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#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
  54struct stmp3xxx_rtc_data {
  55        struct rtc_device *rtc;
  56        void __iomem *io;
  57        int irq_alarm;
  58};
  59
  60static 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 */
  73static 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
  82static 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 */
  92static 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
 107static 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
 127static 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
 135static 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
 148static 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
 157static 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
 175static 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
 237out_irq_alarm:
 238        rtc_device_unregister(rtc_data->rtc);
 239out_remap:
 240        platform_set_drvdata(pdev, NULL);
 241        iounmap(rtc_data->io);
 242out_free:
 243        kfree(rtc_data);
 244        return err;
 245}
 246
 247#ifdef CONFIG_PM
 248static int stmp3xxx_rtc_suspend(struct platform_device *dev, pm_message_t state)
 249{
 250        return 0;
 251}
 252
 253static 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
 269static const struct of_device_id rtc_dt_ids[] = {
 270        { .compatible = "fsl,stmp3xxx-rtc", },
 271        { /* sentinel */ }
 272};
 273MODULE_DEVICE_TABLE(of, rtc_dt_ids);
 274
 275static 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
 287module_platform_driver(stmp3xxx_rtcdrv);
 288
 289MODULE_DESCRIPTION("STMP3xxx RTC Driver");
 290MODULE_AUTHOR("dmitry pervushin <dpervushin@embeddedalley.com> and "
 291                "Wolfram Sang <w.sang@pengutronix.de>");
 292MODULE_LICENSE("GPL");
 293
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.