linux-kernel - Re: [PATCH RFC 1/3] reset: replace boolean parameters with flags parameter

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Date: Sat, 22 Jun 2024 09:47:18 +0200
From: Uwe Kleine-König <u.kleine-koenig@...libre.com>
To: Philipp Zabel <p.zabel@...gutronix.de>
Cc: Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>, 
	Masami Hiramatsu <mhiramat@...nel.org>, Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>, 
	Geert Uytterhoeven <geert+renesas@...der.be>, linux-kernel@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, kernel@...gutronix.de
Subject: Re: [PATCH RFC 1/3] reset: replace boolean parameters with flags
 parameter

Hello Philipp,

I like the idea in general. Just a detail concern down below.

On Fri, Jun 21, 2024 at 04:45:02PM +0200, Philipp Zabel wrote:
> @@ -999,8 +1001,9 @@ static struct reset_controller_dev *__reset_find_rcdev(const struct of_phandle_a
>  
>  struct reset_control *
>  __of_reset_control_get(struct device_node *node, const char *id, int index,
> -		       bool shared, bool optional, bool acquired)
> +		       enum reset_control_flags flags)
>  {
> +	bool optional = flags & RESET_CONTROL_FLAGS_BIT_OPTIONAL;
>  	bool gpio_fallback = false;
>  	struct reset_control *rstc;
>  	struct reset_controller_dev *rcdev;
> @@ -1065,7 +1068,7 @@ __of_reset_control_get(struct device_node *node, const char *id, int index,
>  	}
>  
>  	/* reset_list_mutex also protects the rcdev's reset_control list */
> -	rstc = __reset_control_get_internal(rcdev, rstc_id, shared, acquired);
> +	rstc = __reset_control_get_internal(rcdev, rstc_id, flags);

If RESET_CONTROL_FLAGS_BIT_OPTIONAL was passed to
__of_reset_control_get(), you're forwarding it to
__reset_control_get_internal(). But the latter doesn't do anything with
that flag. I wonder if the API would be still less prone to error if
you'd filter out RESET_CONTROL_FLAGS_BIT_OPTIONAL before passing to
__reset_control_get_internal() and in __reset_control_get_internal() add
a check for unsupported flags.

>  out_unlock:
>  	mutex_unlock(&reset_list_mutex);
> @@ -1096,8 +1099,9 @@ __reset_controller_by_name(const char *name)
>  
>  static struct reset_control *
>  __reset_control_get_from_lookup(struct device *dev, const char *con_id,
> -				bool shared, bool optional, bool acquired)
> +				enum reset_control_flags flags)
>  {
> +	bool optional = flags & RESET_CONTROL_FLAGS_BIT_OPTIONAL;
>  	const struct reset_control_lookup *lookup;
>  	struct reset_controller_dev *rcdev;
>  	const char *dev_id = dev_name(dev);
> [...]
> @@ -1422,7 +1423,7 @@ EXPORT_SYMBOL_GPL(of_reset_control_array_get);
>   * Returns pointer to allocated reset_control on success or error on failure
>   */
>  struct reset_control *
> -devm_reset_control_array_get(struct device *dev, bool shared, bool optional)
> +devm_reset_control_array_get(struct device *dev, enum reset_control_flags flags)
>  {
>  	struct reset_control **ptr, *rstc;
>  
> @@ -1431,7 +1432,7 @@ devm_reset_control_array_get(struct device *dev, bool shared, bool optional)
>  	if (!ptr)
>  		return ERR_PTR(-ENOMEM);
>  
> -	rstc = of_reset_control_array_get(dev->of_node, shared, optional, true);
> +	rstc = of_reset_control_array_get(dev->of_node, flags);

Is it an error if the new devm_reset_control_array_get() is called
without RESET_CONTROL_FLAGS_BIT_ACQUIRED in flags?

>  	if (IS_ERR_OR_NULL(rstc)) {
>  		devres_free(ptr);
>  		return rstc;

Best regards
Uwe

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