linux-kernel - [PATCH V2] tty: serial: fsl_lpuart: Add missing wakeup event reporting

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Message-Id: <20250924025607.2515833-1-sherry.sun@nxp.com>
Date: Wed, 24 Sep 2025 10:56:07 +0800
From: Sherry Sun <sherry.sun@....com>
To: gregkh@...uxfoundation.org,
	jirislaby@...nel.org,
	shenwei.wang@....com,
	peng.fan@....com,
	frank.li@....com
Cc: linux-serial@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	imx@...ts.linux.dev
Subject: [PATCH V2] tty: serial: fsl_lpuart: Add missing wakeup event reporting

Current lpuart wakeup event would not report itself as wakeup source
through sysfs. Add pm_wakeup_event() to support it.

Signed-off-by: Sherry Sun <sherry.sun@....com>
---
Changes in V2:
1. Improve the commit message as Frank suggested.
2. Move wake_active above u32 stat.
3. Use (stat & (UARTSTAT_RDRF | UARTSTAT_RXEDGIF)) instead of (stat &
   UARTSTAT_RDRF || stat & UARTSTAT_RXEDGIF).
---
 drivers/tty/serial/fsl_lpuart.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index c9519e649e82..1bd7ec9c81ea 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -3087,6 +3087,8 @@ static int lpuart_suspend_noirq(struct device *dev)
 static int lpuart_resume_noirq(struct device *dev)
 {
 	struct lpuart_port *sport = dev_get_drvdata(dev);
+	struct tty_port *port = &sport->port.state->port;
+	bool wake_active;
 	u32 stat;
 
 	pinctrl_pm_select_default_state(dev);
@@ -3098,6 +3100,12 @@ static int lpuart_resume_noirq(struct device *dev)
 		if (lpuart_is_32(sport)) {
 			stat = lpuart32_read(&sport->port, UARTSTAT);
 			lpuart32_write(&sport->port, stat, UARTSTAT);
+
+			/* check whether lpuart wakeup was triggered */
+			wake_active = stat & (UARTSTAT_RDRF | UARTSTAT_RXEDGIF);
+
+			if (wake_active && irqd_is_wakeup_set(irq_get_irq_data(sport->port.irq)))
+				pm_wakeup_event(tty_port_tty_get(port)->dev, 0);
 		}
 	}
 
-- 
2.34.1