linux-kernel - Re: [PATCH 7/9] reset: make the provider of reset-gpios the parent of the reset device

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Message-ID: <95bbec130437846d4b902ce4161ccf0f33c26c59.camel@pengutronix.de>
Date: Mon, 06 Oct 2025 17:19:43 +0200
From: Philipp Zabel <p.zabel@...gutronix.de>
To: Bartosz Golaszewski <brgl@...ev.pl>, Linus Walleij	
 <linus.walleij@...aro.org>, Andy Shevchenko
 <andriy.shevchenko@...ux.intel.com>,  Daniel Scally <djrscally@...il.com>,
 Heikki Krogerus <heikki.krogerus@...ux.intel.com>, Sakari Ailus	
 <sakari.ailus@...ux.intel.com>, Greg Kroah-Hartman
 <gregkh@...uxfoundation.org>,  "Rafael J. Wysocki"	 <rafael@...nel.org>,
 Danilo Krummrich <dakr@...nel.org>, Krzysztof Kozlowski	 <krzk@...nel.org>
Cc: linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-acpi@...r.kernel.org, Bartosz Golaszewski
 <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH 7/9] reset: make the provider of reset-gpios the parent
 of the reset device

Hi Bartosz,

On Mo, 2025-10-06 at 15:00 +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> 
> Auxiliary devices really do need a parent so ahead of converting the
> reset-gpios driver to registering on the auxiliary bus, make the GPIO
> device that provides the reset GPIO the parent of the reset-gpio device.
> To that end move the lookup of the GPIO device by fwnode to the
> beginning of __reset_add_reset_gpio_device() which has the added benefor

Typo: benefit.

> of bailing out earlier, before allocating resources for the virtual
> device, if the chip is not up yet.
> 
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> ---
>  drivers/reset/core.c | 18 ++++++++++--------
>  1 file changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/reset/core.c b/drivers/reset/core.c
> index 5a696e2dbcc224a633e2b321da53b7bc699cb5f3..ad85ddc8dd9fcf8b512cb09168586e0afca257f1 100644
> --- a/drivers/reset/core.c
> +++ b/drivers/reset/core.c
> @@ -849,11 +849,11 @@ static void __reset_control_put_internal(struct reset_control *rstc)
>  	kref_put(&rstc->refcnt, __reset_control_release);
>  }
>  
> -static int __reset_add_reset_gpio_lookup(int id, struct device_node *np,
> +static int __reset_add_reset_gpio_lookup(struct gpio_device *gdev, int id,
> +					 struct device_node *np,
>  					 unsigned int gpio,
>  					 unsigned int of_flags)
>  {
> -	const struct fwnode_handle *fwnode = of_fwnode_handle(np);
>  	unsigned int lookup_flags;
>  	const char *label_tmp;
>  
> @@ -868,10 +868,6 @@ static int __reset_add_reset_gpio_lookup(int id, struct device_node *np,
>  		return -EINVAL;
>  	}
>  
> -	struct gpio_device *gdev __free(gpio_device_put) = gpio_device_find_by_fwnode(fwnode);
> -	if (!gdev)
> -		return -EPROBE_DEFER;
> -
>  	label_tmp = gpio_device_get_label(gdev);

This is the only remaining use of gdev in
__reset_add_reset_gpio_lookup().
It would make sense to move this as well and only pass the label.

Given that all this is removed in patch 9, this is not super important.

>  	if (!label_tmp)
>  		return -EINVAL;
> @@ -919,6 +915,11 @@ static int __reset_add_reset_gpio_device(const struct of_phandle_args *args)
>  	if (args->args_count != 2)
>  		return -ENOENT;
>  
> +	struct gpio_device *gdev __free(gpio_device_put) =
> +		gpio_device_find_by_fwnode(of_fwnode_handle(args->np));

We are mixing cleanup helpers with gotos in this function, which the
documentation in cleanup.h explicitly advises against.

I know the current code is already guilty, but could you take this
opportunity to prepend a patch that splits the part under guard() into
a separate function?

I'd also move this block after the lockdep_assert_not_held() below.


regards
Philipp