// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Real Time Clock interface for StrongARM SA1x00 and XScale PXA2xx
*
* Copyright (c) 2000 Nils Faerber
*
* Based on rtc.c by Paul Gortmaker
*
* Original Driver by Nils Faerber <[email protected]>
*
* Modifications from:
* CIH <[email protected]>
* Nicolas Pitre <[email protected]>
* Andrew Christian <[email protected]>
*
* Converted to the RTC subsystem and Driver Model
* by Richard Purdie <[email protected]>
*/
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/clk.h>
#include <linux/rtc.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/of.h>
#include <linux/pm.h>
#include <linux/bitops.h>
#include <linux/io.h>
#define RTSR_HZE BIT(3) /* HZ interrupt enable */
#define RTSR_ALE BIT(2) /* RTC alarm interrupt enable */
#define RTSR_HZ BIT(1) /* HZ rising-edge detected */
#define RTSR_AL BIT(0) /* RTC alarm detected */
#include "rtc-sa1100.h"
#define RTC_DEF_DIVIDER (32768 - 1)
#define RTC_DEF_TRIM 0
#define RTC_FREQ 1024
static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id)
{
struct sa1100_rtc *info = dev_get_drvdata(dev_id);
struct rtc_device *rtc = info->rtc;
unsigned int rtsr;
unsigned long events = 0;
spin_lock(&info->lock);
rtsr = readl_relaxed(info->rtsr);
/* clear interrupt sources */
writel_relaxed(0, info->rtsr);
/* Fix for a nasty initialization problem the in SA11xx RTSR register.
* See also the comments in sa1100_rtc_probe(). */
if (rtsr & (RTSR_ALE | RTSR_HZE)) {
/* This is the original code, before there was the if test
* above. This code does not clear interrupts that were not
* enabled. */
writel_relaxed((RTSR_AL | RTSR_HZ) & (rtsr >> 2), info->rtsr);
} else {
/* For some reason, it is possible to enter this routine
* without interruptions enabled, it has been tested with
* several units (Bug in SA11xx chip?).
*
* This situation leads to an infinite "loop" of interrupt
* routine calling and as a result the processor seems to
* lock on its first call to open(). */
writel_relaxed(RTSR_AL | RTSR_HZ, info->rtsr);
}
/* clear alarm interrupt if it has occurred */
if (rtsr & RTSR_AL)
rtsr &= ~RTSR_ALE;
writel_relaxed(rtsr & (RTSR_ALE | RTSR_HZE), info->rtsr);
/* update irq data & counter */
if (rtsr & RTSR_AL)
events |= RTC_AF | RTC_IRQF;
if (rtsr & RTSR_HZ)
events |= RTC_UF | RTC_IRQF;
rtc_update_irq(rtc, 1, events);
spin_unlock(&info->lock);
return IRQ_HANDLED;
}
static int sa1100_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
u32 rtsr;
struct sa1100_rtc *info = dev_get_drvdata(dev);
spin_lock_irq(&info->lock);
rtsr = readl_relaxed(info->rtsr);
if (enabled)
rtsr |= RTSR_ALE;
else
rtsr &= ~RTSR_ALE;
writel_relaxed(rtsr, info->rtsr);
spin_unlock_irq(&info->lock);
return 0;
}
static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct sa1100_rtc *info = dev_get_drvdata(dev);
rtc_time64_to_tm(readl_relaxed(info->rcnr), tm);
return 0;
}
static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct sa1100_rtc *info = dev_get_drvdata(dev);
writel_relaxed(rtc_tm_to_time64(tm), info->rcnr);
return 0;
}
static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
u32 rtsr;
struct sa1100_rtc *info = dev_get_drvdata(dev);
rtsr = readl_relaxed(info->rtsr);
alrm->enabled = (rtsr & RTSR_ALE) ? 1 : 0;
alrm->pending = (rtsr & RTSR_AL) ? 1 : 0;
return 0;
}
static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct sa1100_rtc *info = dev_get_drvdata(dev);
spin_lock_irq(&info->lock);
writel_relaxed(readl_relaxed(info->rtsr) &
(RTSR_HZE | RTSR_ALE | RTSR_AL), info->rtsr);
writel_relaxed(rtc_tm_to_time64(&alrm->time), info->rtar);
if (alrm->enabled)
writel_relaxed(readl_relaxed(info->rtsr) | RTSR_ALE, info->rtsr);
else
writel_relaxed(readl_relaxed(info->rtsr) & ~RTSR_ALE, info->rtsr);
spin_unlock_irq(&info->lock);
return 0;
}
static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq)
{
struct sa1100_rtc *info = dev_get_drvdata(dev);
seq_printf(seq, "trim/divider\t\t: 0x%08x\n", readl_relaxed(info->rttr));
seq_printf(seq, "RTSR\t\t\t: 0x%08x\n", readl_relaxed(info->rtsr));
return 0;
}
static const struct rtc_class_ops sa1100_rtc_ops = {
.read_time = sa1100_rtc_read_time,
.set_time = sa1100_rtc_set_time,
.read_alarm = sa1100_rtc_read_alarm,
.set_alarm = sa1100_rtc_set_alarm,
.proc = sa1100_rtc_proc,
.alarm_irq_enable = sa1100_rtc_alarm_irq_enable,
};
int sa1100_rtc_init(struct platform_device *pdev, struct sa1100_rtc *info)
{
int ret;
spin_lock_init(&info->lock);
info->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(info->clk)) {
dev_err(&pdev->dev, "failed to find rtc clock source\n");
return PTR_ERR(info->clk);
}
ret = clk_prepare_enable(info->clk);
if (ret)
return ret;
/*
* According to the manual we should be able to let RTTR be zero
* and then a default diviser for a 32.768KHz clock is used.
