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 #include <linux/of_device.h>
  29
  30 #include <mach/common.h>
  31
  32 #define STMP3XXX_RTC_CTRL                       0x0
  33 #define STMP3XXX_RTC_CTRL_SET                   0x4
  34 #define STMP3XXX_RTC_CTRL_CLR                   0x8
  35 #define STMP3XXX_RTC_CTRL_ALARM_IRQ_EN          0x00000001
  36 #define STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN        0x00000002
  37 #define STMP3XXX_RTC_CTRL_ALARM_IRQ             0x00000004
  38
  39 #define STMP3XXX_RTC_STAT                       0x10
  40 #define STMP3XXX_RTC_STAT_STALE_SHIFT           16
  41 #define STMP3XXX_RTC_STAT_RTC_PRESENT           0x80000000
  42
  43 #define STMP3XXX_RTC_SECONDS                    0x30
  44
  45 #define STMP3XXX_RTC_ALARM                      0x40
  46
  47 #define STMP3XXX_RTC_PERSISTENT0                0x60
  48 #define STMP3XXX_RTC_PERSISTENT0_SET            0x64
  49 #define STMP3XXX_RTC_PERSISTENT0_CLR            0x68
  50 #define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN  0x00000002
  51 #define STMP3XXX_RTC_PERSISTENT0_ALARM_EN       0x00000004
  52 #define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE     0x00000080
  53
  54 struct stmp3xxx_rtc_data {
  55         struct rtc_device *rtc;
  56         void __iomem *io;
  57         int irq_alarm;
  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 = readl(rtc_data->io + STMP3XXX_RTC_CTRL);
  96
  97         if (status & STMP3XXX_RTC_CTRL_ALARM_IRQ) {
  98                 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ,
  99                                 rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 100                 rtc_update_irq(rtc_data->rtc, 1, RTC_AF | RTC_IRQF);
 101                 return IRQ_HANDLED;
 102         }
 103
 104         return IRQ_NONE;
 105 }
 106
 107 static int stmp3xxx_alarm_irq_enable(struct device *dev, unsigned int enabled)
 108 {
 109         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 110
 111         if (enabled) {
 112                 writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
 113                                 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN,
 114                                 rtc_data->io + STMP3XXX_RTC_PERSISTENT0_SET);
 115                 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 116                                 rtc_data->io + STMP3XXX_RTC_CTRL_SET);
 117         } else {
 118                 writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
 119                                 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN,
 120                                 rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
 121                 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 122                                 rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 123         }
 124         return 0;
 125 }
 126
 127 static int stmp3xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 128 {
 129         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 130
 131         rtc_time_to_tm(readl(rtc_data->io + STMP3XXX_RTC_ALARM), &alm->time);
 132         return 0;
 133 }
 134
 135 static int stmp3xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 136 {
 137         unsigned long t;
 138         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 139
 140         rtc_tm_to_time(&alm->time, &t);
 141         writel(t, rtc_data->io + STMP3XXX_RTC_ALARM);
 142
 143         stmp3xxx_alarm_irq_enable(dev, alm->enabled);
 144
 145         return 0;
 146 }
 147
 148 static struct rtc_class_ops stmp3xxx_rtc_ops = {
 149         .alarm_irq_enable =
 150                           stmp3xxx_alarm_irq_enable,
 151         .read_time      = stmp3xxx_rtc_gettime,
 152         .set_mmss       = stmp3xxx_rtc_set_mmss,
 153         .read_alarm     = stmp3xxx_rtc_read_alarm,
 154         .set_alarm      = stmp3xxx_rtc_set_alarm,
 155 };
 156
 157 static int stmp3xxx_rtc_remove(struct platform_device *pdev)
 158 {
 159         struct stmp3xxx_rtc_data *rtc_data = platform_get_drvdata(pdev);
 160
 161         if (!rtc_data)
 162                 return 0;
 163
 164         writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 165                         rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 166         free_irq(rtc_data->irq_alarm, &pdev->dev);
 167         rtc_device_unregister(rtc_data->rtc);
 168         platform_set_drvdata(pdev, NULL);
 169         iounmap(rtc_data->io);
