[PATCH v6 0/5] Unified fwnode endpoint parser

[PATCH v6 0/5] Unified fwnode endpoint parser

[Sakari Ailus]

Hi folks,

We have a large influx of new, unmerged, drivers that are now parsing
fwnode endpoints and each one of them is doing this a little bit
differently. The needs are still exactly the same for the graph data
structure is device independent. This is still a non-trivial task and the
majority of the driver implementations are buggy, just buggy in different
ways.

Facilitate parsing endpoints by adding a convenience function for parsing
the endpoints, and make the omap3isp and rcar-vin drivers use them as an
example.

since v5:

- Use v4l2_async_ prefix for static functions as well (4th patch)

- Use memcpy() to copy array rather than a loop

- Document that the v4l2_async_subdev pointer in driver specific struct
  must be the first member

- Improve documentation of the added functions (4th and 5th
  patches)

	- Arguments

	- More thorough explation of the purpose, usage and object
	  lifetime

- Added acks

since v4:

- Prepend the set with three documentation fixes.

- The driver's async struct must begin with struct v4l2_async_subdev. Fix this
  for omap3isp and document it.

- Improve documentation for new functions.

- Don't use devm_ family of functions for allocating memory. Introduce
  v4l2_async_notifier_release() to release memory resources.

- Rework both v4l2_async_notifier_fwnode_parse_endpoints() and
  v4l2_async_notifier_fwnode_parse_endpoint() and the local functions they
  call. This should make the code cleaner. Despite the name, for linking
  and typical usage reasons the functions remain in v4l2-fwnode.c.

- Convert rcar-vin to use v4l2_async_notifier_fwnode_parse_endpoint().

- Use kvmalloc() for allocating the notifier's subdevs array.

- max_subdevs argument for notifier_realloc is now the total maximum
  number of subdevs, not the number of available subdevs.

- Use fwnode_device_is_available() to make sure the device actually
  exists.

- Move the note telling v4l2_async_notifier_fwnode_parse_endpoints()
  should not be used by new drivers to the last patch adding
  v4l2_async_notifier_fwnode_parse_endpoint().

since v3:

- Rebase on current mediatree master.

since v2:

- Rebase on CCP2 support patches.

- Prepend a patch cleaning up omap3isp driver a little.

since v1:

- The first patch has been merged (it was a bugfix).

- In anticipation that the parsing can take place over several iterations,
  take the existing number of async sub-devices into account when
  re-allocating an array of async sub-devices.

- Rework the first patch to better anticipate parsing single endpoint at a
  time by a driver.

- Add a second patch that adds a function for parsing endpoints one at a
  time based on port and endpoint numbers.

Sakari Ailus (5):
  v4l: fwnode: Move KernelDoc documentation to the header
  v4l: async: Add V4L2 async documentation to the documentation build
  docs-rst: v4l: Include Qualcomm CAMSS in documentation build
  v4l: fwnode: Support generic parsing of graph endpoints in a device
  v4l: fwnode: Support generic parsing of graph endpoints in a single
    port

 Documentation/media/kapi/v4l2-async.rst     |   3 +
 Documentation/media/kapi/v4l2-core.rst      |   1 +
 Documentation/media/v4l-drivers/index.rst   |   1 +
 drivers/media/platform/omap3isp/isp.c       | 115 ++++---------
 drivers/media/platform/omap3isp/isp.h       |   5 +-
 drivers/media/platform/rcar-vin/rcar-core.c | 111 ++++--------
 drivers/media/platform/rcar-vin/rcar-dma.c  |  10 +-
 drivers/media/platform/rcar-vin/rcar-v4l2.c |  14 +-
 drivers/media/platform/rcar-vin/rcar-vin.h  |   4 +-
 drivers/media/v4l2-core/v4l2-async.c        |  16 ++
 drivers/media/v4l2-core/v4l2-fwnode.c       | 253 +++++++++++++++++++---------
 include/media/v4l2-async.h                  |  24 ++-
 include/media/v4l2-fwnode.h                 | 178 ++++++++++++++++++-
 13 files changed, 481 insertions(+), 254 deletions(-)
 create mode 100644 Documentation/media/kapi/v4l2-async.rst

-- 
2.11.0

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[PATCH v6 0/5] Unified fwnode endpoint parser

[Sakari Ailus]

Hi folks,

We have a large influx of new, unmerged, drivers that are now parsing
fwnode endpoints and each one of them is doing this a little bit
differently. The needs are still exactly the same for the graph data
structure is device independent. This is still a non-trivial task and the
majority of the driver implementations are buggy, just buggy in different
ways.

Facilitate parsing endpoints by adding a convenience function for parsing
the endpoints, and make the omap3isp and rcar-vin drivers use them as an
example.

since v5:

- Use v4l2_async_ prefix for static functions as well (4th patch)

- Use memcpy() to copy array rather than a loop

- Document that the v4l2_async_subdev pointer in driver specific struct
  must be the first member

- Improve documentation of the added functions (4th and 5th
  patches)

	- Arguments

	- More thorough explation of the purpose, usage and object
	  lifetime

- Added acks

since v4:

- Prepend the set with three documentation fixes.

- The driver's async struct must begin with struct v4l2_async_subdev. Fix this
  for omap3isp and document it.

- Improve documentation for new functions.

- Don't use devm_ family of functions for allocating memory. Introduce
  v4l2_async_notifier_release() to release memory resources.

- Rework both v4l2_async_notifier_fwnode_parse_endpoints() and
  v4l2_async_notifier_fwnode_parse_endpoint() and the local functions they
  call. This should make the code cleaner. Despite the name, for linking
  and typical usage reasons the functions remain in v4l2-fwnode.c.

- Convert rcar-vin to use v4l2_async_notifier_fwnode_parse_endpoint().

- Use kvmalloc() for allocating the notifier's subdevs array.

- max_subdevs argument for notifier_realloc is now the total maximum
  number of subdevs, not the number of available subdevs.

- Use fwnode_device_is_available() to make sure the device actually
  exists.

- Move the note telling v4l2_async_notifier_fwnode_parse_endpoints()
  should not be used by new drivers to the last patch adding
  v4l2_async_notifier_fwnode_parse_endpoint().

since v3:

- Rebase on current mediatree master.

since v2:

- Rebase on CCP2 support patches.

- Prepend a patch cleaning up omap3isp driver a little.

since v1:

- The first patch has been merged (it was a bugfix).

- In anticipation that the parsing can take place over several iterations,
  take the existing number of async sub-devices into account when
  re-allocating an array of async sub-devices.

- Rework the first patch to better anticipate parsing single endpoint at a
  time by a driver.

- Add a second patch that adds a function for parsing endpoints one at a
  time based on port and endpoint numbers.

Sakari Ailus (5):
  v4l: fwnode: Move KernelDoc documentation to the header
  v4l: async: Add V4L2 async documentation to the documentation build
  docs-rst: v4l: Include Qualcomm CAMSS in documentation build
  v4l: fwnode: Support generic parsing of graph endpoints in a device
  v4l: fwnode: Support generic parsing of graph endpoints in a single
    port

 Documentation/media/kapi/v4l2-async.rst     |   3 +
 Documentation/media/kapi/v4l2-core.rst      |   1 +
 Documentation/media/v4l-drivers/index.rst   |   1 +
 drivers/media/platform/omap3isp/isp.c       | 115 ++++---------
 drivers/media/platform/omap3isp/isp.h       |   5 +-
 drivers/media/platform/rcar-vin/rcar-core.c | 111 ++++--------
 drivers/media/platform/rcar-vin/rcar-dma.c  |  10 +-
 drivers/media/platform/rcar-vin/rcar-v4l2.c |  14 +-
 drivers/media/platform/rcar-vin/rcar-vin.h  |   4 +-
 drivers/media/v4l2-core/v4l2-async.c        |  16 ++
 drivers/media/v4l2-core/v4l2-fwnode.c       | 253 +++++++++++++++++++---------
 include/media/v4l2-async.h                  |  24 ++-
 include/media/v4l2-fwnode.h                 | 178 ++++++++++++++++++-
 13 files changed, 481 insertions(+), 254 deletions(-)
 create mode 100644 Documentation/media/kapi/v4l2-async.rst

-- 
2.11.0

[PATCH v6 1/5] v4l: fwnode: Move KernelDoc documentation to the header

[Sakari Ailus]

In V4L2 the practice is to have the KernelDoc documentation in the header
and not in .c source code files. This consequientally makes the V4L2
fwnode function documentation part of the Media documentation build.

Also correct the link related function and argument naming in
documentation.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
---
 drivers/media/v4l2-core/v4l2-fwnode.c | 75 --------------------------------
 include/media/v4l2-fwnode.h           | 81 ++++++++++++++++++++++++++++++++++-
 2 files changed, 80 insertions(+), 76 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
index 40b2fbfe8865..706f9e7b90f1 100644
--- a/drivers/media/v4l2-core/v4l2-fwnode.c
+++ b/drivers/media/v4l2-core/v4l2-fwnode.c
@@ -181,25 +181,6 @@ v4l2_fwnode_endpoint_parse_csi1_bus(struct fwnode_handle *fwnode,
 		vep->bus_type = V4L2_MBUS_CSI1;
 }
 
-/**
- * v4l2_fwnode_endpoint_parse() - parse all fwnode node properties
- * @fwnode: pointer to the endpoint's fwnode handle
- * @vep: pointer to the V4L2 fwnode data structure
- *
- * All properties are optional. If none are found, we don't set any flags. This
- * means the port has a static configuration and no properties have to be
- * specified explicitly. If any properties that identify the bus as parallel
- * are found and slave-mode isn't set, we set V4L2_MBUS_MASTER. Similarly, if
- * we recognise the bus as serial CSI-2 and clock-noncontinuous isn't set, we
- * set the V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag. The caller should hold a
- * reference to @fwnode.
- *
- * NOTE: This function does not parse properties the size of which is variable
- * without a low fixed limit. Please use v4l2_fwnode_endpoint_alloc_parse() in
- * new drivers instead.
- *
- * Return: 0 on success or a negative error code on failure.
- */
 int v4l2_fwnode_endpoint_parse(struct fwnode_handle *fwnode,
 			       struct v4l2_fwnode_endpoint *vep)
 {
@@ -239,14 +220,6 @@ int v4l2_fwnode_endpoint_parse(struct fwnode_handle *fwnode,
 }
 EXPORT_SYMBOL_GPL(v4l2_fwnode_endpoint_parse);
 
-/*
- * v4l2_fwnode_endpoint_free() - free the V4L2 fwnode acquired by
- * v4l2_fwnode_endpoint_alloc_parse()
- * @vep - the V4L2 fwnode the resources of which are to be released
- *
- * It is safe to call this function with NULL argument or on a V4L2 fwnode the
- * parsing of which failed.
- */
 void v4l2_fwnode_endpoint_free(struct v4l2_fwnode_endpoint *vep)
 {
 	if (IS_ERR_OR_NULL(vep))
@@ -257,29 +230,6 @@ void v4l2_fwnode_endpoint_free(struct v4l2_fwnode_endpoint *vep)
 }
 EXPORT_SYMBOL_GPL(v4l2_fwnode_endpoint_free);
 
-/**
- * v4l2_fwnode_endpoint_alloc_parse() - parse all fwnode node properties
- * @fwnode: pointer to the endpoint's fwnode handle
- *
- * All properties are optional. If none are found, we don't set any flags. This
- * means the port has a static configuration and no properties have to be
- * specified explicitly. If any properties that identify the bus as parallel
- * are found and slave-mode isn't set, we set V4L2_MBUS_MASTER. Similarly, if
- * we recognise the bus as serial CSI-2 and clock-noncontinuous isn't set, we
- * set the V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag. The caller should hold a
- * reference to @fwnode.
- *
- * v4l2_fwnode_endpoint_alloc_parse() has two important differences to
- * v4l2_fwnode_endpoint_parse():
- *
- * 1. It also parses variable size data.
- *
- * 2. The memory it has allocated to store the variable size data must be freed
- *    using v4l2_fwnode_endpoint_free() when no longer needed.
- *
- * Return: Pointer to v4l2_fwnode_endpoint if successful, on an error pointer
- * on error.
- */
 struct v4l2_fwnode_endpoint *v4l2_fwnode_endpoint_alloc_parse(
 	struct fwnode_handle *fwnode)
 {
@@ -322,24 +272,6 @@ struct v4l2_fwnode_endpoint *v4l2_fwnode_endpoint_alloc_parse(
 }
 EXPORT_SYMBOL_GPL(v4l2_fwnode_endpoint_alloc_parse);
 
-/**
- * v4l2_fwnode_endpoint_parse_link() - parse a link between two endpoints
- * @__fwnode: pointer to the endpoint's fwnode at the local end of the link
- * @link: pointer to the V4L2 fwnode link data structure
- *
- * Fill the link structure with the local and remote nodes and port numbers.
- * The local_node and remote_node fields are set to point to the local and
- * remote port's parent nodes respectively (the port parent node being the
- * parent node of the port node if that node isn't a 'ports' node, or the
- * grand-parent node of the port node otherwise).
- *
- * A reference is taken to both the local and remote nodes, the caller must use
- * v4l2_fwnode_endpoint_put_link() to drop the references when done with the
- * link.
- *
- * Return: 0 on success, or -ENOLINK if the remote endpoint fwnode can't be
- * found.
- */
 int v4l2_fwnode_parse_link(struct fwnode_handle *__fwnode,
 			   struct v4l2_fwnode_link *link)
 {
@@ -374,13 +306,6 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *__fwnode,
 }
 EXPORT_SYMBOL_GPL(v4l2_fwnode_parse_link);
 
-/**
- * v4l2_fwnode_put_link() - drop references to nodes in a link
- * @link: pointer to the V4L2 fwnode link data structure
- *
- * Drop references to the local and remote nodes in the link. This function
- * must be called on every link parsed with v4l2_fwnode_parse_link().
- */
 void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link)
 {
 	fwnode_handle_put(link->local_node);
diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
index 7adec9851d9e..68eb22ba571b 100644
--- a/include/media/v4l2-fwnode.h
+++ b/include/media/v4l2-fwnode.h
@@ -113,13 +113,92 @@ struct v4l2_fwnode_link {
 	unsigned int remote_port;
 };
 
+/**
+ * v4l2_fwnode_endpoint_parse() - parse all fwnode node properties
+ * @fwnode: pointer to the endpoint's fwnode handle
+ * @vep: pointer to the V4L2 fwnode data structure
+ *
+ * All properties are optional. If none are found, we don't set any flags. This
+ * means the port has a static configuration and no properties have to be
+ * specified explicitly. If any properties that identify the bus as parallel
+ * are found and slave-mode isn't set, we set V4L2_MBUS_MASTER. Similarly, if
+ * we recognise the bus as serial CSI-2 and clock-noncontinuous isn't set, we
+ * set the V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag. The caller should hold a
+ * reference to @fwnode.
+ *
+ * NOTE: This function does not parse properties the size of which is variable
+ * without a low fixed limit. Please use v4l2_fwnode_endpoint_alloc_parse() in
+ * new drivers instead.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
 int v4l2_fwnode_endpoint_parse(struct fwnode_handle *fwnode,
 			       struct v4l2_fwnode_endpoint *vep);
+
+/*
+ * v4l2_fwnode_endpoint_free() - free the V4L2 fwnode acquired by
+ * v4l2_fwnode_endpoint_alloc_parse()
+ * @vep - the V4L2 fwnode the resources of which are to be released
+ *
+ * It is safe to call this function with NULL argument or on a V4L2 fwnode the
+ * parsing of which failed.
+ */
+void v4l2_fwnode_endpoint_free(struct v4l2_fwnode_endpoint *vep);
+
+/**
+ * v4l2_fwnode_endpoint_alloc_parse() - parse all fwnode node properties
+ * @fwnode: pointer to the endpoint's fwnode handle
+ *
+ * All properties are optional. If none are found, we don't set any flags. This
+ * means the port has a static configuration and no properties have to be
+ * specified explicitly. If any properties that identify the bus as parallel
+ * are found and slave-mode isn't set, we set V4L2_MBUS_MASTER. Similarly, if
+ * we recognise the bus as serial CSI-2 and clock-noncontinuous isn't set, we
+ * set the V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag. The caller should hold a
+ * reference to @fwnode.
+ *
+ * v4l2_fwnode_endpoint_alloc_parse() has two important differences to
+ * v4l2_fwnode_endpoint_parse():
+ *
+ * 1. It also parses variable size data.
+ *
+ * 2. The memory it has allocated to store the variable size data must be freed
+ *    using v4l2_fwnode_endpoint_free() when no longer needed.
+ *
+ * Return: Pointer to v4l2_fwnode_endpoint if successful, on an error pointer
+ * on error.
+ */
 struct v4l2_fwnode_endpoint *v4l2_fwnode_endpoint_alloc_parse(
 	struct fwnode_handle *fwnode);
-void v4l2_fwnode_endpoint_free(struct v4l2_fwnode_endpoint *vep);
+
+/**
+ * v4l2_fwnode_parse_link() - parse a link between two endpoints
+ * @fwnode: pointer to the endpoint's fwnode at the local end of the link
+ * @link: pointer to the V4L2 fwnode link data structure
+ *
+ * Fill the link structure with the local and remote nodes and port numbers.
+ * The local_node and remote_node fields are set to point to the local and
+ * remote port's parent nodes respectively (the port parent node being the
+ * parent node of the port node if that node isn't a 'ports' node, or the
+ * grand-parent node of the port node otherwise).
+ *
+ * A reference is taken to both the local and remote nodes, the caller must use
+ * v4l2_fwnode_put_link() to drop the references when done with the
+ * link.
+ *
+ * Return: 0 on success, or -ENOLINK if the remote endpoint fwnode can't be
+ * found.
+ */
 int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,
 			   struct v4l2_fwnode_link *link);
+
+/**
+ * v4l2_fwnode_put_link() - drop references to nodes in a link
+ * @link: pointer to the V4L2 fwnode link data structure
+ *
+ * Drop references to the local and remote nodes in the link. This function
+ * must be called on every link parsed with v4l2_fwnode_parse_link().
+ */
 void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link);
 
 #endif /* _V4L2_FWNODE_H */
-- 
2.11.0

[PATCH v6 2/5] v4l: async: Add V4L2 async documentation to the documentation build

[Sakari Ailus]

The V4L2 async wasn't part of the documentation build. Fix this.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
---
 Documentation/media/kapi/v4l2-async.rst | 3 +++
 Documentation/media/kapi/v4l2-core.rst  | 1 +
 2 files changed, 4 insertions(+)
 create mode 100644 Documentation/media/kapi/v4l2-async.rst

diff --git a/Documentation/media/kapi/v4l2-async.rst b/Documentation/media/kapi/v4l2-async.rst
new file mode 100644
index 000000000000..523ff9eb09a0
--- /dev/null
+++ b/Documentation/media/kapi/v4l2-async.rst
@@ -0,0 +1,3 @@
+V4L2 async kAPI
+^^^^^^^^^^^^^^^
+.. kernel-doc:: include/media/v4l2-async.h
diff --git a/Documentation/media/kapi/v4l2-core.rst b/Documentation/media/kapi/v4l2-core.rst
index c7434f38fd9c..5cf292037a48 100644
--- a/Documentation/media/kapi/v4l2-core.rst
+++ b/Documentation/media/kapi/v4l2-core.rst
@@ -19,6 +19,7 @@ Video4Linux devices
     v4l2-mc
     v4l2-mediabus
     v4l2-mem2mem
+    v4l2-async
     v4l2-fwnode
     v4l2-rect
     v4l2-tuner
-- 
2.11.0

[PATCH v6 3/5] docs-rst: v4l: Include Qualcomm CAMSS in documentation build

[Sakari Ailus]

Qualcomm CAMSS was left out from documentation build. Fix this.

Signed-off-by: Sakari Ailus <sakari.ailus-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
---
 Documentation/media/v4l-drivers/index.rst | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/media/v4l-drivers/index.rst b/Documentation/media/v4l-drivers/index.rst
index 10f2ce42ece2..5c202e23616b 100644
--- a/Documentation/media/v4l-drivers/index.rst
+++ b/Documentation/media/v4l-drivers/index.rst
@@ -50,6 +50,7 @@ For more details see the file COPYING in the source distribution of Linux.
 	philips
 	pvrusb2
 	pxa_camera
+	qcom_camss
 	radiotrack
 	rcar-fdp1
 	saa7134
-- 
2.11.0

--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
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[PATCH v6 3/5] docs-rst: v4l: Include Qualcomm CAMSS in documentation build

[Sakari Ailus]

Qualcomm CAMSS was left out from documentation build. Fix this.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 Documentation/media/v4l-drivers/index.rst | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/media/v4l-drivers/index.rst b/Documentation/media/v4l-drivers/index.rst
index 10f2ce42ece2..5c202e23616b 100644
--- a/Documentation/media/v4l-drivers/index.rst
+++ b/Documentation/media/v4l-drivers/index.rst
@@ -50,6 +50,7 @@ For more details see the file COPYING in the source distribution of Linux.
 	philips
 	pvrusb2
 	pxa_camera
+	qcom_camss
 	radiotrack
 	rcar-fdp1
 	saa7134
-- 
2.11.0

[PATCH v6 4/5] v4l: fwnode: Support generic parsing of graph endpoints in a device

[Sakari Ailus]

The current practice is that drivers iterate over their endpoints and
parse each endpoint separately. This is very similar in a number of
drivers, implement a generic function for the job. Driver specific matters
can be taken into account in the driver specific callback.

