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rtc: brcmstb-waketimer: support level alarm_irq

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Some devices (e.g. BCM72112) use an alarm_irq interrupt that is
connected to a level interrupt controller rather than an edge
interrupt controller. In this case, the interrupt cannot be left
enabled by the irq handler while preserving the hardware wake-up
signal on wake capable devices or an interrupt storm will occur.

The alarm_expired flag is introduced to allow the disabling of
the interrupt when an alarm expires and to support balancing the
calls to disable_irq() and enable_irq() in accordance with the
existing design.

Fixes: 24304a8715 ("rtc: brcmstb-waketimer: allow use as non-wake alarm")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20230830224747.1663044-1-opendmb@gmail.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Doug Berger 2023-08-30 15:47:47 -07:00 committed by Alexandre Belloni
parent d4277fa4a1
commit e005a9b35b
1 changed files with 42 additions and 5 deletions
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47
drivers/rtc/rtc-brcmstb-waketimer.c
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@ -1,6 +1,6 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright © 2014-2017 Broadcom
* Copyright © 2014-2023 Broadcom
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@ -34,6 +34,7 @@ struct brcmstb_waketmr {
u32 rate;
unsigned long rtc_alarm;
bool alarm_en;
bool alarm_expired;
};
#define BRCMSTB_WKTMR_EVENT 0x00
@ -64,6 +65,11 @@ static inline void brcmstb_waketmr_clear_alarm(struct brcmstb_waketmr *timer)
writel_relaxed(reg - 1, timer->base + BRCMSTB_WKTMR_ALARM);
writel_relaxed(WKTMR_ALARM_EVENT, timer->base + BRCMSTB_WKTMR_EVENT);
(void)readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT);
if (timer->alarm_expired) {
timer->alarm_expired = false;
/* maintain call balance */
enable_irq(timer->alarm_irq);
}
}
static void brcmstb_waketmr_set_alarm(struct brcmstb_waketmr *timer,
@ -105,10 +111,17 @@ static irqreturn_t brcmstb_alarm_irq(int irq, void *data)
return IRQ_HANDLED;
if (timer->alarm_en) {
if (!device_may_wakeup(timer->dev))
if (device_may_wakeup(timer->dev)) {
disable_irq_nosync(irq);
timer->alarm_expired = true;
} else {
writel_relaxed(WKTMR_ALARM_EVENT,
timer->base + BRCMSTB_WKTMR_EVENT);
}
rtc_update_irq(timer->rtc, 1, RTC_IRQF | RTC_AF);
} else {
writel_relaxed(WKTMR_ALARM_EVENT,
timer->base + BRCMSTB_WKTMR_EVENT);
}
return IRQ_HANDLED;
@ -221,8 +234,14 @@ static int brcmstb_waketmr_alarm_enable(struct device *dev,
!brcmstb_waketmr_is_pending(timer))
return -EINVAL;
timer->alarm_en = true;
if (timer->alarm_irq)
if (timer->alarm_irq) {
if (timer->alarm_expired) {
timer->alarm_expired = false;
/* maintain call balance */
enable_irq(timer->alarm_irq);
}
enable_irq(timer->alarm_irq);
}
} else if (!enabled && timer->alarm_en) {
if (timer->alarm_irq)
disable_irq(timer->alarm_irq);
@ -352,6 +371,17 @@ static int brcmstb_waketmr_suspend(struct device *dev)
return brcmstb_waketmr_prepare_suspend(timer);
}
static int brcmstb_waketmr_suspend_noirq(struct device *dev)
{
struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
/* Catch any alarms occurring prior to noirq */
if (timer->alarm_expired && device_may_wakeup(dev))
return -EBUSY;
return 0;
}
static int brcmstb_waketmr_resume(struct device *dev)
{
struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
@ -368,10 +398,17 @@ static int brcmstb_waketmr_resume(struct device *dev)
return ret;
}
#else
#define brcmstb_waketmr_suspend NULL
#define brcmstb_waketmr_suspend_noirq NULL
#define brcmstb_waketmr_resume NULL
#endif /* CONFIG_PM_SLEEP */
static SIMPLE_DEV_PM_OPS(brcmstb_waketmr_pm_ops,
brcmstb_waketmr_suspend, brcmstb_waketmr_resume);
static const struct dev_pm_ops brcmstb_waketmr_pm_ops = {
.suspend = brcmstb_waketmr_suspend,
.suspend_noirq = brcmstb_waketmr_suspend_noirq,
.resume = brcmstb_waketmr_resume,
};
static const __maybe_unused struct of_device_id brcmstb_waketmr_of_match[] = {
{ .compatible = "brcm,brcmstb-waketimer" },