[v1,2/3] device property: Add fwnode_graph_get_port_parent

Commit Message

Kieran Bingham May 17, 2017, 3:03 p.m. UTC

From: Kieran Bingham <[e-mail]>

V4L2 async notifiers can pass the endpoint fwnode rather than the device
fwnode.

Provide a helper to obtain the parent device fwnode without first
parsing the remote-endpoint as per fwnode_graph_get_remote_port_parent.

Signed-off-by: Kieran Bingham <[e-mail]>
---
 drivers/base/property.c  | 25 +++++++++++++++++++++++++
 include/linux/property.h |  2 ++
 2 files changed, 27 insertions(+)

Comments

Laurent Pinchart May 18, 2017, 1:36 p.m. UTC | #1

Hi Kieran,

Thank you for the patch.

On Wednesday 17 May 2017 16:03:38 Kieran Bingham wrote:
> From: Kieran Bingham <[e-mail]>
> 
> V4L2 async notifiers can pass the endpoint fwnode rather than the device
> fwnode.

I'm not sure I would mention V4L2 in the commit message, as this is generic.

> Provide a helper to obtain the parent device fwnode without first
> parsing the remote-endpoint as per fwnode_graph_get_remote_port_parent.
> 
> Signed-off-by: Kieran Bingham <[e-mail]>
> ---
>  drivers/base/property.c  | 25 +++++++++++++++++++++++++
>  include/linux/property.h |  2 ++
>  2 files changed, 27 insertions(+)
> 
> diff --git a/drivers/base/property.c b/drivers/base/property.c
> index 627ebc9b570d..caf4316fe565 100644
> --- a/drivers/base/property.c
> +++ b/drivers/base/property.c
> @@ -1245,6 +1245,31 @@ fwnode_graph_get_next_endpoint(struct fwnode_handle
> *fwnode, EXPORT_SYMBOL_GPL(fwnode_graph_get_next_endpoint);
> 
>  /**
> + * fwnode_graph_get_port_parent - Return device node of a port endpoint
> + * @fwnode: Endpoint firmware node pointing of the port
> + *
> + * Extracts firmware node of the device the @fwnode belongs to.

I'm not too familiar with the fwnode API, but I know it's written in C, where 
functions don't extract something but return a value :-) How about

Return: the firmware node of the device the @endpoint belongs to.

> + */
> +struct fwnode_handle *
> +fwnode_graph_get_port_parent(struct fwnode_handle *fwnode)

This is akin to writing (unsigned int integer)

How about calling the variable endpoint ? That would also make the 
documentation clearer in my opinion, with "the @fwnode belongs to" replaced 
with "the @endpoint belongs to".

> +{
> +	struct fwnode_handle *parent = NULL;
> +
> +	if (is_of_node(fwnode)) {
> +		struct device_node *node;
> +
> +		node = of_graph_get_port_parent(to_of_node(fwnode));
> +		if (node)
> +			parent = &node->fwnode;

This part looks good to me, with the above small change,

Reviewed-by: Laurent Pinchart <[e-mail]>

> +	} else if (is_acpi_node(fwnode)) {
> +		parent = acpi_node_get_parent(fwnode);

I can't comment on this one though.

> +	}
> +
> +	return parent;
> +}
> +EXPORT_SYMBOL_GPL(fwnode_graph_get_port_parent);
> +
> +/**
>   * fwnode_graph_get_remote_port_parent - Return fwnode of a remote device
>   * @fwnode: Endpoint firmware node pointing to the remote endpoint
>   *
> diff --git a/include/linux/property.h b/include/linux/property.h
> index 2f482616a2f2..624129b86c82 100644
> --- a/include/linux/property.h
> +++ b/include/linux/property.h
> @@ -274,6 +274,8 @@ void *device_get_mac_address(struct device *dev, char
> *addr, int alen);
> 
>  struct fwnode_handle *fwnode_graph_get_next_endpoint(
>  	struct fwnode_handle *fwnode, struct fwnode_handle *prev);
> +struct fwnode_handle *fwnode_graph_get_port_parent(
> +	struct fwnode_handle *fwnode);
>  struct fwnode_handle *fwnode_graph_get_remote_port_parent(
>  	struct fwnode_handle *fwnode);
>  struct fwnode_handle *fwnode_graph_get_remote_port(

