[PATCH] drivers/of: Improve documentation on match string

[PATCH] drivers/of: Improve documentation on match string

[Miquel Sabaté Solà]

The description of the function now explicitly states that it's
an *exact* match for the given string (i.e. not a submatch). It also
better states all the possible return values.

Moreover, this commit also makes sure that -ENODATA is returned if
prop->length is zero, just like it's done in other functions such as
'of_property_read_string'.

Signed-off-by: Miquel Sabaté Solà <mikisabate@gmail.com>
---
 drivers/of/property.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/of/property.c b/drivers/of/property.c
index 164d77cb9445..1ff51d93178f 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -452,12 +452,17 @@ EXPORT_SYMBOL_GPL(of_property_read_string);

 /**
  * of_property_match_string() - Find string in a list and return index
- * @np: pointer to node containing string list property
+ * @np: pointer to the node containing the string list property
  * @propname: string list property name
- * @string: pointer to string to search for in string list
+ * @string: pointer to the string to search for in the string list
  *
- * This function searches a string list property and returns the index
- * of a specific string value.
+ * Search for an exact match of string in a device node property which is a
+ * list of strings.
+ *
+ * Return: the index of the first occurrence of the string on success, -EINVAL
+ * if the property does not exist, -ENODATA if the property does not have a
+ * value, and -EILSEQ if the string is not null-terminated within the length of
+ * the property data.
  */
 int of_property_match_string(const struct device_node *np, const char *propname,
 			     const char *string)
@@ -469,7 +474,7 @@ int of_property_match_string(const struct device_node *np, const char *propname,

 	if (!prop)
 		return -EINVAL;
-	if (!prop->value)
+	if (!prop->value || !prop->length)
 		return -ENODATA;

 	p = prop->value;
--
2.46.0

Re: [PATCH] drivers/of: Improve documentation on match string

[Rob Herring]

On Tue, Sep 10, 2024 at 04:24:22PM +0200, Miquel Sabaté Solà wrote:
> The description of the function now explicitly states that it's
> an *exact* match for the given string (i.e. not a submatch). It also
> better states all the possible return values.
> 
> Moreover, this commit also makes sure that -ENODATA is returned if
> prop->length is zero, just like it's done in other functions such as
> 'of_property_read_string'.

'also' in a commit message is a sign this should be 2 commits. However, 
more below.

> 
> Signed-off-by: Miquel Sabaté Solà <mikisabate@gmail.com>
> ---
>  drivers/of/property.c | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/of/property.c b/drivers/of/property.c
> index 164d77cb9445..1ff51d93178f 100644
> --- a/drivers/of/property.c
> +++ b/drivers/of/property.c
> @@ -452,12 +452,17 @@ EXPORT_SYMBOL_GPL(of_property_read_string);
> 
>  /**
>   * of_property_match_string() - Find string in a list and return index
> - * @np: pointer to node containing string list property
> + * @np: pointer to the node containing the string list property
>   * @propname: string list property name
> - * @string: pointer to string to search for in string list
> + * @string: pointer to the string to search for in the string list
>   *
> - * This function searches a string list property and returns the index
> - * of a specific string value.
> + * Search for an exact match of string in a device node property which is a
> + * list of strings.
> + *
> + * Return: the index of the first occurrence of the string on success, -EINVAL
> + * if the property does not exist, -ENODATA if the property does not have a
> + * value, and -EILSEQ if the string is not null-terminated within the length of
> + * the property data.
>   */
>  int of_property_match_string(const struct device_node *np, const char *propname,
>  			     const char *string)
> @@ -469,7 +474,7 @@ int of_property_match_string(const struct device_node *np, const char *propname,
> 
>  	if (!prop)
>  		return -EINVAL;
> -	if (!prop->value)
> +	if (!prop->value || !prop->length)

This is redundant. If length is 0, then 'end' will be equal to p and 
we'll return -ENODATA.

>  		return -ENODATA;
> 
>  	p = prop->value;
> --
> 2.46.0
> 

Re: [PATCH] drivers/of: Improve documentation on match string

[Miquel Sabaté Solà]

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On dc., de set. 11 2024, Rob Herring wrote:

> On Tue, Sep 10, 2024 at 04:24:22PM +0200, Miquel Sabaté Solà wrote:
>> The description of the function now explicitly states that it's
>> an *exact* match for the given string (i.e. not a submatch). It also
>> better states all the possible return values.
>> 
>> Moreover, this commit also makes sure that -ENODATA is returned if
>> prop->length is zero, just like it's done in other functions such as
>> 'of_property_read_string'.
>
> 'also' in a commit message is a sign this should be 2 commits. However, 
> more below.
>
>> 
>> Signed-off-by: Miquel Sabaté Solà <mikisabate@gmail.com>
>> ---
>>  drivers/of/property.c | 15 ++++++++++-----
>>  1 file changed, 10 insertions(+), 5 deletions(-)
>> 
>> diff --git a/drivers/of/property.c b/drivers/of/property.c
>> index 164d77cb9445..1ff51d93178f 100644
>> --- a/drivers/of/property.c
>> +++ b/drivers/of/property.c
>> @@ -452,12 +452,17 @@ EXPORT_SYMBOL_GPL(of_property_read_string);
>> 
>>  /**
>>   * of_property_match_string() - Find string in a list and return index
>> - * @np: pointer to node containing string list property
>> + * @np: pointer to the node containing the string list property
>>   * @propname: string list property name
>> - * @string: pointer to string to search for in string list
>> + * @string: pointer to the string to search for in the string list
>>   *
>> - * This function searches a string list property and returns the index
>> - * of a specific string value.
>> + * Search for an exact match of string in a device node property which is a
>> + * list of strings.
>> + *
>> + * Return: the index of the first occurrence of the string on success, -EINVAL
>> + * if the property does not exist, -ENODATA if the property does not have a
>> + * value, and -EILSEQ if the string is not null-terminated within the length of
>> + * the property data.
>>   */
>>  int of_property_match_string(const struct device_node *np, const char *propname,
>>  			     const char *string)
>> @@ -469,7 +474,7 @@ int of_property_match_string(const struct device_node *np, const char *propname,
>> 
>>  	if (!prop)
>>  		return -EINVAL;
>> -	if (!prop->value)
>> +	if (!prop->value || !prop->length)
>
> This is redundant. If length is 0, then 'end' will be equal to p and 
> we'll return -ENODATA.
>

Yikes, I missed it... You are totally right, sorry about that.

>>  		return -ENODATA;
>> 
>>  	p = prop->value;
>> --
>> 2.46.0
>> 

Thanks for the review. I will submit a new version of the patch just
with the documentation part.

Thanks!
Miquel

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