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  * Copyright 2011 Wolfram Sang, Pengutronix e.K.
  10  */
  11
  12 /*
  13  * The code contained herein is licensed under the GNU General Public
  14  * License. You may obtain a copy of the GNU General Public License
  15  * Version 2 or later at the following locations:
  16  *
  17  * http://www.opensource.org/licenses/gpl-license.html
  18  * http://www.gnu.org/copyleft/gpl.html
  19  */
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22 #include <linux/io.h>
  23 #include <linux/init.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/rtc.h>
  27 #include <linux/slab.h>
  28
  29 #include <mach/common.h>
  30
  31 #define STMP3XXX_RTC_CTRL                       0x0
  32 #define STMP3XXX_RTC_CTRL_SET                   0x4
  33 #define STMP3XXX_RTC_CTRL_CLR                   0x8
  34 #define STMP3XXX_RTC_CTRL_ALARM_IRQ_EN          0x00000001
  35 #define STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN        0x00000002
  36 #define STMP3XXX_RTC_CTRL_ALARM_IRQ             0x00000004
  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         void __iomem *io;
  56         int irq_alarm;
  57 };
  58
  59 static void stmp3xxx_wait_time(struct stmp3xxx_rtc_data *rtc_data)
  60 {
  61         /*
  62          * The datasheet doesn't say which way round the
  63          * NEW_REGS/STALE_REGS bitfields go. In fact it's 0x1=P0,
  64          * 0x2=P1, .., 0x20=P5, 0x40=ALARM, 0x80=SECONDS
  65          */
  66         while (readl(rtc_data->io + STMP3XXX_RTC_STAT) &
  67                         (0x80 << STMP3XXX_RTC_STAT_STALE_SHIFT))
  68                 cpu_relax();
  69 }
  70
  71 /* Time read/write */
  72 static int stmp3xxx_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
  73 {
  74         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
  75
  76         stmp3xxx_wait_time(rtc_data);
  77         rtc_time_to_tm(readl(rtc_data->io + STMP3XXX_RTC_SECONDS), rtc_tm);
  78         return 0;
  79 }
  80
  81 static int stmp3xxx_rtc_set_mmss(struct device *dev, unsigned long t)
  82 {
  83         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
  84
  85         writel(t, rtc_data->io + STMP3XXX_RTC_SECONDS);
  86         stmp3xxx_wait_time(rtc_data);
  87         return 0;
  88 }
  89
  90 /* interrupt(s) handler */
  91 static irqreturn_t stmp3xxx_rtc_interrupt(int irq, void *dev_id)
  92 {
  93         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev_id);
  94         u32 status = readl(rtc_data->io + STMP3XXX_RTC_CTRL);
  95
  96         if (status & STMP3XXX_RTC_CTRL_ALARM_IRQ) {
  97                 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ,
  98                                 rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
  99                 rtc_update_irq(rtc_data->rtc, 1, RTC_AF | RTC_IRQF);
 100                 return IRQ_HANDLED;
 101         }
 102
 103         return IRQ_NONE;
 104 }
 105
 106 static int stmp3xxx_alarm_irq_enable(struct device *dev, unsigned int enabled)
 107 {
 108         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 109
 110         if (enabled) {
 111                 writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
 112                                 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN,
 113                                 rtc_data->io + STMP3XXX_RTC_PERSISTENT0_SET);
 114                 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 115                                 rtc_data->io + STMP3XXX_RTC_CTRL_SET);
 116         } else {
 117                 writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
 118                                 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN,
 119                                 rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
 120                 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 121                                 rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 122         }
 123         return 0;
 124 }
 125
 126 static int stmp3xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 127 {
 128         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 129
 130         rtc_time_to_tm(readl(rtc_data->io + STMP3XXX_RTC_ALARM), &alm->time);
 131         return 0;
 132 }
 133
 134 static int stmp3xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 135 {
 136         unsigned long t;
 137         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 138
 139         rtc_tm_to_time(&alm->time, &t);
 140         writel(t, rtc_data->io + STMP3XXX_RTC_ALARM);
 141
 142         stmp3xxx_alarm_irq_enable(dev, alm->enabled);
 143
 144         return 0;
 145 }
 146
 147 static struct rtc_class_ops stmp3xxx_rtc_ops = {
 148         .alarm_irq_enable =
 149                           stmp3xxx_alarm_irq_enable,
 150         .read_time      = stmp3xxx_rtc_gettime,
 151         .set_mmss       = stmp3xxx_rtc_set_mmss,
 152         .read_alarm     = stmp3xxx_rtc_read_alarm,
 153         .set_alarm      = stmp3xxx_rtc_set_alarm,
 154 };
 155
