drivers/rtc/rtc-stmp3xxx.c

   1 /*
   2  * Freescale STMP37XX/STMP378X Real Time Clock driver
   3  *
   4  * Copyright (c) 2007 Sigmatel, Inc.
   5  * Peter Hartley, <peter.hartley@sigmatel.com>
   6  *
   7  * Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved.
   8  * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
   9  */
  10
  11 /*
  12  * The code contained herein is licensed under the GNU General Public
  13  * License. You may obtain a copy of the GNU General Public License
  14  * Version 2 or later at the following locations:
  15  *
  16  * http://www.opensource.org/licenses/gpl-license.html
  17  * http://www.gnu.org/copyleft/gpl.html
  18  */
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/io.h>
  22 #include <linux/init.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/rtc.h>
  26 #include <linux/slab.h>
  27
  28 #include <mach/common.h>
  29
  30 #define STMP3XXX_RTC_CTRL                       0x0
  31 #define STMP3XXX_RTC_CTRL_SET                   0x4
  32 #define STMP3XXX_RTC_CTRL_CLR                   0x8
  33 #define STMP3XXX_RTC_CTRL_ALARM_IRQ_EN          0x00000001
  34 #define STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN        0x00000002
  35 #define STMP3XXX_RTC_CTRL_ALARM_IRQ             0x00000004
  36 #define STMP3XXX_RTC_CTRL_ONEMSEC_IRQ           0x00000008
  37
  38 #define STMP3XXX_RTC_STAT                       0x10
  39 #define STMP3XXX_RTC_STAT_STALE_SHIFT           16
  40 #define STMP3XXX_RTC_STAT_RTC_PRESENT           0x80000000
  41
  42 #define STMP3XXX_RTC_SECONDS                    0x30
  43
  44 #define STMP3XXX_RTC_ALARM                      0x40
  45
  46 #define STMP3XXX_RTC_PERSISTENT0                0x60
  47 #define STMP3XXX_RTC_PERSISTENT0_SET            0x64
  48 #define STMP3XXX_RTC_PERSISTENT0_CLR            0x68
  49 #define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN  0x00000002
  50 #define STMP3XXX_RTC_PERSISTENT0_ALARM_EN       0x00000004
  51 #define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE     0x00000080
  52
  53 struct stmp3xxx_rtc_data {
  54         struct rtc_device *rtc;
  55         unsigned irq_count;
  56         void __iomem *io;
  57         int irq_alarm, irq_1msec;
  58 };
  59
  60 static void stmp3xxx_wait_time(struct stmp3xxx_rtc_data *rtc_data)
  61 {
  62         /*
  63          * The datasheet doesn't say which way round the
  64          * NEW_REGS/STALE_REGS bitfields go. In fact it's 0x1=P0,
  65          * 0x2=P1, .., 0x20=P5, 0x40=ALARM, 0x80=SECONDS
  66          */
  67         while (readl(rtc_data->io + STMP3XXX_RTC_STAT) &
  68                         (0x80 << STMP3XXX_RTC_STAT_STALE_SHIFT))
  69                 cpu_relax();
  70 }
  71
  72 /* Time read/write */
  73 static int stmp3xxx_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
  74 {
  75         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
  76
  77         stmp3xxx_wait_time(rtc_data);
  78         rtc_time_to_tm(readl(rtc_data->io + STMP3XXX_RTC_SECONDS), rtc_tm);
  79         return 0;
  80 }
  81
  82 static int stmp3xxx_rtc_set_mmss(struct device *dev, unsigned long t)
  83 {
  84         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
  85
  86         writel(t, rtc_data->io + STMP3XXX_RTC_SECONDS);
  87         stmp3xxx_wait_time(rtc_data);
  88         return 0;
  89 }
  90
  91 /* interrupt(s) handler */
  92 static irqreturn_t stmp3xxx_rtc_interrupt(int irq, void *dev_id)
  93 {
  94         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev_id);
  95         u32 status;
  96         u32 events = 0;
  97
  98         status = readl(rtc_data->io + STMP3XXX_RTC_CTRL) &
  99                         (STMP3XXX_RTC_CTRL_ALARM_IRQ |
 100                          STMP3XXX_RTC_CTRL_ONEMSEC_IRQ);
 101
 102         if (status & STMP3XXX_RTC_CTRL_ALARM_IRQ) {
 103                 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ,
 104                                 rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 105                 events |= RTC_AF | RTC_IRQF;
 106         }
 107
 108         if (status & STMP3XXX_RTC_CTRL_ONEMSEC_IRQ) {