* Apparently this doesn't work, at least for my SA1110 rev 5.
* If the clock divider is uninitialized then reset it to the
* default value to get the 1Hz clock.
*/
if (readl_relaxed(info->rttr) == 0) {
writel_relaxed(RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16), info->rttr);
dev_warn(&pdev->dev, "warning: "
"initializing default clock divider/trim value\n");
/* The current RTC value probably doesn't make sense either */
writel_relaxed(0, info->rcnr);
}
info->rtc->ops = &sa1100_rtc_ops;
info->rtc->max_user_freq = RTC_FREQ;
info->rtc->range_max = U32_MAX;
ret = devm_rtc_register_device(info->rtc);
if (ret) {
clk_disable_unprepare(info->clk);
return ret;
}
/* Fix for a nasty initialization problem the in SA11xx RTSR register.
* See also the comments in sa1100_rtc_interrupt().
*
* Sometimes bit 1 of the RTSR (RTSR_HZ) will wake up 1, which means an
* interrupt pending, even though interrupts were never enabled.
* In this case, this bit it must be reset before enabling
* interruptions to avoid a nonexistent interrupt to occur.
*
* In principle, the same problem would apply to bit 0, although it has
* never been observed to happen.
*
* This issue is addressed both here and in sa1100_rtc_interrupt().
* If the issue is not addressed here, in the times when the processor
* wakes up with the bit set there will be one spurious interrupt.
*
* The issue is also dealt with in sa1100_rtc_interrupt() to be on the
* safe side, once the condition that lead to this strange
* initialization is unknown and could in principle happen during
* normal processing.
*
* Notice that clearing bit 1 and 0 is accomplished by writting ONES to
* the corresponding bits in RTSR. */
writel_relaxed(RTSR_AL | RTSR_HZ, info->rtsr);
return 0;
}
EXPORT_SYMBOL_GPL(sa1100_rtc_init);
static int sa1100_rtc_probe(struct platform_device *pdev)
{
struct sa1100_rtc *info;
void __iomem *base;
int irq_1hz, irq_alarm;
int ret;
irq_1hz = platform_get_irq_byname(pdev, "rtc 1Hz");
irq_alarm = platform_get_irq_byname(pdev, "rtc alarm");
if (irq_1hz < 0 || irq_alarm < 0)
return -ENODEV;
info = devm_kzalloc(&pdev->dev, sizeof(struct sa1100_rtc), GFP_KERNEL);
if (!info)
return -ENOMEM;
info->irq_1hz = irq_1hz;
info->irq_alarm = irq_alarm;
info->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(info->rtc))
return PTR_ERR(info->rtc);
ret = devm_request_irq(&pdev->dev, irq_1hz, sa1100_rtc_interrupt, 0,
"rtc 1Hz", &pdev->dev);
if (ret) {
dev_err(&pdev->dev, "IRQ %d already in use.\n", irq_1hz);
return ret;
}
ret = devm_request_irq(&pdev->dev, irq_alarm, sa1100_rtc_interrupt, 0,
"rtc Alrm", &pdev->dev);
if (ret) {
dev_err(&pdev->dev, "IRQ %d already in use.\n", irq_alarm);
return ret;
}
base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(base))
return PTR_ERR(base);
if (IS_ENABLED(CONFIG_ARCH_SA1100) ||
of_device_is_compatible(pdev->dev.of_node, "mrvl,sa1100-rtc")) {
info->rcnr = base + 0x04;
info->rtsr = base + 0x10;
info->rtar = base + 0x00;
info->rttr = base + 0x08;
} else {
info->rcnr = base + 0x0;
info->rtsr = base + 0x8;
info->rtar = base + 0x4;
info->rttr = base + 0xc;
}
platform_set_drvdata(pdev, info);
device_init_wakeup(&pdev->dev, 1);
return sa1100_rtc_init(pdev, info);
}
static void sa1100_rtc_remove(struct platform_device *pdev)
{
struct sa1100_rtc *info = platform_get_drvdata(pdev);
if (info) {
spin_lock_irq(&info->lock);
writel_relaxed(0, info->rtsr);
spin_unlock_irq(&info->lock);
clk_disable_unprepare(info->clk);
}
}
#ifdef CONFIG_PM_SLEEP
static int sa1100_rtc_suspend(struct device *dev)
{
struct sa1100_rtc *info = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
enable_irq_wake(info->irq_alarm);
return 0;
}
static int sa1100_rtc_resume(struct device *dev)
{
struct sa1100_rtc *info = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
disable_irq_wake(info->irq_alarm);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(sa1100_rtc_pm_ops, sa1100_rtc_suspend,
sa1100_rtc_resume);
#ifdef CONFIG_OF
static const struct of_device_id sa1100_rtc_dt_ids[] = {
{ .compatible = "mrvl,sa1100-rtc", },
{ .compatible = "mrvl,mmp-rtc", },
{}
};
MODULE_DEVICE_TABLE(of, sa1100_rtc_dt_ids);
#endif
static struct platform_driver sa1100_rtc_driver = {
.probe = sa1100_rtc_probe,
.remove_new = sa1100_rtc_remove,
.driver = {
.name = "sa1100-rtc",
.pm = &sa1100_rtc_pm_ops,
.of_match_table = of_match_ptr(sa1100_rtc_dt_ids),
},
};
module_platform_driver(sa1100_rtc_driver);
MODULE_AUTHOR("Richard Purdie <[email protected]>");
MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:sa1100-rtc");
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