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         int                     irq_hz;
  82         struct rtc_device       *rtc;
  83         spinlock_t              lock;           /* Protects this structure */
  84 };
  85
  86 static irqreturn_t vt8500_rtc_irq(int irq, void *dev_id)
  87 {
  88         struct vt8500_rtc *vt8500_rtc = dev_id;
  89         u32 isr;
  90         unsigned long events = 0;
  91
  92         spin_lock(&vt8500_rtc->lock);
  93
  94         /* clear interrupt sources */
  95         isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
  96         writel(isr, vt8500_rtc->regbase + VT8500_RTC_IS);
  97
  98         spin_unlock(&vt8500_rtc->lock);
  99
 100         if (isr & 1)
 101                 events |= RTC_AF | RTC_IRQF;
 102
 103         /* Only second/minute interrupts are supported */
 104         if (isr & 2)
 105                 events |= RTC_UF | RTC_IRQF;
 106
 107         rtc_update_irq(vt8500_rtc->rtc, 1, events);
 108
 109         return IRQ_HANDLED;
 110 }
 111
 112 static int vt8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
 113 {
 114         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 115         u32 date, time;
 116
 117         date = readl(vt8500_rtc->regbase + VT8500_RTC_DR);
 118         time = readl(vt8500_rtc->regbase + VT8500_RTC_TR);
 119
 120         tm->tm_sec = bcd2bin(time & TIME_SEC_MASK);
 121         tm->tm_min = bcd2bin((time & TIME_MIN_MASK) >> TIME_MIN_S);
 122         tm->tm_hour = bcd2bin((time & TIME_HOUR_MASK) >> TIME_HOUR_S);
 123         tm->tm_mday = bcd2bin(date & DATE_DAY_MASK);
 124         tm->tm_mon = bcd2bin((date & DATE_MONTH_MASK) >> DATE_MONTH_S);
 125         tm->tm_year = bcd2bin((date & DATE_YEAR_MASK) >> DATE_YEAR_S)
 126                         + ((date >> DATE_CENTURY_S) & 1 ? 200 : 100);
 127         tm->tm_wday = (time & TIME_DOW_MASK) >> TIME_DOW_S;
 128
 129         return 0;
 130 }
 131
 132 static int vt8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
 133 {
 134         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 135
 136         if (tm->tm_year < 100) {
 137                 dev_warn(dev, "Only years 2000-2199 are supported by the "
 138                               "hardware!\n");
 139                 return -EINVAL;
 140         }
 141
 142         writel((bin2bcd(tm->tm_year - 100) << DATE_YEAR_S)
 143                 | (bin2bcd(tm->tm_mon) << DATE_MONTH_S)
 144                 | (bin2bcd(tm->tm_mday)),
 145                 vt8500_rtc->regbase + VT8500_RTC_DS);
 146         writel((bin2bcd(tm->tm_wday) << TIME_DOW_S)
 147                 | (bin2bcd(tm->tm_hour) << TIME_HOUR_S)
 148                 | (bin2bcd(tm->tm_min) << TIME_MIN_S)
 149                 | (bin2bcd(tm->tm_sec)),
 150                 vt8500_rtc->regbase + VT8500_RTC_TS);
 151
 152         return 0;
 153 }
 154
 155 static int vt8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 156 {
 157         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 158         u32 isr, alarm;
 159
 160         alarm = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
 161         isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
 162
 163         alrm->time.tm_mday = bcd2bin((alarm & ALARM_DAY_MASK) >> ALARM_DAY_S);
 164         alrm->time.tm_hour = bcd2bin((alarm & TIME_HOUR_MASK) >> TIME_HOUR_S);
 165         alrm->time.tm_min = bcd2bin((alarm & TIME_MIN_MASK) >> TIME_MIN_S);
 166         alrm->time.tm_sec = bcd2bin((alarm & TIME_SEC_MASK));
 167
 168         alrm->enabled = (alarm & ALARM_ENABLE_MASK) ? 1 : 0;
 169
 170         alrm->pending = (isr & 1) ? 1 : 0;
 171         return rtc_valid_tm(&alrm->time);
