linux/drivers/rtc/rtc-pl030.c
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   1/*
   2 *  linux/drivers/rtc/rtc-pl030.c
   3 *
   4 *  Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License version 2 as
   8 * published by the Free Software Foundation.
   9 */
  10#include <linux/module.h>
  11#include <linux/rtc.h>
  12#include <linux/init.h>
  13#include <linux/interrupt.h>
  14#include <linux/amba/bus.h>
  15#include <linux/io.h>
  16#include <linux/slab.h>
  17
  18#define RTC_DR          (0)
  19#define RTC_MR          (4)
  20#define RTC_STAT        (8)
  21#define RTC_EOI         (8)
  22#define RTC_LR          (12)
  23#define RTC_CR          (16)
  24#define RTC_CR_MIE      (1 << 0)
  25
  26struct pl030_rtc {
  27        struct rtc_device       *rtc;
  28        void __iomem            *base;
  29};
  30
  31static irqreturn_t pl030_interrupt(int irq, void *dev_id)
  32{
  33        struct pl030_rtc *rtc = dev_id;
  34        writel(0, rtc->base + RTC_EOI);
  35        return IRQ_HANDLED;
  36}
  37
  38static int pl030_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  39{
  40        struct pl030_rtc *rtc = dev_get_drvdata(dev);
  41
  42        rtc_time_to_tm(readl(rtc->base + RTC_MR), &alrm->time);
  43        return 0;
  44}
  45
  46static int pl030_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  47{
  48        struct pl030_rtc *rtc = dev_get_drvdata(dev);
  49        unsigned long time;
  50        int ret;
  51
  52        /*
  53         * At the moment, we can only deal with non-wildcarded alarm times.
  54         */
  55        ret = rtc_valid_tm(&alrm->time);
  56        if (ret == 0)
  57                ret = rtc_tm_to_time(&alrm->time, &time);
  58        if (ret == 0)
  59                writel(time, rtc->base + RTC_MR);
  60        return ret;
  61}
  62
  63static int pl030_read_time(struct device *dev, struct rtc_time *tm)
  64{
  65        struct pl030_rtc *rtc = dev_get_drvdata(dev);
  66
  67        rtc_time_to_tm(readl(rtc->base + RTC_DR), tm);
  68
  69        return 0;
  70}
  71
  72/*
  73 * Set the RTC time.  Unfortunately, we can't accurately set
  74 * the point at which the counter updates.
  75 *
  76 * Also, since RTC_LR is transferred to RTC_CR on next rising
  77 * edge of the 1Hz clock, we must write the time one second
  78 * in advance.
  79 */
  80static int pl030_set_time(struct device *dev, struct rtc_time *tm)
  81{
  82        struct pl030_rtc *rtc = dev_get_drvdata(dev);
  83        unsigned long time;
  84        int ret;
  85
  86        ret = rtc_tm_to_time(tm, &time);
  87        if (ret == 0)
  88                writel(time + 1, rtc->base + RTC_LR);
  89
  90        return ret;
  91}
  92
  93static const struct rtc_class_ops pl030_ops = {
  94        .read_time      = pl030_read_time,
  95        .set_time       = pl030_set_time,
  96        .read_alarm     = pl030_read_alarm,
  97        .set_alarm      = pl030_set_alarm,
  98};
  99
 100static int pl030_probe(struct amba_device *dev, const struct amba_id *id)
 101{
 102        struct pl030_rtc *rtc;
 103        int ret;
 104
 105        ret = amba_request_regions(dev, NULL);
 106        if (ret)
 107                goto err_req;
 108
 109        rtc = kmalloc(sizeof(*rtc), GFP_KERNEL);
 110        if (!rtc) {
 111                ret = -ENOMEM;
 112                goto err_rtc;
 113        }
 114
 115        rtc->base = ioremap(dev->res.start, resource_size(&dev->res));
 116        if (!rtc->base) {
 117                ret = -ENOMEM;
 118                goto err_map;
 119        }
 120
 121        __raw_writel(0, rtc->base + RTC_CR);
 122        __raw_writel(0, rtc->base + RTC_EOI);
 123
 124        amba_set_drvdata(dev, rtc);
 125
 126        ret = request_irq(dev->irq[0], pl030_interrupt, 0,
 127                          "rtc-pl030", rtc);
 128        if (ret)
 129                goto err_irq;
 130
 131        rtc->rtc = rtc_device_register("pl030", &dev->dev, &pl030_ops,
 132                                       THIS_MODULE);
 133        if (IS_ERR(rtc->rtc)) {
 134                ret = PTR_ERR(rtc->rtc);
 135                goto err_reg;
 136        }
 137
 138        return 0;
 139
 140 err_reg:
 141        free_irq(dev->irq[0], rtc);
 142 err_irq:
 143        iounmap(rtc->base);
 144 err_map:
 145        kfree(rtc);
 146 err_rtc:
 147        amba_release_regions(dev);
 148 err_req:
 149        return ret;
 150}
 151
 152static int pl030_remove(struct amba_device *dev)
 153{
 154        struct pl030_rtc *rtc = amba_get_drvdata(dev);
 155
 156        amba_set_drvdata(dev, NULL);
 157
 158        writel(0, rtc->base + RTC_CR);
 159
 160        free_irq(dev->irq[0], rtc);
 161        rtc_device_unregister(rtc->rtc);
 162        iounmap(rtc->base);
 163        kfree(rtc);
 164        amba_release_regions(dev);
 165
 166        return 0;
 167}
 168
 169static struct amba_id pl030_ids[] = {
 170        {
 171                .id     = 0x00041030,
 172                .mask   = 0x000fffff,
 173        },
 174        { 0, 0 },
 175};
 176
 177MODULE_DEVICE_TABLE(amba, pl030_ids);
 178
 179static struct amba_driver pl030_driver = {
 180        .drv            = {
 181                .name   = "rtc-pl030",
 182        },
 183        .probe          = pl030_probe,
 184        .remove         = pl030_remove,
 185        .id_table       = pl030_ids,
 186};
 187
 188module_amba_driver(pl030_driver);
 189
 190MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
 191MODULE_DESCRIPTION("ARM AMBA PL030 RTC Driver");
 192MODULE_LICENSE("GPL");
 193
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