Re: [PATCH v4 02/10] gpio: mxc: fix wakeup_pads bit operations

[Frank Li <Frank.li@oss.nxp.com>]

On Wed, Oct 07, 2026 at 06:44:17PM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
>
> gpio_set_wake_irq() can be called concurrently for different pins on
> the same port, so we need to use atomic bitops when modifying
> wakeup_pads.

So Need to use atomic ..

>
> wakeup_pads is a u32, while assign_bit() operates on unsigned long
> pointers. On 64-bit platforms, this causes an 8-byte read-modify-write
> on a 4-byte field, corrupting the adjacent is_pad_wakeup member.

is_pad_wakeup is not member, that's local variable. so should be

"corrupting the adjacent is_pad_wakeup local variable"

> Change wakeup_pads to unsigned long and reorder to avoid the overlap.

reorder can't "avoid the overlay"

Change "corrupting the adjacent is_pad_wakeup" already avoid the overlap.


>
> And the enable/disable path unconditionally sets/clears the wakeup_pads
> bit even when enable_irq_wake()/disable_irq_wake() fails. Only update
> the bit on success.
>
> While at here, simplify the logic by consolidating into a single
> irq_set_irq_wake() call based on the enable parameter.

And use irq_set_irq_wake() simple code. this part need seperate patch.

Frank

>
> Fixes: f60c9eac54af ("gpio: mxc: enable pad wakeup on i.MX8x platforms")
> Assisted-by: LLM
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
>  drivers/gpio/gpio-mxc.c | 25 ++++++++++---------------
>  1 file changed, 10 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpio/gpio-mxc.c b/drivers/gpio/gpio-mxc.c
> index e05f276a50e8..627fff6f1886 100644
> --- a/drivers/gpio/gpio-mxc.c
> +++ b/drivers/gpio/gpio-mxc.c
> @@ -71,8 +71,8 @@ struct mxc_gpio_port {
>  	u32 both_edges;
>  	struct mxc_gpio_reg_saved gpio_saved_reg;
>  	bool power_off;
> -	u32 wakeup_pads;
>  	bool is_pad_wakeup;
> +	unsigned long wakeup_pads;
>  	u32 pad_type[32];
>  	const struct mxc_gpio_hwdata *hwdata;
>  };
> @@ -325,21 +325,16 @@ static int gpio_set_wake_irq(struct irq_data *d, u32 enable)
>  	u32 gpio_idx = d->hwirq;
>  	int ret;
>
> -	if (enable) {
> -		if (port->irq_high && (gpio_idx >= 16))
> -			ret = enable_irq_wake(port->irq_high);
> -		else
> -			ret = enable_irq_wake(port->irq);
> -		port->wakeup_pads |= BIT(gpio_idx);
> -	} else {
> -		if (port->irq_high && (gpio_idx >= 16))
> -			ret = disable_irq_wake(port->irq_high);
> -		else
> -			ret = disable_irq_wake(port->irq);
> -		port->wakeup_pads &= ~BIT(gpio_idx);
> -	}
> +	if (port->irq_high && (gpio_idx >= 16))
> +		ret = irq_set_irq_wake(port->irq_high, enable);
> +	else
> +		ret = irq_set_irq_wake(port->irq, enable);
> +	if (ret)
> +		return ret;
>
> -	return ret;
> +	assign_bit(gpio_idx, &port->wakeup_pads, enable);
> +
> +	return 0;
>  }
>
>  static int mxc_gpio_init_gc(struct mxc_gpio_port *port, int irq_base)
>
> --
> 2.51.0
>
>