Sakari Ailus May 18, 2017, 3:26 p.m. UTC | #2

Hi Kieran,

On Wed, May 17, 2017 at 04:03:38PM +0100, Kieran Bingham wrote:
> From: Kieran Bingham <[e-mail]>
> 
> V4L2 async notifiers can pass the endpoint fwnode rather than the device
> fwnode.
> 
> Provide a helper to obtain the parent device fwnode without first
> parsing the remote-endpoint as per fwnode_graph_get_remote_port_parent.
> 
> Signed-off-by: Kieran Bingham <[e-mail]>

Could you rebase this on my fwnode cleanup patchset here, please? I'd be
happy to apply it on top of the set.

<URL:https://git.linuxtv.org/sailus/media_tree.git/log/?h=acpi-graph-cleaned>

This function becomes quite simple, see
fwnode_graph_get_remote_port_parent().

Kieran Bingham May 19, 2017, 1:34 p.m. UTC | #3

Hi Laurent,

On 18/05/17 14:36, Laurent Pinchart wrote:
> Hi Kieran,
> 
> Thank you for the patch.
> 
> On Wednesday 17 May 2017 16:03:38 Kieran Bingham wrote:
>> From: Kieran Bingham <[e-mail]>
>>
>> V4L2 async notifiers can pass the endpoint fwnode rather than the device
>> fwnode.
> 
> I'm not sure I would mention V4L2 in the commit message, as this is generic.

Good point

>> Provide a helper to obtain the parent device fwnode without first
>> parsing the remote-endpoint as per fwnode_graph_get_remote_port_parent.
>>
>> Signed-off-by: Kieran Bingham <[e-mail]>
>> ---
>>  drivers/base/property.c  | 25 +++++++++++++++++++++++++
>>  include/linux/property.h |  2 ++
>>  2 files changed, 27 insertions(+)
>>
>> diff --git a/drivers/base/property.c b/drivers/base/property.c
>> index 627ebc9b570d..caf4316fe565 100644
>> --- a/drivers/base/property.c
>> +++ b/drivers/base/property.c
>> @@ -1245,6 +1245,31 @@ fwnode_graph_get_next_endpoint(struct fwnode_handle
>> *fwnode, EXPORT_SYMBOL_GPL(fwnode_graph_get_next_endpoint);
>>
>>  /**
>> + * fwnode_graph_get_port_parent - Return device node of a port endpoint
>> + * @fwnode: Endpoint firmware node pointing of the port
>> + *
>> + * Extracts firmware node of the device the @fwnode belongs to.
> 
> I'm not too familiar with the fwnode API, but I know it's written in C, where 
> functions don't extract something but return a value :-) How about
> 
> Return: the firmware node of the device the @endpoint belongs to.
> 

I'm not averse to the reword - but it is different to the other functions in the
same context:

fwnode_graph_get_remote_endpoint(struct fwnode_handle *fwnode)
 * Extracts firmware node of a remote endpoint the @fwnode points to.

struct fwnode_handle *fwnode_graph_get_remote_port(struct fwnode_handle *fwnode)
 * Extracts firmware node of a remote port the @fwnode points to.

fwnode_graph_get_remote_port_parent(struct fwnode_handle *fwnode)
 * Extracts firmware node of a remote device the @fwnode points to.

Then with this function becoming:

fwnode_graph_get_port_parent(struct fwnode_handle *endpoint)
 * Returns firmware node of the device the @endpoint belongs to.


I guess those could be changed too ...


>> + */
>> +struct fwnode_handle *
>> +fwnode_graph_get_port_parent(struct fwnode_handle *fwnode)
> 
> This is akin to writing (unsigned int integer)

Yes, good point there - I was thinking of the fwnode as an object itself, but
really it's representing the endpoint, and the fwnode is the class type :)

> 
> How about calling the variable endpoint ? That would also make the 
> documentation clearer in my opinion, with "the @fwnode belongs to" replaced 
> with "the @endpoint belongs to".

