175 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * linux/drivers/rtc/rtc-pl030.c4 *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 set63 * the point at which the counter updates.64 *65 * Also, since RTC_LR is transferred to RTC_CR on next rising66 * edge of the 1Hz clock, we must write the time one second67 * 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