linux/drivers/rtc/rtc-stmp3xxx.c
<<
>>
Prefs
   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
  53struct stmp3xxx_rtc_data {
  54        struct rtc_device *rtc;
  55        void __iomem *io;
  56        int irq_alarm;
  57};
  58
  59static 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 */
  72static 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
  81static 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 */
  91static 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
 106static 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
 126static 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
 134static 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
 147static 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
 156static 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
 174static 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
 236out_irq_alarm:
 237        rtc_device_unregister(rtc_data->rtc);
 238out_remap:
 239        platform_set_drvdata(pdev, NULL);
 240        iounmap(rtc_data->io);
 241out_free:
 242        kfree(rtc_data);
 243        return err;
 244}
 245
 246#ifdef CONFIG_PM
 247static int stmp3xxx_rtc_suspend(struct platform_device *dev, pm_message_t state)
 248{
 249        return 0;
 250}
 251
 252static 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
 268static 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
 279module_platform_driver(stmp3xxx_rtcdrv);
 280
 281MODULE_DESCRIPTION("STMP3xxx RTC Driver");
 282MODULE_AUTHOR("dmitry pervushin <dpervushin@embeddedalley.com> and "
 283                "Wolfram Sang <w.sang@pengutronix.de>");
 284MODULE_LICENSE("GPL");
 285