Agreed

> 
>> +{
>> +	struct fwnode_handle *parent = NULL;
>> +
>> +	if (is_of_node(fwnode)) {
>> +		struct device_node *node;
>> +
>> +		node = of_graph_get_port_parent(to_of_node(fwnode));
>> +		if (node)
>> +			parent = &node->fwnode;
> 
> This part looks good to me, with the above small change,
> 
> Reviewed-by: Laurent Pinchart <[e-mail]>

Thanks,

I'll add this if the code doesn't change drastically based on Sakari's suggestion.

> 
>> +	} else if (is_acpi_node(fwnode)) {
>> +		parent = acpi_node_get_parent(fwnode);
> 
> I can't comment on this one though.
> 
>> +	}
>> +
>> +	return parent;
>> +}
>> +EXPORT_SYMBOL_GPL(fwnode_graph_get_port_parent);
>> +
>> +/**
>>   * fwnode_graph_get_remote_port_parent - Return fwnode of a remote device
>>   * @fwnode: Endpoint firmware node pointing to the remote endpoint
>>   *
>> diff --git a/include/linux/property.h b/include/linux/property.h
>> index 2f482616a2f2..624129b86c82 100644
>> --- a/include/linux/property.h
>> +++ b/include/linux/property.h
>> @@ -274,6 +274,8 @@ void *device_get_mac_address(struct device *dev, char
>> *addr, int alen);
>>
>>  struct fwnode_handle *fwnode_graph_get_next_endpoint(
>>  	struct fwnode_handle *fwnode, struct fwnode_handle *prev);
>> +struct fwnode_handle *fwnode_graph_get_port_parent(
>> +	struct fwnode_handle *fwnode);
>>  struct fwnode_handle *fwnode_graph_get_remote_port_parent(
>>  	struct fwnode_handle *fwnode);
>>  struct fwnode_handle *fwnode_graph_get_remote_port(
>

Laurent Pinchart May 19, 2017, 2:42 p.m. UTC | #4

Hi Kieran,

On Friday 19 May 2017 14:34:33 Kieran Bingham wrote:
> On 18/05/17 14:36, Laurent Pinchart wrote:
> > On Wednesday 17 May 2017 16:03:38 Kieran Bingham wrote:
> >> From: Kieran Bingham <[e-mail]>
> >> 
> >> V4L2 async notifiers can pass the endpoint fwnode rather than the device
> >> fwnode.
> > 
> > I'm not sure I would mention V4L2 in the commit message, as this is
> > generic.
>
> Good point
> 
> >> Provide a helper to obtain the parent device fwnode without first
> >> parsing the remote-endpoint as per fwnode_graph_get_remote_port_parent.
> >> 
> >> Signed-off-by: Kieran Bingham <[e-mail]>
> >> ---
> >> 
> >>  drivers/base/property.c  | 25 +++++++++++++++++++++++++
> >>  include/linux/property.h |  2 ++
> >>  2 files changed, 27 insertions(+)
> >> 
> >> diff --git a/drivers/base/property.c b/drivers/base/property.c
> >> index 627ebc9b570d..caf4316fe565 100644
> >> --- a/drivers/base/property.c
> >> +++ b/drivers/base/property.c
> >> @@ -1245,6 +1245,31 @@ fwnode_graph_get_next_endpoint(struct
> >> fwnode_handle
> >> *fwnode, EXPORT_SYMBOL_GPL(fwnode_graph_get_next_endpoint);
> >> 
> >>  /**
> >> 
> >> + * fwnode_graph_get_port_parent - Return device node of a port endpoint
> >> + * @fwnode: Endpoint firmware node pointing of the port
> >> + *
> >> + * Extracts firmware node of the device the @fwnode belongs to.
> > 
> > I'm not too familiar with the fwnode API, but I know it's written in C,
> > where functions don't extract something but return a value :-) How about
> > 
> > Return: the firmware node of the device the @endpoint belongs to.
> 
> I'm not averse to the reword - but it is different to the other functions in
> the same context:
> 
> fwnode_graph_get_remote_endpoint(struct fwnode_handle *fwnode)
>  * Extracts firmware node of a remote endpoint the @fwnode points to.
> 
> struct fwnode_handle *fwnode_graph_get_remote_port(struct fwnode_handle
> *fwnode)
>  * Extracts firmware node of a remote port the @fwnode points to.
> 
> fwnode_graph_get_remote_port_parent(struct fwnode_handle *fwnode)
>  * Extracts firmware node of a remote device the @fwnode points to.
> 
> Then with this function becoming:
> 
> fwnode_graph_get_port_parent(struct fwnode_handle *endpoint)
>  * Returns firmware node of the device the @endpoint belongs to.
> 
> 
> I guess those could be changed too ...