Convert the omap3isp as an example.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/media/platform/omap3isp/isp.c | 115 ++++++++++-------------------
 drivers/media/platform/omap3isp/isp.h |   5 +-
 drivers/media/v4l2-core/v4l2-async.c  |  16 +++++
 drivers/media/v4l2-core/v4l2-fwnode.c | 131 ++++++++++++++++++++++++++++++++++
 include/media/v4l2-async.h            |  24 ++++++-
 include/media/v4l2-fwnode.h           |  48 +++++++++++++
 6 files changed, 254 insertions(+), 85 deletions(-)

diff --git a/drivers/media/platform/omap3isp/isp.c b/drivers/media/platform/omap3isp/isp.c
index 1a428fe9f070..a546cf774d40 100644
--- a/drivers/media/platform/omap3isp/isp.c
+++ b/drivers/media/platform/omap3isp/isp.c
@@ -2001,6 +2001,7 @@ static int isp_remove(struct platform_device *pdev)
 	__omap3isp_put(isp, false);
 
 	media_entity_enum_cleanup(&isp->crashed);
+	v4l2_async_notifier_release(&isp->notifier);
 
 	return 0;
 }
@@ -2011,44 +2012,41 @@ enum isp_of_phy {
 	ISP_OF_PHY_CSIPHY2,
 };
 
-static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
-			    struct isp_async_subdev *isd)
+static int isp_fwnode_parse(struct device *dev,
+			    struct v4l2_fwnode_endpoint *vep,
+			    struct v4l2_async_subdev *asd)
 {
+	struct isp_async_subdev *isd =
+		container_of(asd, struct isp_async_subdev, asd);
 	struct isp_bus_cfg *buscfg = &isd->bus;
-	struct v4l2_fwnode_endpoint vep;
-	unsigned int i;
-	int ret;
 	bool csi1 = false;
-
-	ret = v4l2_fwnode_endpoint_parse(fwnode, &vep);
-	if (ret)
-		return ret;
+	unsigned int i;
 
 	dev_dbg(dev, "parsing endpoint %pOF, interface %u\n",
-		to_of_node(fwnode), vep.base.port);
+		to_of_node(vep->base.local_fwnode), vep->base.port);
 
-	switch (vep.base.port) {
+	switch (vep->base.port) {
 	case ISP_OF_PHY_PARALLEL:
 		buscfg->interface = ISP_INTERFACE_PARALLEL;
 		buscfg->bus.parallel.data_lane_shift =
-			vep.bus.parallel.data_shift;
+			vep->bus.parallel.data_shift;
 		buscfg->bus.parallel.clk_pol =
-			!!(vep.bus.parallel.flags
+			!!(vep->bus.parallel.flags
 			   & V4L2_MBUS_PCLK_SAMPLE_FALLING);
 		buscfg->bus.parallel.hs_pol =
-			!!(vep.bus.parallel.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW);
+			!!(vep->bus.parallel.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW);
 		buscfg->bus.parallel.vs_pol =
-			!!(vep.bus.parallel.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW);
+			!!(vep->bus.parallel.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW);
 		buscfg->bus.parallel.fld_pol =
-			!!(vep.bus.parallel.flags & V4L2_MBUS_FIELD_EVEN_LOW);
+			!!(vep->bus.parallel.flags & V4L2_MBUS_FIELD_EVEN_LOW);
 		buscfg->bus.parallel.data_pol =
-			!!(vep.bus.parallel.flags & V4L2_MBUS_DATA_ACTIVE_LOW);
-		buscfg->bus.parallel.bt656 = vep.bus_type == V4L2_MBUS_BT656;
+			!!(vep->bus.parallel.flags & V4L2_MBUS_DATA_ACTIVE_LOW);
+		buscfg->bus.parallel.bt656 = vep->bus_type == V4L2_MBUS_BT656;
 		break;
 
 	case ISP_OF_PHY_CSIPHY1:
 	case ISP_OF_PHY_CSIPHY2:
-		switch (vep.bus_type) {
+		switch (vep->bus_type) {
 		case V4L2_MBUS_CCP2:
 		case V4L2_MBUS_CSI1:
 			dev_dbg(dev, "CSI-1/CCP-2 configuration\n");
@@ -2060,11 +2058,11 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
 			break;
 		default:
 			dev_err(dev, "unsupported bus type %u\n",
-				vep.bus_type);
+				vep->bus_type);
 			return -EINVAL;
 		}
 
-		switch (vep.base.port) {
+		switch (vep->base.port) {
 		case ISP_OF_PHY_CSIPHY1:
 			if (csi1)
 				buscfg->interface = ISP_INTERFACE_CCP2B_PHY1;
@@ -2080,47 +2078,47 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
 		}
 		if (csi1) {
 			buscfg->bus.ccp2.lanecfg.clk.pos =
-				vep.bus.mipi_csi1.clock_lane;
+				vep->bus.mipi_csi1.clock_lane;
 			buscfg->bus.ccp2.lanecfg.clk.pol =
-				vep.bus.mipi_csi1.lane_polarity[0];
+				vep->bus.mipi_csi1.lane_polarity[0];
 			dev_dbg(dev, "clock lane polarity %u, pos %u\n",
 				buscfg->bus.ccp2.lanecfg.clk.pol,
 				buscfg->bus.ccp2.lanecfg.clk.pos);
 
 			buscfg->bus.ccp2.lanecfg.data[0].pos =
-				vep.bus.mipi_csi1.data_lane;
+				vep->bus.mipi_csi1.data_lane;
 			buscfg->bus.ccp2.lanecfg.data[0].pol =
-				vep.bus.mipi_csi1.lane_polarity[1];
+				vep->bus.mipi_csi1.lane_polarity[1];
 
 			dev_dbg(dev, "data lane polarity %u, pos %u\n",
 				buscfg->bus.ccp2.lanecfg.data[0].pol,
 				buscfg->bus.ccp2.lanecfg.data[0].pos);
 
 			buscfg->bus.ccp2.strobe_clk_pol =
-				vep.bus.mipi_csi1.clock_inv;
-			buscfg->bus.ccp2.phy_layer = vep.bus.mipi_csi1.strobe;
+				vep->bus.mipi_csi1.clock_inv;
+			buscfg->bus.ccp2.phy_layer = vep->bus.mipi_csi1.strobe;
 			buscfg->bus.ccp2.ccp2_mode =
-				vep.bus_type == V4L2_MBUS_CCP2;
+				vep->bus_type == V4L2_MBUS_CCP2;
 			buscfg->bus.ccp2.vp_clk_pol = 1;
 
 			buscfg->bus.ccp2.crc = 1;
 		} else {
 			buscfg->bus.csi2.lanecfg.clk.pos =
-				vep.bus.mipi_csi2.clock_lane;
+				vep->bus.mipi_csi2.clock_lane;
 			buscfg->bus.csi2.lanecfg.clk.pol =
-				vep.bus.mipi_csi2.lane_polarities[0];
+				vep->bus.mipi_csi2.lane_polarities[0];
 			dev_dbg(dev, "clock lane polarity %u, pos %u\n",
 				buscfg->bus.csi2.lanecfg.clk.pol,
 				buscfg->bus.csi2.lanecfg.clk.pos);
 
 			buscfg->bus.csi2.num_data_lanes =
-				vep.bus.mipi_csi2.num_data_lanes;
+				vep->bus.mipi_csi2.num_data_lanes;
 
 			for (i = 0; i < buscfg->bus.csi2.num_data_lanes; i++) {
 				buscfg->bus.csi2.lanecfg.data[i].pos =
-					vep.bus.mipi_csi2.data_lanes[i];
+					vep->bus.mipi_csi2.data_lanes[i];
 				buscfg->bus.csi2.lanecfg.data[i].pol =
-					vep.bus.mipi_csi2.lane_polarities[i + 1];
+					vep->bus.mipi_csi2.lane_polarities[i + 1];
 				dev_dbg(dev,
 					"data lane %u polarity %u, pos %u\n", i,
 					buscfg->bus.csi2.lanecfg.data[i].pol,
@@ -2137,57 +2135,13 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
 
 	default:
 		dev_warn(dev, "%pOF: invalid interface %u\n",
-			 to_of_node(fwnode), vep.base.port);
+			 to_of_node(vep->base.local_fwnode), vep->base.port);
 		return -EINVAL;
 	}
 
 	return 0;
 }
 
-static int isp_fwnodes_parse(struct device *dev,
-			     struct v4l2_async_notifier *notifier)
-{
-	struct fwnode_handle *fwnode = NULL;
-
-	notifier->subdevs = devm_kcalloc(
-		dev, ISP_MAX_SUBDEVS, sizeof(*notifier->subdevs), GFP_KERNEL);
-	if (!notifier->subdevs)
-		return -ENOMEM;
-
-	while (notifier->num_subdevs < ISP_MAX_SUBDEVS &&
-	       (fwnode = fwnode_graph_get_next_endpoint(
-			of_fwnode_handle(dev->of_node), fwnode))) {
-		struct isp_async_subdev *isd;
-
-		isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
-		if (!isd)
-			goto error;
-
-		if (isp_fwnode_parse(dev, fwnode, isd)) {
-			devm_kfree(dev, isd);
-			continue;
-		}
-
-		notifier->subdevs[notifier->num_subdevs] = &isd->asd;
-
-		isd->asd.match.fwnode.fwnode =
-			fwnode_graph_get_remote_port_parent(fwnode);
-		if (!isd->asd.match.fwnode.fwnode) {
-			dev_warn(dev, "bad remote port parent\n");
-			goto error;
-		}
-
-		isd->asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
-		notifier->num_subdevs++;
-	}
-
-	return notifier->num_subdevs;
-
-error:
-	fwnode_handle_put(fwnode);
-	return -EINVAL;
-}
-
 static int isp_subdev_notifier_complete(struct v4l2_async_notifier *async)
 {
 	struct isp_device *isp = container_of(async, struct isp_device,
@@ -2256,7 +2210,9 @@ static int isp_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	ret = isp_fwnodes_parse(&pdev->dev, &isp->notifier);
+	ret = v4l2_async_notifier_parse_fwnode_endpoints(
+		&pdev->dev, &isp->notifier, sizeof(struct isp_async_subdev),
+		isp_fwnode_parse);
 	if (ret < 0)
 		return ret;
 
@@ -2407,6 +2363,7 @@ static int isp_probe(struct platform_device *pdev)
 	__omap3isp_put(isp, false);
 error:
 	mutex_destroy(&isp->isp_mutex);
+	v4l2_async_notifier_release(&isp->notifier);
 
 	return ret;
 }
diff --git a/drivers/media/platform/omap3isp/isp.h b/drivers/media/platform/omap3isp/isp.h
index e528df6efc09..8b9043db94b3 100644
--- a/drivers/media/platform/omap3isp/isp.h
+++ b/drivers/media/platform/omap3isp/isp.h
@@ -220,14 +220,11 @@ struct isp_device {
 
 	unsigned int sbl_resources;
 	unsigned int subclk_resources;
-
-#define ISP_MAX_SUBDEVS		8
-	struct v4l2_subdev *subdevs[ISP_MAX_SUBDEVS];
 };
 
 struct isp_async_subdev {
-	struct isp_bus_cfg bus;
 	struct v4l2_async_subdev asd;
+	struct isp_bus_cfg bus;
 };
 
 #define v4l2_subdev_to_bus_cfg(sd) \
diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
index 851f128eba22..c490acf5ae82 100644
--- a/drivers/media/v4l2-core/v4l2-async.c
+++ b/drivers/media/v4l2-core/v4l2-async.c
@@ -22,6 +22,7 @@
 
 #include <media/v4l2-async.h>
 #include <media/v4l2-device.h>
+#include <media/v4l2-fwnode.h>
 #include <media/v4l2-subdev.h>
 
 static bool match_i2c(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
@@ -278,6 +279,21 @@ void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
 }
 EXPORT_SYMBOL(v4l2_async_notifier_unregister);
 
+void v4l2_async_notifier_release(struct v4l2_async_notifier *notifier)
+{
+	unsigned int i;
+
+	if (!notifier->max_subdevs)
+		return;
+
+	for (i = 0; i < notifier->num_subdevs; i++)
+		kfree(notifier->subdevs[i]);
+
+	kvfree(notifier->subdevs);
+	notifier->max_subdevs = 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_async_notifier_release);
+
 int v4l2_async_register_subdev(struct v4l2_subdev *sd)
 {
 	struct v4l2_async_notifier *notifier;
diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
index 706f9e7b90f1..2496d76eef4b 100644
--- a/drivers/media/v4l2-core/v4l2-fwnode.c
+++ b/drivers/media/v4l2-core/v4l2-fwnode.c
@@ -19,6 +19,7 @@
  */
 #include <linux/acpi.h>
 #include <linux/kernel.h>
+#include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/property.h>
@@ -26,6 +27,7 @@
 #include <linux/string.h>
 #include <linux/types.h>
 
+#include <media/v4l2-async.h>
 #include <media/v4l2-fwnode.h>
 
 enum v4l2_fwnode_bus_type {
@@ -313,6 +315,135 @@ void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link)
 }
 EXPORT_SYMBOL_GPL(v4l2_fwnode_put_link);
 
+static int v4l2_async_notifier_realloc(struct v4l2_async_notifier *notifier,
+				       unsigned int max_subdevs)
+{
+	struct v4l2_async_subdev **subdevs;
+
+	if (max_subdevs <= notifier->max_subdevs)
+		return 0;
+
+	subdevs = kvmalloc_array(
+		max_subdevs, sizeof(*notifier->subdevs),
+		GFP_KERNEL | __GFP_ZERO);
+	if (!subdevs)
+		return -ENOMEM;
+
+	if (notifier->subdevs) {
+		memcpy(subdevs, notifier->subdevs,
+		       sizeof(*subdevs) * notifier->num_subdevs);
+
+		kvfree(notifier->subdevs);
+	}
+
+	notifier->subdevs = subdevs;
+	notifier->max_subdevs = max_subdevs;
+
+	return 0;
+}
+
+static int v4l2_async_notifier_fwnode_parse_endpoint(
+	struct device *dev, struct v4l2_async_notifier *notifier,
+	struct fwnode_handle *endpoint, unsigned int asd_struct_size,
+	int (*parse_single)(struct device *dev,
+			    struct v4l2_fwnode_endpoint *vep,
+			    struct v4l2_async_subdev *asd))
+{
+	struct v4l2_async_subdev *asd;
+	struct v4l2_fwnode_endpoint *vep;
+	int ret = 0;
+
+	asd = kzalloc(asd_struct_size, GFP_KERNEL);
+	if (!asd)
+		return -ENOMEM;
+
+	asd->match.fwnode.fwnode =
+		fwnode_graph_get_remote_port_parent(endpoint);
+	if (!asd->match.fwnode.fwnode) {
+		dev_warn(dev, "bad remote port parent\n");
+		ret = -EINVAL;
+		goto out_err;
+	}
+
+	/* Ignore endpoints the parsing of which failed. */
+	vep = v4l2_fwnode_endpoint_alloc_parse(endpoint);
+	if (IS_ERR(vep)) {
+		ret = PTR_ERR(vep);
+		dev_warn(dev, "unable to parse V4L2 fwnode endpoint (%d)\n",
+			 ret);
+		goto out_err;
+	}
+
+	ret = parse_single(dev, vep, asd);
+	v4l2_fwnode_endpoint_free(vep);
+	if (ret) {
+		dev_warn(dev, "driver could not parse endpoint (%d)\n", ret);
+		goto out_err;
+	}
+
+	asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
+	notifier->subdevs[notifier->num_subdevs] = asd;
+	notifier->num_subdevs++;
+
+	return 0;
+
+out_err:
+	fwnode_handle_put(asd->match.fwnode.fwnode);
+	kfree(asd);
+
+	return ret;
+}
+
+int v4l2_async_notifier_parse_fwnode_endpoints(
+	struct device *dev, struct v4l2_async_notifier *notifier,
+	size_t asd_struct_size,
+	int (*parse_single)(struct device *dev,
+			    struct v4l2_fwnode_endpoint *vep,
+			    struct v4l2_async_subdev *asd))
+{
+	struct fwnode_handle *fwnode = NULL;
+	unsigned int max_subdevs = notifier->max_subdevs;
+	int ret;
+
+	if (asd_struct_size < sizeof(struct v4l2_async_subdev) ||
+	    notifier->v4l2_dev)
+		return -EINVAL;
+
+	for (fwnode = NULL; (fwnode = fwnode_graph_get_next_endpoint(
+				     dev_fwnode(dev), fwnode)); )
+		if (fwnode_device_is_available(
+			    fwnode_graph_get_port_parent(fwnode)))
+			max_subdevs++;
+
+	/* No subdevs to add? Return here. */
+	if (max_subdevs == notifier->max_subdevs)
+		return 0;
+
+	ret = v4l2_async_notifier_realloc(notifier, max_subdevs);
+	if (ret)
+		return ret;
+
+	for (fwnode = NULL; (fwnode = fwnode_graph_get_next_endpoint(
+				     dev_fwnode(dev), fwnode)); ) {
+		if (!fwnode_device_is_available(
+			    fwnode_graph_get_port_parent(fwnode)))
+			continue;
+
+		if (WARN_ON(notifier->num_subdevs >= notifier->max_subdevs))
+			break;
+
+		ret = v4l2_async_notifier_fwnode_parse_endpoint(
+			dev, notifier, fwnode, asd_struct_size, parse_single);
+		if (ret < 0)
+			break;
+	}
+
+	fwnode_handle_put(fwnode);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(v4l2_async_notifier_parse_fwnode_endpoints);
+
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Sakari Ailus <sakari.ailus@linux.intel.com>");
 MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@samsung.com>");
diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
index c69d8c8a66d0..cf13c7311a1c 100644
--- a/include/media/v4l2-async.h
+++ b/include/media/v4l2-async.h
@@ -18,7 +18,6 @@ struct device;
 struct device_node;
 struct v4l2_device;
 struct v4l2_subdev;
-struct v4l2_async_notifier;
 
 /* A random max subdevice number, used to allocate an array on stack */
 #define V4L2_MAX_SUBDEVS 128U
@@ -50,6 +49,10 @@ enum v4l2_async_match_type {
  * @match:	union of per-bus type matching data sets
  * @list:	used to link struct v4l2_async_subdev objects, waiting to be
  *		probed, to a notifier->waiting list
+ *
+ * When the struct is used as the first member of a driver specific
+ * struct, the driver specific struct shall contain the @struct
+ * v4l2_async_subdev as its first member.
  */
 struct v4l2_async_subdev {
 	enum v4l2_async_match_type match_type;
@@ -78,7 +81,8 @@ struct v4l2_async_subdev {
 /**
  * struct v4l2_async_notifier - v4l2_device notifier data
  *
- * @num_subdevs: number of subdevices
+ * @num_subdevs: number of subdevices used in subdevs array
+ * @max_subdevs: number of subdevices allocated in subdevs array
  * @subdevs:	array of pointers to subdevice descriptors
  * @v4l2_dev:	pointer to struct v4l2_device
  * @waiting:	list of struct v4l2_async_subdev, waiting for their drivers
@@ -90,6 +94,7 @@ struct v4l2_async_subdev {
  */
 struct v4l2_async_notifier {
 	unsigned int num_subdevs;
+	unsigned int max_subdevs;
 	struct v4l2_async_subdev **subdevs;
 	struct v4l2_device *v4l2_dev;
 	struct list_head waiting;
@@ -121,6 +126,21 @@ int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
 void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier);
 
 /**
+ * v4l2_async_notifier_release - release notifier resources
+ * @notifier: the notifier the resources of which are to be released
+ *
+ * Release memory resources related to a notifier, including the async
+ * sub-devices allocated for the purposes of the notifier. The user is
+ * responsible for releasing the notifier's resources after calling
+ * @v4l2_async_notifier_parse_fwnode_endpoints.
+ *
+ * There is no harm from calling v4l2_async_notifier_release in other
+ * cases as long as its memory has been zeroed after it has been
+ * allocated.
+ */
+void v4l2_async_notifier_release(struct v4l2_async_notifier *notifier);
+
+/**
  * v4l2_async_register_subdev - registers a sub-device to the asynchronous
  * 	subdevice framework
  *
diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
index 68eb22ba571b..d063ab4ff67b 100644
--- a/include/media/v4l2-fwnode.h
+++ b/include/media/v4l2-fwnode.h
@@ -25,6 +25,8 @@
 #include <media/v4l2-mediabus.h>
 
 struct fwnode_handle;
+struct v4l2_async_notifier;
+struct v4l2_async_subdev;
 
 #define V4L2_FWNODE_CSI2_MAX_DATA_LANES	4
 
@@ -201,4 +203,50 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,
  */
 void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link);
 
+/**
+ * v4l2_async_notifier_parse_fwnode_endpoints - Parse V4L2 fwnode endpoints in a
+ *						device node
+ * @dev: the device the endpoints of which are to be parsed
+ * @notifier: notifier for @dev
+ * @asd_struct_size: size of the driver's async sub-device struct, including
+ *		     sizeof(struct v4l2_async_subdev). The &struct
+ *		     v4l2_async_subdev shall be the first member of
+ *		     the driver's async sub-device struct, i.e. both
+ *		     begin at the same memory address.
+ * @parse_single: driver's callback function called on each V4L2 fwnode endpoint
+ *
+ * Parse the fwnode endpoints of the @dev device and populate the async sub-
+ * devices array of the notifier. The @parse_endpoint callback function is
+ * called for each endpoint with the corresponding async sub-device pointer to
+ * let the caller initialize the driver-specific part of the async sub-device
+ * structure.
+ *
+ * The notifier memory shall be zeroed before this function is called on the
+ * notifier.
+ *
+ * This function may not be called on a registered notifier and may be called on
+ * a notifier only once. When using this function, the user may not access the
+ * notifier's subdevs array nor change notifier's num_subdevs field, these are
+ * reserved for the framework's internal use only.
+ *
+ * The @struct v4l2_fwnode_endpoint passed to the callback function
+ * @parse_single is released once the function is finished. If there is a need
+ * to retain that configuration, the user needs to allocate memory for it.
+ *
+ * Any notifier populated using this function must be released with a call to
+ * v4l2_async_notifier_release() after it has been unregistered and the async
+ * sub-devices are no longer in use.
+ *
+ * Return: %0 on success, including when no async sub-devices are found
+ *	   %-ENOMEM if memory allocation failed
+ *	   %-EINVAL if graph or endpoint parsing failed
+ *	   Other error codes as returned by @parse_single
+ */
+int v4l2_async_notifier_parse_fwnode_endpoints(
+	struct device *dev, struct v4l2_async_notifier *notifier,
+	size_t asd_struct_size,
+	int (*parse_single)(struct device *dev,
+			    struct v4l2_fwnode_endpoint *vep,
+			    struct v4l2_async_subdev *asd));
+
 #endif /* _V4L2_FWNODE_H */
-- 
2.11.0

[PATCH v6 5/5] v4l: fwnode: Support generic parsing of graph endpoints in a single port

[Sakari Ailus]

This is the preferred way to parse the endpoints.

Comment rcar-vin as an example.

