diff mbox

[1/3] of: Add of_match_machine helper

Message ID 1407452515-2390-2-git-send-email-ttynkkynen@nvidia.com
State Changes Requested, archived
Headers show

Commit Message

Tuomas Tynkkynen Aug. 7, 2014, 11:01 p.m. UTC
Add of_match_machine function to test the device tree root for an
of_match array. This can be useful when testing SoC versions at runtime,
for example.

Signed-off-by: Tuomas Tynkkynen <ttynkkynen@nvidia.com>
---
 drivers/of/base.c  | 21 +++++++++++++++++++++
 include/linux/of.h |  3 +++
 2 files changed, 24 insertions(+)

Comments

Thierry Reding Aug. 8, 2014, 9:41 a.m. UTC | #1
On Fri, Aug 08, 2014 at 02:01:53AM +0300, Tuomas Tynkkynen wrote:
> Add of_match_machine function to test the device tree root for an
> of_match array. This can be useful when testing SoC versions at runtime,
> for example.
> 
> Signed-off-by: Tuomas Tynkkynen <ttynkkynen@nvidia.com>
> ---
>  drivers/of/base.c  | 21 +++++++++++++++++++++
>  include/linux/of.h |  3 +++
>  2 files changed, 24 insertions(+)
> 
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index d8574ad..37798ea 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -977,6 +977,27 @@ struct device_node *of_find_matching_node_and_match(struct device_node *from,
>  EXPORT_SYMBOL(of_find_matching_node_and_match);
>  
>  /**
> + * of_match_machine - Tell if root of device tree has a matching of_match struct
> + *	@matches:	array of of device match structures to search in
> + *
> + *	Returns the result of of_match_node for the root node.
> + */

I was going to say that this kerneldoc is weirdly formatted, but when I
looked at the other kerneldoc comments in this file it seems that they
use similarly weird formatting...

> +const struct of_device_id *of_match_machine(const struct of_device_id *matches)
> +{
> +	const struct of_device_id *match;
> +	struct device_node *root;
> +
> +	root = of_find_node_by_path("/");
> +	if (!root)
> +		return NULL;
> +
> +	match = of_match_node(matches, root);
> +	of_node_put(root);
> +	return match;
> +}
> +EXPORT_SYMBOL(of_match_machine);

I wonder if of_find_node_by_path("/") is somewhat overkill here. Perhaps
simply of_node_get(of_allnodes) would be more appropriate here since the
function is implemented in the core?

Thierry
Tuomas Tynkkynen Aug. 8, 2014, 1:23 p.m. UTC | #2
On 08/08/14 12:41, Thierry Reding wrote:
> 
>> +const struct of_device_id *of_match_machine(const struct of_device_id *matches)
>> +{
>> +	const struct of_device_id *match;
>> +	struct device_node *root;
>> +
>> +	root = of_find_node_by_path("/");
>> +	if (!root)
>> +		return NULL;
>> +
>> +	match = of_match_node(matches, root);
>> +	of_node_put(root);
>> +	return match;
>> +}
>> +EXPORT_SYMBOL(of_match_machine);
> 
> I wonder if of_find_node_by_path("/") is somewhat overkill here. Perhaps
> simply of_node_get(of_allnodes) would be more appropriate here since the
> function is implemented in the core?

of_machine_is_compatible() uses of_find_node_by_path("/") as well, of_allnodes
seems to be only used when during iterating. So I'd prefer to have them
consistent.
Rob Herring Aug. 8, 2014, 7:01 p.m. UTC | #3
On Fri, Aug 8, 2014 at 8:23 AM, Tuomas Tynkkynen <ttynkkynen@nvidia.com> wrote:
>
>
> On 08/08/14 12:41, Thierry Reding wrote:
>>
>>> +const struct of_device_id *of_match_machine(const struct of_device_id *matches)
>>> +{
>>> +    const struct of_device_id *match;
>>> +    struct device_node *root;
>>> +
>>> +    root = of_find_node_by_path("/");
>>> +    if (!root)
>>> +            return NULL;
>>> +
>>> +    match = of_match_node(matches, root);
>>> +    of_node_put(root);
>>> +    return match;
>>> +}
>>> +EXPORT_SYMBOL(of_match_machine);
>>
>> I wonder if of_find_node_by_path("/") is somewhat overkill here. Perhaps
>> simply of_node_get(of_allnodes) would be more appropriate here since the
>> function is implemented in the core?
>
> of_machine_is_compatible() uses of_find_node_by_path("/") as well, of_allnodes
> seems to be only used when during iterating. So I'd prefer to have them
> consistent.

Agreed.