My point is that the kerneldoc format documents return values with a "Return:" 
tag. The documentation for the function can still provide extra information.

> >> + */
> >> +struct fwnode_handle *
> >> +fwnode_graph_get_port_parent(struct fwnode_handle *fwnode)
> > 
> > This is akin to writing (unsigned int integer)
> 
> Yes, good point there - I was thinking of the fwnode as an object itself,
> but really it's representing the endpoint, and the fwnode is the class type
> :)
>
> > How about calling the variable endpoint ? That would also make the
> > documentation clearer in my opinion, with "the @fwnode belongs to"
> > replaced with "the @endpoint belongs to".
> 
> Agreed
> 
> >> +{
> >> +	struct fwnode_handle *parent = NULL;
> >> +
> >> +	if (is_of_node(fwnode)) {
> >> +		struct device_node *node;
> >> +
> >> +		node = of_graph_get_port_parent(to_of_node(fwnode));
> >> +		if (node)
> >> +			parent = &node->fwnode;
> > 
> > This part looks good to me, with the above small change,
> > 
> > Reviewed-by: Laurent Pinchart <[e-mail]>
> 
> Thanks,
> 
> I'll add this if the code doesn't change drastically based on Sakari's
> suggestion.
>
> >> +	} else if (is_acpi_node(fwnode)) {
> >> +		parent = acpi_node_get_parent(fwnode);
> > 
> > I can't comment on this one though.
> > 
> >> +	}
> >> +
> >> +	return parent;
> >> +}
> >> +EXPORT_SYMBOL_GPL(fwnode_graph_get_port_parent);
> >> +
> >> +/**
> >> 
> >>   * fwnode_graph_get_remote_port_parent - Return fwnode of a remote
> >>   device
> >>   * @fwnode: Endpoint firmware node pointing to the remote endpoint
> >>   *
> >> 
> >> diff --git a/include/linux/property.h b/include/linux/property.h
> >> index 2f482616a2f2..624129b86c82 100644
> >> --- a/include/linux/property.h
> >> +++ b/include/linux/property.h
> >> @@ -274,6 +274,8 @@ void *device_get_mac_address(struct device *dev, char
> >> *addr, int alen);
> >> 
> >>  struct fwnode_handle *fwnode_graph_get_next_endpoint(
> >>  
> >>  	struct fwnode_handle *fwnode, struct fwnode_handle *prev);
> >> 
> >> +struct fwnode_handle *fwnode_graph_get_port_parent(
> >> +	struct fwnode_handle *fwnode);
> >> 
> >>  struct fwnode_handle *fwnode_graph_get_remote_port_parent(
> >>  
> >>  	struct fwnode_handle *fwnode);
> >>  
> >>  struct fwnode_handle *fwnode_graph_get_remote_port(