Signed-off-by: Sakari Ailus <sakari.ailus-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
---
 drivers/media/platform/rcar-vin/rcar-core.c | 111 ++++++++--------------------
 drivers/media/platform/rcar-vin/rcar-dma.c  |  10 +--
 drivers/media/platform/rcar-vin/rcar-v4l2.c |  14 ++--
 drivers/media/platform/rcar-vin/rcar-vin.h  |   4 +-
 drivers/media/v4l2-core/v4l2-fwnode.c       |  47 ++++++++++++
 include/media/v4l2-fwnode.h                 |  49 ++++++++++++
 6 files changed, 142 insertions(+), 93 deletions(-)

diff --git a/drivers/media/platform/rcar-vin/rcar-core.c b/drivers/media/platform/rcar-vin/rcar-core.c
index 142de447aaaa..4378806be1d4 100644
--- a/drivers/media/platform/rcar-vin/rcar-core.c
+++ b/drivers/media/platform/rcar-vin/rcar-core.c
@@ -21,6 +21,7 @@
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 
+#include <media/v4l2-async.h>
 #include <media/v4l2-fwnode.h>
 
 #include "rcar-vin.h"
@@ -77,14 +78,14 @@ static int rvin_digital_notify_complete(struct v4l2_async_notifier *notifier)
 	int ret;
 
 	/* Verify subdevices mbus format */
-	if (!rvin_mbus_supported(&vin->digital)) {
+	if (!rvin_mbus_supported(vin->digital)) {
 		vin_err(vin, "Unsupported media bus format for %s\n",
-			vin->digital.subdev->name);
+			vin->digital->subdev->name);
 		return -EINVAL;
 	}
 
 	vin_dbg(vin, "Found media bus format for %s: %d\n",
-		vin->digital.subdev->name, vin->digital.code);
+		vin->digital->subdev->name, vin->digital->code);
 
 	ret = v4l2_device_register_subdev_nodes(&vin->v4l2_dev);
 	if (ret < 0) {
@@ -103,7 +104,7 @@ static void rvin_digital_notify_unbind(struct v4l2_async_notifier *notifier,
 
 	vin_dbg(vin, "unbind digital subdev %s\n", subdev->name);
 	rvin_v4l2_remove(vin);
-	vin->digital.subdev = NULL;
+	vin->digital->subdev = NULL;
 }
 
 static int rvin_digital_notify_bound(struct v4l2_async_notifier *notifier,
@@ -120,117 +121,67 @@ static int rvin_digital_notify_bound(struct v4l2_async_notifier *notifier,
 	ret = rvin_find_pad(subdev, MEDIA_PAD_FL_SOURCE);
 	if (ret < 0)
 		return ret;
-	vin->digital.source_pad = ret;
+	vin->digital->source_pad = ret;
 
 	ret = rvin_find_pad(subdev, MEDIA_PAD_FL_SINK);
-	vin->digital.sink_pad = ret < 0 ? 0 : ret;
+	vin->digital->sink_pad = ret < 0 ? 0 : ret;
 
-	vin->digital.subdev = subdev;
+	vin->digital->subdev = subdev;
 
 	vin_dbg(vin, "bound subdev %s source pad: %u sink pad: %u\n",
-		subdev->name, vin->digital.source_pad,
-		vin->digital.sink_pad);
+		subdev->name, vin->digital->source_pad,
+		vin->digital->sink_pad);
 
 	return 0;
 }
 
-static int rvin_digitial_parse_v4l2(struct rvin_dev *vin,
-				    struct device_node *ep,
-				    struct v4l2_mbus_config *mbus_cfg)
+static int rvin_digital_parse_v4l2(struct device *dev,
+				   struct v4l2_fwnode_endpoint *vep,
+				   struct v4l2_async_subdev *asd)
 {
-	struct v4l2_fwnode_endpoint v4l2_ep;
-	int ret;
-
-	ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(ep), &v4l2_ep);
-	if (ret) {
-		vin_err(vin, "Could not parse v4l2 endpoint\n");
-		return -EINVAL;
-	}
+	struct rvin_dev *vin = dev_get_drvdata(dev);
+	struct rvin_graph_entity *rvge =
+		container_of(asd, struct rvin_graph_entity, asd);
 
-	mbus_cfg->type = v4l2_ep.bus_type;
+	rvge->mbus_cfg.type = vep->bus_type;
 
-	switch (mbus_cfg->type) {
+	switch (rvge->mbus_cfg.type) {
 	case V4L2_MBUS_PARALLEL:
 		vin_dbg(vin, "Found PARALLEL media bus\n");
-		mbus_cfg->flags = v4l2_ep.bus.parallel.flags;
+		rvge->mbus_cfg.flags = vep->bus.parallel.flags;
 		break;
 	case V4L2_MBUS_BT656:
 		vin_dbg(vin, "Found BT656 media bus\n");
-		mbus_cfg->flags = 0;
+		rvge->mbus_cfg.flags = 0;
 		break;
 	default:
 		vin_err(vin, "Unknown media bus type\n");
 		return -EINVAL;
 	}
 
-	return 0;
-}
-
-static int rvin_digital_graph_parse(struct rvin_dev *vin)
-{
-	struct device_node *ep, *np;
-	int ret;
-
-	vin->digital.asd.match.fwnode.fwnode = NULL;
-	vin->digital.subdev = NULL;
-
-	/*
-	 * Port 0 id 0 is local digital input, try to get it.
-	 * Not all instances can or will have this, that is OK
-	 */
-	ep = of_graph_get_endpoint_by_regs(vin->dev->of_node, 0, 0);
-	if (!ep)
-		return 0;
-
-	np = of_graph_get_remote_port_parent(ep);
-	if (!np) {
-		vin_err(vin, "No remote parent for digital input\n");
-		of_node_put(ep);
-		return -EINVAL;
-	}
-	of_node_put(np);
-
-	ret = rvin_digitial_parse_v4l2(vin, ep, &vin->digital.mbus_cfg);
-	of_node_put(ep);
-	if (ret)
-		return ret;
-
-	vin->digital.asd.match.fwnode.fwnode = of_fwnode_handle(np);
-	vin->digital.asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
+	vin->digital = rvge;
 
 	return 0;
 }
 
 static int rvin_digital_graph_init(struct rvin_dev *vin)
 {
-	struct v4l2_async_subdev **subdevs = NULL;
 	int ret;
 
-	ret = rvin_digital_graph_parse(vin);
+	ret = v4l2_async_notifier_parse_fwnode_endpoint(
+		vin->dev, &vin->notifier, 0, 0,
+		sizeof(struct rvin_graph_entity), rvin_digital_parse_v4l2);
 	if (ret)
 		return ret;
 
-	if (!vin->digital.asd.match.fwnode.fwnode) {
-		vin_dbg(vin, "No digital subdevice found\n");
-		return -ENODEV;
-	}
-
-	/* Register the subdevices notifier. */
-	subdevs = devm_kzalloc(vin->dev, sizeof(*subdevs), GFP_KERNEL);
-	if (subdevs == NULL)
-		return -ENOMEM;
+	if (vin->notifier.num_subdevs > 0)
+		vin_dbg(vin, "Found digital subdevice %pOF\n",
+			to_of_node(
+				vin->notifier.subdevs[0]->match.fwnode.fwnode));
 
-	subdevs[0] = &vin->digital.asd;
-
-	vin_dbg(vin, "Found digital subdevice %pOF\n",
-		to_of_node(subdevs[0]->match.fwnode.fwnode));
-
-	vin->notifier.num_subdevs = 1;
-	vin->notifier.subdevs = subdevs;
 	vin->notifier.bound = rvin_digital_notify_bound;
 	vin->notifier.unbind = rvin_digital_notify_unbind;
 	vin->notifier.complete = rvin_digital_notify_complete;
-
 	ret = v4l2_async_notifier_register(&vin->v4l2_dev, &vin->notifier);
 	if (ret < 0) {
 		vin_err(vin, "Notifier registration failed\n");
@@ -290,6 +241,8 @@ static int rcar_vin_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	platform_set_drvdata(pdev, vin);
+
 	ret = rvin_digital_graph_init(vin);
 	if (ret < 0)
 		goto error;
@@ -297,11 +250,10 @@ static int rcar_vin_probe(struct platform_device *pdev)
 	pm_suspend_ignore_children(&pdev->dev, true);
 	pm_runtime_enable(&pdev->dev);
 
-	platform_set_drvdata(pdev, vin);
-
 	return 0;
 error:
 	rvin_dma_remove(vin);
+	v4l2_async_notifier_release(&vin->notifier);
 
 	return ret;
 }
@@ -313,6 +265,7 @@ static int rcar_vin_remove(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 
 	v4l2_async_notifier_unregister(&vin->notifier);
+	v4l2_async_notifier_release(&vin->notifier);
 
 	rvin_dma_remove(vin);
 
diff --git a/drivers/media/platform/rcar-vin/rcar-dma.c b/drivers/media/platform/rcar-vin/rcar-dma.c
index b136844499f6..23fdff7a7370 100644
--- a/drivers/media/platform/rcar-vin/rcar-dma.c
+++ b/drivers/media/platform/rcar-vin/rcar-dma.c
@@ -183,7 +183,7 @@ static int rvin_setup(struct rvin_dev *vin)
 	/*
 	 * Input interface
 	 */
-	switch (vin->digital.code) {
+	switch (vin->digital->code) {
 	case MEDIA_BUS_FMT_YUYV8_1X16:
 		/* BT.601/BT.1358 16bit YCbCr422 */
 		vnmc |= VNMC_INF_YUV16;
@@ -191,7 +191,7 @@ static int rvin_setup(struct rvin_dev *vin)
 		break;
 	case MEDIA_BUS_FMT_UYVY8_2X8:
 		/* BT.656 8bit YCbCr422 or BT.601 8bit YCbCr422 */
-		vnmc |= vin->digital.mbus_cfg.type == V4L2_MBUS_BT656 ?
+		vnmc |= vin->digital->mbus_cfg.type == V4L2_MBUS_BT656 ?
 			VNMC_INF_YUV8_BT656 : VNMC_INF_YUV8_BT601;
 		input_is_yuv = true;
 		break;
@@ -200,7 +200,7 @@ static int rvin_setup(struct rvin_dev *vin)
 		break;
 	case MEDIA_BUS_FMT_UYVY10_2X10:
 		/* BT.656 10bit YCbCr422 or BT.601 10bit YCbCr422 */
-		vnmc |= vin->digital.mbus_cfg.type == V4L2_MBUS_BT656 ?
+		vnmc |= vin->digital->mbus_cfg.type == V4L2_MBUS_BT656 ?
 			VNMC_INF_YUV10_BT656 : VNMC_INF_YUV10_BT601;
 		input_is_yuv = true;
 		break;
@@ -212,11 +212,11 @@ static int rvin_setup(struct rvin_dev *vin)
 	dmr2 = VNDMR2_FTEV | VNDMR2_VLV(1);
 
 	/* Hsync Signal Polarity Select */
-	if (!(vin->digital.mbus_cfg.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW))
+	if (!(vin->digital->mbus_cfg.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW))
 		dmr2 |= VNDMR2_HPS;
 
 	/* Vsync Signal Polarity Select */
-	if (!(vin->digital.mbus_cfg.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW))
+	if (!(vin->digital->mbus_cfg.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW))
 		dmr2 |= VNDMR2_VPS;
 
 	/*
diff --git a/drivers/media/platform/rcar-vin/rcar-v4l2.c b/drivers/media/platform/rcar-vin/rcar-v4l2.c
index dd37ea811680..b479b882da12 100644
--- a/drivers/media/platform/rcar-vin/rcar-v4l2.c
+++ b/drivers/media/platform/rcar-vin/rcar-v4l2.c
@@ -111,7 +111,7 @@ static int rvin_reset_format(struct rvin_dev *vin)
 	struct v4l2_mbus_framefmt *mf = &fmt.format;
 	int ret;
 
-	fmt.pad = vin->digital.source_pad;
+	fmt.pad = vin->digital->source_pad;
 
 	ret = v4l2_subdev_call(vin_to_source(vin), pad, get_fmt, NULL, &fmt);
 	if (ret)
@@ -172,13 +172,13 @@ static int __rvin_try_format_source(struct rvin_dev *vin,
 
 	sd = vin_to_source(vin);
 
-	v4l2_fill_mbus_format(&format.format, pix, vin->digital.code);
+	v4l2_fill_mbus_format(&format.format, pix, vin->digital->code);
 
 	pad_cfg = v4l2_subdev_alloc_pad_config(sd);
 	if (pad_cfg == NULL)
 		return -ENOMEM;
 
-	format.pad = vin->digital.source_pad;
+	format.pad = vin->digital->source_pad;
 
 	field = pix->field;
 
@@ -555,7 +555,7 @@ static int rvin_enum_dv_timings(struct file *file, void *priv_fh,
 	if (timings->pad)
 		return -EINVAL;
 
-	timings->pad = vin->digital.sink_pad;
+	timings->pad = vin->digital->sink_pad;
 
 	ret = v4l2_subdev_call(sd, pad, enum_dv_timings, timings);
 
@@ -607,7 +607,7 @@ static int rvin_dv_timings_cap(struct file *file, void *priv_fh,
 	if (cap->pad)
 		return -EINVAL;
 
-	cap->pad = vin->digital.sink_pad;
+	cap->pad = vin->digital->sink_pad;
 
 	ret = v4l2_subdev_call(sd, pad, dv_timings_cap, cap);
 
@@ -625,7 +625,7 @@ static int rvin_g_edid(struct file *file, void *fh, struct v4l2_edid *edid)
 	if (edid->pad)
 		return -EINVAL;
 
-	edid->pad = vin->digital.sink_pad;
+	edid->pad = vin->digital->sink_pad;
 
 	ret = v4l2_subdev_call(sd, pad, get_edid, edid);
 
@@ -643,7 +643,7 @@ static int rvin_s_edid(struct file *file, void *fh, struct v4l2_edid *edid)
 	if (edid->pad)
 		return -EINVAL;
 
-	edid->pad = vin->digital.sink_pad;
+	edid->pad = vin->digital->sink_pad;
 
 	ret = v4l2_subdev_call(sd, pad, set_edid, edid);
 
diff --git a/drivers/media/platform/rcar-vin/rcar-vin.h b/drivers/media/platform/rcar-vin/rcar-vin.h
index 9bfb5a7c4dc4..5382078143fb 100644
--- a/drivers/media/platform/rcar-vin/rcar-vin.h
+++ b/drivers/media/platform/rcar-vin/rcar-vin.h
@@ -126,7 +126,7 @@ struct rvin_dev {
 	struct v4l2_device v4l2_dev;
 	struct v4l2_ctrl_handler ctrl_handler;
 	struct v4l2_async_notifier notifier;
-	struct rvin_graph_entity digital;
+	struct rvin_graph_entity *digital;
 
 	struct mutex lock;
 	struct vb2_queue queue;
@@ -145,7 +145,7 @@ struct rvin_dev {
 	struct v4l2_rect compose;
 };
 
-#define vin_to_source(vin)		vin->digital.subdev
+#define vin_to_source(vin)		((vin)->digital->subdev)
 
 /* Debug */
 #define vin_dbg(d, fmt, arg...)		dev_dbg(d->dev, fmt, ##arg)
diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
index 2496d76eef4b..4720e8a043cf 100644
--- a/drivers/media/v4l2-core/v4l2-fwnode.c
+++ b/drivers/media/v4l2-core/v4l2-fwnode.c
@@ -444,6 +444,53 @@ int v4l2_async_notifier_parse_fwnode_endpoints(
 }
 EXPORT_SYMBOL_GPL(v4l2_async_notifier_parse_fwnode_endpoints);
 
+int v4l2_async_notifier_parse_fwnode_endpoint(
+	struct device *dev, struct v4l2_async_notifier *notifier,
+	unsigned int port_id, unsigned int endpoint_id, size_t asd_struct_size,
+	int (*parse_single)(struct device *dev,
+			    struct v4l2_fwnode_endpoint *vep,
+			    struct v4l2_async_subdev *asd))
+{
+	struct fwnode_handle *fwnode = NULL;
+	int ret;
+
+	while ((fwnode = fwnode_graph_get_next_endpoint(
+			dev_fwnode(dev), fwnode))) {
+		struct fwnode_endpoint ep;
+
+		ret = fwnode_graph_parse_endpoint(fwnode, &ep);
+		if (ret < 0)
+			continue;
+
+		if (!fwnode_device_is_available(
+			    fwnode_graph_get_port_parent(fwnode)))
+			continue;
+
+		if (ep.port == port_id && ep.id == endpoint_id)
+			break;
+	}
+
+	if (!fwnode)
+		return -ENOENT;
+
+	ret = v4l2_async_notifier_realloc(notifier, notifier->num_subdevs + 1);
+	if (ret)
+		goto out_err;
+
+	ret = v4l2_async_notifier_fwnode_parse_endpoint(
+		dev, notifier, fwnode, asd_struct_size, parse_single);
+	if (ret)
+		goto out_err;
+
+	return 0;
+
+out_err:
+	fwnode_handle_put(fwnode);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(v4l2_async_notifier_parse_fwnode_endpoint);
+
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Sakari Ailus <sakari.ailus-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>");
 MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>");
diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
index d063ab4ff67b..dd13604178b4 100644
--- a/include/media/v4l2-fwnode.h
+++ b/include/media/v4l2-fwnode.h
@@ -249,4 +249,53 @@ int v4l2_async_notifier_parse_fwnode_endpoints(
 			    struct v4l2_fwnode_endpoint *vep,
 			    struct v4l2_async_subdev *asd));
 
+/**
+ * v4l2_async_notifier_parse_fwnode_endpoint - Set up async notifier for an
+ *					       fwnode based sub-device
+ * @dev: @struct device pointer
+ * @notifier: pointer to &struct v4l2_async_notifier
+ * @port_id: port number
+ * @endpoint_id: endpoint number
+ * @asd_struct_size: size of the driver's async sub-device struct, including
+ *		     sizeof(struct v4l2_async_subdev). The &struct
+ *		     v4l2_async_subdev shall be the first member of
+ *		     the driver's async sub-device struct, i.e. both
+ *		     begin at the same memory address.
+ * @parse_single: driver's callback function called on each V4L2 fwnode endpoint
+ *
+ * Parse the fwnode endpoint of the @dev device corresponding to the given port
+ * and endpoint numbres and populate the async sub- devices array of the
+ * notifier. The @parse_endpoint callback function is called for the endpoint
+ * with the corresponding async sub-device pointer to let the caller initialize
+ * the driver-specific part of the async sub-device structure.
+ *
+ * The notifier memory shall be zeroed before this function is called on the
+ * notifier.
+ *
+ * This function may not be called on a registered notifier and may be called on
+ * a notifier once or more times, but may not be called more than once on a
+ * given port / endpoint pair. When using this function, the user may not access
+ * the notifier's subdevs array nor change notifier's num_subdevs field, these
+ * are reserved for the framework's internal use only.
+ *
+ * The @struct v4l2_fwnode_endpoint passed to the callback function
+ * @parse_single is released once the function is finished. If there is a need
+ * to retain that configuration, the user needs to allocate memory for it.
+ *
+ * Any notifier populated using this function must be released with a call to
+ * v4l2_async_notifier_release() after it has been unregistered and the async
+ * sub-devices are no longer in use.
+ *
+ * Return: %0 on success, including when no async sub-devices are found
+ *	   %-ENOMEM if memory allocation failed
+ *	   %-EINVAL if graph or endpoint parsing failed
+ *	   Other error codes as returned by @parse_single
+ */
+int v4l2_async_notifier_parse_fwnode_endpoint(
+	struct device *dev, struct v4l2_async_notifier *notifier,
+	unsigned int port_id, unsigned int endpoint_id, size_t asd_struct_size,
+	int (*parse_single)(struct device *dev,
+			    struct v4l2_fwnode_endpoint *vep,
+			    struct v4l2_async_subdev *asd));
+
 #endif /* _V4L2_FWNODE_H */
-- 
2.11.0

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[PATCH v6 5/5] v4l: fwnode: Support generic parsing of graph endpoints in a single port

[Sakari Ailus]

This is the preferred way to parse the endpoints.

Comment rcar-vin as an example.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/media/platform/rcar-vin/rcar-core.c | 111 ++++++++--------------------
 drivers/media/platform/rcar-vin/rcar-dma.c  |  10 +--
 drivers/media/platform/rcar-vin/rcar-v4l2.c |  14 ++--
 drivers/media/platform/rcar-vin/rcar-vin.h  |   4 +-
 drivers/media/v4l2-core/v4l2-fwnode.c       |  47 ++++++++++++
 include/media/v4l2-fwnode.h                 |  49 ++++++++++++
 6 files changed, 142 insertions(+), 93 deletions(-)

diff --git a/drivers/media/platform/rcar-vin/rcar-core.c b/drivers/media/platform/rcar-vin/rcar-core.c
index 142de447aaaa..4378806be1d4 100644
--- a/drivers/media/platform/rcar-vin/rcar-core.c
+++ b/drivers/media/platform/rcar-vin/rcar-core.c
@@ -21,6 +21,7 @@
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 
+#include <media/v4l2-async.h>
 #include <media/v4l2-fwnode.h>
 
 #include "rcar-vin.h"
@@ -77,14 +78,14 @@ static int rvin_digital_notify_complete(struct v4l2_async_notifier *notifier)
 	int ret;
 
 	/* Verify subdevices mbus format */
-	if (!rvin_mbus_supported(&vin->digital)) {
+	if (!rvin_mbus_supported(vin->digital)) {
 		vin_err(vin, "Unsupported media bus format for %s\n",
-			vin->digital.subdev->name);
+			vin->digital->subdev->name);
 		return -EINVAL;
 	}
 
 	vin_dbg(vin, "Found media bus format for %s: %d\n",
-		vin->digital.subdev->name, vin->digital.code);
+		vin->digital->subdev->name, vin->digital->code);
 
 	ret = v4l2_device_register_subdev_nodes(&vin->v4l2_dev);
 	if (ret < 0) {
@@ -103,7 +104,7 @@ static void rvin_digital_notify_unbind(struct v4l2_async_notifier *notifier,
 
 	vin_dbg(vin, "unbind digital subdev %s\n", subdev->name);
 	rvin_v4l2_remove(vin);
-	vin->digital.subdev = NULL;
+	vin->digital->subdev = NULL;
 }
 
 static int rvin_digital_notify_bound(struct v4l2_async_notifier *notifier,
@@ -120,117 +121,67 @@ static int rvin_digital_notify_bound(struct v4l2_async_notifier *notifier,
 	ret = rvin_find_pad(subdev, MEDIA_PAD_FL_SOURCE);
 	if (ret < 0)
 		return ret;
-	vin->digital.source_pad = ret;
+	vin->digital->source_pad = ret;
 
 	ret = rvin_find_pad(subdev, MEDIA_PAD_FL_SINK);
-	vin->digital.sink_pad = ret < 0 ? 0 : ret;
+	vin->digital->sink_pad = ret < 0 ? 0 : ret;
 
-	vin->digital.subdev = subdev;
+	vin->digital->subdev = subdev;
 
 	vin_dbg(vin, "bound subdev %s source pad: %u sink pad: %u\n",
-		subdev->name, vin->digital.source_pad,
-		vin->digital.sink_pad);
+		subdev->name, vin->digital->source_pad,
+		vin->digital->sink_pad);
 
 	return 0;
 }
 
-static int rvin_digitial_parse_v4l2(struct rvin_dev *vin,
-				    struct device_node *ep,
-				    struct v4l2_mbus_config *mbus_cfg)
+static int rvin_digital_parse_v4l2(struct device *dev,
+				   struct v4l2_fwnode_endpoint *vep,
+				   struct v4l2_async_subdev *asd)
 {
-	struct v4l2_fwnode_endpoint v4l2_ep;
-	int ret;
-
-	ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(ep), &v4l2_ep);
-	if (ret) {
-		vin_err(vin, "Could not parse v4l2 endpoint\n");
-		return -EINVAL;
-	}
+	struct rvin_dev *vin = dev_get_drvdata(dev);
+	struct rvin_graph_entity *rvge =
+		container_of(asd, struct rvin_graph_entity, asd);
 
-	mbus_cfg->type = v4l2_ep.bus_type;
+	rvge->mbus_cfg.type = vep->bus_type;
 
-	switch (mbus_cfg->type) {
+	switch (rvge->mbus_cfg.type) {
 	case V4L2_MBUS_PARALLEL:
 		vin_dbg(vin, "Found PARALLEL media bus\n");
-		mbus_cfg->flags = v4l2_ep.bus.parallel.flags;
+		rvge->mbus_cfg.flags = vep->bus.parallel.flags;
 		break;
 	case V4L2_MBUS_BT656:
 		vin_dbg(vin, "Found BT656 media bus\n");
-		mbus_cfg->flags = 0;
+		rvge->mbus_cfg.flags = 0;
 		break;
 	default:
 		vin_err(vin, "Unknown media bus type\n");
 		return -EINVAL;
 	}
 