 172 }
 173
 174 static int vt8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 175 {
 176         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 177
 178         writel((alrm->enabled ? ALARM_ENABLE_MASK : 0)
 179                 | (bin2bcd(alrm->time.tm_mday) << ALARM_DAY_S)
 180                 | (bin2bcd(alrm->time.tm_hour) << TIME_HOUR_S)
 181                 | (bin2bcd(alrm->time.tm_min) << TIME_MIN_S)
 182                 | (bin2bcd(alrm->time.tm_sec)),
 183                 vt8500_rtc->regbase + VT8500_RTC_AS);
 184
 185         return 0;
 186 }
 187
 188 static int vt8500_alarm_irq_enable(struct device *dev, unsigned int enabled)
 189 {
 190         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 191         unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
 192
 193         if (enabled)
 194                 tmp |= ALARM_ENABLE_MASK;
 195         else
 196                 tmp &= ~ALARM_ENABLE_MASK;
 197
 198         writel(tmp, vt8500_rtc->regbase + VT8500_RTC_AS);
 199         return 0;
 200 }
 201
 202 static int vt8500_update_irq_enable(struct device *dev, unsigned int enabled)
 203 {
 204         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
 205         unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_CR);
 206
 207         if (enabled)
 208                 tmp |= VT8500_RTC_CR_SM_SEC | VT8500_RTC_CR_SM_ENABLE;
 209         else
 210                 tmp &= ~VT8500_RTC_CR_SM_ENABLE;
 211
 212         writel(tmp, vt8500_rtc->regbase + VT8500_RTC_CR);
 213         return 0;
 214 }
 215
 216 static const struct rtc_class_ops vt8500_rtc_ops = {
 217         .read_time = vt8500_rtc_read_time,
 218         .set_time = vt8500_rtc_set_time,
 219         .read_alarm = vt8500_rtc_read_alarm,
 220         .set_alarm = vt8500_rtc_set_alarm,
 221         .alarm_irq_enable = vt8500_alarm_irq_enable,
 222         .update_irq_enable = vt8500_update_irq_enable,
 223 };
 224
 225 static int __devinit vt8500_rtc_probe(struct platform_device *pdev)
 226 {
 227         struct vt8500_rtc *vt8500_rtc;
 228         int ret;
 229
 230         vt8500_rtc = kzalloc(sizeof(struct vt8500_rtc), GFP_KERNEL);
 231         if (!vt8500_rtc)
 232                 return -ENOMEM;
 233
 234         spin_lock_init(&vt8500_rtc->lock);
 235         platform_set_drvdata(pdev, vt8500_rtc);
 236
 237         vt8500_rtc->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 238         if (!vt8500_rtc->res) {
 239                 dev_err(&pdev->dev, "No I/O memory resource defined\n");
 240                 ret = -ENXIO;
 241                 goto err_free;
 242         }
 243
 244         vt8500_rtc->irq_alarm = platform_get_irq(pdev, 0);
 245         if (vt8500_rtc->irq_alarm < 0) {
 246                 dev_err(&pdev->dev, "No alarm IRQ resource defined\n");
 247                 ret = -ENXIO;
 248                 goto err_free;
 249         }
 250
 251         vt8500_rtc->irq_hz = platform_get_irq(pdev, 1);
 252         if (vt8500_rtc->irq_hz < 0) {
 253                 dev_err(&pdev->dev, "No 1Hz IRQ resource defined\n");
 254                 ret = -ENXIO;
 255                 goto err_free;
 256         }
 257
 258         vt8500_rtc->res = request_mem_region(vt8500_rtc->res->start,
 259                                              resource_size(vt8500_rtc->res),
 260                                              "vt8500-rtc");
 261         if (vt8500_rtc->res == NULL) {
 262                 dev_err(&pdev->dev, "failed to request I/O memory\n");
 263                 ret = -EBUSY;
 264                 goto err_free;
 265         }
 266
 267         vt8500_rtc->regbase = ioremap(vt8500_rtc->res->start,