Sakari Ailus May 22, 2017, 6:18 a.m. UTC | #5

Hi Laurent and Kieran,

On Fri, May 19, 2017 at 05:42:07PM +0300, Laurent Pinchart wrote:
> Hi Kieran,
> 
> On Friday 19 May 2017 14:34:33 Kieran Bingham wrote:
> > On 18/05/17 14:36, Laurent Pinchart wrote:
> > > On Wednesday 17 May 2017 16:03:38 Kieran Bingham wrote:
> > >> From: Kieran Bingham <[e-mail]>
> > >> 
> > >> V4L2 async notifiers can pass the endpoint fwnode rather than the device
> > >> fwnode.
> > > 
> > > I'm not sure I would mention V4L2 in the commit message, as this is
> > > generic.
> >
> > Good point
> > 
> > >> Provide a helper to obtain the parent device fwnode without first
> > >> parsing the remote-endpoint as per fwnode_graph_get_remote_port_parent.
> > >> 
> > >> Signed-off-by: Kieran Bingham <[e-mail]>
> > >> ---
> > >> 
> > >>  drivers/base/property.c  | 25 +++++++++++++++++++++++++
> > >>  include/linux/property.h |  2 ++
> > >>  2 files changed, 27 insertions(+)
> > >> 
> > >> diff --git a/drivers/base/property.c b/drivers/base/property.c
> > >> index 627ebc9b570d..caf4316fe565 100644
> > >> --- a/drivers/base/property.c
> > >> +++ b/drivers/base/property.c
> > >> @@ -1245,6 +1245,31 @@ fwnode_graph_get_next_endpoint(struct
> > >> fwnode_handle
> > >> *fwnode, EXPORT_SYMBOL_GPL(fwnode_graph_get_next_endpoint);
> > >> 
> > >>  /**
> > >> 
> > >> + * fwnode_graph_get_port_parent - Return device node of a port endpoint
> > >> + * @fwnode: Endpoint firmware node pointing of the port
> > >> + *
> > >> + * Extracts firmware node of the device the @fwnode belongs to.
> > > 
> > > I'm not too familiar with the fwnode API, but I know it's written in C,
> > > where functions don't extract something but return a value :-) How about
> > > 
> > > Return: the firmware node of the device the @endpoint belongs to.
> > 
> > I'm not averse to the reword - but it is different to the other functions in
> > the same context:
> > 
> > fwnode_graph_get_remote_endpoint(struct fwnode_handle *fwnode)
> >  * Extracts firmware node of a remote endpoint the @fwnode points to.
> > 
> > struct fwnode_handle *fwnode_graph_get_remote_port(struct fwnode_handle
> > *fwnode)
> >  * Extracts firmware node of a remote port the @fwnode points to.
> > 
> > fwnode_graph_get_remote_port_parent(struct fwnode_handle *fwnode)
> >  * Extracts firmware node of a remote device the @fwnode points to.
> > 
> > Then with this function becoming:
> > 
> > fwnode_graph_get_port_parent(struct fwnode_handle *endpoint)
> >  * Returns firmware node of the device the @endpoint belongs to.
> > 
> > 
> > I guess those could be changed too ...
> 
> My point is that the kerneldoc format documents return values with a "Return:" 
> tag. The documentation for the function can still provide extra information.

Yeah, let's do this right and then fix the rest. I've already submitted the
pull request on this one --- the origin of that text is actually the V4L2 OF
framework. Feel free to submit a patch that fixes it, I can do it as well.

Patch

diff --git a/drivers/base/property.c b/drivers/base/property.c
index 627ebc9b570d..caf4316fe565 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -1245,6 +1245,31 @@  fwnode_graph_get_next_endpoint(struct fwnode_handle *fwnode,
 EXPORT_SYMBOL_GPL(fwnode_graph_get_next_endpoint);
 
 /**
+ * fwnode_graph_get_port_parent - Return device node of a port endpoint
+ * @fwnode: Endpoint firmware node pointing of the port
+ *
+ * Extracts firmware node of the device the @fwnode belongs to.
+ */
+struct fwnode_handle *
+fwnode_graph_get_port_parent(struct fwnode_handle *fwnode)
+{
+	struct fwnode_handle *parent = NULL;
+
+	if (is_of_node(fwnode)) {
+		struct device_node *node;
+
+		node = of_graph_get_port_parent(to_of_node(fwnode));
+		if (node)
+			parent = &node->fwnode;
+	} else if (is_acpi_node(fwnode)) {
+		parent = acpi_node_get_parent(fwnode);
+	}
+
+	return parent;
+}
+EXPORT_SYMBOL_GPL(fwnode_graph_get_port_parent);
+
+/**
  * fwnode_graph_get_remote_port_parent - Return fwnode of a remote device
  * @fwnode: Endpoint firmware node pointing to the remote endpoint
  *
diff --git a/include/linux/property.h b/include/linux/property.h
index 2f482616a2f2..624129b86c82 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -274,6 +274,8 @@  void *device_get_mac_address(struct device *dev, char *addr, int alen);
 
 struct fwnode_handle *fwnode_graph_get_next_endpoint(
 	struct fwnode_handle *fwnode, struct fwnode_handle *prev);
+struct fwnode_handle *fwnode_graph_get_port_parent(
+	struct fwnode_handle *fwnode);
 struct fwnode_handle *fwnode_graph_get_remote_port_parent(
 	struct fwnode_handle *fwnode);
 struct fwnode_handle *fwnode_graph_get_remote_port(