-	return 0;
-}
-
-static int rvin_digital_graph_parse(struct rvin_dev *vin)
-{
-	struct device_node *ep, *np;
-	int ret;
-
-	vin->digital.asd.match.fwnode.fwnode = NULL;
-	vin->digital.subdev = NULL;
-
-	/*
-	 * Port 0 id 0 is local digital input, try to get it.
-	 * Not all instances can or will have this, that is OK
-	 */
-	ep = of_graph_get_endpoint_by_regs(vin->dev->of_node, 0, 0);
-	if (!ep)
-		return 0;
-
-	np = of_graph_get_remote_port_parent(ep);
-	if (!np) {
-		vin_err(vin, "No remote parent for digital input\n");
-		of_node_put(ep);
-		return -EINVAL;
-	}
-	of_node_put(np);
-
-	ret = rvin_digitial_parse_v4l2(vin, ep, &vin->digital.mbus_cfg);
-	of_node_put(ep);
-	if (ret)
-		return ret;
-
-	vin->digital.asd.match.fwnode.fwnode = of_fwnode_handle(np);
-	vin->digital.asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
+	vin->digital = rvge;
 
 	return 0;
 }
 
 static int rvin_digital_graph_init(struct rvin_dev *vin)
 {
-	struct v4l2_async_subdev **subdevs = NULL;
 	int ret;
 
-	ret = rvin_digital_graph_parse(vin);
+	ret = v4l2_async_notifier_parse_fwnode_endpoint(
+		vin->dev, &vin->notifier, 0, 0,
+		sizeof(struct rvin_graph_entity), rvin_digital_parse_v4l2);
 	if (ret)
 		return ret;
 
-	if (!vin->digital.asd.match.fwnode.fwnode) {
-		vin_dbg(vin, "No digital subdevice found\n");
-		return -ENODEV;
-	}
-
-	/* Register the subdevices notifier. */
-	subdevs = devm_kzalloc(vin->dev, sizeof(*subdevs), GFP_KERNEL);
-	if (subdevs == NULL)
-		return -ENOMEM;
+	if (vin->notifier.num_subdevs > 0)
+		vin_dbg(vin, "Found digital subdevice %pOF\n",
+			to_of_node(
+				vin->notifier.subdevs[0]->match.fwnode.fwnode));
 
-	subdevs[0] = &vin->digital.asd;
-
-	vin_dbg(vin, "Found digital subdevice %pOF\n",
-		to_of_node(subdevs[0]->match.fwnode.fwnode));
-
-	vin->notifier.num_subdevs = 1;
-	vin->notifier.subdevs = subdevs;
 	vin->notifier.bound = rvin_digital_notify_bound;
 	vin->notifier.unbind = rvin_digital_notify_unbind;
 	vin->notifier.complete = rvin_digital_notify_complete;
-
 	ret = v4l2_async_notifier_register(&vin->v4l2_dev, &vin->notifier);
 	if (ret < 0) {
 		vin_err(vin, "Notifier registration failed\n");
@@ -290,6 +241,8 @@ static int rcar_vin_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	platform_set_drvdata(pdev, vin);
+
 	ret = rvin_digital_graph_init(vin);
 	if (ret < 0)
 		goto error;
@@ -297,11 +250,10 @@ static int rcar_vin_probe(struct platform_device *pdev)
 	pm_suspend_ignore_children(&pdev->dev, true);
 	pm_runtime_enable(&pdev->dev);
 
-	platform_set_drvdata(pdev, vin);
-
 	return 0;
 error:
 	rvin_dma_remove(vin);
+	v4l2_async_notifier_release(&vin->notifier);
 
 	return ret;
 }
@@ -313,6 +265,7 @@ static int rcar_vin_remove(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 
 	v4l2_async_notifier_unregister(&vin->notifier);
+	v4l2_async_notifier_release(&vin->notifier);
 
 	rvin_dma_remove(vin);
 
diff --git a/drivers/media/platform/rcar-vin/rcar-dma.c b/drivers/media/platform/rcar-vin/rcar-dma.c
index b136844499f6..23fdff7a7370 100644
--- a/drivers/media/platform/rcar-vin/rcar-dma.c
+++ b/drivers/media/platform/rcar-vin/rcar-dma.c
@@ -183,7 +183,7 @@ static int rvin_setup(struct rvin_dev *vin)
 	/*
 	 * Input interface
 	 */
-	switch (vin->digital.code) {
+	switch (vin->digital->code) {
 	case MEDIA_BUS_FMT_YUYV8_1X16:
 		/* BT.601/BT.1358 16bit YCbCr422 */
 		vnmc |= VNMC_INF_YUV16;
@@ -191,7 +191,7 @@ static int rvin_setup(struct rvin_dev *vin)
 		break;
 	case MEDIA_BUS_FMT_UYVY8_2X8:
 		/* BT.656 8bit YCbCr422 or BT.601 8bit YCbCr422 */
-		vnmc |= vin->digital.mbus_cfg.type == V4L2_MBUS_BT656 ?
+		vnmc |= vin->digital->mbus_cfg.type == V4L2_MBUS_BT656 ?
 			VNMC_INF_YUV8_BT656 : VNMC_INF_YUV8_BT601;
 		input_is_yuv = true;
 		break;
@@ -200,7 +200,7 @@ static int rvin_setup(struct rvin_dev *vin)
 		break;
 	case MEDIA_BUS_FMT_UYVY10_2X10:
 		/* BT.656 10bit YCbCr422 or BT.601 10bit YCbCr422 */
-		vnmc |= vin->digital.mbus_cfg.type == V4L2_MBUS_BT656 ?
+		vnmc |= vin->digital->mbus_cfg.type == V4L2_MBUS_BT656 ?
 			VNMC_INF_YUV10_BT656 : VNMC_INF_YUV10_BT601;
 		input_is_yuv = true;
 		break;
@@ -212,11 +212,11 @@ static int rvin_setup(struct rvin_dev *vin)
 	dmr2 = VNDMR2_FTEV | VNDMR2_VLV(1);
 
 	/* Hsync Signal Polarity Select */
-	if (!(vin->digital.mbus_cfg.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW))
+	if (!(vin->digital->mbus_cfg.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW))
 		dmr2 |= VNDMR2_HPS;
 
 	/* Vsync Signal Polarity Select */
-	if (!(vin->digital.mbus_cfg.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW))
+	if (!(vin->digital->mbus_cfg.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW))
 		dmr2 |= VNDMR2_VPS;
 
 	/*
diff --git a/drivers/media/platform/rcar-vin/rcar-v4l2.c b/drivers/media/platform/rcar-vin/rcar-v4l2.c
index dd37ea811680..b479b882da12 100644
--- a/drivers/media/platform/rcar-vin/rcar-v4l2.c
+++ b/drivers/media/platform/rcar-vin/rcar-v4l2.c
@@ -111,7 +111,7 @@ static int rvin_reset_format(struct rvin_dev *vin)
 	struct v4l2_mbus_framefmt *mf = &fmt.format;
 	int ret;
 
-	fmt.pad = vin->digital.source_pad;
+	fmt.pad = vin->digital->source_pad;
 
 	ret = v4l2_subdev_call(vin_to_source(vin), pad, get_fmt, NULL, &fmt);
 	if (ret)
@@ -172,13 +172,13 @@ static int __rvin_try_format_source(struct rvin_dev *vin,
 
 	sd = vin_to_source(vin);
 
-	v4l2_fill_mbus_format(&format.format, pix, vin->digital.code);
+	v4l2_fill_mbus_format(&format.format, pix, vin->digital->code);
 
 	pad_cfg = v4l2_subdev_alloc_pad_config(sd);
 	if (pad_cfg == NULL)
 		return -ENOMEM;
 
-	format.pad = vin->digital.source_pad;
+	format.pad = vin->digital->source_pad;
 
 	field = pix->field;
 
@@ -555,7 +555,7 @@ static int rvin_enum_dv_timings(struct file *file, void *priv_fh,
 	if (timings->pad)
 		return -EINVAL;
 
-	timings->pad = vin->digital.sink_pad;
+	timings->pad = vin->digital->sink_pad;
 
 	ret = v4l2_subdev_call(sd, pad, enum_dv_timings, timings);
 
@@ -607,7 +607,7 @@ static int rvin_dv_timings_cap(struct file *file, void *priv_fh,
 	if (cap->pad)
 		return -EINVAL;
 
-	cap->pad = vin->digital.sink_pad;
+	cap->pad = vin->digital->sink_pad;
 
 	ret = v4l2_subdev_call(sd, pad, dv_timings_cap, cap);
 
@@ -625,7 +625,7 @@ static int rvin_g_edid(struct file *file, void *fh, struct v4l2_edid *edid)
 	if (edid->pad)
 		return -EINVAL;
 
-	edid->pad = vin->digital.sink_pad;
+	edid->pad = vin->digital->sink_pad;
 
 	ret = v4l2_subdev_call(sd, pad, get_edid, edid);
 
@@ -643,7 +643,7 @@ static int rvin_s_edid(struct file *file, void *fh, struct v4l2_edid *edid)
 	if (edid->pad)
 		return -EINVAL;
 
-	edid->pad = vin->digital.sink_pad;
+	edid->pad = vin->digital->sink_pad;
 
 	ret = v4l2_subdev_call(sd, pad, set_edid, edid);
 
diff --git a/drivers/media/platform/rcar-vin/rcar-vin.h b/drivers/media/platform/rcar-vin/rcar-vin.h
index 9bfb5a7c4dc4..5382078143fb 100644
--- a/drivers/media/platform/rcar-vin/rcar-vin.h
+++ b/drivers/media/platform/rcar-vin/rcar-vin.h
@@ -126,7 +126,7 @@ struct rvin_dev {
 	struct v4l2_device v4l2_dev;
 	struct v4l2_ctrl_handler ctrl_handler;
 	struct v4l2_async_notifier notifier;
-	struct rvin_graph_entity digital;
+	struct rvin_graph_entity *digital;
 
 	struct mutex lock;
 	struct vb2_queue queue;
@@ -145,7 +145,7 @@ struct rvin_dev {
 	struct v4l2_rect compose;
 };
 
-#define vin_to_source(vin)		vin->digital.subdev
+#define vin_to_source(vin)		((vin)->digital->subdev)
 
 /* Debug */
 #define vin_dbg(d, fmt, arg...)		dev_dbg(d->dev, fmt, ##arg)
diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
index 2496d76eef4b..4720e8a043cf 100644
--- a/drivers/media/v4l2-core/v4l2-fwnode.c
+++ b/drivers/media/v4l2-core/v4l2-fwnode.c
@@ -444,6 +444,53 @@ int v4l2_async_notifier_parse_fwnode_endpoints(
 }
 EXPORT_SYMBOL_GPL(v4l2_async_notifier_parse_fwnode_endpoints);
 
+int v4l2_async_notifier_parse_fwnode_endpoint(
+	struct device *dev, struct v4l2_async_notifier *notifier,
+	unsigned int port_id, unsigned int endpoint_id, size_t asd_struct_size,
+	int (*parse_single)(struct device *dev,
+			    struct v4l2_fwnode_endpoint *vep,
+			    struct v4l2_async_subdev *asd))
+{
+	struct fwnode_handle *fwnode = NULL;
+	int ret;
+
+	while ((fwnode = fwnode_graph_get_next_endpoint(
+			dev_fwnode(dev), fwnode))) {
+		struct fwnode_endpoint ep;
+
+		ret = fwnode_graph_parse_endpoint(fwnode, &ep);
+		if (ret < 0)
+			continue;
+
+		if (!fwnode_device_is_available(
+			    fwnode_graph_get_port_parent(fwnode)))
+			continue;
+
+		if (ep.port == port_id && ep.id == endpoint_id)
+			break;
+	}
+
+	if (!fwnode)
+		return -ENOENT;
+
+	ret = v4l2_async_notifier_realloc(notifier, notifier->num_subdevs + 1);
+	if (ret)
+		goto out_err;
+
+	ret = v4l2_async_notifier_fwnode_parse_endpoint(
+		dev, notifier, fwnode, asd_struct_size, parse_single);
+	if (ret)
+		goto out_err;
+
+	return 0;
+
+out_err:
+	fwnode_handle_put(fwnode);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(v4l2_async_notifier_parse_fwnode_endpoint);
+
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Sakari Ailus <sakari.ailus@linux.intel.com>");
 MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@samsung.com>");
diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
index d063ab4ff67b..dd13604178b4 100644
--- a/include/media/v4l2-fwnode.h
+++ b/include/media/v4l2-fwnode.h
@@ -249,4 +249,53 @@ int v4l2_async_notifier_parse_fwnode_endpoints(
 			    struct v4l2_fwnode_endpoint *vep,
 			    struct v4l2_async_subdev *asd));
 
+/**
+ * v4l2_async_notifier_parse_fwnode_endpoint - Set up async notifier for an
+ *					       fwnode based sub-device
+ * @dev: @struct device pointer
+ * @notifier: pointer to &struct v4l2_async_notifier
+ * @port_id: port number
+ * @endpoint_id: endpoint number
+ * @asd_struct_size: size of the driver's async sub-device struct, including
+ *		     sizeof(struct v4l2_async_subdev). The &struct
+ *		     v4l2_async_subdev shall be the first member of
+ *		     the driver's async sub-device struct, i.e. both
+ *		     begin at the same memory address.
+ * @parse_single: driver's callback function called on each V4L2 fwnode endpoint
+ *
+ * Parse the fwnode endpoint of the @dev device corresponding to the given port
+ * and endpoint numbres and populate the async sub- devices array of the
+ * notifier. The @parse_endpoint callback function is called for the endpoint
+ * with the corresponding async sub-device pointer to let the caller initialize
+ * the driver-specific part of the async sub-device structure.
+ *
+ * The notifier memory shall be zeroed before this function is called on the
+ * notifier.
+ *
+ * This function may not be called on a registered notifier and may be called on
+ * a notifier once or more times, but may not be called more than once on a
+ * given port / endpoint pair. When using this function, the user may not access
+ * the notifier's subdevs array nor change notifier's num_subdevs field, these
+ * are reserved for the framework's internal use only.
+ *
+ * The @struct v4l2_fwnode_endpoint passed to the callback function
+ * @parse_single is released once the function is finished. If there is a need
+ * to retain that configuration, the user needs to allocate memory for it.
+ *
+ * Any notifier populated using this function must be released with a call to
+ * v4l2_async_notifier_release() after it has been unregistered and the async
+ * sub-devices are no longer in use.
+ *
+ * Return: %0 on success, including when no async sub-devices are found
+ *	   %-ENOMEM if memory allocation failed
+ *	   %-EINVAL if graph or endpoint parsing failed
+ *	   Other error codes as returned by @parse_single
+ */
+int v4l2_async_notifier_parse_fwnode_endpoint(
+	struct device *dev, struct v4l2_async_notifier *notifier,
+	unsigned int port_id, unsigned int endpoint_id, size_t asd_struct_size,
+	int (*parse_single)(struct device *dev,
+			    struct v4l2_fwnode_endpoint *vep,
+			    struct v4l2_async_subdev *asd));
+
 #endif /* _V4L2_FWNODE_H */
-- 
2.11.0

[PATCH v6.1 4/5] v4l: fwnode: Support generic parsing of graph endpoints in a device

[Sakari Ailus]

The current practice is that drivers iterate over their endpoints and
parse each endpoint separately. This is very similar in a number of
drivers, implement a generic function for the job. Driver specific matters
can be taken into account in the driver specific callback.

Convert the omap3isp as an example.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
since v6:

- Set notifier->subdevs NULL and notifier->num_subdevs 0 in
  v4l2_async_notifier_release().

 drivers/media/platform/omap3isp/isp.c | 115 ++++++++++-------------------
 drivers/media/platform/omap3isp/isp.h |   5 +-
 drivers/media/v4l2-core/v4l2-async.c  |  16 +++++
 drivers/media/v4l2-core/v4l2-fwnode.c | 131 ++++++++++++++++++++++++++++++++++
 include/media/v4l2-async.h            |  24 ++++++-
 include/media/v4l2-fwnode.h           |  48 +++++++++++++
 6 files changed, 254 insertions(+), 85 deletions(-)

diff --git a/drivers/media/platform/omap3isp/isp.c b/drivers/media/platform/omap3isp/isp.c
index 1a428fe9f070..a546cf774d40 100644
--- a/drivers/media/platform/omap3isp/isp.c
+++ b/drivers/media/platform/omap3isp/isp.c
@@ -2001,6 +2001,7 @@ static int isp_remove(struct platform_device *pdev)
 	__omap3isp_put(isp, false);
 
 	media_entity_enum_cleanup(&isp->crashed);
+	v4l2_async_notifier_release(&isp->notifier);
 
 	return 0;
 }
@@ -2011,44 +2012,41 @@ enum isp_of_phy {
 	ISP_OF_PHY_CSIPHY2,
 };
 
-static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
-			    struct isp_async_subdev *isd)
+static int isp_fwnode_parse(struct device *dev,
+			    struct v4l2_fwnode_endpoint *vep,
+			    struct v4l2_async_subdev *asd)
 {
+	struct isp_async_subdev *isd =
+		container_of(asd, struct isp_async_subdev, asd);
 	struct isp_bus_cfg *buscfg = &isd->bus;
-	struct v4l2_fwnode_endpoint vep;
-	unsigned int i;
-	int ret;
 	bool csi1 = false;
-
-	ret = v4l2_fwnode_endpoint_parse(fwnode, &vep);
-	if (ret)
-		return ret;
+	unsigned int i;
 
 	dev_dbg(dev, "parsing endpoint %pOF, interface %u\n",
-		to_of_node(fwnode), vep.base.port);
+		to_of_node(vep->base.local_fwnode), vep->base.port);
 
-	switch (vep.base.port) {
+	switch (vep->base.port) {
 	case ISP_OF_PHY_PARALLEL:
 		buscfg->interface = ISP_INTERFACE_PARALLEL;
 		buscfg->bus.parallel.data_lane_shift =
-			vep.bus.parallel.data_shift;
+			vep->bus.parallel.data_shift;
 		buscfg->bus.parallel.clk_pol =
-			!!(vep.bus.parallel.flags
+			!!(vep->bus.parallel.flags
 			   & V4L2_MBUS_PCLK_SAMPLE_FALLING);
 		buscfg->bus.parallel.hs_pol =
-			!!(vep.bus.parallel.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW);
+			!!(vep->bus.parallel.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW);
 		buscfg->bus.parallel.vs_pol =
-			!!(vep.bus.parallel.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW);
+			!!(vep->bus.parallel.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW);
 		buscfg->bus.parallel.fld_pol =
-			!!(vep.bus.parallel.flags & V4L2_MBUS_FIELD_EVEN_LOW);
+			!!(vep->bus.parallel.flags & V4L2_MBUS_FIELD_EVEN_LOW);
 		buscfg->bus.parallel.data_pol =
-			!!(vep.bus.parallel.flags & V4L2_MBUS_DATA_ACTIVE_LOW);
-		buscfg->bus.parallel.bt656 = vep.bus_type == V4L2_MBUS_BT656;
+			!!(vep->bus.parallel.flags & V4L2_MBUS_DATA_ACTIVE_LOW);
+		buscfg->bus.parallel.bt656 = vep->bus_type == V4L2_MBUS_BT656;
 		break;
 
 	case ISP_OF_PHY_CSIPHY1:
 	case ISP_OF_PHY_CSIPHY2:
-		switch (vep.bus_type) {
+		switch (vep->bus_type) {
 		case V4L2_MBUS_CCP2:
 		case V4L2_MBUS_CSI1:
 			dev_dbg(dev, "CSI-1/CCP-2 configuration\n");
@@ -2060,11 +2058,11 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
 			break;
 		default:
 			dev_err(dev, "unsupported bus type %u\n",
-				vep.bus_type);
+				vep->bus_type);
 			return -EINVAL;
 		}
 
-		switch (vep.base.port) {
+		switch (vep->base.port) {
 		case ISP_OF_PHY_CSIPHY1:
 			if (csi1)
 				buscfg->interface = ISP_INTERFACE_CCP2B_PHY1;
@@ -2080,47 +2078,47 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
 		}
 		if (csi1) {
 			buscfg->bus.ccp2.lanecfg.clk.pos =
-				vep.bus.mipi_csi1.clock_lane;
+				vep->bus.mipi_csi1.clock_lane;
 			buscfg->bus.ccp2.lanecfg.clk.pol =
-				vep.bus.mipi_csi1.lane_polarity[0];
+				vep->bus.mipi_csi1.lane_polarity[0];
 			dev_dbg(dev, "clock lane polarity %u, pos %u\n",
 				buscfg->bus.ccp2.lanecfg.clk.pol,
 				buscfg->bus.ccp2.lanecfg.clk.pos);
 
 			buscfg->bus.ccp2.lanecfg.data[0].pos =
-				vep.bus.mipi_csi1.data_lane;
+				vep->bus.mipi_csi1.data_lane;
 			buscfg->bus.ccp2.lanecfg.data[0].pol =
-				vep.bus.mipi_csi1.lane_polarity[1];
+				vep->bus.mipi_csi1.lane_polarity[1];
 
 			dev_dbg(dev, "data lane polarity %u, pos %u\n",
 				buscfg->bus.ccp2.lanecfg.data[0].pol,
 				buscfg->bus.ccp2.lanecfg.data[0].pos);
 
 			buscfg->bus.ccp2.strobe_clk_pol =
-				vep.bus.mipi_csi1.clock_inv;
-			buscfg->bus.ccp2.phy_layer = vep.bus.mipi_csi1.strobe;
+				vep->bus.mipi_csi1.clock_inv;
+			buscfg->bus.ccp2.phy_layer = vep->bus.mipi_csi1.strobe;
 			buscfg->bus.ccp2.ccp2_mode =
-				vep.bus_type == V4L2_MBUS_CCP2;
+				vep->bus_type == V4L2_MBUS_CCP2;
 			buscfg->bus.ccp2.vp_clk_pol = 1;
 
 			buscfg->bus.ccp2.crc = 1;
 		} else {
 			buscfg->bus.csi2.lanecfg.clk.pos =
-				vep.bus.mipi_csi2.clock_lane;
+				vep->bus.mipi_csi2.clock_lane;
 			buscfg->bus.csi2.lanecfg.clk.pol =
-				vep.bus.mipi_csi2.lane_polarities[0];
+				vep->bus.mipi_csi2.lane_polarities[0];
 			dev_dbg(dev, "clock lane polarity %u, pos %u\n",
 				buscfg->bus.csi2.lanecfg.clk.pol,
 				buscfg->bus.csi2.lanecfg.clk.pos);
 
 			buscfg->bus.csi2.num_data_lanes =
-				vep.bus.mipi_csi2.num_data_lanes;
+				vep->bus.mipi_csi2.num_data_lanes;
 
 			for (i = 0; i < buscfg->bus.csi2.num_data_lanes; i++) {
 				buscfg->bus.csi2.lanecfg.data[i].pos =
-					vep.bus.mipi_csi2.data_lanes[i];
+					vep->bus.mipi_csi2.data_lanes[i];
 				buscfg->bus.csi2.lanecfg.data[i].pol =
-					vep.bus.mipi_csi2.lane_polarities[i + 1];
+					vep->bus.mipi_csi2.lane_polarities[i + 1];
 				dev_dbg(dev,
 					"data lane %u polarity %u, pos %u\n", i,
 					buscfg->bus.csi2.lanecfg.data[i].pol,
@@ -2137,57 +2135,13 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
 
 	default:
 		dev_warn(dev, "%pOF: invalid interface %u\n",
-			 to_of_node(fwnode), vep.base.port);
+			 to_of_node(vep->base.local_fwnode), vep->base.port);
 		return -EINVAL;
 	}
 
 	return 0;
 }
 
-static int isp_fwnodes_parse(struct device *dev,
-			     struct v4l2_async_notifier *notifier)
-{
-	struct fwnode_handle *fwnode = NULL;
-
-	notifier->subdevs = devm_kcalloc(
-		dev, ISP_MAX_SUBDEVS, sizeof(*notifier->subdevs), GFP_KERNEL);
-	if (!notifier->subdevs)
-		return -ENOMEM;
-
-	while (notifier->num_subdevs < ISP_MAX_SUBDEVS &&
-	       (fwnode = fwnode_graph_get_next_endpoint(
-			of_fwnode_handle(dev->of_node), fwnode))) {
-		struct isp_async_subdev *isd;
-
-		isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
-		if (!isd)
-			goto error;
-
-		if (isp_fwnode_parse(dev, fwnode, isd)) {
-			devm_kfree(dev, isd);
-			continue;
-		}
-
-		notifier->subdevs[notifier->num_subdevs] = &isd->asd;
-
-		isd->asd.match.fwnode.fwnode =
-			fwnode_graph_get_remote_port_parent(fwnode);
-		if (!isd->asd.match.fwnode.fwnode) {
-			dev_warn(dev, "bad remote port parent\n");
-			goto error;
-		}
-
-		isd->asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
-		notifier->num_subdevs++;
-	}
-
-	return notifier->num_subdevs;
-
-error:
-	fwnode_handle_put(fwnode);
-	return -EINVAL;
-}
-
 static int isp_subdev_notifier_complete(struct v4l2_async_notifier *async)
 {
 	struct isp_device *isp = container_of(async, struct isp_device,
@@ -2256,7 +2210,9 @@ static int isp_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	ret = isp_fwnodes_parse(&pdev->dev, &isp->notifier);
+	ret = v4l2_async_notifier_parse_fwnode_endpoints(
+		&pdev->dev, &isp->notifier, sizeof(struct isp_async_subdev),
+		isp_fwnode_parse);
 	if (ret < 0)
 		return ret;
 