 109                 writel(STMP3XXX_RTC_CTRL_ONEMSEC_IRQ,
 110                                 rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 111                 if (++rtc_data->irq_count % 1000 == 0) {
 112                         events |= RTC_UF | RTC_IRQF;
 113                         rtc_data->irq_count = 0;
 114                 }
 115         }
 116
 117         if (events)
 118                 rtc_update_irq(rtc_data->rtc, 1, events);
 119
 120         return IRQ_HANDLED;
 121 }
 122
 123 static int stmp3xxx_alarm_irq_enable(struct device *dev, unsigned int enabled)
 124 {
 125         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 126
 127         if (enabled) {
 128                 writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
 129                                 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN,
 130                                 rtc_data->io + STMP3XXX_RTC_PERSISTENT0_SET);
 131                 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 132                                 rtc_data->io + STMP3XXX_RTC_CTRL_SET);
 133         } else {
 134                 writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
 135                                 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN,
 136                                 rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
 137                 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 138                                 rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 139         }
 140         return 0;
 141 }
 142
 143 static int stmp3xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 144 {
 145         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 146
 147         rtc_time_to_tm(readl(rtc_data->io + STMP3XXX_RTC_ALARM), &alm->time);
 148         return 0;
 149 }
 150
 151 static int stmp3xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 152 {
 153         unsigned long t;
 154         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 155
 156         rtc_tm_to_time(&alm->time, &t);
 157         writel(t, rtc_data->io + STMP3XXX_RTC_ALARM);
 158         return 0;
 159 }
 160
 161 static struct rtc_class_ops stmp3xxx_rtc_ops = {
 162         .alarm_irq_enable =
 163                           stmp3xxx_alarm_irq_enable,
 164         .read_time      = stmp3xxx_rtc_gettime,
 165         .set_mmss       = stmp3xxx_rtc_set_mmss,
 166         .read_alarm     = stmp3xxx_rtc_read_alarm,
 167         .set_alarm      = stmp3xxx_rtc_set_alarm,
 168 };
 169
 170 static int stmp3xxx_rtc_remove(struct platform_device *pdev)
 171 {
 172         struct stmp3xxx_rtc_data *rtc_data = platform_get_drvdata(pdev);
 173
 174         if (!rtc_data)
 175                 return 0;
 176
 177         writel(STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN |
 178                         STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 179                         rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 180         free_irq(rtc_data->irq_alarm, &pdev->dev);
 181         free_irq(rtc_data->irq_1msec, &pdev->dev);
 182         rtc_device_unregister(rtc_data->rtc);
 183         platform_set_drvdata(pdev, NULL);
 184         iounmap(rtc_data->io);
 185         kfree(rtc_data);
 186
 187         return 0;
 188 }
 189
 190 static int stmp3xxx_rtc_probe(struct platform_device *pdev)
 191 {
 192         struct stmp3xxx_rtc_data *rtc_data;
 193         struct resource *r;
 194         int err;
 195
 196         rtc_data = kzalloc(sizeof *rtc_data, GFP_KERNEL);
 197         if (!rtc_data)
 198                 return -ENOMEM;
 199
 200         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 201         if (!r) {
 202                 dev_err(&pdev->dev, "failed to get resource\n");
 203                 err = -ENXIO;
 204                 goto out_free;
 205         }
 206
 207         rtc_data->io = ioremap(r->start, resource_size(r));
 208         if (!rtc_data->io) {
 209                 dev_err(&pdev->dev, "ioremap failed\n");
 210                 err = -EIO;
 211                 goto out_free;
 212         }
 213
