)        /* Enable periodic irqs */
  74 #define VT8500_RTC_CR_SM_SEC    (1 << 3)        /* 0: 1Hz/60, 1: 1Hz */
  75 #define VT8500_RTC_CR_CALIB     (1 << 4)        /* Enable calibration */
  76
  77 struct vt8500_rtc {
  78         void __iomem            *regbase;
  79         struct resource         *res;
  80         int                     irq_alarm;
  81         struct rtc_device       *rtc;
  82         spinlock_t              lock;           /* Protects this structure */
  83 };
  84
  85 static irqreturn_t vt8500_rtc_irq(int irq, void *dev_id)
  86 {
  87         struct vt8500_rtc *vt8500_rtc = dev_id;
  88         u32 isr;
  89         unsigned long events = 0;
  90
  91         spin_lock(&vt8500_rtc->lock);
  92
  93         /* clear interrupt sources */
  94         isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
  95         writel(isr, vt8500_rtc->regbase + VT8500_RTC_IS);
  96
  97         spin_unlock(&vt8500_rtc->lock);
  98
  99         if (isr & 1)
 100                 events |= RTC_AF | RTC_IRQF;
 101
 102         rtc_update_irq(vt8500_rtc->rtc, 1, events);
 103
 104         return IRQ_HANDLED;
 105 }
 106
 107 static int vt8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
 108 {
 109         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 110         u32 date, time;
 111
 112         date = readl(vt8500_rtc->regbase + VT8500_RTC_DR);
 113         time = readl(vt8500_rtc->regbase + VT8500_RTC_TR);
 114
 115         tm->tm_sec = bcd2bin(time & TIME_SEC_MASK);
 116         tm->tm_min = bcd2bin((time & TIME_MIN_MASK) >> TIME_MIN_S);
 117         tm->tm_hour = bcd2bin((time & TIME_HOUR_MASK) >> TIME_HOUR_S);
 118         tm->tm_mday = bcd2bin(date & DATE_DAY_MASK);
 119         tm->tm_mon = bcd2bin((date & DATE_MONTH_MASK) >> DATE_MONTH_S);
 120         tm->tm_year = bcd2bin((date & DATE_YEAR_MASK) >> DATE_YEAR_S)
 121                         + ((date >> DATE_CENTURY_S) & 1 ? 200 : 100);
 122         tm->tm_wday = (time & TIME_DOW_MASK) >> TIME_DOW_S;
 123
 124         return 0;
 125 }
 126
 127 static int vt8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
 128 {
 129         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 130
 131         if (tm->tm_year < 100) {
 132                 dev_warn(dev, "Only years 2000-2199 are supported by the "
 133                               "hardware!\n");
 134                 return -EINVAL;
 135         }
 136
 137         writel((bin2bcd(tm->tm_year - 100) << DATE_YEAR_S)
 138                 | (bin2bcd(tm->tm_mon) << DATE_MONTH_S)
 139                 | (bin2bcd(tm->tm_mday)),
 140                 vt8500_rtc->regbase + VT8500_RTC_DS);
 141         writel((bin2bcd(tm->tm_wday) << TIME_DOW_S)
 142                 | (bin2bcd(tm->tm_hour) << TIME_HOUR_S)
 143                 | (bin2bcd(tm->tm_min) << TIME_MIN_S)
 144                 | (bin2bcd(tm->tm_sec)),
 145                 vt8500_rtc->regbase + VT8500_RTC_TS);
 146
 147         return 0;
 148 }
 149
 150 static int vt8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 151 {
 152         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 153         u32 isr, alarm;
 154
 155         alarm = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
 156         isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
 157
 158         alrm->time.tm_mday = bcd2bin((alarm & ALARM_DAY_MASK) >> ALARM_DAY_S);
 159         alrm->time.tm_hour = bcd2bin((alarm & TIME_HOUR_MASK) >> TIME_HOUR_S);
 160         alrm->time.tm_min = bcd2bin((alarm & TIME_MIN_MASK) >> TIME_MIN_S);
 161         alrm->time.tm_sec = bcd2bin((alarm & TIME_SEC_MASK));
 162
 163         alrm->enabled = (alarm & ALARM_ENABLE_MASK) ? 1 : 0;
 164
 165         alrm->pending = (isr & 1) ? 1 : 0;
 166         return rtc_valid_tm(&alrm->time);
 167 }
 168
 169 static int vt8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 170 {
 171         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 172
 173         writel((alrm->enabled ? ALARM_ENABLE_MASK : 0)
 174                 | (bin2bcd(alrm->time.tm_mday) << ALARM_DAY_S)
 175                 | (bin2bcd(alrm->time.tm_hour) << TIME_HOUR_S)
 176                 | (bin2bcd(alrm->time.tm_min) << TIME_MIN_S)
 177                 | (bin2bcd(alrm->time.tm_sec)),
 178                 vt8500_rtc->regbase + VT8500_RTC_AS);
 179
 180         return 0;
 181 }
 182
 183 static int vt8500_alarm_irq_enable(struct device *dev, unsigned int enabled)
 184 {
 185         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 186         unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
 187
 188         if (enabled)
