[PATCH 1/1] device property: Add fwnode_name_eq()

[PATCH 1/1] device property: Add fwnode_name_eq()

[Sakari Ailus]

Add fwnode_name_eq() to implement the functionality of of_node_name_eq()
on fwnode property API. The same convention of ending the comparison at
'@' (besides '\0') is applied on also both ACPI and swnode. The function
is intended for comparing unit address-less node names on DT and firmware
or swnodes compliant with DT bindings.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
Hi Laurent,

Would you be able to use this to replace of_node_name_eq()?

It's fully untested.

I didn't add an op for it as it rather looks like all the implentations
would be the same (but with different container struct).

 drivers/base/property.c  | 28 ++++++++++++++++++++++++++++
 include/linux/property.h |  1 +
 2 files changed, 29 insertions(+)

diff --git a/drivers/base/property.c b/drivers/base/property.c
index 8c40abed7852..766ac3fc8cc5 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -594,6 +594,34 @@ const char *fwnode_get_name_prefix(const struct fwnode_handle *fwnode)
 	return fwnode_call_ptr_op(fwnode, get_name_prefix);
 }
 
+/**
+ * fwnode_name_eq - Return true if node name is equal
+ * @fwnode The firmware node
+ * @name: The name to which to compare the node name
+ *
+ * Compare the name provided as an argument to the name of the node, stopping
+ * the comparison to either '\0' or '@' character, whichever comes first. This
+ * function is generally used for comparing node names while ignoring the
+ * possible unit address of the node.
+ *
+ * Return: true if the node name matches with the name provided in the @name
+ * argument, false otherwise.
+ */
+bool fwnode_name_eq(const struct fwnode_handle *fwnode, const char *name)
+{
+	const char *node_name;
+	unsigned int len;
+
+	node_name = fwnode_get_name(fwnode);
+	if (!node_name)
+		return false;
+
+	len = strchrnul(node_name, '@') - node_name;
+
+	return strlen(name) == len && !strncmp(node_name, name, len);
+}
+EXPORT_SYMBOL_GPL(fwnode_name_eq);
+
 /**
  * fwnode_get_parent - Return parent firwmare node
  * @fwnode: Firmware whose parent is retrieved
diff --git a/include/linux/property.h b/include/linux/property.h
index 083a1f41364b..096ade186601 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -108,6 +108,7 @@ struct fwnode_handle *fwnode_find_reference(const struct fwnode_handle *fwnode,
 
 const char *fwnode_get_name(const struct fwnode_handle *fwnode);
 const char *fwnode_get_name_prefix(const struct fwnode_handle *fwnode);
+bool fwnode_name_eq(const struct fwnode_handle *fwnode, const char *name);
 
 struct fwnode_handle *fwnode_get_parent(const struct fwnode_handle *fwnode);
 struct fwnode_handle *fwnode_get_next_parent(struct fwnode_handle *fwnode);
-- 
2.39.2

Re: [PATCH 1/1] device property: Add fwnode_name_eq()

[Andy Shevchenko]

On Tue, Oct 31, 2023 at 03:53:06PM +0200, Sakari Ailus wrote:
> Add fwnode_name_eq() to implement the functionality of of_node_name_eq()
> on fwnode property API. The same convention of ending the comparison at
> '@' (besides '\0') is applied on also both ACPI and swnode. The function
> is intended for comparing unit address-less node names on DT and firmware
> or swnodes compliant with DT bindings.

Some comments below.

...

> Would you be able to use this to replace of_node_name_eq()?

Can you point out to the use case? Maybe it can be rewritten using existing
APIs?

...

> +	len = strchrnul(node_name, '@') - node_name;

> +	return strlen(name) == len && !strncmp(node_name, name, len);

Seems like this is reimplementation of str_has_prefix().

	len = strchrnul(node_name, '@') - node_name;
	return str_has_prefix(node_name, name) == len;

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 1/1] device property: Add fwnode_name_eq()

[Sakari Ailus]

Hi Andy,

On Tue, Oct 31, 2023 at 06:32:17PM +0200, Andy Shevchenko wrote:
> On Tue, Oct 31, 2023 at 03:53:06PM +0200, Sakari Ailus wrote:
> > Add fwnode_name_eq() to implement the functionality of of_node_name_eq()
> > on fwnode property API. The same convention of ending the comparison at
> > '@' (besides '\0') is applied on also both ACPI and swnode. The function
> > is intended for comparing unit address-less node names on DT and firmware
> > or swnodes compliant with DT bindings.
> 
> Some comments below.
> 
> ...
> 
> > Would you be able to use this to replace of_node_name_eq()?
> 
> Can you point out to the use case? Maybe it can be rewritten using existing
> APIs?

Parsing DT for THine THP7321 ISP:
<URL:https://lore.kernel.org/linux-media/20231030133247.11243-1-laurent.pinchart@ideasonboard.com/T/#t>.

The driver shouldn't be bothered with separating the node name from the
unit address (separated by '@').

> 
> ...
> 
> > +	len = strchrnul(node_name, '@') - node_name;
> 
> > +	return strlen(name) == len && !strncmp(node_name, name, len);
> 
> Seems like this is reimplementation of str_has_prefix().
> 
> 	len = strchrnul(node_name, '@') - node_name;
> 	return str_has_prefix(node_name, name) == len;

I'll use this in v2.

-- 
Regards,

Sakari Ailus

Re: [PATCH 1/1] device property: Add fwnode_name_eq()

[kernel test robot]

Hi Sakari,

kernel test robot noticed the following build warnings:

[auto build test WARNING on driver-core/driver-core-testing]
[also build test WARNING on driver-core/driver-core-next driver-core/driver-core-linus linus/master v6.6 next-20231031]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Sakari-Ailus/device-property-Add-fwnode_name_eq/20231031-224454
base:   driver-core/driver-core-testing
patch link:    https://lore.kernel.org/r/20231031135306.1106640-1-sakari.ailus%40linux.intel.com
patch subject: [PATCH 1/1] device property: Add fwnode_name_eq()
config: sh-allnoconfig (https://download.01.org/0day-ci/archive/20231101/202311010542.1tRHV0in-lkp@intel.com/config)
compiler: sh4-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231101/202311010542.1tRHV0in-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202311010542.1tRHV0in-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/base/property.c:611: warning: Function parameter or member 'fwnode' not described in 'fwnode_name_eq'


vim +611 drivers/base/property.c

   596	
   597	/**
   598	 * fwnode_name_eq - Return true if node name is equal
   599	 * @fwnode The firmware node
   600	 * @name: The name to which to compare the node name
   601	 *
   602	 * Compare the name provided as an argument to the name of the node, stopping
   603	 * the comparison to either '\0' or '@' character, whichever comes first. This
   604	 * function is generally used for comparing node names while ignoring the
   605	 * possible unit address of the node.
   606	 *
   607	 * Return: true if the node name matches with the name provided in the @name
   608	 * argument, false otherwise.
   609	 */
   610	bool fwnode_name_eq(const struct fwnode_handle *fwnode, const char *name)
 > 611	{
   612		const char *node_name;
   613		unsigned int len;
   614	
   615		node_name = fwnode_get_name(fwnode);
   616		if (!node_name)
   617			return false;
   618	
   619		len = strchrnul(node_name, '@') - node_name;
   620	
   621		return strlen(name) == len && !strncmp(node_name, name, len);
   622	}
   623	EXPORT_SYMBOL_GPL(fwnode_name_eq);
   624	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki