linux-kernel - Re: [PATCH 01/13] of: Add wrappers to match root node with OF device ID tables

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Message-ID: <aQz8rW9GE66xPYrL@lizhi-Precision-Tower-5810>
Date: Thu, 6 Nov 2025 14:53:17 -0500
From: Frank Li <Frank.li@....com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc: Rob Herring <robh@...nel.org>, Saravana Kannan <saravanak@...gle.com>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Matthias Brugger <matthias.bgg@...il.com>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
	Yangtao Li <tiny.windzz@...il.com>, Chen-Yu Tsai <wens@...nel.org>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	Samuel Holland <samuel@...lland.org>,
	Lorenzo Pieralisi <lpieralisi@...nel.org>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Bjorn Andersson <andersson@...nel.org>,
	Konrad Dybcio <konradybcio@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Nicolas Ferre <nicolas.ferre@...rochip.com>,
	Alexandre Belloni <alexandre.belloni@...tlin.com>,
	Claudiu Beznea <claudiu.beznea@...on.dev>,
	Maximilian Luz <luzmaximilian@...il.com>,
	Hans de Goede <hansg@...nel.org>,
	Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
	Daniel Lezcano <daniel.lezcano@...nel.org>,
	Thierry Reding <thierry.reding@...il.com>,
	Jonathan Hunter <jonathanh@...dia.com>, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-mediatek@...ts.infradead.org, linux-sunxi@...ts.linux.dev,
	linux-arm-msm@...r.kernel.org, platform-driver-x86@...r.kernel.org,
	linux-tegra@...r.kernel.org
Subject: Re: [PATCH 01/13] of: Add wrappers to match root node with OF device
 ID tables

On Thu, Nov 06, 2025 at 08:07:08PM +0100, Krzysztof Kozlowski wrote:
> Several drivers duplicate same code for getting reference to the root
> node, matching it against 'struct of_device_id' table and getting out
> the match data from the table entry.
>
> There is a of_machine_compatible_match() wrapper but it takes array of
> strings, which is not suitable for many drivers since they want the
> driver data associated with each compatible.
>
> Add two wrappers, similar to existing of_device_get_match_data():
> 1. of_machine_device_match() doing only matching against 'struct
>    of_device_id' and returning bool.
> 2. of_machine_get_match_data() doing the matching and returning
>    associated driver data for found compatible.
>
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
>
> ---
>
> All further patches depend on this.
> ---

...
>
> +/**
> + * of_machine_device_match - Test root of device tree against a of_device_id array
> + * @matches:	NULL terminated array of of_device_id match structures to search in
> + *
> + * Returns true if the root node has any of the given compatible values in its
> + * compatible property.
> + */
> +bool of_machine_device_match(const struct of_device_id *matches)

Will it be more useful if pass down path

of_machine_device_match(const char* path, const struct of_device_id *matches)

caller just pass "\", or NULL point as root

> +{
> +	struct device_node *root;
> +	const struct of_device_id *match = NULL;
> +
> +	root = of_find_node_by_path("/");

Use clean up will simplify code

	struct device_node *root = __free(device_node) = of_find_node_by_path("/");

Frank
> +	if (root) {
> +		match = of_match_node(matches, root);
> +		of_node_put(root);
> +	}
> +
> +	return match != NULL;
> +}
> +EXPORT_SYMBOL(of_machine_device_match);
> +
...
>
> --
> 2.48.1
>