Re: [PATCH v2 5/6] software node: Introduce SOFTWARE_NODE_REFERENCE() helper macro

From: Daniel Scally <djrscally@gmail.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
	linux-acpi@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Yong Zhi <yong.zhi@intel.com>,
	Sakari Ailus <sakari.ailus@linux.intel.com>,
	Bingbu Cao <bingbu.cao@intel.com>,
	Tianshu Qiu <tian.shu.qiu@intel.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Heikki Krogerus <heikki.krogerus@linux.intel.com>
Subject: Re: [PATCH v2 5/6] software node: Introduce SOFTWARE_NODE_REFERENCE() helper macro
Date: Mon, 29 Mar 2021 23:45:29 +0100	[thread overview]
Message-ID: <5e76c3b8-d154-e5ca-25d8-290376469e5a@gmail.com> (raw)
In-Reply-To: <20210329151207.36619-5-andriy.shevchenko@linux.intel.com>

Hi Andy

On 29/03/2021 16:12, Andy Shevchenko wrote:
> This is useful to assign software node reference with arguments
> in a common way. Moreover, we have already couple of users that
> may be converted. And by the fact, one of them is moved right here
> to use the helper.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
> v2: no changes
>  drivers/base/test/property-entry-test.c | 11 ++---------
>  include/linux/property.h                | 13 ++++++++-----
>  2 files changed, 10 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/base/test/property-entry-test.c b/drivers/base/test/property-entry-test.c
> index abe03315180f..c2e455d46ffd 100644
> --- a/drivers/base/test/property-entry-test.c
> +++ b/drivers/base/test/property-entry-test.c
> @@ -370,15 +370,8 @@ static void pe_test_reference(struct kunit *test)
>  	};
>  
>  	static const struct software_node_ref_args refs[] = {
> -		{
> -			.node = &nodes[0],
> -			.nargs = 0,
> -		},
> -		{
> -			.node = &nodes[1],
> -			.nargs = 2,
> -			.args = { 3, 4 },
> -		},
> +		SOFTWARE_NODE_REFERENCE(&nodes[0]),
> +		SOFTWARE_NODE_REFERENCE(&nodes[1], 3, 4),
>  	};
>  
>  	const struct property_entry entries[] = {
> diff --git a/include/linux/property.h b/include/linux/property.h
> index dd4687b56239..0d876316e61d 100644
> --- a/include/linux/property.h
> +++ b/include/linux/property.h
> @@ -254,6 +254,13 @@ struct software_node_ref_args {
>  	u64 args[NR_FWNODE_REFERENCE_ARGS];
>  };
>  
> +#define SOFTWARE_NODE_REFERENCE(_ref_, ...)			\
> +(const struct software_node_ref_args) {				\
> +	.node = _ref_,						\
> +	.nargs = ARRAY_SIZE(((u64[]){ 0, ##__VA_ARGS__ })) - 1,	\
> +	.args = { __VA_ARGS__ },				\
> +}
> +
>  /**
>   * struct property_entry - "Built-in" device property representation.
>   * @name: Name of the property.
> @@ -362,11 +369,7 @@ struct property_entry {
>  	.name = _name_,							\
>  	.length = sizeof(struct software_node_ref_args),		\
>  	.type = DEV_PROP_REF,						\
> -	{ .pointer = &(const struct software_node_ref_args) {		\
> -		.node = _ref_,						\
> -		.nargs = ARRAY_SIZE(((u64[]){ 0, ##__VA_ARGS__ })) - 1,	\
> -		.args = { __VA_ARGS__ },				\
> -	} },								\
> +	{ .pointer = &SOFTWARE_NODE_REFERENCE(_ref_, ##__VA_ARGS__), },	\
>  }

What are the .args intended to be used for? I actually had it in mind to
replace this with a simple pointer to a struct software_node, because I
can't see any users of them and the fact that it's actually storing a
pointer to a new variable is something that confused me for a good long
time when I wrote the cio2-bridge (though that's mostly due to my
relative inexperience of course, but still)

>  
>  struct property_entry *