linux-kernel - [PATCH] rtc: pm8xxx: Disable alarm irq if alarm time is less than rtc time and alarm irq is enabled

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Message-Id: <20211126074845.9160-1-quic_jianbinz@quicinc.com>
Date:   Fri, 26 Nov 2021 15:48:45 +0800
From:   jianbin zhang <quic_jianbinz@...cinc.com>
To:     alexandre.belloni@...tlin.com, a.zummo@...ertech.it
Cc:     jianbinz <quic_jianbinz@...cinc.com>, linux-kernel@...r.kernel.org,
        linux-rtc@...r.kernel.org
Subject: [PATCH] rtc: pm8xxx: Disable alarm irq if alarm time is less than rtc time and alarm irq is enabled

From: jianbinz <quic_jianbinz@...cinc.com>

If device is boot up by rtc alarm, the alarm irq will still be enabled and
the alarm time is smaller than current rtc time before any alarm is set or canceled.

If the device is shutdown this time, the device will reboot automatically.

So disable irq if alarm time is less than rtc time and irq is enabled.

Reproduced steps:
1/ set the alarm
2/ shutdown
3/ alarm happens, the device boots
4/ shutdown
5/ alarm irq is still set, device boots again

The plan to solve the issue is to acknowledge and clear the irq at step
3 in pm8xxx driver.

Signed-off-by: jianbin zhang <quic_jianbinz@...cinc.com>
---
 drivers/rtc/rtc-pm8xxx.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-pm8xxx.c b/drivers/rtc/rtc-pm8xxx.c
index 29a1c65661e9..c8a75d3e9c43 100644
--- a/drivers/rtc/rtc-pm8xxx.c
+++ b/drivers/rtc/rtc-pm8xxx.c
@@ -267,16 +267,19 @@ static int pm8xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 {
 	int rc;
 	unsigned int ctrl_reg;
+	unsigned long irq_flags;
 	u8 value[NUM_8_BIT_RTC_REGS];
 	unsigned long secs;
 	struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
 	const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
 
+	spin_lock_irqsave(&rtc_dd->ctrl_reg_lock, irq_flags);
+
 	rc = regmap_bulk_read(rtc_dd->regmap, regs->alarm_rw, value,
 			      sizeof(value));
 	if (rc) {
 		dev_err(dev, "RTC alarm time read failed\n");
-		return rc;
+		goto rtc_rw_fail;
 	}
 
 	secs = value[0] | (value[1] << 8) | (value[2] << 16) |
@@ -287,14 +290,30 @@ static int pm8xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 	rc = regmap_read(rtc_dd->regmap, regs->alarm_ctrl, &ctrl_reg);
 	if (rc) {
 		dev_err(dev, "Read from RTC alarm control register failed\n");
-		return rc;
+		goto rtc_rw_fail;
+	}
+
+	if (ctrl_reg && (rtc_tm_to_ktime(alarm->time) >=
+				rtc_dd->rtc->aie_timer.node.expires)) {
+		ctrl_reg &= ~regs->alarm_en;
+		rc = regmap_write(rtc_dd->regmap, regs->alarm_ctrl, ctrl_reg);
+		if (rc) {
+			dev_err(dev, "Update RTC control register failed \n");
+			goto rtc_rw_fail;
+		}
 	}
 	alarm->enabled = !!(ctrl_reg & PM8xxx_RTC_ALARM_ENABLE);
 
+	spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
+
 	dev_dbg(dev, "Alarm set for - h:m:s=%ptRt, y-m-d=%ptRdr\n",
 		&alarm->time, &alarm->time);
 
 	return 0;
+
+rtc_rw_fail:
+	spin_unlock_irqrestore(&rtc_dd->ctrl_reg_lock, irq_flags);
+	return rc;
 }
 
 static int pm8xxx_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
-- 
2.17.1