@@ -2407,6 +2363,7 @@ static int isp_probe(struct platform_device *pdev)
 	__omap3isp_put(isp, false);
 error:
 	mutex_destroy(&isp->isp_mutex);
+	v4l2_async_notifier_release(&isp->notifier);
 
 	return ret;
 }
diff --git a/drivers/media/platform/omap3isp/isp.h b/drivers/media/platform/omap3isp/isp.h
index e528df6efc09..8b9043db94b3 100644
--- a/drivers/media/platform/omap3isp/isp.h
+++ b/drivers/media/platform/omap3isp/isp.h
@@ -220,14 +220,11 @@ struct isp_device {
 
 	unsigned int sbl_resources;
 	unsigned int subclk_resources;
-
-#define ISP_MAX_SUBDEVS		8
-	struct v4l2_subdev *subdevs[ISP_MAX_SUBDEVS];
 };
 
 struct isp_async_subdev {
-	struct isp_bus_cfg bus;
 	struct v4l2_async_subdev asd;
+	struct isp_bus_cfg bus;
 };
 
 #define v4l2_subdev_to_bus_cfg(sd) \
diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
index 851f128eba22..6740a241d4a1 100644
--- a/drivers/media/v4l2-core/v4l2-async.c
+++ b/drivers/media/v4l2-core/v4l2-async.c
@@ -22,6 +22,7 @@
 
 #include <media/v4l2-async.h>
 #include <media/v4l2-device.h>
+#include <media/v4l2-fwnode.h>
 #include <media/v4l2-subdev.h>
 
 static bool match_i2c(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
@@ -278,6 +279,21 @@ void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
 }
 EXPORT_SYMBOL(v4l2_async_notifier_unregister);
 
+void v4l2_async_notifier_release(struct v4l2_async_notifier *notifier)
+{
+	unsigned int i;
+
+	for (i = 0; i < notifier->num_subdevs; i++)
+		kfree(notifier->subdevs[i]);
+
+	notifier->max_subdevs = 0;
+	notifier->num_subdevs = 0;
+
+	kvfree(notifier->subdevs);
+	notifier->subdevs = NULL;
+}
+EXPORT_SYMBOL_GPL(v4l2_async_notifier_release);
+
 int v4l2_async_register_subdev(struct v4l2_subdev *sd)
 {
 	struct v4l2_async_notifier *notifier;
diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
index 706f9e7b90f1..2496d76eef4b 100644
--- a/drivers/media/v4l2-core/v4l2-fwnode.c
+++ b/drivers/media/v4l2-core/v4l2-fwnode.c
@@ -19,6 +19,7 @@
  */
 #include <linux/acpi.h>
 #include <linux/kernel.h>
+#include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/property.h>
@@ -26,6 +27,7 @@
 #include <linux/string.h>
 #include <linux/types.h>
 
+#include <media/v4l2-async.h>
 #include <media/v4l2-fwnode.h>
 
 enum v4l2_fwnode_bus_type {
@@ -313,6 +315,135 @@ void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link)
 }
 EXPORT_SYMBOL_GPL(v4l2_fwnode_put_link);
 
+static int v4l2_async_notifier_realloc(struct v4l2_async_notifier *notifier,
+				       unsigned int max_subdevs)
+{
+	struct v4l2_async_subdev **subdevs;
+
+	if (max_subdevs <= notifier->max_subdevs)
+		return 0;
+
+	subdevs = kvmalloc_array(
+		max_subdevs, sizeof(*notifier->subdevs),
+		GFP_KERNEL | __GFP_ZERO);
+	if (!subdevs)
+		return -ENOMEM;
+
+	if (notifier->subdevs) {
+		memcpy(subdevs, notifier->subdevs,
+		       sizeof(*subdevs) * notifier->num_subdevs);
+
+		kvfree(notifier->subdevs);
+	}
+
+	notifier->subdevs = subdevs;
+	notifier->max_subdevs = max_subdevs;
+
+	return 0;
+}
+
+static int v4l2_async_notifier_fwnode_parse_endpoint(
+	struct device *dev, struct v4l2_async_notifier *notifier,
+	struct fwnode_handle *endpoint, unsigned int asd_struct_size,
+	int (*parse_single)(struct device *dev,
+			    struct v4l2_fwnode_endpoint *vep,
+			    struct v4l2_async_subdev *asd))
+{
+	struct v4l2_async_subdev *asd;
+	struct v4l2_fwnode_endpoint *vep;
+	int ret = 0;
+
+	asd = kzalloc(asd_struct_size, GFP_KERNEL);
+	if (!asd)
+		return -ENOMEM;
+
+	asd->match.fwnode.fwnode =
+		fwnode_graph_get_remote_port_parent(endpoint);
+	if (!asd->match.fwnode.fwnode) {
+		dev_warn(dev, "bad remote port parent\n");
+		ret = -EINVAL;
+		goto out_err;
+	}
+
+	/* Ignore endpoints the parsing of which failed. */
+	vep = v4l2_fwnode_endpoint_alloc_parse(endpoint);
+	if (IS_ERR(vep)) {
+		ret = PTR_ERR(vep);
+		dev_warn(dev, "unable to parse V4L2 fwnode endpoint (%d)\n",
+			 ret);
+		goto out_err;
+	}
+
+	ret = parse_single(dev, vep, asd);
+	v4l2_fwnode_endpoint_free(vep);
+	if (ret) {
+		dev_warn(dev, "driver could not parse endpoint (%d)\n", ret);
+		goto out_err;
+	}
+
+	asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
+	notifier->subdevs[notifier->num_subdevs] = asd;
+	notifier->num_subdevs++;
+
+	return 0;
+
+out_err:
+	fwnode_handle_put(asd->match.fwnode.fwnode);
+	kfree(asd);
+
+	return ret;
+}
+
+int v4l2_async_notifier_parse_fwnode_endpoints(
+	struct device *dev, struct v4l2_async_notifier *notifier,
+	size_t asd_struct_size,
+	int (*parse_single)(struct device *dev,
+			    struct v4l2_fwnode_endpoint *vep,
+			    struct v4l2_async_subdev *asd))
+{
+	struct fwnode_handle *fwnode = NULL;
+	unsigned int max_subdevs = notifier->max_subdevs;
+	int ret;
+
+	if (asd_struct_size < sizeof(struct v4l2_async_subdev) ||
+	    notifier->v4l2_dev)
+		return -EINVAL;
+
+	for (fwnode = NULL; (fwnode = fwnode_graph_get_next_endpoint(
+				     dev_fwnode(dev), fwnode)); )
+		if (fwnode_device_is_available(
+			    fwnode_graph_get_port_parent(fwnode)))
+			max_subdevs++;
+
+	/* No subdevs to add? Return here. */
+	if (max_subdevs == notifier->max_subdevs)
+		return 0;
+
+	ret = v4l2_async_notifier_realloc(notifier, max_subdevs);
+	if (ret)
+		return ret;
+
+	for (fwnode = NULL; (fwnode = fwnode_graph_get_next_endpoint(
+				     dev_fwnode(dev), fwnode)); ) {
+		if (!fwnode_device_is_available(
+			    fwnode_graph_get_port_parent(fwnode)))
+			continue;
+
+		if (WARN_ON(notifier->num_subdevs >= notifier->max_subdevs))
+			break;
+
+		ret = v4l2_async_notifier_fwnode_parse_endpoint(
+			dev, notifier, fwnode, asd_struct_size, parse_single);
+		if (ret < 0)
+			break;
+	}
+
+	fwnode_handle_put(fwnode);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(v4l2_async_notifier_parse_fwnode_endpoints);
+
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Sakari Ailus <sakari.ailus@linux.intel.com>");
 MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@samsung.com>");
diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
index c69d8c8a66d0..cf13c7311a1c 100644
--- a/include/media/v4l2-async.h
+++ b/include/media/v4l2-async.h
@@ -18,7 +18,6 @@ struct device;
 struct device_node;
 struct v4l2_device;
 struct v4l2_subdev;
-struct v4l2_async_notifier;
 
 /* A random max subdevice number, used to allocate an array on stack */
 #define V4L2_MAX_SUBDEVS 128U
@@ -50,6 +49,10 @@ enum v4l2_async_match_type {
  * @match:	union of per-bus type matching data sets
  * @list:	used to link struct v4l2_async_subdev objects, waiting to be
  *		probed, to a notifier->waiting list
+ *
+ * When the struct is used as the first member of a driver specific
+ * struct, the driver specific struct shall contain the @struct
+ * v4l2_async_subdev as its first member.
  */
 struct v4l2_async_subdev {
 	enum v4l2_async_match_type match_type;
@@ -78,7 +81,8 @@ struct v4l2_async_subdev {
 /**
  * struct v4l2_async_notifier - v4l2_device notifier data
  *
- * @num_subdevs: number of subdevices
+ * @num_subdevs: number of subdevices used in subdevs array
+ * @max_subdevs: number of subdevices allocated in subdevs array
  * @subdevs:	array of pointers to subdevice descriptors
  * @v4l2_dev:	pointer to struct v4l2_device
  * @waiting:	list of struct v4l2_async_subdev, waiting for their drivers
@@ -90,6 +94,7 @@ struct v4l2_async_subdev {
  */
 struct v4l2_async_notifier {
 	unsigned int num_subdevs;
+	unsigned int max_subdevs;
 	struct v4l2_async_subdev **subdevs;
 	struct v4l2_device *v4l2_dev;
 	struct list_head waiting;
@@ -121,6 +126,21 @@ int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
 void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier);
 
 /**
+ * v4l2_async_notifier_release - release notifier resources
+ * @notifier: the notifier the resources of which are to be released
+ *
+ * Release memory resources related to a notifier, including the async
+ * sub-devices allocated for the purposes of the notifier. The user is
+ * responsible for releasing the notifier's resources after calling
+ * @v4l2_async_notifier_parse_fwnode_endpoints.
+ *
+ * There is no harm from calling v4l2_async_notifier_release in other
+ * cases as long as its memory has been zeroed after it has been
+ * allocated.
+ */
+void v4l2_async_notifier_release(struct v4l2_async_notifier *notifier);
+
+/**
  * v4l2_async_register_subdev - registers a sub-device to the asynchronous
  * 	subdevice framework
  *
diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
index 68eb22ba571b..d063ab4ff67b 100644
--- a/include/media/v4l2-fwnode.h
+++ b/include/media/v4l2-fwnode.h
@@ -25,6 +25,8 @@
 #include <media/v4l2-mediabus.h>
 
 struct fwnode_handle;
+struct v4l2_async_notifier;
+struct v4l2_async_subdev;
 
 #define V4L2_FWNODE_CSI2_MAX_DATA_LANES	4
 
@@ -201,4 +203,50 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,
  */
 void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link);
 
+/**
+ * v4l2_async_notifier_parse_fwnode_endpoints - Parse V4L2 fwnode endpoints in a
+ *						device node
+ * @dev: the device the endpoints of which are to be parsed
+ * @notifier: notifier for @dev
+ * @asd_struct_size: size of the driver's async sub-device struct, including
+ *		     sizeof(struct v4l2_async_subdev). The &struct
+ *		     v4l2_async_subdev shall be the first member of
+ *		     the driver's async sub-device struct, i.e. both
+ *		     begin at the same memory address.
+ * @parse_single: driver's callback function called on each V4L2 fwnode endpoint
+ *
+ * Parse the fwnode endpoints of the @dev device and populate the async sub-
+ * devices array of the notifier. The @parse_endpoint callback function is
+ * called for each endpoint with the corresponding async sub-device pointer to
+ * let the caller initialize the driver-specific part of the async sub-device
+ * structure.
+ *
+ * The notifier memory shall be zeroed before this function is called on the
+ * notifier.
+ *
+ * This function may not be called on a registered notifier and may be called on
+ * a notifier only once. When using this function, the user may not access the
+ * notifier's subdevs array nor change notifier's num_subdevs field, these are
+ * reserved for the framework's internal use only.
+ *
+ * The @struct v4l2_fwnode_endpoint passed to the callback function
+ * @parse_single is released once the function is finished. If there is a need
+ * to retain that configuration, the user needs to allocate memory for it.
+ *
+ * Any notifier populated using this function must be released with a call to
+ * v4l2_async_notifier_release() after it has been unregistered and the async
+ * sub-devices are no longer in use.
+ *
+ * Return: %0 on success, including when no async sub-devices are found
+ *	   %-ENOMEM if memory allocation failed
+ *	   %-EINVAL if graph or endpoint parsing failed
+ *	   Other error codes as returned by @parse_single
+ */
+int v4l2_async_notifier_parse_fwnode_endpoints(
+	struct device *dev, struct v4l2_async_notifier *notifier,
+	size_t asd_struct_size,
+	int (*parse_single)(struct device *dev,
+			    struct v4l2_fwnode_endpoint *vep,
+			    struct v4l2_async_subdev *asd));
+
 #endif /* _V4L2_FWNODE_H */
-- 
2.11.0

Re: [PATCH v6 1/5] v4l: fwnode: Move KernelDoc documentation to the header

[Hans Verkuil]

On 30/08/17 13:49, Sakari Ailus wrote:
> In V4L2 the practice is to have the KernelDoc documentation in the header
> and not in .c source code files. This consequientally makes the V4L2
> fwnode function documentation part of the Media documentation build.
> 
> Also correct the link related function and argument naming in
> documentation.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas-1zkq55x86MTxsAP9Fp7wbw@public.gmane.org>

Acked-by: Hans Verkuil <hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>

Regards,

	Hans

> ---
>  drivers/media/v4l2-core/v4l2-fwnode.c | 75 --------------------------------
>  include/media/v4l2-fwnode.h           | 81 ++++++++++++++++++++++++++++++++++-
>  2 files changed, 80 insertions(+), 76 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
> index 40b2fbfe8865..706f9e7b90f1 100644
> --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> @@ -181,25 +181,6 @@ v4l2_fwnode_endpoint_parse_csi1_bus(struct fwnode_handle *fwnode,
>  		vep->bus_type = V4L2_MBUS_CSI1;
>  }
>  
> -/**
> - * v4l2_fwnode_endpoint_parse() - parse all fwnode node properties
> - * @fwnode: pointer to the endpoint's fwnode handle
> - * @vep: pointer to the V4L2 fwnode data structure
> - *
> - * All properties are optional. If none are found, we don't set any flags. This
> - * means the port has a static configuration and no properties have to be
> - * specified explicitly. If any properties that identify the bus as parallel
> - * are found and slave-mode isn't set, we set V4L2_MBUS_MASTER. Similarly, if
> - * we recognise the bus as serial CSI-2 and clock-noncontinuous isn't set, we
> - * set the V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag. The caller should hold a
> - * reference to @fwnode.
> - *
> - * NOTE: This function does not parse properties the size of which is variable
> - * without a low fixed limit. Please use v4l2_fwnode_endpoint_alloc_parse() in
> - * new drivers instead.
> - *
> - * Return: 0 on success or a negative error code on failure.
> - */
>  int v4l2_fwnode_endpoint_parse(struct fwnode_handle *fwnode,
>  			       struct v4l2_fwnode_endpoint *vep)
>  {
> @@ -239,14 +220,6 @@ int v4l2_fwnode_endpoint_parse(struct fwnode_handle *fwnode,
>  }
>  EXPORT_SYMBOL_GPL(v4l2_fwnode_endpoint_parse);
>  
> -/*
> - * v4l2_fwnode_endpoint_free() - free the V4L2 fwnode acquired by
> - * v4l2_fwnode_endpoint_alloc_parse()
> - * @vep - the V4L2 fwnode the resources of which are to be released
> - *
> - * It is safe to call this function with NULL argument or on a V4L2 fwnode the
> - * parsing of which failed.
> - */
>  void v4l2_fwnode_endpoint_free(struct v4l2_fwnode_endpoint *vep)
>  {
>  	if (IS_ERR_OR_NULL(vep))
> @@ -257,29 +230,6 @@ void v4l2_fwnode_endpoint_free(struct v4l2_fwnode_endpoint *vep)
>  }
>  EXPORT_SYMBOL_GPL(v4l2_fwnode_endpoint_free);
>  
> -/**
> - * v4l2_fwnode_endpoint_alloc_parse() - parse all fwnode node properties
> - * @fwnode: pointer to the endpoint's fwnode handle
> - *
> - * All properties are optional. If none are found, we don't set any flags. This
> - * means the port has a static configuration and no properties have to be
> - * specified explicitly. If any properties that identify the bus as parallel
> - * are found and slave-mode isn't set, we set V4L2_MBUS_MASTER. Similarly, if
> - * we recognise the bus as serial CSI-2 and clock-noncontinuous isn't set, we
> - * set the V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag. The caller should hold a
> - * reference to @fwnode.
> - *
> - * v4l2_fwnode_endpoint_alloc_parse() has two important differences to
> - * v4l2_fwnode_endpoint_parse():
> - *
> - * 1. It also parses variable size data.
> - *
> - * 2. The memory it has allocated to store the variable size data must be freed
> - *    using v4l2_fwnode_endpoint_free() when no longer needed.
> - *
> - * Return: Pointer to v4l2_fwnode_endpoint if successful, on an error pointer
> - * on error.
> - */
>  struct v4l2_fwnode_endpoint *v4l2_fwnode_endpoint_alloc_parse(
>  	struct fwnode_handle *fwnode)
>  {
> @@ -322,24 +272,6 @@ struct v4l2_fwnode_endpoint *v4l2_fwnode_endpoint_alloc_parse(
>  }
>  EXPORT_SYMBOL_GPL(v4l2_fwnode_endpoint_alloc_parse);
>  
> -/**
> - * v4l2_fwnode_endpoint_parse_link() - parse a link between two endpoints
> - * @__fwnode: pointer to the endpoint's fwnode at the local end of the link
> - * @link: pointer to the V4L2 fwnode link data structure
> - *
> - * Fill the link structure with the local and remote nodes and port numbers.
> - * The local_node and remote_node fields are set to point to the local and
> - * remote port's parent nodes respectively (the port parent node being the
> - * parent node of the port node if that node isn't a 'ports' node, or the
> - * grand-parent node of the port node otherwise).
> - *
> - * A reference is taken to both the local and remote nodes, the caller must use
> - * v4l2_fwnode_endpoint_put_link() to drop the references when done with the
> - * link.
> - *
> - * Return: 0 on success, or -ENOLINK if the remote endpoint fwnode can't be
> - * found.
> - */
>  int v4l2_fwnode_parse_link(struct fwnode_handle *__fwnode,
>  			   struct v4l2_fwnode_link *link)
>  {
> @@ -374,13 +306,6 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *__fwnode,
>  }
>  EXPORT_SYMBOL_GPL(v4l2_fwnode_parse_link);
>  
> -/**
> - * v4l2_fwnode_put_link() - drop references to nodes in a link
> - * @link: pointer to the V4L2 fwnode link data structure
> - *
> - * Drop references to the local and remote nodes in the link. This function
> - * must be called on every link parsed with v4l2_fwnode_parse_link().
> - */
>  void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link)
>  {
>  	fwnode_handle_put(link->local_node);
> diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
> index 7adec9851d9e..68eb22ba571b 100644
> --- a/include/media/v4l2-fwnode.h
> +++ b/include/media/v4l2-fwnode.h
> @@ -113,13 +113,92 @@ struct v4l2_fwnode_link {
>  	unsigned int remote_port;
>  };
>  
> +/**
> + * v4l2_fwnode_endpoint_parse() - parse all fwnode node properties
> + * @fwnode: pointer to the endpoint's fwnode handle
> + * @vep: pointer to the V4L2 fwnode data structure
> + *
> + * All properties are optional. If none are found, we don't set any flags. This
> + * means the port has a static configuration and no properties have to be
> + * specified explicitly. If any properties that identify the bus as parallel
> + * are found and slave-mode isn't set, we set V4L2_MBUS_MASTER. Similarly, if
> + * we recognise the bus as serial CSI-2 and clock-noncontinuous isn't set, we
> + * set the V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag. The caller should hold a
> + * reference to @fwnode.
> + *
> + * NOTE: This function does not parse properties the size of which is variable
> + * without a low fixed limit. Please use v4l2_fwnode_endpoint_alloc_parse() in
> + * new drivers instead.
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
>  int v4l2_fwnode_endpoint_parse(struct fwnode_handle *fwnode,
>  			       struct v4l2_fwnode_endpoint *vep);
> +
> +/*
> + * v4l2_fwnode_endpoint_free() - free the V4L2 fwnode acquired by
> + * v4l2_fwnode_endpoint_alloc_parse()
> + * @vep - the V4L2 fwnode the resources of which are to be released
> + *
> + * It is safe to call this function with NULL argument or on a V4L2 fwnode the
> + * parsing of which failed.
> + */
> +void v4l2_fwnode_endpoint_free(struct v4l2_fwnode_endpoint *vep);
> +
> +/**
> + * v4l2_fwnode_endpoint_alloc_parse() - parse all fwnode node properties
> + * @fwnode: pointer to the endpoint's fwnode handle
> + *
> + * All properties are optional. If none are found, we don't set any flags. This
> + * means the port has a static configuration and no properties have to be
> + * specified explicitly. If any properties that identify the bus as parallel
> + * are found and slave-mode isn't set, we set V4L2_MBUS_MASTER. Similarly, if
> + * we recognise the bus as serial CSI-2 and clock-noncontinuous isn't set, we
> + * set the V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag. The caller should hold a
> + * reference to @fwnode.
> + *
> + * v4l2_fwnode_endpoint_alloc_parse() has two important differences to
> + * v4l2_fwnode_endpoint_parse():
> + *
> + * 1. It also parses variable size data.
> + *
> + * 2. The memory it has allocated to store the variable size data must be freed
> + *    using v4l2_fwnode_endpoint_free() when no longer needed.
> + *
> + * Return: Pointer to v4l2_fwnode_endpoint if successful, on an error pointer
> + * on error.
> + */
>  struct v4l2_fwnode_endpoint *v4l2_fwnode_endpoint_alloc_parse(
>  	struct fwnode_handle *fwnode);
> -void v4l2_fwnode_endpoint_free(struct v4l2_fwnode_endpoint *vep);
> +
> +/**
> + * v4l2_fwnode_parse_link() - parse a link between two endpoints
> + * @fwnode: pointer to the endpoint's fwnode at the local end of the link
> + * @link: pointer to the V4L2 fwnode link data structure
> + *
> + * Fill the link structure with the local and remote nodes and port numbers.
> + * The local_node and remote_node fields are set to point to the local and
> + * remote port's parent nodes respectively (the port parent node being the
> + * parent node of the port node if that node isn't a 'ports' node, or the
> + * grand-parent node of the port node otherwise).
> + *
> + * A reference is taken to both the local and remote nodes, the caller must use
> + * v4l2_fwnode_put_link() to drop the references when done with the
> + * link.
> + *
> + * Return: 0 on success, or -ENOLINK if the remote endpoint fwnode can't be
> + * found.
> + */
>  int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,
>  			   struct v4l2_fwnode_link *link);
> +
> +/**
> + * v4l2_fwnode_put_link() - drop references to nodes in a link
> + * @link: pointer to the V4L2 fwnode link data structure
> + *
> + * Drop references to the local and remote nodes in the link. This function
> + * must be called on every link parsed with v4l2_fwnode_parse_link().
> + */
>  void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link);
>  
>  #endif /* _V4L2_FWNODE_H */
> 

