linux-kernel - [PATCH v2 4/5] rtc: mt6397: Add BBPU alarm status reset and shutdown handling

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20251120121805.6775-5-ot_shunxi.zhang@mediatek.com>
Date: Thu, 20 Nov 2025 20:18:00 +0800
From: <ot_shunxi.zhang@...iatek.com>
To: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, Matthias Brugger
	<matthias.bgg@...il.com>, AngeloGioacchino Del Regno
	<angelogioacchino.delregno@...labora.com>, Eddie Huang
	<eddie.huang@...iatek.com>, Sean Wang <sean.wang@...iatek.com>, Alexandre
 Belloni <alexandre.belloni@...tlin.com>, Lee Jones <lee@...nel.org>, Shunxi
 Zhang <ot_shunxi.zhang@...iatek.com>, <Vince-WL.Liu@...iatek.com>,
	<sirius.wang@...iatek.com>, <Jh.Hsu@...iatek.com>
CC: <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-mediatek@...ts.infradead.org>
Subject: [PATCH v2 4/5] rtc: mt6397: Add BBPU alarm status reset and shutdown handling

From: Shunxi Zhang <ot_shunxi.zhang@...iatek.com>

Function "mtk_rtc_reset_bbpu_alarm_status" is added to address the
issue that the RTC BBPU alarm state remains after the RTC alarm
has occurred.

Additionally, function "mtk_rtc_shutdown" is added to address the
issue of the platform being powered on again after shutdown because
the RTC_BBPU alarm state was not cleared.

Signed-off-by: Shunxi Zhang <ot_shunxi.zhang@...iatek.com>
---
 drivers/rtc/rtc-mt6397.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/drivers/rtc/rtc-mt6397.c b/drivers/rtc/rtc-mt6397.c
index b8f44a00de5d..8bf7e0822ef0 100644
--- a/drivers/rtc/rtc-mt6397.c
+++ b/drivers/rtc/rtc-mt6397.c
@@ -37,6 +37,21 @@ static int mtk_rtc_write_trigger(struct mt6397_rtc *rtc)
 	return ret;
 }
 
+static void mtk_rtc_reset_bbpu_alarm_status(struct mt6397_rtc *rtc)
+{
+	u32 bbpu = RTC_BBPU_KEY | RTC_BBPU_PWREN | RTC_BBPU_RESET_AL;
+	int ret;
+
+	ret = regmap_write(rtc->regmap, rtc->addr_base + RTC_BBPU, bbpu);
+	if (ret < 0) {
+		dev_err(rtc->rtc_dev->dev.parent, "%s: write rtc bbpu error\n",
+			__func__);
+		return;
+	}
+
+	mtk_rtc_write_trigger(rtc);
+}
+
 static irqreturn_t mtk_rtc_irq_handler_thread(int irq, void *data)
 {
 	struct mt6397_rtc *rtc = data;
@@ -51,6 +66,9 @@ static irqreturn_t mtk_rtc_irq_handler_thread(int irq, void *data)
 		if (regmap_write(rtc->regmap, rtc->addr_base + RTC_IRQ_EN,
 				 irqen) == 0)
 			mtk_rtc_write_trigger(rtc);
+
+		if (rtc->alarm_sta_supported)
+			mtk_rtc_reset_bbpu_alarm_status(rtc);
 		mutex_unlock(&rtc->lock);
 
 		return IRQ_HANDLED;
@@ -249,6 +267,7 @@ static int mtk_rtc_probe(struct platform_device *pdev)
 	struct resource *res;
 	struct mt6397_chip *mt6397_chip = dev_get_drvdata(pdev->dev.parent);
 	struct mt6397_rtc *rtc;
+	struct device_node *np = pdev->dev.of_node;
 	int ret;
 
 	rtc = devm_kzalloc(&pdev->dev, sizeof(struct mt6397_rtc), GFP_KERNEL);
@@ -275,6 +294,8 @@ static int mtk_rtc_probe(struct platform_device *pdev)
 	if (IS_ERR(rtc->rtc_dev))
 		return PTR_ERR(rtc->rtc_dev);
 
+	rtc->alarm_sta_supported = of_property_read_bool(np, "mediatek,alarm-sta-supported");
+
 	ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
 					mtk_rtc_irq_handler_thread,
 					IRQF_ONESHOT | IRQF_TRIGGER_HIGH,
@@ -297,6 +318,14 @@ static int mtk_rtc_probe(struct platform_device *pdev)
 	return devm_rtc_register_device(rtc->rtc_dev);
 }
 
+static void mtk_rtc_shutdown(struct platform_device *pdev)
+{
+	struct mt6397_rtc *rtc = platform_get_drvdata(pdev);
+
+	if (rtc->alarm_sta_supported)
+		mtk_rtc_reset_bbpu_alarm_status(rtc);
+}
+
 #ifdef CONFIG_PM_SLEEP
 static int mt6397_rtc_suspend(struct device *dev)
 {
@@ -346,6 +375,7 @@ static struct platform_driver mtk_rtc_driver = {
 		.pm = &mt6397_pm_ops,
 	},
 	.probe = mtk_rtc_probe,
+	.shutdown = mtk_rtc_shutdown,
 };
 
 module_platform_driver(mtk_rtc_driver);
-- 
2.45.2