 156 static int stmp3xxx_rtc_remove(struct platform_device *pdev)
 157 {
 158         struct stmp3xxx_rtc_data *rtc_data = platform_get_drvdata(pdev);
 159
 160         if (!rtc_data)
 161                 return 0;
 162
 163         writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 164                         rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 165         free_irq(rtc_data->irq_alarm, &pdev->dev);
 166         rtc_device_unregister(rtc_data->rtc);
 167         platform_set_drvdata(pdev, NULL);
 168         iounmap(rtc_data->io);
 169         kfree(rtc_data);
 170
 171         return 0;
 172 }
 173
 174 static int stmp3xxx_rtc_probe(struct platform_device *pdev)
 175 {
 176         struct stmp3xxx_rtc_data *rtc_data;
 177         struct resource *r;
 178         int err;
 179
 180         rtc_data = kzalloc(sizeof *rtc_data, GFP_KERNEL);
 181         if (!rtc_data)
 182                 return -ENOMEM;
 183
 184         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 185         if (!r) {
 186                 dev_err(&pdev->dev, "failed to get resource\n");
 187                 err = -ENXIO;
 188                 goto out_free;
 189         }
 190
 191         rtc_data->io = ioremap(r->start, resource_size(r));
 192         if (!rtc_data->io) {
 193                 dev_err(&pdev->dev, "ioremap failed\n");
 194                 err = -EIO;
 195                 goto out_free;
 196         }
 197
 198         rtc_data->irq_alarm = platform_get_irq(pdev, 0);
 199
 200         if (!(readl(STMP3XXX_RTC_STAT + rtc_data->io) &
 201                         STMP3XXX_RTC_STAT_RTC_PRESENT)) {
 202                 dev_err(&pdev->dev, "no device onboard\n");
 203                 err = -ENODEV;
 204                 goto out_remap;
 205         }
 206
 207         platform_set_drvdata(pdev, rtc_data);
 208
 209         mxs_reset_block(rtc_data->io);
 210         writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
 211                         STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN |
 212                         STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE,
 213                         rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
 214
 215         writel(STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN |
 216                         STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 217                         rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 218
 219         rtc_data->rtc = rtc_device_register(pdev->name, &pdev->dev,
 220                                 &stmp3xxx_rtc_ops, THIS_MODULE);
 221         if (IS_ERR(rtc_data->rtc)) {
 222                 err = PTR_ERR(rtc_data->rtc);
 223                 goto out_remap;
 224         }
 225
 226         err = request_irq(rtc_data->irq_alarm, stmp3xxx_rtc_interrupt, 0,
 227                         "RTC alarm", &pdev->dev);
 228         if (err) {
 229                 dev_err(&pdev->dev, "Cannot claim IRQ%d\n",
 230                         rtc_data->irq_alarm);
 231                 goto out_irq_alarm;
 232         }
 233
 234         return 0;
 235
 236 out_irq_alarm:
 237         rtc_device_unregister(rtc_data->rtc);
 238 out_remap:
 239         platform_set_drvdata(pdev, NULL);
 240         iounmap(rtc_data->io);
 241 out_free:
 242         kfree(rtc_data);
 243         return err;
 244 }
 245
 246 #ifdef CONFIG_PM
 247 static int stmp3xxx_rtc_suspend(struct platform_device *dev, pm_message_t state)
 248 {
 249         return 0;
 250 }
 251
 252 static int stmp3xxx_rtc_resume(struct platform_device *dev)
 253 {
 254         struct stmp3xxx_rtc_data *rtc_data = platform_get_drvdata(dev);
 255
 256         mxs_reset_block(rtc_data->io);
 257         writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
 258                         STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN |
 259                         STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE,
 260                         rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
 261         return 0;
 262 }
 263 #else
 264 #define stmp3xxx_rtc_suspend    NULL
 265 #define stmp3xxx_rtc_resume     NULL
 266 #endif
 267
 268 static struct platform_driver stmp3xxx_rtcdrv = {
 269         .probe          = stmp3xxx_rtc_probe,
 270         .remove         = stmp3xxx_rtc_remove,
 271         .suspend        = stmp3xxx_rtc_suspend,
 272         .resume         = stmp3xxx_rtc_resume,
 273         .driver         = {
 274                 .name   = "stmp3xxx-rtc",
 275                 .owner  = THIS_MODULE,
 276         },
 277 };
 278
 279 static int __init stmp3xxx_rtc_init(void)
 280 {
 281         return platform_driver_register(&stmp3xxx_rtcdrv);
 282 }
 283
 284 static void __exit stmp3xxx_rtc_exit(void)
 285 {
 286         platform_driver_unregister(&stmp3xxx_rtcdrv);
 287 }
 288
 289 module_init(stmp3xxx_rtc_init);
 290 module_exit(stmp3xxx_rtc_exit);
 291
 292 MODULE_DESCRIPTION("STMP3xxx RTC Driver");
 293 MODULE_AUTHOR("dmitry pervushin <dpervushin@embeddedalley.com> and "
 294                 "Wolfram Sang <w.sang@pengutronix.de>");
 295 MODULE_LICENSE("GPL");