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Re: [PATCH v6 1/5] v4l: fwnode: Move KernelDoc documentation to the header

[Hans Verkuil]

On 30/08/17 13:49, Sakari Ailus wrote:
> In V4L2 the practice is to have the KernelDoc documentation in the header
> and not in .c source code files. This consequientally makes the V4L2
> fwnode function documentation part of the Media documentation build.
> 
> Also correct the link related function and argument naming in
> documentation.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>

Regards,

	Hans

> ---
>  drivers/media/v4l2-core/v4l2-fwnode.c | 75 --------------------------------
>  include/media/v4l2-fwnode.h           | 81 ++++++++++++++++++++++++++++++++++-
>  2 files changed, 80 insertions(+), 76 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
> index 40b2fbfe8865..706f9e7b90f1 100644
> --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> @@ -181,25 +181,6 @@ v4l2_fwnode_endpoint_parse_csi1_bus(struct fwnode_handle *fwnode,
>  		vep->bus_type = V4L2_MBUS_CSI1;
>  }
>  
> -/**
> - * v4l2_fwnode_endpoint_parse() - parse all fwnode node properties
> - * @fwnode: pointer to the endpoint's fwnode handle
> - * @vep: pointer to the V4L2 fwnode data structure
> - *
> - * All properties are optional. If none are found, we don't set any flags. This
> - * means the port has a static configuration and no properties have to be
> - * specified explicitly. If any properties that identify the bus as parallel
> - * are found and slave-mode isn't set, we set V4L2_MBUS_MASTER. Similarly, if
> - * we recognise the bus as serial CSI-2 and clock-noncontinuous isn't set, we
> - * set the V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag. The caller should hold a
> - * reference to @fwnode.
> - *
> - * NOTE: This function does not parse properties the size of which is variable
> - * without a low fixed limit. Please use v4l2_fwnode_endpoint_alloc_parse() in
> - * new drivers instead.
> - *
> - * Return: 0 on success or a negative error code on failure.
> - */
>  int v4l2_fwnode_endpoint_parse(struct fwnode_handle *fwnode,
>  			       struct v4l2_fwnode_endpoint *vep)
>  {
> @@ -239,14 +220,6 @@ int v4l2_fwnode_endpoint_parse(struct fwnode_handle *fwnode,
>  }
>  EXPORT_SYMBOL_GPL(v4l2_fwnode_endpoint_parse);
>  
> -/*
> - * v4l2_fwnode_endpoint_free() - free the V4L2 fwnode acquired by
> - * v4l2_fwnode_endpoint_alloc_parse()
> - * @vep - the V4L2 fwnode the resources of which are to be released
> - *
> - * It is safe to call this function with NULL argument or on a V4L2 fwnode the
> - * parsing of which failed.
> - */
>  void v4l2_fwnode_endpoint_free(struct v4l2_fwnode_endpoint *vep)
>  {
>  	if (IS_ERR_OR_NULL(vep))
> @@ -257,29 +230,6 @@ void v4l2_fwnode_endpoint_free(struct v4l2_fwnode_endpoint *vep)
>  }
>  EXPORT_SYMBOL_GPL(v4l2_fwnode_endpoint_free);
>  
> -/**
> - * v4l2_fwnode_endpoint_alloc_parse() - parse all fwnode node properties
> - * @fwnode: pointer to the endpoint's fwnode handle
> - *
> - * All properties are optional. If none are found, we don't set any flags. This
> - * means the port has a static configuration and no properties have to be
> - * specified explicitly. If any properties that identify the bus as parallel
> - * are found and slave-mode isn't set, we set V4L2_MBUS_MASTER. Similarly, if
> - * we recognise the bus as serial CSI-2 and clock-noncontinuous isn't set, we
> - * set the V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag. The caller should hold a
> - * reference to @fwnode.
> - *
> - * v4l2_fwnode_endpoint_alloc_parse() has two important differences to
> - * v4l2_fwnode_endpoint_parse():
> - *
> - * 1. It also parses variable size data.
> - *
> - * 2. The memory it has allocated to store the variable size data must be freed
> - *    using v4l2_fwnode_endpoint_free() when no longer needed.
> - *
> - * Return: Pointer to v4l2_fwnode_endpoint if successful, on an error pointer
> - * on error.
> - */
>  struct v4l2_fwnode_endpoint *v4l2_fwnode_endpoint_alloc_parse(
>  	struct fwnode_handle *fwnode)
>  {
> @@ -322,24 +272,6 @@ struct v4l2_fwnode_endpoint *v4l2_fwnode_endpoint_alloc_parse(
>  }
>  EXPORT_SYMBOL_GPL(v4l2_fwnode_endpoint_alloc_parse);
>  
> -/**
> - * v4l2_fwnode_endpoint_parse_link() - parse a link between two endpoints
> - * @__fwnode: pointer to the endpoint's fwnode at the local end of the link
> - * @link: pointer to the V4L2 fwnode link data structure
> - *
> - * Fill the link structure with the local and remote nodes and port numbers.
> - * The local_node and remote_node fields are set to point to the local and
> - * remote port's parent nodes respectively (the port parent node being the
> - * parent node of the port node if that node isn't a 'ports' node, or the
> - * grand-parent node of the port node otherwise).
> - *
> - * A reference is taken to both the local and remote nodes, the caller must use
> - * v4l2_fwnode_endpoint_put_link() to drop the references when done with the
> - * link.
> - *
> - * Return: 0 on success, or -ENOLINK if the remote endpoint fwnode can't be
> - * found.
> - */
>  int v4l2_fwnode_parse_link(struct fwnode_handle *__fwnode,
>  			   struct v4l2_fwnode_link *link)
>  {
> @@ -374,13 +306,6 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *__fwnode,
>  }
>  EXPORT_SYMBOL_GPL(v4l2_fwnode_parse_link);
>  
> -/**
> - * v4l2_fwnode_put_link() - drop references to nodes in a link
> - * @link: pointer to the V4L2 fwnode link data structure
> - *
> - * Drop references to the local and remote nodes in the link. This function
> - * must be called on every link parsed with v4l2_fwnode_parse_link().
> - */
>  void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link)
>  {
>  	fwnode_handle_put(link->local_node);
> diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
> index 7adec9851d9e..68eb22ba571b 100644
> --- a/include/media/v4l2-fwnode.h
> +++ b/include/media/v4l2-fwnode.h
> @@ -113,13 +113,92 @@ struct v4l2_fwnode_link {
>  	unsigned int remote_port;
>  };
>  
> +/**
> + * v4l2_fwnode_endpoint_parse() - parse all fwnode node properties
> + * @fwnode: pointer to the endpoint's fwnode handle
> + * @vep: pointer to the V4L2 fwnode data structure
> + *
> + * All properties are optional. If none are found, we don't set any flags. This
> + * means the port has a static configuration and no properties have to be
> + * specified explicitly. If any properties that identify the bus as parallel
> + * are found and slave-mode isn't set, we set V4L2_MBUS_MASTER. Similarly, if
> + * we recognise the bus as serial CSI-2 and clock-noncontinuous isn't set, we
> + * set the V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag. The caller should hold a
> + * reference to @fwnode.
> + *
> + * NOTE: This function does not parse properties the size of which is variable
> + * without a low fixed limit. Please use v4l2_fwnode_endpoint_alloc_parse() in
> + * new drivers instead.
> + *
> + * Return: 0 on success or a negative error code on failure.
> + */
>  int v4l2_fwnode_endpoint_parse(struct fwnode_handle *fwnode,
>  			       struct v4l2_fwnode_endpoint *vep);
> +
> +/*
> + * v4l2_fwnode_endpoint_free() - free the V4L2 fwnode acquired by
> + * v4l2_fwnode_endpoint_alloc_parse()
> + * @vep - the V4L2 fwnode the resources of which are to be released
> + *
> + * It is safe to call this function with NULL argument or on a V4L2 fwnode the
> + * parsing of which failed.
> + */
> +void v4l2_fwnode_endpoint_free(struct v4l2_fwnode_endpoint *vep);
> +
> +/**
> + * v4l2_fwnode_endpoint_alloc_parse() - parse all fwnode node properties
> + * @fwnode: pointer to the endpoint's fwnode handle
> + *
> + * All properties are optional. If none are found, we don't set any flags. This
> + * means the port has a static configuration and no properties have to be
> + * specified explicitly. If any properties that identify the bus as parallel
> + * are found and slave-mode isn't set, we set V4L2_MBUS_MASTER. Similarly, if
> + * we recognise the bus as serial CSI-2 and clock-noncontinuous isn't set, we
> + * set the V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag. The caller should hold a
> + * reference to @fwnode.
> + *
> + * v4l2_fwnode_endpoint_alloc_parse() has two important differences to
> + * v4l2_fwnode_endpoint_parse():
> + *
> + * 1. It also parses variable size data.
> + *
> + * 2. The memory it has allocated to store the variable size data must be freed
> + *    using v4l2_fwnode_endpoint_free() when no longer needed.
> + *
> + * Return: Pointer to v4l2_fwnode_endpoint if successful, on an error pointer
> + * on error.
> + */
>  struct v4l2_fwnode_endpoint *v4l2_fwnode_endpoint_alloc_parse(
>  	struct fwnode_handle *fwnode);
> -void v4l2_fwnode_endpoint_free(struct v4l2_fwnode_endpoint *vep);
> +
> +/**
> + * v4l2_fwnode_parse_link() - parse a link between two endpoints
> + * @fwnode: pointer to the endpoint's fwnode at the local end of the link
> + * @link: pointer to the V4L2 fwnode link data structure
> + *
> + * Fill the link structure with the local and remote nodes and port numbers.
> + * The local_node and remote_node fields are set to point to the local and
> + * remote port's parent nodes respectively (the port parent node being the
> + * parent node of the port node if that node isn't a 'ports' node, or the
> + * grand-parent node of the port node otherwise).
> + *
> + * A reference is taken to both the local and remote nodes, the caller must use
> + * v4l2_fwnode_put_link() to drop the references when done with the
> + * link.
> + *
> + * Return: 0 on success, or -ENOLINK if the remote endpoint fwnode can't be
> + * found.
> + */
>  int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,
>  			   struct v4l2_fwnode_link *link);
> +
> +/**
> + * v4l2_fwnode_put_link() - drop references to nodes in a link
> + * @link: pointer to the V4L2 fwnode link data structure
> + *
> + * Drop references to the local and remote nodes in the link. This function
> + * must be called on every link parsed with v4l2_fwnode_parse_link().
> + */
>  void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link);
>  
>  #endif /* _V4L2_FWNODE_H */
> 

Re: [PATCH v6 2/5] v4l: async: Add V4L2 async documentation to the documentation build

[Hans Verkuil]

On 30/08/17 13:49, Sakari Ailus wrote:
> The V4L2 async wasn't part of the documentation build. Fix this.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas-1zkq55x86MTxsAP9Fp7wbw@public.gmane.org>

Acked-by: Hans Verkuil <hans.verkuil-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>

Regards,

	Hans


> ---
>  Documentation/media/kapi/v4l2-async.rst | 3 +++
>  Documentation/media/kapi/v4l2-core.rst  | 1 +
>  2 files changed, 4 insertions(+)
>  create mode 100644 Documentation/media/kapi/v4l2-async.rst
> 
> diff --git a/Documentation/media/kapi/v4l2-async.rst b/Documentation/media/kapi/v4l2-async.rst
> new file mode 100644
> index 000000000000..523ff9eb09a0
> --- /dev/null
> +++ b/Documentation/media/kapi/v4l2-async.rst
> @@ -0,0 +1,3 @@
> +V4L2 async kAPI
> +^^^^^^^^^^^^^^^
> +.. kernel-doc:: include/media/v4l2-async.h
> diff --git a/Documentation/media/kapi/v4l2-core.rst b/Documentation/media/kapi/v4l2-core.rst
> index c7434f38fd9c..5cf292037a48 100644
> --- a/Documentation/media/kapi/v4l2-core.rst
> +++ b/Documentation/media/kapi/v4l2-core.rst
> @@ -19,6 +19,7 @@ Video4Linux devices
>      v4l2-mc
>      v4l2-mediabus
>      v4l2-mem2mem
> +    v4l2-async
>      v4l2-fwnode
>      v4l2-rect
>      v4l2-tuner
> 

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Re: [PATCH v6 2/5] v4l: async: Add V4L2 async documentation to the documentation build

[Hans Verkuil]

On 30/08/17 13:49, Sakari Ailus wrote:
> The V4L2 async wasn't part of the documentation build. Fix this.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>

Regards,

	Hans


> ---
>  Documentation/media/kapi/v4l2-async.rst | 3 +++
>  Documentation/media/kapi/v4l2-core.rst  | 1 +
>  2 files changed, 4 insertions(+)
>  create mode 100644 Documentation/media/kapi/v4l2-async.rst
> 
> diff --git a/Documentation/media/kapi/v4l2-async.rst b/Documentation/media/kapi/v4l2-async.rst
> new file mode 100644
> index 000000000000..523ff9eb09a0
> --- /dev/null
> +++ b/Documentation/media/kapi/v4l2-async.rst
> @@ -0,0 +1,3 @@
> +V4L2 async kAPI
> +^^^^^^^^^^^^^^^
> +.. kernel-doc:: include/media/v4l2-async.h
> diff --git a/Documentation/media/kapi/v4l2-core.rst b/Documentation/media/kapi/v4l2-core.rst
> index c7434f38fd9c..5cf292037a48 100644
> --- a/Documentation/media/kapi/v4l2-core.rst
> +++ b/Documentation/media/kapi/v4l2-core.rst
> @@ -19,6 +19,7 @@ Video4Linux devices
>      v4l2-mc
>      v4l2-mediabus
>      v4l2-mem2mem
> +    v4l2-async
>      v4l2-fwnode
>      v4l2-rect
>      v4l2-tuner
> 

Re: [PATCH v6 3/5] docs-rst: v4l: Include Qualcomm CAMSS in documentation build

[Hans Verkuil]

On 30/08/17 13:49, Sakari Ailus wrote:
> Qualcomm CAMSS was left out from documentation build. Fix this.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>

Regards,

	Hans


> ---
>  Documentation/media/v4l-drivers/index.rst | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/Documentation/media/v4l-drivers/index.rst b/Documentation/media/v4l-drivers/index.rst
> index 10f2ce42ece2..5c202e23616b 100644
> --- a/Documentation/media/v4l-drivers/index.rst
> +++ b/Documentation/media/v4l-drivers/index.rst
> @@ -50,6 +50,7 @@ For more details see the file COPYING in the source distribution of Linux.
>  	philips
>  	pvrusb2
>  	pxa_camera
> +	qcom_camss
>  	radiotrack
>  	rcar-fdp1
>  	saa7134
> 

Re: [PATCH v6.1 4/5] v4l: fwnode: Support generic parsing of graph endpoints in a device

[Hans Verkuil]

Hi Sakari,

On 30/08/17 14:45, Sakari Ailus wrote:
> The current practice is that drivers iterate over their endpoints and
> parse each endpoint separately. This is very similar in a number of
> drivers, implement a generic function for the job. Driver specific matters
> can be taken into account in the driver specific callback.
> 
> Convert the omap3isp as an example.

It would be much easier to review if the omap3isp conversion was done in a
separate patch. Ditto for the rcar conversion, and I prefer to have both
at the end of the patch series, after the core code patches.