 268                                       resource_size(vt8500_rtc->res));
 269         if (!vt8500_rtc->regbase) {
 270                 dev_err(&pdev->dev, "Unable to map RTC I/O memory\n");
 271                 ret = -EBUSY;
 272                 goto err_release;
 273         }
 274
 275         /* Enable the second/minute interrupt generation and enable RTC */
 276         writel(VT8500_RTC_CR_ENABLE | VT8500_RTC_CR_24H
 277                 | VT8500_RTC_CR_SM_ENABLE | VT8500_RTC_CR_SM_SEC,
 278                vt8500_rtc->regbase + VT8500_RTC_CR);
 279
 280         vt8500_rtc->rtc = rtc_device_register("vt8500-rtc", &pdev->dev,
 281                                               &vt8500_rtc_ops, THIS_MODULE);
 282         if (IS_ERR(vt8500_rtc->rtc)) {
 283                 ret = PTR_ERR(vt8500_rtc->rtc);
 284                 dev_err(&pdev->dev,
 285                         "Failed to register RTC device -> %d\n", ret);
 286                 goto err_unmap;
 287         }
 288
 289         ret = request_irq(vt8500_rtc->irq_hz, vt8500_rtc_irq, 0,
 290                           "rtc 1Hz", vt8500_rtc);
 291         if (ret < 0) {
 292                 dev_err(&pdev->dev, "can't get irq %i, err %d\n",
 293                         vt8500_rtc->irq_hz, ret);
 294                 goto err_unreg;
 295         }
 296
 297         ret = request_irq(vt8500_rtc->irq_alarm, vt8500_rtc_irq, 0,
 298                           "rtc alarm", vt8500_rtc);
 299         if (ret < 0) {
 300                 dev_err(&pdev->dev, "can't get irq %i, err %d\n",
 301                         vt8500_rtc->irq_alarm, ret);
 302                 goto err_free_hz;
 303         }
 304
 305         return 0;
 306
 307 err_free_hz:
 308         free_irq(vt8500_rtc->irq_hz, vt8500_rtc);
 309 err_unreg:
 310         rtc_device_unregister(vt8500_rtc->rtc);
 311 err_unmap:
 312         iounmap(vt8500_rtc->regbase);
 313 err_release:
 314         release_mem_region(vt8500_rtc->res->start,
 315                            resource_size(vt8500_rtc->res));
 316 err_free:
 317         kfree(vt8500_rtc);
 318         return ret;
 319 }
 320
 321 static int __devexit vt8500_rtc_remove(struct platform_device *pdev)
 322 {
 323         struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);
 324
 325         free_irq(vt8500_rtc->irq_alarm, vt8500_rtc);
 326         free_irq(vt8500_rtc->irq_hz, vt8500_rtc);
 327
 328         rtc_device_unregister(vt8500_rtc->rtc);
 329
 330         /* Disable alarm matching */
 331         writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);
 332         iounmap(vt8500_rtc->regbase);
 333         release_mem_region(vt8500_rtc->res->start,
 334                            resource_size(vt8500_rtc->res));
 335
 336         kfree(vt8500_rtc);
 337         platform_set_drvdata(pdev, NULL);
 338
 339         return 0;
 340 }
 341
 342 static struct platform_driver vt8500_rtc_driver = {
 343         .probe          = vt8500_rtc_probe,
 344         .remove         = __devexit_p(vt8500_rtc_remove),
 345         .driver         = {
 346                 .name   = "vt8500-rtc",
 347                 .owner  = THIS_MODULE,
 348         },
 349 };
 350
 351 static int __init vt8500_rtc_init(void)
 352 {
 353         return platform_driver_register(&vt8500_rtc_driver);
 354 }
 355 module_init(vt8500_rtc_init);
 356
 357 static void __exit vt8500_rtc_exit(void)
 358 {
 359         platform_driver_unregister(&vt8500_rtc_driver);
 360 }
 361 module_exit(vt8500_rtc_exit);
 362
 363 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
 364 MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
 365 MODULE_LICENSE("GPL");
 366 MODULE_ALIAS("platform:vt8500-rtc");