Re: [PATCH 3/9] gpio: mxc: cache compatible checks at probe time

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

On Sat, Oct 03, 2026 at 08:06:45PM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
>
> mxc_gpio_generic_config() and mxc_gpio_set_pad_wakeup() call
> of_device_is_compatible() on every invocation to determine pad wakeup
> capability and i.MX8QM-specific behavior. These properties are
> invariant for the lifetime of the device.
>
> Cache them as bool fields (has_pad_wakeup, is_imx8qm) in mxc_gpio_port
> during probe, eliminating repeated device tree string comparisons in
> the suspend/resume hot path.
>
> Assisted-by: LLM
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
>  drivers/gpio/gpio-mxc.c | 24 ++++++++++++++----------
>  1 file changed, 14 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpio/gpio-mxc.c b/drivers/gpio/gpio-mxc.c
> index 8a755ac1af83..1c27232f6a80 100644
> --- a/drivers/gpio/gpio-mxc.c
> +++ b/drivers/gpio/gpio-mxc.c
> @@ -73,6 +73,8 @@ struct mxc_gpio_port {
>  	bool power_off;
>  	unsigned long wakeup_pads;
>  	bool is_pad_wakeup;
> +	bool has_pad_wakeup;
> +	bool is_imx8qm;
>  	u32 pad_type[32];
>  	const struct mxc_gpio_hwdata *hwdata;
>  };
> @@ -457,6 +459,14 @@ static int mxc_gpio_probe(struct platform_device *pdev)
>  	if (of_device_is_compatible(np, "fsl,imx7d-gpio"))
>  		port->power_off = true;
>
> +	if (of_device_is_compatible(np, "fsl,imx8dxl-gpio") ||
> +	    of_device_is_compatible(np, "fsl,imx8qxp-gpio") ||
> +	    of_device_is_compatible(np, "fsl,imx8qm-gpio"))
> +		port->has_pad_wakeup = true;

can you move has_pad_wakeup/is_imx8qm in mxc_gpio_hw_data?

Frank

> +
> +	if (of_device_is_compatible(np, "fsl,imx8qm-gpio"))
> +		port->is_imx8qm = true;
> +
>  	pm_runtime_get_noresume(&pdev->dev);
>  	pm_runtime_set_active(&pdev->dev);
>  	pm_runtime_enable(&pdev->dev);
> @@ -570,15 +580,10 @@ static void mxc_gpio_restore_regs(struct mxc_gpio_port *port)
>  static bool mxc_gpio_generic_config(struct mxc_gpio_port *port,
>  		unsigned int offset, unsigned long conf)
>  {
> -	struct device_node *np = port->dev->of_node;
> -
> -	if (of_device_is_compatible(np, "fsl,imx8dxl-gpio") ||
> -	    of_device_is_compatible(np, "fsl,imx8qxp-gpio") ||
> -	    of_device_is_compatible(np, "fsl,imx8qm-gpio"))
> -		return (gpiochip_generic_config(&port->gen_gc.gc,
> -						offset, conf) == 0);
> +	if (!port->has_pad_wakeup)
> +		return false;
>
> -	return false;
> +	return (gpiochip_generic_config(&port->gen_gc.gc, offset, conf) == 0);
>  }
>
>  static bool mxc_gpio_set_pad_wakeup(struct mxc_gpio_port *port, bool enable)
> @@ -586,7 +591,6 @@ static bool mxc_gpio_set_pad_wakeup(struct mxc_gpio_port *port, bool enable)
>  	unsigned long config;
>  	bool ret = false;
>  	int i, type;
> -	bool is_imx8qm = of_device_is_compatible(port->dev->of_node, "fsl,imx8qm-gpio");
>
>  	static const u32 pad_type_map[] = {
>  		IMX_SCU_WAKEUP_OFF,		/* 0 */
> @@ -608,7 +612,7 @@ static bool mxc_gpio_set_pad_wakeup(struct mxc_gpio_port *port, bool enable)
>  			else
>  				config = IMX_SCU_WAKEUP_OFF;
>
> -			if (is_imx8qm && config == IMX_SCU_WAKEUP_FALL_EDGE) {
> +			if (port->is_imx8qm && config == IMX_SCU_WAKEUP_FALL_EDGE) {
>  				dev_warn_once(port->dev,
>  					      "No falling-edge support for wakeup on i.MX8QM\n");
>  				config = IMX_SCU_WAKEUP_OFF;
>
> --
> 2.51.0
>
>