tty: serial: imx: Only configure the wake register when device is set as wakeup source

Currently, the i.MX UART driver enables wake-related registers for all
UART devices by default. However, this is unnecessary for devices that
are not configured as wakeup sources. To address this, add a
device_may_wakeup() check before configuring the UART wake-related
registers.

Fixes: db1a9b55004c ("tty: serial: imx: Allow UART to be a source for wakeup")
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20251002045259.2725461-2-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 500dfc009d03e8e7f9938168ce62690bedc4d0ae..90e2ea1e8afe5c6fcac1721fff2e929180853498 100644 (file)
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -2697,8 +2697,22 @@ static void imx_uart_save_context(struct imx_port *sport)
 /* called with irq off */
 static void imx_uart_enable_wakeup(struct imx_port *sport, bool on)
 {
+       struct tty_port *port = &sport->port.state->port;
+       struct device *tty_dev;
+       bool may_wake = false;
        u32 ucr3;
 
+       scoped_guard(tty_port_tty, port) {
+               struct tty_struct *tty = scoped_tty();
+
+               tty_dev = tty->dev;
+               may_wake = tty_dev && device_may_wakeup(tty_dev);
+       }
+
+       /* only configure the wake register when device set as wakeup source */
+       if (!may_wake)
+               return;
+
        uart_port_lock_irq(&sport->port);
 
        ucr3 = imx_uart_readl(sport, UCR3);