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// SPDX-License-Identifier: GPL-2.0
/* drivers/rtc/rtc-goldfish.c
*
* Copyright (C) 2007 Google, Inc.
* Copyright (C) 2017 Imagination Technologies Ltd.
*/
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#define TIMER_TIME_LOW 0x00 /* get low bits of current time */
/* and update TIMER_TIME_HIGH */
#define TIMER_TIME_HIGH 0x04 /* get high bits of time at last */
/* TIMER_TIME_LOW read */
#define TIMER_ALARM_LOW 0x08 /* set low bits of alarm and */
/* activate it */
#define TIMER_ALARM_HIGH 0x0c /* set high bits of next alarm */
#define TIMER_IRQ_ENABLED 0x10
#define TIMER_CLEAR_ALARM 0x14
#define TIMER_ALARM_STATUS 0x18
#define TIMER_CLEAR_INTERRUPT 0x1c
struct goldfish_rtc {
void __iomem *base;
int irq;
struct rtc_device *rtc;
};
static int goldfish_rtc_read_alarm(struct device *dev,
struct rtc_wkalrm *alrm)
{
u64 rtc_alarm;
u64 rtc_alarm_low;
u64 rtc_alarm_high;
void __iomem *base;
struct goldfish_rtc *rtcdrv;
rtcdrv = dev_get_drvdata(dev);
base = rtcdrv->base;
rtc_alarm_low = readl(base + TIMER_ALARM_LOW);
rtc_alarm_high = readl(base + TIMER_ALARM_HIGH);
rtc_alarm = (rtc_alarm_high << 32) | rtc_alarm_low;
do_div(rtc_alarm, NSEC_PER_SEC);
memset(alrm, 0, sizeof(struct rtc_wkalrm));
rtc_time64_to_tm(rtc_alarm, &alrm->time);
if (readl(base + TIMER_ALARM_STATUS))
alrm->enabled = 1;
else
alrm->enabled = 0;
return 0;
}
static int goldfish_rtc_set_alarm(struct device *dev,
struct rtc_wkalrm *alrm)
{
struct goldfish_rtc *rtcdrv;
u64 rtc_alarm64;
u64 rtc_status_reg;
void __iomem *base;
rtcdrv = dev_get_drvdata(dev);
base = rtcdrv->base;
if (alrm->enabled) {
rtc_alarm64 = rtc_tm_to_time64(&alrm->time) * NSEC_PER_SEC;
writel((rtc_alarm64 >> 32), base + TIMER_ALARM_HIGH);
writel(rtc_alarm64, base + TIMER_ALARM_LOW);
writel(1, base + TIMER_IRQ_ENABLED);
} else {
/*
* if this function was called with enabled=0
* then it could mean that the application is
* trying to cancel an ongoing alarm
*/
rtc_status_reg = readl(base + TIMER_ALARM_STATUS);
if (rtc_status_reg)
writel(1, base + TIMER_CLEAR_ALARM);
}
return 0;
}
static int goldfish_rtc_alarm_irq_enable(struct device *dev,
unsigned int enabled)
{
void __iomem *base;
struct goldfish_rtc *rtcdrv;
rtcdrv = dev_get_drvdata(dev);
base = rtcdrv->base;
if (enabled)
writel(1, base + TIMER_IRQ_ENABLED);
else
writel(0, base + TIMER_IRQ_ENABLED);
return 0;
}
static irqreturn_t goldfish_rtc_interrupt(int irq, void *dev_id)
{
struct goldfish_rtc *rtcdrv = dev_id;
void __iomem *base = rtcdrv->base;
writel(1, base + TIMER_CLEAR_INTERRUPT);
rtc_update_irq(rtcdrv->rtc, 1, RTC_IRQF | RTC_AF);
return IRQ_HANDLED;
}
static int goldfish_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct goldfish_rtc *rtcdrv;
void __iomem *base;
u64 time_high;
u64 time_low;
u64 time;
rtcdrv = dev_get_drvdata(dev);
base = rtcdrv->base;
time_low = readl(base + TIMER_TIME_LOW);
time_high = readl(base + TIMER_TIME_HIGH);
time = (time_high << 32) | time_low;
do_div(time, NSEC_PER_SEC);
rtc_time64_to_tm(time, tm);
return 0;
}
static int goldfish_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct goldfish_rtc *rtcdrv;
void __iomem *base;
u64 now64;
rtcdrv = dev_get_drvdata(dev);
base = rtcdrv->base;
now64 = rtc_tm_to_time64(tm) * NSEC_PER_SEC;
writel((now64 >> 32), base + TIMER_TIME_HIGH);
writel(now64, base + TIMER_TIME_LOW);
return 0;
}
static const struct rtc_class_ops goldfish_rtc_ops = {
.read_time = goldfish_rtc_read_time,
.set_time = goldfish_rtc_set_time,
.read_alarm = goldfish_rtc_read_alarm,
.set_alarm = goldfish_rtc_set_alarm,
.alarm_irq_enable = goldfish_rtc_alarm_irq_enable
};
static int goldfish_rtc_probe(struct platform_device *pdev)
{
struct goldfish_rtc *rtcdrv;
int err;
rtcdrv = devm_kzalloc(&pdev->dev, sizeof(*rtcdrv), GFP_KERNEL);
if (!rtcdrv)
return -ENOMEM;
platform_set_drvdata(pdev, rtcdrv);
rtcdrv->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(rtcdrv->base))
return PTR_ERR(rtcdrv->base);
rtcdrv->irq = platform_get_irq(pdev, 0);
if (rtcdrv->irq < 0)
return -ENODEV;
rtcdrv->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(rtcdrv->rtc))
return PTR_ERR(rtcdrv->rtc);
rtcdrv->rtc->ops = &goldfish_rtc_ops;
rtcdrv->rtc->range_max = U64_MAX / NSEC_PER_SEC;
err = devm_request_irq(&pdev->dev, rtcdrv->irq,
goldfish_rtc_interrupt,
0, pdev->name, rtcdrv);
if (err)
return err;
return devm_rtc_register_device(rtcdrv->rtc);
}
static const struct of_device_id goldfish_rtc_of_match[] = {
{ .compatible = "google,goldfish-rtc", },
{},
};
MODULE_DEVICE_TABLE(of, goldfish_rtc_of_match);
static struct platform_driver goldfish_rtc = {
.probe = goldfish_rtc_probe,
.driver = {
.name = "goldfish_rtc",
.of_match_table = goldfish_rtc_of_match,
}
};
module_platform_driver(goldfish_rtc);
MODULE_LICENSE("GPL v2");
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