 214         rtc_data->irq_alarm = platform_get_irq(pdev, 0);
 215         rtc_data->irq_1msec = platform_get_irq(pdev, 1);
 216
 217         if (!(readl(STMP3XXX_RTC_STAT + rtc_data->io) &
 218                         STMP3XXX_RTC_STAT_RTC_PRESENT)) {
 219                 dev_err(&pdev->dev, "no device onboard\n");
 220                 err = -ENODEV;
 221                 goto out_remap;
 222         }
 223
 224         platform_set_drvdata(pdev, rtc_data);
 225
 226         mxs_reset_block(rtc_data->io);
 227         writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
 228                         STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN |
 229                         STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE,
 230                         rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
 231
 232         rtc_data->rtc = rtc_device_register(pdev->name, &pdev->dev,
 233                                 &stmp3xxx_rtc_ops, THIS_MODULE);
 234         if (IS_ERR(rtc_data->rtc)) {
 235                 err = PTR_ERR(rtc_data->rtc);
 236                 goto out_remap;
 237         }
 238
 239         rtc_data->irq_count = 0;
 240         err = request_irq(rtc_data->irq_alarm, stmp3xxx_rtc_interrupt,
 241                         IRQF_DISABLED, "RTC alarm", &pdev->dev);
 242         if (err) {
 243                 dev_err(&pdev->dev, "Cannot claim IRQ%d\n",
 244                         rtc_data->irq_alarm);
 245                 goto out_irq_alarm;
 246         }
 247         err = request_irq(rtc_data->irq_1msec, stmp3xxx_rtc_interrupt,
 248                         IRQF_DISABLED, "RTC tick", &pdev->dev);
 249         if (err) {
 250                 dev_err(&pdev->dev, "Cannot claim IRQ%d\n",
 251                         rtc_data->irq_1msec);
 252                 goto out_irq1;
 253         }
 254
 255         return 0;
 256
 257 out_irq1:
 258         free_irq(rtc_data->irq_alarm, &pdev->dev);
 259 out_irq_alarm:
 260         writel(STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN |
 261                         STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 262                         rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 263         rtc_device_unregister(rtc_data->rtc);
 264 out_remap:
 265         platform_set_drvdata(pdev, NULL);
 266         iounmap(rtc_data->io);
 267 out_free:
 268         kfree(rtc_data);
 269         return err;
 270 }
 271
 272 #ifdef CONFIG_PM
 273 static int stmp3xxx_rtc_suspend(struct platform_device *dev, pm_message_t state)
 274 {
 275         return 0;
 276 }
 277
 278 static int stmp3xxx_rtc_resume(struct platform_device *dev)
 279 {
 280         struct stmp3xxx_rtc_data *rtc_data = platform_get_drvdata(dev);
 281
 282         mxs_reset_block(rtc_data->io);
 283         writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
 284                         STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN |
 285                         STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE,
 286                         rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
 287         return 0;
 288 }
 289 #else
 290 #define stmp3xxx_rtc_suspend    NULL
 291 #define stmp3xxx_rtc_resume     NULL
 292 #endif
 293
 294 static struct platform_driver stmp3xxx_rtcdrv = {
 295         .probe          = stmp3xxx_rtc_probe,
 296         .remove         = stmp3xxx_rtc_remove,
 297         .suspend        = stmp3xxx_rtc_suspend,
 298         .resume         = stmp3xxx_rtc_resume,
 299         .driver         = {
 300                 .name   = "stmp3xxx-rtc",
 301                 .owner  = THIS_MODULE,
 302         },
 303 };
 304
 305 static int __init stmp3xxx_rtc_init(void)
 306 {
 307         return platform_driver_register(&stmp3xxx_rtcdrv);
 308 }
 309
 310 static void __exit stmp3xxx_rtc_exit(void)
 311 {
 312         platform_driver_unregister(&stmp3xxx_rtcdrv);
 313 }
 314
 315 module_init(stmp3xxx_rtc_init);
 316 module_exit(stmp3xxx_rtc_exit);
 317
 318 MODULE_DESCRIPTION("STMP3xxx RTC Driver");
 319 MODULE_AUTHOR("dmitry pervushin <dpervushin@embeddedalley.com>");
 320 MODULE_LICENSE("GPL");