linux-kernel - Re: [PATCH V3 2/2] tty: serial: imx: Add missing wakeup event reporting

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Message-ID: <aNVkhvmZ4GThHNqD@lizhi-Precision-Tower-5810>
Date: Thu, 25 Sep 2025 11:49:26 -0400
From: Frank Li <Frank.li@....com>
To: Sherry Sun <sherry.sun@....com>
Cc: gregkh@...uxfoundation.org, jirislaby@...nel.org, shawnguo@...nel.org,
	s.hauer@...gutronix.de, kernel@...gutronix.de, festevam@...il.com,
	shenwei.wang@....com, peng.fan@....com,
	linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org,
	imx@...ts.linux.dev
Subject: Re: [PATCH V3 2/2] tty: serial: imx: Add missing wakeup event
 reporting

On Thu, Sep 25, 2025 at 05:11:32PM +0800, Sherry Sun wrote:
> Current imx uart 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>
> ---
>  drivers/tty/serial/imx.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
> index 87d841c0b22f..0eb3f5b8f820 100644
> --- a/drivers/tty/serial/imx.c
> +++ b/drivers/tty/serial/imx.c
> @@ -30,7 +30,7 @@
>  #include <linux/iopoll.h>
>  #include <linux/dma-mapping.h>
>
> -#include <asm/irq.h>
> +#include <linux/irq.h>
>  #include <linux/dma/imx-dma.h>
>
>  #include "serial_mctrl_gpio.h"
> @@ -2700,8 +2700,8 @@ static void imx_uart_enable_wakeup(struct imx_port *sport, bool on)
>  	struct tty_port *port = &sport->port.state->port;
>  	struct tty_struct *tty;
>  	struct device *tty_dev;
> -	bool may_wake = false;
> -	u32 ucr3;
> +	bool may_wake = false, wake_active = false;
> +	u32 ucr3, usr1;
>
>  	tty = tty_port_tty_get(port);
>  	if (tty) {
> @@ -2716,12 +2716,14 @@ static void imx_uart_enable_wakeup(struct imx_port *sport, bool on)
>
>  	uart_port_lock_irq(&sport->port);
>
> +	usr1 = imx_uart_readl(sport, USR1);
>  	ucr3 = imx_uart_readl(sport, UCR3);
>  	if (on) {
>  		imx_uart_writel(sport, USR1_AWAKE, USR1);
>  		ucr3 |= UCR3_AWAKEN;
>  	} else {
>  		ucr3 &= ~UCR3_AWAKEN;
> +		wake_active = usr1 & USR1_AWAKE;
>  	}
>  	imx_uart_writel(sport, ucr3, UCR3);
>
> @@ -2732,10 +2734,14 @@ static void imx_uart_enable_wakeup(struct imx_port *sport, bool on)
>  			ucr1 |= UCR1_RTSDEN;
>  		} else {
>  			ucr1 &= ~UCR1_RTSDEN;
> +			wake_active |= !!(usr1 & USR1_RTSD);

I think you miss understand my means. suppose bool type only support
||, &&, ==, !=, !

	wake_active = wake_active || (usr1 & USR1_RTSD);

a |= b actually equal to a = a | b.

bool | u32,  bool convert to u32 then bitwise to u32, algthough it is
allowed, but it is strange, like bool++ is strange.  (true | 0x2 is 0x3)

bool || u32, u32 convert to bool, bool || bool is perfered.
(true || 0x2 is true)

your case the result is the same.

If sparse don't report warning, it should be fine.

Frank
  		}
>  		imx_uart_writel(sport, ucr1, UCR1);
>  	}
>
> +	if (wake_active && irqd_is_wakeup_set(irq_get_irq_data(sport->port.irq)))
> +		pm_wakeup_event(tty_port_tty_get(port)->dev, 0);
> +
>  	uart_port_unlock_irq(&sport->port);
>  }
>
> --
> 2.34.1
>