linux-kernel - Re: [PATCH] gpio: omap: do not register driver in probe()

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Message-Id: <DFW0SC4QG4W8.C7BRHX02W3IK@kernel.org>
Date: Fri, 23 Jan 2026 14:57:45 +0100
From: "Danilo Krummrich" <dakr@...nel.org>
To: <gregkh@...uxfoundation.org>, <rafael@...nel.org>, <broonie@...nel.org>,
 <will@...nel.org>, <grygorii.strashko@...com>, <ssantosh@...nel.org>,
 <khilman@...nel.org>, <linusw@...nel.org>, <brgl@...nel.org>
Cc: <driver-core@...ts.linux.dev>, <linux-kernel@...r.kernel.org>,
 <linux-omap@...r.kernel.org>, <linux-gpio@...r.kernel.org>, "Danilo
 Krummrich" <dakr@...nel.org>
Subject: Re: [PATCH] gpio: omap: do not register driver in probe()

On Fri Jan 23, 2026 at 2:31 PM CET, Danilo Krummrich wrote:
> diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
> index e136e81794df..8db71a2db9ff 100644
> --- a/drivers/gpio/gpio-omap.c
> +++ b/drivers/gpio/gpio-omap.c
> @@ -800,9 +800,7 @@ static struct platform_device omap_mpuio_device = {
>  static inline void omap_mpuio_init(struct gpio_bank *bank)
>  {
>  	platform_set_drvdata(&omap_mpuio_device, bank);
> -
> -	if (platform_driver_register(&omap_mpuio_driver) == 0)
> -		(void) platform_device_register(&omap_mpuio_device);
> +	(void)platform_device_register(&omap_mpuio_device);
>  }

On a second look, it recognize that this did abuse the fact that
platform_driver_register() fails when attempting to register a driver multiple
times to avoid registering the same static device multiple times.

So, I guess this has to be changed to:

diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
index 8db71a2db9ff..3e1ac34994fb 100644
--- a/drivers/gpio/gpio-omap.c
+++ b/drivers/gpio/gpio-omap.c
@@ -799,8 +799,13 @@ static struct platform_device omap_mpuio_device = {

 static inline void omap_mpuio_init(struct gpio_bank *bank)
 {
+       static bool registered = false;
+
        platform_set_drvdata(&omap_mpuio_device, bank);
-       (void)platform_device_register(&omap_mpuio_device);
+       if (!registered) {
+               (void)platform_device_register(&omap_mpuio_device);
+               registered = true;
+       }
 }

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