 189                 tmp |= ALARM_ENABLE_MASK;
 190         else
 191                 tmp &= ~ALARM_ENABLE_MASK;
 192
 193         writel(tmp, vt8500_rtc->regbase + VT8500_RTC_AS);
 194         return 0;
 195 }
 196
 197 static const struct rtc_class_ops vt8500_rtc_ops = {
 198         .read_time = vt8500_rtc_read_time,
 199         .set_time = vt8500_rtc_set_time,
 200         .read_alarm = vt8500_rtc_read_alarm,
 201         .set_alarm = vt8500_rtc_set_alarm,
 202         .alarm_irq_enable = vt8500_alarm_irq_enable,
 203 };
 204
 205 static int __devinit vt8500_rtc_probe(struct platform_device *pdev)
 206 {
 207         struct vt8500_rtc *vt8500_rtc;
 208         int ret;
 209
 210         vt8500_rtc = kzalloc(sizeof(struct vt8500_rtc), GFP_KERNEL);
 211         if (!vt8500_rtc)
 212                 return -ENOMEM;
 213
 214         spin_lock_init(&vt8500_rtc->lock);
 215         platform_set_drvdata(pdev, vt8500_rtc);
 216
 217         vt8500_rtc->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 218         if (!vt8500_rtc->res) {
 219                 dev_err(&pdev->dev, "No I/O memory resource defined\n");
 220                 ret = -ENXIO;
 221                 goto err_free;
 222         }
 223
 224         vt8500_rtc->irq_alarm = platform_get_irq(pdev, 0);
 225         if (vt8500_rtc->irq_alarm < 0) {
 226                 dev_err(&pdev->dev, "No alarm IRQ resource defined\n");
 227                 ret = -ENXIO;
 228                 goto err_free;
 229         }
 230
 231         vt8500_rtc->res = request_mem_region(vt8500_rtc->res->start,
 232                                              resource_size(vt8500_rtc->res),
 233                                              "vt8500-rtc");
 234         if (vt8500_rtc->res == NULL) {
 235                 dev_err(&pdev->dev, "failed to request I/O memory\n");
 236                 ret = -EBUSY;
 237                 goto err_free;
 238         }
 239
 240         vt8500_rtc->regbase = ioremap(vt8500_rtc->res->start,
 241                                       resource_size(vt8500_rtc->res));
 242         if (!vt8500_rtc->regbase) {
 243                 dev_err(&pdev->dev, "Unable to map RTC I/O memory\n");
 244                 ret = -EBUSY;
 245                 goto err_release;
 246         }
 247
 248         /* Enable RTC and set it to 24-hour mode */
 249         writel(VT8500_RTC_CR_ENABLE | VT8500_RTC_CR_24H,
 250                vt8500_rtc->regbase + VT8500_RTC_CR);
 251
 252         vt8500_rtc->rtc = rtc_device_register("vt8500-rtc", &pdev->dev,
 253                                               &vt8500_rtc_ops, THIS_MODULE);
 254         if (IS_ERR(vt8500_rtc->rtc)) {
 255                 ret = PTR_ERR(vt8500_rtc->rtc);
 256                 dev_err(&pdev->dev,
 257                         "Failed to register RTC device -> %d\n", ret);
 258                 goto err_unmap;
 259         }
 260
 261         ret = request_irq(vt8500_rtc->irq_alarm, vt8500_rtc_irq, 0,
 262                           "rtc alarm", vt8500_rtc);
 263         if (ret < 0) {
 264                 dev_err(&pdev->dev, "can't get irq %i, err %d\n",
 265                         vt8500_rtc->irq_alarm, ret);
 266                 goto err_unreg;
 267         }
 268
 269         return 0;
 270
 271 err_unreg:
 272         rtc_device_unregister(vt8500_rtc->rtc);
 273 err_unmap:
 274         iounmap(vt8500_rtc->regbase);
 275 err_release:
 276         release_mem_region(vt8500_rtc->res->start,
 277                            resource_size(vt8500_rtc->res));
 278 err_free:
 279         kfree(vt8500_rtc);
 280         return ret;
 281 }
 282
 283 static int __devexit 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         kfree(vt8500_rtc);
 298         platform_set_drvdata(pdev, NULL);
 299
 300         return 0;
 301 }
 302
 303 static struct platform_driver vt8500_rtc_driver = {
 304         .probe          = vt8500_rtc_probe,
 305         .remove         = __devexit_p(vt8500_rtc_remove),
 306         .driver         = {
 307                 .name   = "vt8500-rtc",
 308                 .owner  = THIS_MODULE,
 309         },
 310 };
 311
 312 static int __init vt8500_rtc_init(void)
 313 {
 314         return platform_driver_register(&vt8500_rtc_driver);
 315 }
 316 module_init(vt8500_rtc_init);
 317
 318 static void __exit vt8500_rtc_exit(void)
 319 {
 320         platform_driver_unregister(&vt8500_rtc_driver);
 321 }
 322 module_exit(vt8500_rtc_exit);
 323
 324 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
 325 MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
 326 MODULE_LICENSE("GPL");
 327 MODULE_ALIAS("platform:vt8500-rtc");