linux-kernel - Re: [PATCH v1 2/4] of: Reimplement of_machine_is_compatible() using of_machine_compatible

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Message-ID: <20231207202641.GA3351234-robh@kernel.org>
Date:   Thu, 7 Dec 2023 14:26:41 -0600
From:   Rob Herring <robh@...nel.org>
To:     Christophe Leroy <christophe.leroy@...roup.eu>
Cc:     Michael Ellerman <mpe@...erman.id.au>,
        Nicholas Piggin <npiggin@...il.com>,
        Frank Rowand <frowand.list@...il.com>,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH v1 2/4] of: Reimplement of_machine_is_compatible() using
 of_machine_compatible_match()

On Wed, Dec 06, 2023 at 05:13:33PM +0100, Christophe Leroy wrote:
> of_machine_compatible_match() works with a table of strings.
> of_machine_is_compatible() is a simplier version with only one string.
> 
> Re-implement of_machine_is_compatible() by setting a table of strings
> with a single string then using of_machine_compatible_match().
> 
> Suggested-by: Rob Herring <robh+dt@...nel.org>
> Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
> ---
>  drivers/of/base.c  | 22 +---------------------
>  include/linux/of.h | 15 ++++++++++++++-
>  2 files changed, 15 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index 9020be2eb4d5..73c3a754bad1 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -414,27 +414,7 @@ bool of_machine_compatible_match(const char *const *compats)
>  
>  	return rc != 0;
>  }
> -
> -/**
> - * of_machine_is_compatible - Test root of device tree for a given compatible value
> - * @compat: compatible string to look for in root node's compatible property.
> - *
> - * Return: A positive integer if the root node has the given value in its
> - * compatible property.
> - */
> -int of_machine_is_compatible(const char *compat)
> -{
> -	struct device_node *root;
> -	int rc = 0;
> -
> -	root = of_find_node_by_path("/");
> -	if (root) {
> -		rc = of_device_is_compatible(root, compat);
> -		of_node_put(root);
> -	}
> -	return rc;
> -}
> -EXPORT_SYMBOL(of_machine_is_compatible);
> +EXPORT_SYMBOL(of_machine_compatible_match);
>  
>  /**
>   *  __of_device_is_available - check if a device is available for use
> diff --git a/include/linux/of.h b/include/linux/of.h
> index e3418babc203..a0f70be5007f 100644
> --- a/include/linux/of.h
> +++ b/include/linux/of.h
> @@ -402,9 +402,22 @@ extern void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align));
>  extern int of_alias_get_id(struct device_node *np, const char *stem);
>  extern int of_alias_get_highest_id(const char *stem);
>  
> -extern int of_machine_is_compatible(const char *compat);
>  bool of_machine_compatible_match(const char *const *compats);
>  
> +/**
> + * of_machine_is_compatible - Test root of device tree for a given compatible value
> + * @compat: compatible string to look for in root node's compatible property.
> + *
> + * Return: A positive integer if the root node has the given value in its
> + * compatible property.

There is a subtle change that we really only return true/false instead 
of a score. In a quick scan, I don't see any callers caring. Lots of 
places we could use a list of compatibles instead though. Maybe this 
should just return a bool instead of int? Either way:

Reviewed-by: Rob Herring <robh@...nel.org>