 170         kfree(rtc_data);
 171
 172         return 0;
 173 }
 174
 175 static int stmp3xxx_rtc_probe(struct platform_device *pdev)
 176 {
 177         struct stmp3xxx_rtc_data *rtc_data;
 178         struct resource *r;
 179         int err;
 180
 181         rtc_data = kzalloc(sizeof *rtc_data, GFP_KERNEL);
 182         if (!rtc_data)
 183                 return -ENOMEM;
 184
 185         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 186         if (!r) {
 187                 dev_err(&pdev->dev, "failed to get resource\n");
 188                 err = -ENXIO;
 189                 goto out_free;
 190         }
 191
 192         rtc_data->io = ioremap(r->start, resource_size(r));
 193         if (!rtc_data->io) {
 194                 dev_err(&pdev->dev, "ioremap failed\n");
 195                 err = -EIO;
 196                 goto out_free;
 197         }
 198
 199         rtc_data->irq_alarm = platform_get_irq(pdev, 0);
 200
 201         if (!(readl(STMP3XXX_RTC_STAT + rtc_data->io) &
 202                         STMP3XXX_RTC_STAT_RTC_PRESENT)) {
 203                 dev_err(&pdev->dev, "no device onboard\n");
 204                 err = -ENODEV;
 205                 goto out_remap;
 206         }
 207
 208         platform_set_drvdata(pdev, rtc_data);
 209
 210         mxs_reset_block(rtc_data->io);
 211         writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
 212                         STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN |
 213                         STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE,
 214                         rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
 215
 216         writel(STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN |
 217                         STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 218                         rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 219
 220         rtc_data->rtc = rtc_device_register(pdev->name, &pdev->dev,
 221                                 &stmp3xxx_rtc_ops, THIS_MODULE);
 222         if (IS_ERR(rtc_data->rtc)) {
 223                 err = PTR_ERR(rtc_data->rtc);
 224                 goto out_remap;
 225         }
 226
 227         err = request_irq(rtc_data->irq_alarm, stmp3xxx_rtc_interrupt, 0,
 228                         "RTC alarm", &pdev->dev);
 229         if (err) {
 230                 dev_err(&pdev->dev, "Cannot claim IRQ%d\n",
 231                         rtc_data->irq_alarm);
 232                 goto out_irq_alarm;
 233         }
 234
 235         return 0;
 236
 237 out_irq_alarm:
 238         rtc_device_unregister(rtc_data->rtc);
 239 out_remap:
 240         platform_set_drvdata(pdev, NULL);
 241         iounmap(rtc_data->io);
 242 out_free:
 243         kfree(rtc_data);
 244         return err;
 245 }
 246
 247 #ifdef CONFIG_PM
 248 static int stmp3xxx_rtc_suspend(struct platform_device *dev, pm_message_t state)
 249 {
 250         return 0;
 251 }
 252
 253 static int stmp3xxx_rtc_resume(struct platform_device *dev)
 254 {
 255         struct stmp3xxx_rtc_data *rtc_data = platform_get_drvdata(dev);
 256
 257         mxs_reset_block(rtc_data->io);
 258         writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
 259                         STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN |
 260                         STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE,
 261                         rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
 262         return 0;
 263 }
 264 #else
 265 #define stmp3xxx_rtc_suspend    NULL
 266 #define stmp3xxx_rtc_resume     NULL
 267 #endif
 268
 269 static const struct of_device_id rtc_dt_ids[] = {
 270         { .compatible = "fsl,stmp3xxx-rtc", },
 271         { /* sentinel */ }
 272 };
 273 MODULE_DEVICE_TABLE(of, rtc_dt_ids);
 274
 275 static struct platform_driver stmp3xxx_rtcdrv = {
 276         .probe          = stmp3xxx_rtc_probe,
 277         .remove         = stmp3xxx_rtc_remove,
 278         .suspend        = stmp3xxx_rtc_suspend,
 279         .resume         = stmp3xxx_rtc_resume,
 280         .driver         = {
 281                 .name   = "stmp3xxx-rtc",
 282                 .owner  = THIS_MODULE,
 283                 .of_match_table = rtc_dt_ids,
 284         },
 285 };
 286
 287 module_platform_driver(stmp3xxx_rtcdrv);
 288
 289 MODULE_DESCRIPTION("STMP3xxx RTC Driver");
 290 MODULE_AUTHOR("dmitry pervushin <dpervushin@embeddedalley.com> and "
 291                 "Wolfram Sang <w.sang@pengutronix.de>");
 292 MODULE_LICENSE("GPL");