linux/drivers/rtc/rtc-pl030.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  linux/drivers/rtc/rtc-pl030.c
   4 *
   5 *  Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
   6 */
   7#include <linux/module.h>
   8#include <linux/rtc.h>
   9#include <linux/init.h>
  10#include <linux/interrupt.h>
  11#include <linux/amba/bus.h>
  12#include <linux/io.h>
  13#include <linux/slab.h>
  14
  15#define RTC_DR          (0)
  16#define RTC_MR          (4)
  17#define RTC_STAT        (8)
  18#define RTC_EOI         (8)
  19#define RTC_LR          (12)
  20#define RTC_CR          (16)
  21#define RTC_CR_MIE      (1 << 0)
  22
  23struct pl030_rtc {
  24        struct rtc_device       *rtc;
  25        void __iomem            *base;
  26};
  27
  28static irqreturn_t pl030_interrupt(int irq, void *dev_id)
  29{
  30        struct pl030_rtc *rtc = dev_id;
  31        writel(0, rtc->base + RTC_EOI);
  32        return IRQ_HANDLED;
  33}
  34
  35static int pl030_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  36{
  37        struct pl030_rtc *rtc = dev_get_drvdata(dev);
  38
  39        rtc_time64_to_tm(readl(rtc->base + RTC_MR), &alrm->time);
  40        return 0;
  41}
  42
  43static int pl030_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  44{
  45        struct pl030_rtc *rtc = dev_get_drvdata(dev);
  46
  47        writel(rtc_tm_to_time64(&alrm->time), rtc->base + RTC_MR);
  48
  49        return 0;
  50}
  51
  52static int pl030_read_time(struct device *dev, struct rtc_time *tm)
  53{
  54        struct pl030_rtc *rtc = dev_get_drvdata(dev);
  55
  56        rtc_time64_to_tm(readl(rtc->base + RTC_DR), tm);
  57
  58        return 0;
  59}
  60
  61/*
  62 * Set the RTC time.  Unfortunately, we can't accurately set
  63 * the point at which the counter updates.
  64 *
  65 * Also, since RTC_LR is transferred to RTC_CR on next rising
  66 * edge of the 1Hz clock, we must write the time one second
  67 * in advance.
  68 */
  69static int pl030_set_time(struct device *dev, struct rtc_time *tm)
  70{
  71        struct pl030_rtc *rtc = dev_get_drvdata(dev);
  72
  73        writel(rtc_tm_to_time64(tm) + 1, rtc->base + RTC_LR);
  74
  75        return 0;
  76}
  77
  78static const struct rtc_class_ops pl030_ops = {
  79        .read_time      = pl030_read_time,
  80        .set_time       = pl030_set_time,
  81        .read_alarm     = pl030_read_alarm,
  82        .set_alarm      = pl030_set_alarm,
  83};
  84
  85static int pl030_probe(struct amba_device *dev, const struct amba_id *id)
  86{
  87        struct pl030_rtc *rtc;
  88        int ret;
  89
  90        ret = amba_request_regions(dev, NULL);
  91        if (ret)
  92                goto err_req;
  93
  94        rtc = devm_kzalloc(&dev->dev, sizeof(*rtc), GFP_KERNEL);
  95        if (!rtc) {
  96                ret = -ENOMEM;
  97                goto err_rtc;
  98        }
  99
 100        rtc->rtc = devm_rtc_allocate_device(&dev->dev);
 101        if (IS_ERR(rtc->rtc)) {
 102                ret = PTR_ERR(rtc->rtc);
 103                goto err_rtc;
 104        }
 105
 106        rtc->rtc->ops = &pl030_ops;
 107        rtc->rtc->range_max = U32_MAX;
 108        rtc->base = ioremap(dev->res.start, resource_size(&dev->res));
 109        if (!rtc->base) {
 110                ret = -ENOMEM;
 111                goto err_rtc;
 112        }
 113
 114        __raw_writel(0, rtc->base + RTC_CR);
 115        __raw_writel(0, rtc->base + RTC_EOI);
 116
 117        amba_set_drvdata(dev, rtc);
 118
 119        ret = request_irq(dev->irq[0], pl030_interrupt, 0,
 120                          "rtc-pl030", rtc);
 121        if (ret)
 122                goto err_irq;
 123
 124        ret = devm_rtc_register_device(rtc->rtc);
 125        if (ret)
 126                goto err_reg;
 127
 128        return 0;
 129
 130 err_reg:
 131        free_irq(dev->irq[0], rtc);
 132 err_irq:
 133        iounmap(rtc->base);
 134 err_rtc:
 135        amba_release_regions(dev);
 136 err_req:
 137        return ret;
 138}
 139
 140static void pl030_remove(struct amba_device *dev)
 141{
 142        struct pl030_rtc *rtc = amba_get_drvdata(dev);
 143
 144        writel(0, rtc->base + RTC_CR);
 145
 146        free_irq(dev->irq[0], rtc);
 147        iounmap(rtc->base);
 148        amba_release_regions(dev);
 149}
 150
 151static struct amba_id pl030_ids[] = {
 152        {
 153                .id     = 0x00041030,
 154                .mask   = 0x000fffff,
 155        },
 156        { 0, 0 },
 157};
 158
 159MODULE_DEVICE_TABLE(amba, pl030_ids);
 160
 161static struct amba_driver pl030_driver = {
 162        .drv            = {
 163                .name   = "rtc-pl030",
 164        },
 165        .probe          = pl030_probe,
 166        .remove         = pl030_remove,
 167        .id_table       = pl030_ids,
 168};
 169
 170module_amba_driver(pl030_driver);
 171
 172MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
 173MODULE_DESCRIPTION("ARM AMBA PL030 RTC Driver");
 174MODULE_LICENSE("GPL");
 175