For the series:

Acked-by: Rob Herring <robh@kernel.org>

Rob
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Grant Likely Aug. 17, 2014, 3:28 p.m. UTC | #4
On Fri, 8 Aug 2014 02:01:53 +0300, Tuomas Tynkkynen <ttynkkynen@nvidia.com> wrote:
> Add of_match_machine function to test the device tree root for an
> of_match array. This can be useful when testing SoC versions at runtime,
> for example.
> 
> Signed-off-by: Tuomas Tynkkynen <ttynkkynen@nvidia.com>
> ---
>  drivers/of/base.c  | 21 +++++++++++++++++++++
>  include/linux/of.h |  3 +++
>  2 files changed, 24 insertions(+)
> 
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index d8574ad..37798ea 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -977,6 +977,27 @@ struct device_node *of_find_matching_node_and_match(struct device_node *from,
>  EXPORT_SYMBOL(of_find_matching_node_and_match);
>  
>  /**
> + * of_match_machine - Tell if root of device tree has a matching of_match struct
> + *	@matches:	array of of device match structures to search in
> + *
> + *	Returns the result of of_match_node for the root node.
> + */
> +const struct of_device_id *of_match_machine(const struct of_device_id *matches)
> +{
> +	const struct of_device_id *match;
> +	struct device_node *root;
> +
> +	root = of_find_node_by_path("/");
> +	if (!root)
> +		return NULL;
> +
> +	match = of_match_node(matches, root);
> +	of_node_put(root);
> +	return match;
> +}
> +EXPORT_SYMBOL(of_match_machine);

Too wordy...

	return of_match_node(matches, of_allnodes);

:-)

It could be a static inline, but I don't think it's even worth having a
helper. The callers could just open code the above.

g.
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Grant Likely Aug. 17, 2014, 3:31 p.m. UTC | #5
On Fri, 8 Aug 2014 14:01:57 -0500, Rob Herring <robherring2@gmail.com> wrote:
> On Fri, Aug 8, 2014 at 8:23 AM, Tuomas Tynkkynen <ttynkkynen@nvidia.com> wrote:
> >
> >
> > On 08/08/14 12:41, Thierry Reding wrote:
> >>
> >>> +const struct of_device_id *of_match_machine(const struct of_device_id *matches)
> >>> +{
> >>> +    const struct of_device_id *match;
> >>> +    struct device_node *root;
> >>> +
> >>> +    root = of_find_node_by_path("/");
> >>> +    if (!root)
> >>> +            return NULL;
> >>> +
> >>> +    match = of_match_node(matches, root);
> >>> +    of_node_put(root);
> >>> +    return match;
> >>> +}
> >>> +EXPORT_SYMBOL(of_match_machine);
> >>
> >> I wonder if of_find_node_by_path("/") is somewhat overkill here. Perhaps
> >> simply of_node_get(of_allnodes) would be more appropriate here since the
> >> function is implemented in the core?
> >
> > of_machine_is_compatible() uses of_find_node_by_path("/") as well, of_allnodes
> > seems to be only used when during iterating. So I'd prefer to have them
> > consistent.
> 
> Agreed.

Disagreed. of_machine_is_compatible should be simplified.

g.
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Tuomas Tynkkynen Aug. 18, 2014, 10:10 a.m. UTC | #6
On 17/08/14 18:28, Grant Likely wrote:
> On Fri, 8 Aug 2014 02:01:53 +0300, Tuomas Tynkkynen <ttynkkynen@nvidia.com> wrote:
[...]
>> +EXPORT_SYMBOL(of_match_machine);
> 
> Too wordy...
> 
> 	return of_match_node(matches, of_allnodes);
> 
> :-)
> 
> It could be a static inline, but I don't think it's even worth having a
> helper. The callers could just open code the above.
> 

Do you mean all the drivers should be referring to of_allnodes directly?
I see that it's indeed exported, but to me that sounds like relying too
much on an implementation detail. In fact, Documentation/devicetree/todo.txt
even seems to have a TODO entry for its removal ("Remove of_allnodes list
and iterate using list of child nodes alone").
diff mbox

Patch

diff --git a/drivers/of/base.c b/drivers/of/base.c
index d8574ad..37798ea 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -977,6 +977,27 @@  struct device_node *of_find_matching_node_and_match(struct device_node *from,
 EXPORT_SYMBOL(of_find_matching_node_and_match);
 
 /**
+ * of_match_machine - Tell if root of device tree has a matching of_match struct
+ *	@matches:	array of of device match structures to search in
+ *
+ *	Returns the result of of_match_node for the root node.
+ */
+const struct of_device_id *of_match_machine(const struct of_device_id *matches)
+{
+	const struct of_device_id *match;
+	struct device_node *root;
+
+	root = of_find_node_by_path("/");
+	if (!root)
+		return NULL;
+
+	match = of_match_node(matches, root);
+	of_node_put(root);
+	return match;
+}
+EXPORT_SYMBOL(of_match_machine);
+
+/**
  * of_modalias_node - Lookup appropriate modalias for a device node
  * @node:	pointer to a device tree node
  * @modalias:	Pointer to buffer that modalias value will be copied into
diff --git a/include/linux/of.h b/include/linux/of.h
index 6c4363b..b7a8817 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -289,6 +289,8 @@  extern int of_n_addr_cells(struct device_node *np);
 extern int of_n_size_cells(struct device_node *np);
 extern const struct of_device_id *of_match_node(
 	const struct of_device_id *matches, const struct device_node *node);
+extern const struct of_device_id *of_match_machine(
+	const struct of_device_id *matches);
 extern int of_modalias_node(struct device_node *node, char *modalias, int len);
 extern void of_print_phandle_args(const char *msg, const struct of_phandle_args *args);
 extern struct device_node *of_parse_phandle(const struct device_node *np,
@@ -584,6 +586,7 @@  static inline const char *of_prop_next_string(struct property *prop,
 
 #define of_match_ptr(_ptr)	NULL
 #define of_match_node(_matches, _node)	NULL
+#define of_match_machine(_matches)	NULL
 #endif /* CONFIG_OF */
 
 #if defined(CONFIG_OF) && defined(CONFIG_NUMA)