[PATCH v1 1/3] of: base: Provide of_graph_get_port_parent()

[PATCH v1 1/3] of: base: Provide of_graph_get_port_parent()

[Kieran Bingham]

From: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>

When handling endpoints, the v4l2 async framework needs to identify the
parent device of a port endpoint.

Adapt the existing of_graph_get_remote_port_parent() such that a caller
can obtain the parent of a port without parsing the remote-endpoint
first.

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
---
 drivers/of/base.c        | 30 ++++++++++++++++++++++--------
 include/linux/of_graph.h |  1 +
 2 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index d7c4629a3a2d..f81100500999 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -2455,6 +2455,27 @@ struct device_node *of_graph_get_endpoint_by_regs(
 EXPORT_SYMBOL(of_graph_get_endpoint_by_regs);
 
 /**
+ * of_graph_get_port_parent() - get port's parent node
+ * @node: pointer to a local endpoint device_node
+ *
+ * Return: device node associated with endpoint @node.
+ *	   Use of_node_put() on it when done.
+ */
+struct device_node *of_graph_get_port_parent(struct device_node *node)
+{
+	unsigned int depth;
+
+	/* Walk 3 levels up only if there is 'ports' node. */
+	for (depth = 3; depth && node; depth--) {
+		node = of_get_next_parent(node);
+		if (depth == 2 && of_node_cmp(node->name, "ports"))
+			break;
+	}
+	return node;
+}
+EXPORT_SYMBOL(of_graph_get_port_parent);
+
+/**
  * of_graph_get_remote_port_parent() - get remote port's parent node
  * @node: pointer to a local endpoint device_node
  *
@@ -2465,18 +2486,11 @@ struct device_node *of_graph_get_remote_port_parent(
 			       const struct device_node *node)
 {
 	struct device_node *np;
-	unsigned int depth;
 
 	/* Get remote endpoint node. */
 	np = of_parse_phandle(node, "remote-endpoint", 0);
 
-	/* Walk 3 levels up only if there is 'ports' node. */
-	for (depth = 3; depth && np; depth--) {
-		np = of_get_next_parent(np);
-		if (depth == 2 && of_node_cmp(np->name, "ports"))
-			break;
-	}
-	return np;
+	return of_graph_get_port_parent(np);
 }
 EXPORT_SYMBOL(of_graph_get_remote_port_parent);
 
diff --git a/include/linux/of_graph.h b/include/linux/of_graph.h
index abdb02eaef06..49bf34880ebc 100644
--- a/include/linux/of_graph.h
+++ b/include/linux/of_graph.h
@@ -48,6 +48,7 @@ struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 					struct device_node *previous);
 struct device_node *of_graph_get_endpoint_by_regs(
 		const struct device_node *parent, int port_reg, int reg);
+struct device_node *of_graph_get_port_parent(struct device_node *node);
 struct device_node *of_graph_get_remote_port_parent(
 					const struct device_node *node);
 struct device_node *of_graph_get_remote_port(const struct device_node *node);
-- 
git-series 0.9.1

Re: [PATCH v1 1/3] of: base: Provide of_graph_get_port_parent()

[Rob Herring]

On Wed, May 17, 2017 at 10:03 AM, Kieran Bingham <kbingham-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:
> From: Kieran Bingham <kieran.bingham+renesas-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
>
> When handling endpoints, the v4l2 async framework needs to identify the
> parent device of a port endpoint.
>
> Adapt the existing of_graph_get_remote_port_parent() such that a caller
> can obtain the parent of a port without parsing the remote-endpoint
> first.

A similar patch is already applied as part of the ASoC graph card support.

Rob
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Re: [PATCH v1 1/3] of: base: Provide of_graph_get_port_parent()

[Kieran Bingham]

On 17/05/17 17:36, Rob Herring wrote:
> On Wed, May 17, 2017 at 10:03 AM, Kieran Bingham <kbingham-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:
>> From: Kieran Bingham <kieran.bingham+renesas-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
>>
>> When handling endpoints, the v4l2 async framework needs to identify the
>> parent device of a port endpoint.
>>
>> Adapt the existing of_graph_get_remote_port_parent() such that a caller
>> can obtain the parent of a port without parsing the remote-endpoint
>> first.
> 
> A similar patch is already applied as part of the ASoC graph card support.
> 
> Rob

Ah yes, a quick google finds it...
:  https://patchwork.kernel.org/patch/9658907/

Surprisingly similar patch ... and a familiar name.

Morimoto-san - you beat me to it :D !

Thanks Rob, (And Morimoto!)

--
Kieran
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Re: [PATCH v1 1/3] of: base: Provide of_graph_get_port_parent()

[Kuninori Morimoto]

Hi Kieran

> >> From: Kieran Bingham <kieran.bingham+renesas-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
> >>
> >> When handling endpoints, the v4l2 async framework needs to identify the
> >> parent device of a port endpoint.
> >>
> >> Adapt the existing of_graph_get_remote_port_parent() such that a caller
> >> can obtain the parent of a port without parsing the remote-endpoint
> >> first.
> > 
> > A similar patch is already applied as part of the ASoC graph card support.
> > 
> > Rob
> 
> Ah yes, a quick google finds it...
> :  https://patchwork.kernel.org/patch/9658907/
> 
> Surprisingly similar patch ... and a familiar name.
> 
> Morimoto-san - you beat me to it :D !

Interesting.
It was applies today to Mark's (= ALSA SoC Maintainer) branch !
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git/commit/?h=topic/of-graph&id=0ef472a973ebbfc20f2f12769e77a8cfd3612778


Best regards
---
Kuninori Morimoto
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Re: [PATCH v1 1/3] of: base: Provide of_graph_get_port_parent()

[Laurent Pinchart]

Hi Kieran,

On Wednesday 17 May 2017 21:02:42 Kieran Bingham wrote:
> On 17/05/17 17:36, Rob Herring wrote:
> > On Wed, May 17, 2017 at 10:03 AM, Kieran Bingham wrote:
> >> From: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> >> 
> >> When handling endpoints, the v4l2 async framework needs to identify the
> >> parent device of a port endpoint.
> >> 
> >> Adapt the existing of_graph_get_remote_port_parent() such that a caller
> >> can obtain the parent of a port without parsing the remote-endpoint
> >> first.
> > 
> > A similar patch is already applied as part of the ASoC graph card support.
> > 
> > Rob
> 
> Ah yes, a quick google finds it...
> 
> :  https://patchwork.kernel.org/patch/9658907/
> 
> Surprisingly similar patch ... and a familiar name.

Very similar indeed, down to identical problems ;-) Quoting your patch,

>  /**
> + * of_graph_get_port_parent() - get port's parent node
> + * @node: pointer to a local endpoint device_node
> + *
> + * Return: device node associated with endpoint @node.
> + *	   Use of_node_put() on it when done.
> + */

The documentation of the return value is a bit confusing to me. I assume that, 
by device node, you meant the DT node corresponding to the device of the 
endpoint which is passed as an argument. However, device node cal also refer 
to struct device_node. Should this be clarified ?

> Morimoto-san - you beat me to it :D !
> 
> Thanks Rob, (And Morimoto!)

-- 
Regards,

Laurent Pinchart