linux-kernel - [PATCH v2 1/1] rtc: rtc-pm8xxx: Retrigger RTC alarm if it's fired before the driver probed

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Message-ID: <20231205064050.31827-1-quic_jianbinz@quicinc.com>
Date:   Tue, 5 Dec 2023 14:40:50 +0800
From:   jianbinz <quic_jianbinz@...cinc.com>
To:     <alexandre.belloni@...tlin.com>, <a.zummo@...ertech.it>
CC:     jianbinz <quic_jianbinz@...cinc.com>, <linux-rtc@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH v2 1/1] rtc: rtc-pm8xxx: Retrigger RTC alarm if it's fired before the driver probed

If the alarm is triggered before the driver gets probed, the alarm
interrupt will be missed and it won't be detected, and the stale
alarm settings will be still retained because of not being cleared.
Check this condition during driver probe, retrigger the alarm and
clear the settings manually if it's such case.

Changes in v2:
*Adapt the V1 patch according to the newest rtc-pm8xxx

Changes in v1:
*During driver probe: read ALARM_EN, read ALARM_DATA, read RTC_RDATA,
if (ALARM_DATA < RTC_DATA), Trigger the alarm event and clear the alarm settins
Link to v1:https://lore.kernel.org/linux-rtc/20220321090514.4523-1-quic_jianbinz@quicinc.com/

Signed-off-by: jianbinz <quic_jianbinz@...cinc.com>
---
 drivers/rtc/rtc-pm8xxx.c | 57 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 53 insertions(+), 4 deletions(-)

diff --git a/drivers/rtc/rtc-pm8xxx.c b/drivers/rtc/rtc-pm8xxx.c
index f6b779c12ca7..eac4e7f23aaa 100644
--- a/drivers/rtc/rtc-pm8xxx.c
+++ b/drivers/rtc/rtc-pm8xxx.c
@@ -309,21 +309,33 @@ static int pm8xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 	return 0;
 }
 
+static int pm8xxx_rtc_read_alarm_raw(struct pm8xxx_rtc *rtc_dd, u32 *secs)
+{
+	const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
+	u8 value[NUM_8_BIT_RTC_REGS];
+	int rc;
+
+	rc = regmap_bulk_read(rtc_dd->regmap, regs->read, value, sizeof(value));
+	if (rc)
+		return rc;
+
+	*secs = get_unaligned_le32(value);
+
+	return 0;
+}
+
 static int pm8xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 {
 	struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
 	const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
-	u8 value[NUM_8_BIT_RTC_REGS];
 	unsigned int ctrl_reg;
 	u32 secs;
 	int rc;
 
-	rc = regmap_bulk_read(rtc_dd->regmap, regs->alarm_rw, value,
-			      sizeof(value));
+	rc = pm8xxx_rtc_read_alarm_raw(rtc_dd, &secs);
 	if (rc)
 		return rc;
 
-	secs = get_unaligned_le32(value);
 	secs += rtc_dd->offset;
 	rtc_time64_to_tm(secs, &alarm->time);
 
@@ -398,6 +410,39 @@ static irqreturn_t pm8xxx_alarm_trigger(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+/*
+ * Trigger the alarm event and clear the alarm settings
+ * if the alarm data has been behind the RTC data which
+ * means the alarm has been triggered before the driver
+ * is probed.
+ */
+static int pm8xxx_rtc_init_alarm(struct pm8xxx_rtc *rtc_dd)
+{
+	int rc;
+	u32 alarm_sec, rtc_sec;
+	unsigned int ctrl_reg, alarm_en;
+	const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
+
+	rc = pm8xxx_rtc_read_raw(rtc_dd, &rtc_sec);
+	if (rc)
+		return rc;
+
+	rc = pm8xxx_rtc_read_alarm_raw(rtc_dd, &alarm_sec);
+	if (rc)
+		return rc;
+
+	rc = regmap_read(rtc_dd->regmap, regs->alarm_ctrl, &ctrl_reg);
+	if (rc)
+		return rc;
+
+	alarm_en = !!(ctrl_reg & PM8xxx_RTC_ALARM_ENABLE);
+
+	if (alarm_en && rtc_sec >= alarm_sec)
+		pm8xxx_alarm_trigger(0, rtc_dd);
+
+	return 0;
+}
+
 static int pm8xxx_rtc_enable(struct pm8xxx_rtc *rtc_dd)
 {
 	const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
@@ -527,6 +572,10 @@ static int pm8xxx_rtc_probe(struct platform_device *pdev)
 	if (rc)
 		return rc;
 
+	rc = pm8xxx_rtc_init_alarm(rtc_dd);
+	if (rc)
+		return rc;
+
 	return 0;
 }
 
-- 
2.17.1