> 
> Signed-off-by: Sakari Ailus <sakari.ailus-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> ---
> since v6:
> 
> - Set notifier->subdevs NULL and notifier->num_subdevs 0 in
>   v4l2_async_notifier_release().
> 
>  drivers/media/platform/omap3isp/isp.c | 115 ++++++++++-------------------
>  drivers/media/platform/omap3isp/isp.h |   5 +-
>  drivers/media/v4l2-core/v4l2-async.c  |  16 +++++
>  drivers/media/v4l2-core/v4l2-fwnode.c | 131 ++++++++++++++++++++++++++++++++++
>  include/media/v4l2-async.h            |  24 ++++++-
>  include/media/v4l2-fwnode.h           |  48 +++++++++++++
>  6 files changed, 254 insertions(+), 85 deletions(-)
> 
> diff --git a/drivers/media/platform/omap3isp/isp.c b/drivers/media/platform/omap3isp/isp.c
> index 1a428fe9f070..a546cf774d40 100644
> --- a/drivers/media/platform/omap3isp/isp.c
> +++ b/drivers/media/platform/omap3isp/isp.c
> @@ -2001,6 +2001,7 @@ static int isp_remove(struct platform_device *pdev)
>  	__omap3isp_put(isp, false);
>  
>  	media_entity_enum_cleanup(&isp->crashed);
> +	v4l2_async_notifier_release(&isp->notifier);
>  
>  	return 0;
>  }
> @@ -2011,44 +2012,41 @@ enum isp_of_phy {
>  	ISP_OF_PHY_CSIPHY2,
>  };
>  
> -static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
> -			    struct isp_async_subdev *isd)
> +static int isp_fwnode_parse(struct device *dev,
> +			    struct v4l2_fwnode_endpoint *vep,
> +			    struct v4l2_async_subdev *asd)
>  {
> +	struct isp_async_subdev *isd =
> +		container_of(asd, struct isp_async_subdev, asd);
>  	struct isp_bus_cfg *buscfg = &isd->bus;
> -	struct v4l2_fwnode_endpoint vep;
> -	unsigned int i;
> -	int ret;
>  	bool csi1 = false;
> -
> -	ret = v4l2_fwnode_endpoint_parse(fwnode, &vep);
> -	if (ret)
> -		return ret;
> +	unsigned int i;
>  
>  	dev_dbg(dev, "parsing endpoint %pOF, interface %u\n",
> -		to_of_node(fwnode), vep.base.port);
> +		to_of_node(vep->base.local_fwnode), vep->base.port);
>  
> -	switch (vep.base.port) {
> +	switch (vep->base.port) {
>  	case ISP_OF_PHY_PARALLEL:
>  		buscfg->interface = ISP_INTERFACE_PARALLEL;
>  		buscfg->bus.parallel.data_lane_shift =
> -			vep.bus.parallel.data_shift;
> +			vep->bus.parallel.data_shift;
>  		buscfg->bus.parallel.clk_pol =
> -			!!(vep.bus.parallel.flags
> +			!!(vep->bus.parallel.flags
>  			   & V4L2_MBUS_PCLK_SAMPLE_FALLING);
>  		buscfg->bus.parallel.hs_pol =
> -			!!(vep.bus.parallel.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW);
> +			!!(vep->bus.parallel.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW);
>  		buscfg->bus.parallel.vs_pol =
> -			!!(vep.bus.parallel.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW);
> +			!!(vep->bus.parallel.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW);
>  		buscfg->bus.parallel.fld_pol =
> -			!!(vep.bus.parallel.flags & V4L2_MBUS_FIELD_EVEN_LOW);
> +			!!(vep->bus.parallel.flags & V4L2_MBUS_FIELD_EVEN_LOW);
>  		buscfg->bus.parallel.data_pol =
> -			!!(vep.bus.parallel.flags & V4L2_MBUS_DATA_ACTIVE_LOW);
> -		buscfg->bus.parallel.bt656 = vep.bus_type == V4L2_MBUS_BT656;
> +			!!(vep->bus.parallel.flags & V4L2_MBUS_DATA_ACTIVE_LOW);
> +		buscfg->bus.parallel.bt656 = vep->bus_type == V4L2_MBUS_BT656;
>  		break;
>  
>  	case ISP_OF_PHY_CSIPHY1:
>  	case ISP_OF_PHY_CSIPHY2:
> -		switch (vep.bus_type) {
> +		switch (vep->bus_type) {
>  		case V4L2_MBUS_CCP2:
>  		case V4L2_MBUS_CSI1:
>  			dev_dbg(dev, "CSI-1/CCP-2 configuration\n");
> @@ -2060,11 +2058,11 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
>  			break;
>  		default:
>  			dev_err(dev, "unsupported bus type %u\n",
> -				vep.bus_type);
> +				vep->bus_type);
>  			return -EINVAL;
>  		}
>  
> -		switch (vep.base.port) {
> +		switch (vep->base.port) {
>  		case ISP_OF_PHY_CSIPHY1:
>  			if (csi1)
>  				buscfg->interface = ISP_INTERFACE_CCP2B_PHY1;
> @@ -2080,47 +2078,47 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
>  		}
>  		if (csi1) {
>  			buscfg->bus.ccp2.lanecfg.clk.pos =
> -				vep.bus.mipi_csi1.clock_lane;
> +				vep->bus.mipi_csi1.clock_lane;
>  			buscfg->bus.ccp2.lanecfg.clk.pol =
> -				vep.bus.mipi_csi1.lane_polarity[0];
> +				vep->bus.mipi_csi1.lane_polarity[0];
>  			dev_dbg(dev, "clock lane polarity %u, pos %u\n",
>  				buscfg->bus.ccp2.lanecfg.clk.pol,
>  				buscfg->bus.ccp2.lanecfg.clk.pos);
>  
>  			buscfg->bus.ccp2.lanecfg.data[0].pos =
> -				vep.bus.mipi_csi1.data_lane;
> +				vep->bus.mipi_csi1.data_lane;
>  			buscfg->bus.ccp2.lanecfg.data[0].pol =
> -				vep.bus.mipi_csi1.lane_polarity[1];
> +				vep->bus.mipi_csi1.lane_polarity[1];
>  
>  			dev_dbg(dev, "data lane polarity %u, pos %u\n",
>  				buscfg->bus.ccp2.lanecfg.data[0].pol,
>  				buscfg->bus.ccp2.lanecfg.data[0].pos);
>  
>  			buscfg->bus.ccp2.strobe_clk_pol =
> -				vep.bus.mipi_csi1.clock_inv;
> -			buscfg->bus.ccp2.phy_layer = vep.bus.mipi_csi1.strobe;
> +				vep->bus.mipi_csi1.clock_inv;
> +			buscfg->bus.ccp2.phy_layer = vep->bus.mipi_csi1.strobe;
>  			buscfg->bus.ccp2.ccp2_mode =
> -				vep.bus_type == V4L2_MBUS_CCP2;
> +				vep->bus_type == V4L2_MBUS_CCP2;
>  			buscfg->bus.ccp2.vp_clk_pol = 1;
>  
>  			buscfg->bus.ccp2.crc = 1;
>  		} else {
>  			buscfg->bus.csi2.lanecfg.clk.pos =
> -				vep.bus.mipi_csi2.clock_lane;
> +				vep->bus.mipi_csi2.clock_lane;
>  			buscfg->bus.csi2.lanecfg.clk.pol =
> -				vep.bus.mipi_csi2.lane_polarities[0];
> +				vep->bus.mipi_csi2.lane_polarities[0];
>  			dev_dbg(dev, "clock lane polarity %u, pos %u\n",
>  				buscfg->bus.csi2.lanecfg.clk.pol,
>  				buscfg->bus.csi2.lanecfg.clk.pos);
>  
>  			buscfg->bus.csi2.num_data_lanes =
> -				vep.bus.mipi_csi2.num_data_lanes;
> +				vep->bus.mipi_csi2.num_data_lanes;
>  
>  			for (i = 0; i < buscfg->bus.csi2.num_data_lanes; i++) {
>  				buscfg->bus.csi2.lanecfg.data[i].pos =
> -					vep.bus.mipi_csi2.data_lanes[i];
> +					vep->bus.mipi_csi2.data_lanes[i];
>  				buscfg->bus.csi2.lanecfg.data[i].pol =
> -					vep.bus.mipi_csi2.lane_polarities[i + 1];
> +					vep->bus.mipi_csi2.lane_polarities[i + 1];
>  				dev_dbg(dev,
>  					"data lane %u polarity %u, pos %u\n", i,
>  					buscfg->bus.csi2.lanecfg.data[i].pol,
> @@ -2137,57 +2135,13 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
>  
>  	default:
>  		dev_warn(dev, "%pOF: invalid interface %u\n",
> -			 to_of_node(fwnode), vep.base.port);
> +			 to_of_node(vep->base.local_fwnode), vep->base.port);
>  		return -EINVAL;
>  	}
>  
>  	return 0;
>  }
>  
> -static int isp_fwnodes_parse(struct device *dev,
> -			     struct v4l2_async_notifier *notifier)
> -{
> -	struct fwnode_handle *fwnode = NULL;
> -
> -	notifier->subdevs = devm_kcalloc(
> -		dev, ISP_MAX_SUBDEVS, sizeof(*notifier->subdevs), GFP_KERNEL);
> -	if (!notifier->subdevs)
> -		return -ENOMEM;
> -
> -	while (notifier->num_subdevs < ISP_MAX_SUBDEVS &&
> -	       (fwnode = fwnode_graph_get_next_endpoint(
> -			of_fwnode_handle(dev->of_node), fwnode))) {
> -		struct isp_async_subdev *isd;
> -
> -		isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
> -		if (!isd)
> -			goto error;
> -
> -		if (isp_fwnode_parse(dev, fwnode, isd)) {
> -			devm_kfree(dev, isd);
> -			continue;
> -		}
> -
> -		notifier->subdevs[notifier->num_subdevs] = &isd->asd;
> -
> -		isd->asd.match.fwnode.fwnode =
> -			fwnode_graph_get_remote_port_parent(fwnode);
> -		if (!isd->asd.match.fwnode.fwnode) {
> -			dev_warn(dev, "bad remote port parent\n");
> -			goto error;
> -		}
> -
> -		isd->asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
> -		notifier->num_subdevs++;
> -	}
> -
> -	return notifier->num_subdevs;
> -
> -error:
> -	fwnode_handle_put(fwnode);
> -	return -EINVAL;
> -}
> -
>  static int isp_subdev_notifier_complete(struct v4l2_async_notifier *async)
>  {
>  	struct isp_device *isp = container_of(async, struct isp_device,
> @@ -2256,7 +2210,9 @@ static int isp_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> -	ret = isp_fwnodes_parse(&pdev->dev, &isp->notifier);
> +	ret = v4l2_async_notifier_parse_fwnode_endpoints(
> +		&pdev->dev, &isp->notifier, sizeof(struct isp_async_subdev),
> +		isp_fwnode_parse);
>  	if (ret < 0)
>  		return ret;
>  
> @@ -2407,6 +2363,7 @@ static int isp_probe(struct platform_device *pdev)
>  	__omap3isp_put(isp, false);
>  error:
>  	mutex_destroy(&isp->isp_mutex);
> +	v4l2_async_notifier_release(&isp->notifier);
>  
>  	return ret;
>  }
> diff --git a/drivers/media/platform/omap3isp/isp.h b/drivers/media/platform/omap3isp/isp.h
> index e528df6efc09..8b9043db94b3 100644
> --- a/drivers/media/platform/omap3isp/isp.h
> +++ b/drivers/media/platform/omap3isp/isp.h
> @@ -220,14 +220,11 @@ struct isp_device {
>  
>  	unsigned int sbl_resources;
>  	unsigned int subclk_resources;
> -
> -#define ISP_MAX_SUBDEVS		8
> -	struct v4l2_subdev *subdevs[ISP_MAX_SUBDEVS];
>  };
>  
>  struct isp_async_subdev {
> -	struct isp_bus_cfg bus;
>  	struct v4l2_async_subdev asd;
> +	struct isp_bus_cfg bus;
>  };
>  
>  #define v4l2_subdev_to_bus_cfg(sd) \
> diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
> index 851f128eba22..6740a241d4a1 100644
> --- a/drivers/media/v4l2-core/v4l2-async.c
> +++ b/drivers/media/v4l2-core/v4l2-async.c
> @@ -22,6 +22,7 @@
>  
>  #include <media/v4l2-async.h>
>  #include <media/v4l2-device.h>
> +#include <media/v4l2-fwnode.h>
>  #include <media/v4l2-subdev.h>
>  
>  static bool match_i2c(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
> @@ -278,6 +279,21 @@ void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
>  }
>  EXPORT_SYMBOL(v4l2_async_notifier_unregister);
>  
> +void v4l2_async_notifier_release(struct v4l2_async_notifier *notifier)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < notifier->num_subdevs; i++)
> +		kfree(notifier->subdevs[i]);
> +
> +	notifier->max_subdevs = 0;
> +	notifier->num_subdevs = 0;
> +
> +	kvfree(notifier->subdevs);
> +	notifier->subdevs = NULL;
> +}
> +EXPORT_SYMBOL_GPL(v4l2_async_notifier_release);
> +
>  int v4l2_async_register_subdev(struct v4l2_subdev *sd)
>  {
>  	struct v4l2_async_notifier *notifier;
> diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
> index 706f9e7b90f1..2496d76eef4b 100644
> --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> @@ -19,6 +19,7 @@
>   */
>  #include <linux/acpi.h>
>  #include <linux/kernel.h>
> +#include <linux/mm.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/property.h>
> @@ -26,6 +27,7 @@
>  #include <linux/string.h>
>  #include <linux/types.h>
>  
> +#include <media/v4l2-async.h>
>  #include <media/v4l2-fwnode.h>
>  
>  enum v4l2_fwnode_bus_type {
> @@ -313,6 +315,135 @@ void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link)
>  }
>  EXPORT_SYMBOL_GPL(v4l2_fwnode_put_link);
>  
> +static int v4l2_async_notifier_realloc(struct v4l2_async_notifier *notifier,
> +				       unsigned int max_subdevs)
> +{
> +	struct v4l2_async_subdev **subdevs;
> +
> +	if (max_subdevs <= notifier->max_subdevs)
> +		return 0;

Should probably be a WARN_ON. Or add a comment saying that this should
never happen.

> +
> +	subdevs = kvmalloc_array(
> +		max_subdevs, sizeof(*notifier->subdevs),
> +		GFP_KERNEL | __GFP_ZERO);
> +	if (!subdevs)
> +		return -ENOMEM;
> +
> +	if (notifier->subdevs) {
> +		memcpy(subdevs, notifier->subdevs,
> +		       sizeof(*subdevs) * notifier->num_subdevs);
> +
> +		kvfree(notifier->subdevs);
> +	}
> +
> +	notifier->subdevs = subdevs;
> +	notifier->max_subdevs = max_subdevs;
> +
> +	return 0;
> +}
> +
> +static int v4l2_async_notifier_fwnode_parse_endpoint(
> +	struct device *dev, struct v4l2_async_notifier *notifier,
> +	struct fwnode_handle *endpoint, unsigned int asd_struct_size,
> +	int (*parse_single)(struct device *dev,
> +			    struct v4l2_fwnode_endpoint *vep,
> +			    struct v4l2_async_subdev *asd))
> +{
> +	struct v4l2_async_subdev *asd;
> +	struct v4l2_fwnode_endpoint *vep;
> +	int ret = 0;
> +
> +	asd = kzalloc(asd_struct_size, GFP_KERNEL);
> +	if (!asd)
> +		return -ENOMEM;
> +
> +	asd->match.fwnode.fwnode =
> +		fwnode_graph_get_remote_port_parent(endpoint);
> +	if (!asd->match.fwnode.fwnode) {
> +		dev_warn(dev, "bad remote port parent\n");
> +		ret = -EINVAL;
> +		goto out_err;
> +	}
> +
> +	/* Ignore endpoints the parsing of which failed. */
> +	vep = v4l2_fwnode_endpoint_alloc_parse(endpoint);
> +	if (IS_ERR(vep)) {
> +		ret = PTR_ERR(vep);
> +		dev_warn(dev, "unable to parse V4L2 fwnode endpoint (%d)\n",
> +			 ret);
> +		goto out_err;
> +	}
> +
> +	ret = parse_single(dev, vep, asd);
> +	v4l2_fwnode_endpoint_free(vep);
> +	if (ret) {
> +		dev_warn(dev, "driver could not parse endpoint (%d)\n", ret);
> +		goto out_err;
> +	}
> +
> +	asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
> +	notifier->subdevs[notifier->num_subdevs] = asd;
> +	notifier->num_subdevs++;
> +
> +	return 0;
> +
> +out_err:
> +	fwnode_handle_put(asd->match.fwnode.fwnode);

Just checking: the fwnode_handle_put argument can safely be NULL?

> +	kfree(asd);
> +
> +	return ret;
> +}
> +
> +int v4l2_async_notifier_parse_fwnode_endpoints(
> +	struct device *dev, struct v4l2_async_notifier *notifier,
> +	size_t asd_struct_size,
> +	int (*parse_single)(struct device *dev,
> +			    struct v4l2_fwnode_endpoint *vep,
> +			    struct v4l2_async_subdev *asd))
> +{
> +	struct fwnode_handle *fwnode = NULL;
> +	unsigned int max_subdevs = notifier->max_subdevs;

I thought the notifier was supposed to be zeroed?

> +	int ret;
> +
> +	if (asd_struct_size < sizeof(struct v4l2_async_subdev) ||
> +	    notifier->v4l2_dev)

This could use a comment why you check for notifier->v4l2_dev. That's not
obvious.

> +		return -EINVAL;

Since we have the requirement that the notifier should be zeroed,
why not do that here?

> +
> +	for (fwnode = NULL; (fwnode = fwnode_graph_get_next_endpoint(
> +				     dev_fwnode(dev), fwnode)); )
> +		if (fwnode_device_is_available(
> +			    fwnode_graph_get_port_parent(fwnode)))
> +			max_subdevs++;
> +
> +	/* No subdevs to add? Return here. */
> +	if (max_subdevs == notifier->max_subdevs)
> +		return 0;
> +
> +	ret = v4l2_async_notifier_realloc(notifier, max_subdevs);
> +	if (ret)
> +		return ret;

I think this is confusing. There is nothing to realloc here. Only in the
next patch (5/5) do you add support for recursively walking the graph and
adding more subdevs.

I would just call kvmalloc_array here.

> +
> +	for (fwnode = NULL; (fwnode = fwnode_graph_get_next_endpoint(
> +				     dev_fwnode(dev), fwnode)); ) {
> +		if (!fwnode_device_is_available(
> +			    fwnode_graph_get_port_parent(fwnode)))
> +			continue;
> +
> +		if (WARN_ON(notifier->num_subdevs >= notifier->max_subdevs))
> +			break;
> +
> +		ret = v4l2_async_notifier_fwnode_parse_endpoint(
> +			dev, notifier, fwnode, asd_struct_size, parse_single);
> +		if (ret < 0)
> +			break;
> +	}
> +
> +	fwnode_handle_put(fwnode);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(v4l2_async_notifier_parse_fwnode_endpoints);
> +
>  MODULE_LICENSE("GPL");
>  MODULE_AUTHOR("Sakari Ailus <sakari.ailus-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>");
>  MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>");
> diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
> index c69d8c8a66d0..cf13c7311a1c 100644
> --- a/include/media/v4l2-async.h
> +++ b/include/media/v4l2-async.h
> @@ -18,7 +18,6 @@ struct device;
>  struct device_node;
>  struct v4l2_device;
>  struct v4l2_subdev;
> -struct v4l2_async_notifier;
>  
>  /* A random max subdevice number, used to allocate an array on stack */
>  #define V4L2_MAX_SUBDEVS 128U
> @@ -50,6 +49,10 @@ enum v4l2_async_match_type {
>   * @match:	union of per-bus type matching data sets
>   * @list:	used to link struct v4l2_async_subdev objects, waiting to be
>   *		probed, to a notifier->waiting list
> + *
> + * When the struct is used as the first member of a driver specific

Just replace "the first member" by "part"...

> + * struct, the driver specific struct shall contain the @struct
> + * v4l2_async_subdev as its first member.

...since you mention in the second part that it has to be the first member.
No need to mention that twice.

>   */
>  struct v4l2_async_subdev {
>  	enum v4l2_async_match_type match_type;
> @@ -78,7 +81,8 @@ struct v4l2_async_subdev {
>  /**
>   * struct v4l2_async_notifier - v4l2_device notifier data
>   *
> - * @num_subdevs: number of subdevices
> + * @num_subdevs: number of subdevices used in subdevs array

in the

> + * @max_subdevs: number of subdevices allocated in subdevs array

in the

>   * @subdevs:	array of pointers to subdevice descriptors
>   * @v4l2_dev:	pointer to struct v4l2_device
>   * @waiting:	list of struct v4l2_async_subdev, waiting for their drivers
> @@ -90,6 +94,7 @@ struct v4l2_async_subdev {
>   */
>  struct v4l2_async_notifier {
>  	unsigned int num_subdevs;
> +	unsigned int max_subdevs;
>  	struct v4l2_async_subdev **subdevs;
>  	struct v4l2_device *v4l2_dev;
>  	struct list_head waiting;
> @@ -121,6 +126,21 @@ int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
>  void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier);
>  
>  /**
> + * v4l2_async_notifier_release - release notifier resources
> + * @notifier: the notifier the resources of which are to be released

Just say: @notifier: pointer to &struct v4l2_async_notifier

> + *
> + * Release memory resources related to a notifier, including the async

s/a/the/

> + * sub-devices allocated for the purposes of the notifier. The user is
> + * responsible for releasing the notifier's resources after calling
> + * @v4l2_async_notifier_parse_fwnode_endpoints.
> + *
> + * There is no harm from calling v4l2_async_notifier_release in other
> + * cases as long as its memory has been zeroed after it has been
> + * allocated.
> + */
> +void v4l2_async_notifier_release(struct v4l2_async_notifier *notifier);
> +
> +/**
>   * v4l2_async_register_subdev - registers a sub-device to the asynchronous
>   * 	subdevice framework
>   *
> diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
> index 68eb22ba571b..d063ab4ff67b 100644
> --- a/include/media/v4l2-fwnode.h
> +++ b/include/media/v4l2-fwnode.h
> @@ -25,6 +25,8 @@
>  #include <media/v4l2-mediabus.h>
>  
>  struct fwnode_handle;
> +struct v4l2_async_notifier;
> +struct v4l2_async_subdev;
>  
>  #define V4L2_FWNODE_CSI2_MAX_DATA_LANES	4
>  
> @@ -201,4 +203,50 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,
>   */
>  void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link);
>  
> +/**
> + * v4l2_async_notifier_parse_fwnode_endpoints - Parse V4L2 fwnode endpoints in a
> + *						device node
> + * @dev: the device the endpoints of which are to be parsed
> + * @notifier: notifier for @dev
> + * @asd_struct_size: size of the driver's async sub-device struct, including
> + *		     sizeof(struct v4l2_async_subdev). The &struct
> + *		     v4l2_async_subdev shall be the first member of
> + *		     the driver's async sub-device struct, i.e. both
> + *		     begin at the same memory address.
> + * @parse_single: driver's callback function called on each V4L2 fwnode endpoint
> + *
> + * Parse the fwnode endpoints of the @dev device and populate the async sub-
> + * devices array of the notifier. The @parse_endpoint callback function is

parse_endpoint -> parse_single

(Actually, I like the name parse_endpoint better)

> + * called for each endpoint with the corresponding async sub-device pointer to
> + * let the caller initialize the driver-specific part of the async sub-device
> + * structure.
> + *
> + * The notifier memory shall be zeroed before this function is called on the
> + * notifier.
> + *
> + * This function may not be called on a registered notifier and may be called on
> + * a notifier only once. When using this function, the user may not access the
> + * notifier's subdevs array nor change notifier's num_subdevs field, these are
> + * reserved for the framework's internal use only.

Ditto for the max_subdevs field, I think.

> + *
> + * The @struct v4l2_fwnode_endpoint passed to the callback function
> + * @parse_single is released once the function is finished. If there is a need
> + * to retain that configuration, the user needs to allocate memory for it.
> + *
> + * Any notifier populated using this function must be released with a call to
> + * v4l2_async_notifier_release() after it has been unregistered and the async
> + * sub-devices are no longer in use.
> + *
> + * Return: %0 on success, including when no async sub-devices are found
> + *	   %-ENOMEM if memory allocation failed
> + *	   %-EINVAL if graph or endpoint parsing failed
> + *	   Other error codes as returned by @parse_single
> + */
> +int v4l2_async_notifier_parse_fwnode_endpoints(
> +	struct device *dev, struct v4l2_async_notifier *notifier,
> +	size_t asd_struct_size,
> +	int (*parse_single)(struct device *dev,
> +			    struct v4l2_fwnode_endpoint *vep,
> +			    struct v4l2_async_subdev *asd));
> +
>  #endif /* _V4L2_FWNODE_H */
> 

Regards,

	Hans
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Re: [PATCH v6.1 4/5] v4l: fwnode: Support generic parsing of graph endpoints in a device

[Hans Verkuil]

Hi Sakari,

On 30/08/17 14:45, Sakari Ailus wrote:
> The current practice is that drivers iterate over their endpoints and
> parse each endpoint separately. This is very similar in a number of
> drivers, implement a generic function for the job. Driver specific matters
> can be taken into account in the driver specific callback.
> 
> Convert the omap3isp as an example.

It would be much easier to review if the omap3isp conversion was done in a
separate patch. Ditto for the rcar conversion, and I prefer to have both
at the end of the patch series, after the core code patches.

> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
> since v6:
> 
> - Set notifier->subdevs NULL and notifier->num_subdevs 0 in
>   v4l2_async_notifier_release().
> 
>  drivers/media/platform/omap3isp/isp.c | 115 ++++++++++-------------------
>  drivers/media/platform/omap3isp/isp.h |   5 +-
>  drivers/media/v4l2-core/v4l2-async.c  |  16 +++++
>  drivers/media/v4l2-core/v4l2-fwnode.c | 131 ++++++++++++++++++++++++++++++++++
>  include/media/v4l2-async.h            |  24 ++++++-
>  include/media/v4l2-fwnode.h           |  48 +++++++++++++
>  6 files changed, 254 insertions(+), 85 deletions(-)
> 
> diff --git a/drivers/media/platform/omap3isp/isp.c b/drivers/media/platform/omap3isp/isp.c
> index 1a428fe9f070..a546cf774d40 100644
> --- a/drivers/media/platform/omap3isp/isp.c
> +++ b/drivers/media/platform/omap3isp/isp.c
> @@ -2001,6 +2001,7 @@ static int isp_remove(struct platform_device *pdev)
>  	__omap3isp_put(isp, false);
>  
>  	media_entity_enum_cleanup(&isp->crashed);
> +	v4l2_async_notifier_release(&isp->notifier);
>  
>  	return 0;
>  }
> @@ -2011,44 +2012,41 @@ enum isp_of_phy {
>  	ISP_OF_PHY_CSIPHY2,
>  };
>  
> -static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
> -			    struct isp_async_subdev *isd)
> +static int isp_fwnode_parse(struct device *dev,
> +			    struct v4l2_fwnode_endpoint *vep,
> +			    struct v4l2_async_subdev *asd)
>  {
> +	struct isp_async_subdev *isd =
> +		container_of(asd, struct isp_async_subdev, asd);
>  	struct isp_bus_cfg *buscfg = &isd->bus;
> -	struct v4l2_fwnode_endpoint vep;
> -	unsigned int i;
> -	int ret;
>  	bool csi1 = false;
> -
> -	ret = v4l2_fwnode_endpoint_parse(fwnode, &vep);
> -	if (ret)
> -		return ret;
> +	unsigned int i;
>  
>  	dev_dbg(dev, "parsing endpoint %pOF, interface %u\n",
> -		to_of_node(fwnode), vep.base.port);
> +		to_of_node(vep->base.local_fwnode), vep->base.port);
>  
> -	switch (vep.base.port) {
> +	switch (vep->base.port) {
>  	case ISP_OF_PHY_PARALLEL:
>  		buscfg->interface = ISP_INTERFACE_PARALLEL;
>  		buscfg->bus.parallel.data_lane_shift =
> -			vep.bus.parallel.data_shift;
> +			vep->bus.parallel.data_shift;
>  		buscfg->bus.parallel.clk_pol =
> -			!!(vep.bus.parallel.flags
> +			!!(vep->bus.parallel.flags
>  			   & V4L2_MBUS_PCLK_SAMPLE_FALLING);
>  		buscfg->bus.parallel.hs_pol =
> -			!!(vep.bus.parallel.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW);
> +			!!(vep->bus.parallel.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW);
>  		buscfg->bus.parallel.vs_pol =
> -			!!(vep.bus.parallel.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW);
> +			!!(vep->bus.parallel.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW);
>  		buscfg->bus.parallel.fld_pol =
> -			!!(vep.bus.parallel.flags & V4L2_MBUS_FIELD_EVEN_LOW);
> +			!!(vep->bus.parallel.flags & V4L2_MBUS_FIELD_EVEN_LOW);
>  		buscfg->bus.parallel.data_pol =
> -			!!(vep.bus.parallel.flags & V4L2_MBUS_DATA_ACTIVE_LOW);
> -		buscfg->bus.parallel.bt656 = vep.bus_type == V4L2_MBUS_BT656;
> +			!!(vep->bus.parallel.flags & V4L2_MBUS_DATA_ACTIVE_LOW);
> +		buscfg->bus.parallel.bt656 = vep->bus_type == V4L2_MBUS_BT656;
>  		break;
>  
>  	case ISP_OF_PHY_CSIPHY1:
>  	case ISP_OF_PHY_CSIPHY2:
> -		switch (vep.bus_type) {
> +		switch (vep->bus_type) {
>  		case V4L2_MBUS_CCP2:
>  		case V4L2_MBUS_CSI1:
>  			dev_dbg(dev, "CSI-1/CCP-2 configuration\n");
> @@ -2060,11 +2058,11 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
>  			break;
>  		default:
>  			dev_err(dev, "unsupported bus type %u\n",
> -				vep.bus_type);
> +				vep->bus_type);
>  			return -EINVAL;
>  		}
>  
> -		switch (vep.base.port) {
> +		switch (vep->base.port) {
>  		case ISP_OF_PHY_CSIPHY1:
>  			if (csi1)
>  				buscfg->interface = ISP_INTERFACE_CCP2B_PHY1;
> @@ -2080,47 +2078,47 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
>  		}
>  		if (csi1) {
>  			buscfg->bus.ccp2.lanecfg.clk.pos =
> -				vep.bus.mipi_csi1.clock_lane;
> +				vep->bus.mipi_csi1.clock_lane;
>  			buscfg->bus.ccp2.lanecfg.clk.pol =
> -				vep.bus.mipi_csi1.lane_polarity[0];
> +				vep->bus.mipi_csi1.lane_polarity[0];
>  			dev_dbg(dev, "clock lane polarity %u, pos %u\n",
>  				buscfg->bus.ccp2.lanecfg.clk.pol,
>  				buscfg->bus.ccp2.lanecfg.clk.pos);
>  
>  			buscfg->bus.ccp2.lanecfg.data[0].pos =
> -				vep.bus.mipi_csi1.data_lane;
> +				vep->bus.mipi_csi1.data_lane;
>  			buscfg->bus.ccp2.lanecfg.data[0].pol =
> -				vep.bus.mipi_csi1.lane_polarity[1];
> +				vep->bus.mipi_csi1.lane_polarity[1];
>  
>  			dev_dbg(dev, "data lane polarity %u, pos %u\n",
>  				buscfg->bus.ccp2.lanecfg.data[0].pol,
>  				buscfg->bus.ccp2.lanecfg.data[0].pos);
>  
>  			buscfg->bus.ccp2.strobe_clk_pol =
> -				vep.bus.mipi_csi1.clock_inv;
> -			buscfg->bus.ccp2.phy_layer = vep.bus.mipi_csi1.strobe;
> +				vep->bus.mipi_csi1.clock_inv;
> +			buscfg->bus.ccp2.phy_layer = vep->bus.mipi_csi1.strobe;
>  			buscfg->bus.ccp2.ccp2_mode =
> -				vep.bus_type == V4L2_MBUS_CCP2;
> +				vep->bus_type == V4L2_MBUS_CCP2;
>  			buscfg->bus.ccp2.vp_clk_pol = 1;
>  
>  			buscfg->bus.ccp2.crc = 1;
>  		} else {
>  			buscfg->bus.csi2.lanecfg.clk.pos =
> -				vep.bus.mipi_csi2.clock_lane;
> +				vep->bus.mipi_csi2.clock_lane;
>  			buscfg->bus.csi2.lanecfg.clk.pol =
> -				vep.bus.mipi_csi2.lane_polarities[0];
> +				vep->bus.mipi_csi2.lane_polarities[0];
>  			dev_dbg(dev, "clock lane polarity %u, pos %u\n",
>  				buscfg->bus.csi2.lanecfg.clk.pol,
>  				buscfg->bus.csi2.lanecfg.clk.pos);
>  
>  			buscfg->bus.csi2.num_data_lanes =
> -				vep.bus.mipi_csi2.num_data_lanes;
> +				vep->bus.mipi_csi2.num_data_lanes;
>  
>  			for (i = 0; i < buscfg->bus.csi2.num_data_lanes; i++) {
>  				buscfg->bus.csi2.lanecfg.data[i].pos =
> -					vep.bus.mipi_csi2.data_lanes[i];
> +					vep->bus.mipi_csi2.data_lanes[i];
>  				buscfg->bus.csi2.lanecfg.data[i].pol =
> -					vep.bus.mipi_csi2.lane_polarities[i + 1];
> +					vep->bus.mipi_csi2.lane_polarities[i + 1];
>  				dev_dbg(dev,
>  					"data lane %u polarity %u, pos %u\n", i,
>  					buscfg->bus.csi2.lanecfg.data[i].pol,
> @@ -2137,57 +2135,13 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
>  
>  	default:
>  		dev_warn(dev, "%pOF: invalid interface %u\n",
> -			 to_of_node(fwnode), vep.base.port);
> +			 to_of_node(vep->base.local_fwnode), vep->base.port);
>  		return -EINVAL;
>  	}
>  
>  	return 0;
>  }
>  
> -static int isp_fwnodes_parse(struct device *dev,
> -			     struct v4l2_async_notifier *notifier)
> -{
> -	struct fwnode_handle *fwnode = NULL;
> -
> -	notifier->subdevs = devm_kcalloc(
> -		dev, ISP_MAX_SUBDEVS, sizeof(*notifier->subdevs), GFP_KERNEL);
> -	if (!notifier->subdevs)
> -		return -ENOMEM;
> -
> -	while (notifier->num_subdevs < ISP_MAX_SUBDEVS &&
> -	       (fwnode = fwnode_graph_get_next_endpoint(
> -			of_fwnode_handle(dev->of_node), fwnode))) {
> -		struct isp_async_subdev *isd;
> -
> -		isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
> -		if (!isd)
> -			goto error;
> -
> -		if (isp_fwnode_parse(dev, fwnode, isd)) {
> -			devm_kfree(dev, isd);
> -			continue;
> -		}
> -
> -		notifier->subdevs[notifier->num_subdevs] = &isd->asd;
> -
> -		isd->asd.match.fwnode.fwnode =
> -			fwnode_graph_get_remote_port_parent(fwnode);
> -		if (!isd->asd.match.fwnode.fwnode) {
> -			dev_warn(dev, "bad remote port parent\n");
> -			goto error;
> -		}
> -
> -		isd->asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
> -		notifier->num_subdevs++;
> -	}
> -
> -	return notifier->num_subdevs;
> -
> -error:
> -	fwnode_handle_put(fwnode);
> -	return -EINVAL;
> -}
> -
>  static int isp_subdev_notifier_complete(struct v4l2_async_notifier *async)
>  {
>  	struct isp_device *isp = container_of(async, struct isp_device,
> @@ -2256,7 +2210,9 @@ static int isp_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> -	ret = isp_fwnodes_parse(&pdev->dev, &isp->notifier);
> +	ret = v4l2_async_notifier_parse_fwnode_endpoints(
> +		&pdev->dev, &isp->notifier, sizeof(struct isp_async_subdev),
> +		isp_fwnode_parse);
>  	if (ret < 0)
>  		return ret;
>  
> @@ -2407,6 +2363,7 @@ static int isp_probe(struct platform_device *pdev)
>  	__omap3isp_put(isp, false);
>  error:
>  	mutex_destroy(&isp->isp_mutex);
> +	v4l2_async_notifier_release(&isp->notifier);
>  
>  	return ret;
>  }
> diff --git a/drivers/media/platform/omap3isp/isp.h b/drivers/media/platform/omap3isp/isp.h
> index e528df6efc09..8b9043db94b3 100644
> --- a/drivers/media/platform/omap3isp/isp.h
> +++ b/drivers/media/platform/omap3isp/isp.h
> @@ -220,14 +220,11 @@ struct isp_device {
>  
>  	unsigned int sbl_resources;
>  	unsigned int subclk_resources;
> -
> -#define ISP_MAX_SUBDEVS		8
> -	struct v4l2_subdev *subdevs[ISP_MAX_SUBDEVS];
>  };
>  
>  struct isp_async_subdev {
> -	struct isp_bus_cfg bus;
>  	struct v4l2_async_subdev asd;
> +	struct isp_bus_cfg bus;
>  };
>  
>  #define v4l2_subdev_to_bus_cfg(sd) \
> diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
> index 851f128eba22..6740a241d4a1 100644
> --- a/drivers/media/v4l2-core/v4l2-async.c
> +++ b/drivers/media/v4l2-core/v4l2-async.c
> @@ -22,6 +22,7 @@
>  
>  #include <media/v4l2-async.h>
>  #include <media/v4l2-device.h>
> +#include <media/v4l2-fwnode.h>
>  #include <media/v4l2-subdev.h>
>  
>  static bool match_i2c(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
> @@ -278,6 +279,21 @@ void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
>  }
>  EXPORT_SYMBOL(v4l2_async_notifier_unregister);
>  
> +void v4l2_async_notifier_release(struct v4l2_async_notifier *notifier)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < notifier->num_subdevs; i++)
> +		kfree(notifier->subdevs[i]);
> +
> +	notifier->max_subdevs = 0;
> +	notifier->num_subdevs = 0;
> +
> +	kvfree(notifier->subdevs);
> +	notifier->subdevs = NULL;
> +}
> +EXPORT_SYMBOL_GPL(v4l2_async_notifier_release);
> +
>  int v4l2_async_register_subdev(struct v4l2_subdev *sd)
>  {
>  	struct v4l2_async_notifier *notifier;
> diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
> index 706f9e7b90f1..2496d76eef4b 100644
> --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> @@ -19,6 +19,7 @@
>   */
>  #include <linux/acpi.h>
>  #include <linux/kernel.h>
> +#include <linux/mm.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/property.h>
> @@ -26,6 +27,7 @@
>  #include <linux/string.h>
>  #include <linux/types.h>
>  
> +#include <media/v4l2-async.h>
>  #include <media/v4l2-fwnode.h>
>  
>  enum v4l2_fwnode_bus_type {
> @@ -313,6 +315,135 @@ void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link)
>  }
>  EXPORT_SYMBOL_GPL(v4l2_fwnode_put_link);
>  
> +static int v4l2_async_notifier_realloc(struct v4l2_async_notifier *notifier,
> +				       unsigned int max_subdevs)
> +{
> +	struct v4l2_async_subdev **subdevs;
> +
> +	if (max_subdevs <= notifier->max_subdevs)
> +		return 0;

Should probably be a WARN_ON. Or add a comment saying that this should
never happen.

> +
> +	subdevs = kvmalloc_array(
> +		max_subdevs, sizeof(*notifier->subdevs),
> +		GFP_KERNEL | __GFP_ZERO);
> +	if (!subdevs)
> +		return -ENOMEM;
> +
> +	if (notifier->subdevs) {
> +		memcpy(subdevs, notifier->subdevs,
> +		       sizeof(*subdevs) * notifier->num_subdevs);
> +
> +		kvfree(notifier->subdevs);
> +	}
> +
> +	notifier->subdevs = subdevs;
> +	notifier->max_subdevs = max_subdevs;
> +
> +	return 0;
> +}
> +
> +static int v4l2_async_notifier_fwnode_parse_endpoint(
> +	struct device *dev, struct v4l2_async_notifier *notifier,
> +	struct fwnode_handle *endpoint, unsigned int asd_struct_size,
> +	int (*parse_single)(struct device *dev,
> +			    struct v4l2_fwnode_endpoint *vep,
> +			    struct v4l2_async_subdev *asd))
> +{
> +	struct v4l2_async_subdev *asd;
> +	struct v4l2_fwnode_endpoint *vep;
> +	int ret = 0;
> +
> +	asd = kzalloc(asd_struct_size, GFP_KERNEL);
> +	if (!asd)
> +		return -ENOMEM;
> +
> +	asd->match.fwnode.fwnode =
> +		fwnode_graph_get_remote_port_parent(endpoint);
> +	if (!asd->match.fwnode.fwnode) {
> +		dev_warn(dev, "bad remote port parent\n");
> +		ret = -EINVAL;
> +		goto out_err;
> +	}
> +
> +	/* Ignore endpoints the parsing of which failed. */
> +	vep = v4l2_fwnode_endpoint_alloc_parse(endpoint);
> +	if (IS_ERR(vep)) {
> +		ret = PTR_ERR(vep);
> +		dev_warn(dev, "unable to parse V4L2 fwnode endpoint (%d)\n",
> +			 ret);
> +		goto out_err;
> +	}
> +
> +	ret = parse_single(dev, vep, asd);
> +	v4l2_fwnode_endpoint_free(vep);
> +	if (ret) {
> +		dev_warn(dev, "driver could not parse endpoint (%d)\n", ret);
> +		goto out_err;
> +	}
> +
> +	asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
> +	notifier->subdevs[notifier->num_subdevs] = asd;
> +	notifier->num_subdevs++;
> +
> +	return 0;
> +
> +out_err:
> +	fwnode_handle_put(asd->match.fwnode.fwnode);

Just checking: the fwnode_handle_put argument can safely be NULL?

> +	kfree(asd);
> +
> +	return ret;
> +}
> +
> +int v4l2_async_notifier_parse_fwnode_endpoints(
> +	struct device *dev, struct v4l2_async_notifier *notifier,
> +	size_t asd_struct_size,
> +	int (*parse_single)(struct device *dev,
> +			    struct v4l2_fwnode_endpoint *vep,
> +			    struct v4l2_async_subdev *asd))
> +{
> +	struct fwnode_handle *fwnode = NULL;
> +	unsigned int max_subdevs = notifier->max_subdevs;

I thought the notifier was supposed to be zeroed?

> +	int ret;
> +
> +	if (asd_struct_size < sizeof(struct v4l2_async_subdev) ||
> +	    notifier->v4l2_dev)

This could use a comment why you check for notifier->v4l2_dev. That's not
obvious.

> +		return -EINVAL;

Since we have the requirement that the notifier should be zeroed,
why not do that here?

> +
> +	for (fwnode = NULL; (fwnode = fwnode_graph_get_next_endpoint(
> +				     dev_fwnode(dev), fwnode)); )
> +		if (fwnode_device_is_available(
> +			    fwnode_graph_get_port_parent(fwnode)))
> +			max_subdevs++;
> +
> +	/* No subdevs to add? Return here. */
> +	if (max_subdevs == notifier->max_subdevs)
> +		return 0;
> +
> +	ret = v4l2_async_notifier_realloc(notifier, max_subdevs);
> +	if (ret)
> +		return ret;

I think this is confusing. There is nothing to realloc here. Only in the
next patch (5/5) do you add support for recursively walking the graph and
adding more subdevs.

I would just call kvmalloc_array here.

> +
> +	for (fwnode = NULL; (fwnode = fwnode_graph_get_next_endpoint(
> +				     dev_fwnode(dev), fwnode)); ) {
> +		if (!fwnode_device_is_available(
> +			    fwnode_graph_get_port_parent(fwnode)))
> +			continue;
> +
> +		if (WARN_ON(notifier->num_subdevs >= notifier->max_subdevs))
> +			break;
> +
> +		ret = v4l2_async_notifier_fwnode_parse_endpoint(
> +			dev, notifier, fwnode, asd_struct_size, parse_single);
> +		if (ret < 0)
> +			break;
> +	}
> +
> +	fwnode_handle_put(fwnode);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(v4l2_async_notifier_parse_fwnode_endpoints);
> +
>  MODULE_LICENSE("GPL");
>  MODULE_AUTHOR("Sakari Ailus <sakari.ailus@linux.intel.com>");
>  MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@samsung.com>");
> diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
> index c69d8c8a66d0..cf13c7311a1c 100644
> --- a/include/media/v4l2-async.h
> +++ b/include/media/v4l2-async.h
> @@ -18,7 +18,6 @@ struct device;
>  struct device_node;
>  struct v4l2_device;
>  struct v4l2_subdev;
> -struct v4l2_async_notifier;
>  
>  /* A random max subdevice number, used to allocate an array on stack */
>  #define V4L2_MAX_SUBDEVS 128U
> @@ -50,6 +49,10 @@ enum v4l2_async_match_type {
>   * @match:	union of per-bus type matching data sets
>   * @list:	used to link struct v4l2_async_subdev objects, waiting to be
>   *		probed, to a notifier->waiting list
> + *
> + * When the struct is used as the first member of a driver specific

Just replace "the first member" by "part"...

> + * struct, the driver specific struct shall contain the @struct
> + * v4l2_async_subdev as its first member.

...since you mention in the second part that it has to be the first member.
No need to mention that twice.

>   */
>  struct v4l2_async_subdev {
>  	enum v4l2_async_match_type match_type;
> @@ -78,7 +81,8 @@ struct v4l2_async_subdev {
>  /**
>   * struct v4l2_async_notifier - v4l2_device notifier data
>   *
> - * @num_subdevs: number of subdevices
> + * @num_subdevs: number of subdevices used in subdevs array

in the

> + * @max_subdevs: number of subdevices allocated in subdevs array

in the

>   * @subdevs:	array of pointers to subdevice descriptors
>   * @v4l2_dev:	pointer to struct v4l2_device
>   * @waiting:	list of struct v4l2_async_subdev, waiting for their drivers
> @@ -90,6 +94,7 @@ struct v4l2_async_subdev {
>   */
>  struct v4l2_async_notifier {
>  	unsigned int num_subdevs;
> +	unsigned int max_subdevs;
>  	struct v4l2_async_subdev **subdevs;
>  	struct v4l2_device *v4l2_dev;
>  	struct list_head waiting;
> @@ -121,6 +126,21 @@ int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
>  void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier);
>  
>  /**
> + * v4l2_async_notifier_release - release notifier resources
> + * @notifier: the notifier the resources of which are to be released

Just say: @notifier: pointer to &struct v4l2_async_notifier

> + *
> + * Release memory resources related to a notifier, including the async

s/a/the/

> + * sub-devices allocated for the purposes of the notifier. The user is
> + * responsible for releasing the notifier's resources after calling
> + * @v4l2_async_notifier_parse_fwnode_endpoints.
> + *
> + * There is no harm from calling v4l2_async_notifier_release in other
> + * cases as long as its memory has been zeroed after it has been
> + * allocated.
> + */
> +void v4l2_async_notifier_release(struct v4l2_async_notifier *notifier);
> +
> +/**
>   * v4l2_async_register_subdev - registers a sub-device to the asynchronous
>   * 	subdevice framework
>   *
> diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
> index 68eb22ba571b..d063ab4ff67b 100644
> --- a/include/media/v4l2-fwnode.h
> +++ b/include/media/v4l2-fwnode.h
> @@ -25,6 +25,8 @@
>  #include <media/v4l2-mediabus.h>
>  
>  struct fwnode_handle;
> +struct v4l2_async_notifier;
> +struct v4l2_async_subdev;
>  
>  #define V4L2_FWNODE_CSI2_MAX_DATA_LANES	4
>  
> @@ -201,4 +203,50 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,
>   */
>  void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link);
>  
> +/**
> + * v4l2_async_notifier_parse_fwnode_endpoints - Parse V4L2 fwnode endpoints in a
> + *						device node
> + * @dev: the device the endpoints of which are to be parsed
> + * @notifier: notifier for @dev
> + * @asd_struct_size: size of the driver's async sub-device struct, including
> + *		     sizeof(struct v4l2_async_subdev). The &struct
> + *		     v4l2_async_subdev shall be the first member of
> + *		     the driver's async sub-device struct, i.e. both
> + *		     begin at the same memory address.
> + * @parse_single: driver's callback function called on each V4L2 fwnode endpoint
> + *
> + * Parse the fwnode endpoints of the @dev device and populate the async sub-
> + * devices array of the notifier. The @parse_endpoint callback function is

parse_endpoint -> parse_single

(Actually, I like the name parse_endpoint better)

> + * called for each endpoint with the corresponding async sub-device pointer to
> + * let the caller initialize the driver-specific part of the async sub-device
> + * structure.
> + *
> + * The notifier memory shall be zeroed before this function is called on the
> + * notifier.
> + *
> + * This function may not be called on a registered notifier and may be called on
> + * a notifier only once. When using this function, the user may not access the
> + * notifier's subdevs array nor change notifier's num_subdevs field, these are
> + * reserved for the framework's internal use only.

Ditto for the max_subdevs field, I think.

> + *
> + * The @struct v4l2_fwnode_endpoint passed to the callback function
> + * @parse_single is released once the function is finished. If there is a need
> + * to retain that configuration, the user needs to allocate memory for it.
> + *
> + * Any notifier populated using this function must be released with a call to
> + * v4l2_async_notifier_release() after it has been unregistered and the async
> + * sub-devices are no longer in use.
> + *
> + * Return: %0 on success, including when no async sub-devices are found
> + *	   %-ENOMEM if memory allocation failed
> + *	   %-EINVAL if graph or endpoint parsing failed
> + *	   Other error codes as returned by @parse_single
> + */
> +int v4l2_async_notifier_parse_fwnode_endpoints(
> +	struct device *dev, struct v4l2_async_notifier *notifier,
> +	size_t asd_struct_size,
> +	int (*parse_single)(struct device *dev,
> +			    struct v4l2_fwnode_endpoint *vep,
> +			    struct v4l2_async_subdev *asd));
> +
>  #endif /* _V4L2_FWNODE_H */
> 

Regards,

	Hans

Re: [PATCH v6 5/5] v4l: fwnode: Support generic parsing of graph endpoints in a single port

[Hans Verkuil]

On 30/08/17 13:49, Sakari Ailus wrote:
> This is the preferred way to parse the endpoints.
> 
> Comment rcar-vin as an example.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
>  drivers/media/platform/rcar-vin/rcar-core.c | 111 ++++++++--------------------
>  drivers/media/platform/rcar-vin/rcar-dma.c  |  10 +--
>  drivers/media/platform/rcar-vin/rcar-v4l2.c |  14 ++--
>  drivers/media/platform/rcar-vin/rcar-vin.h  |   4 +-
>  drivers/media/v4l2-core/v4l2-fwnode.c       |  47 ++++++++++++
>  include/media/v4l2-fwnode.h                 |  49 ++++++++++++
>  6 files changed, 142 insertions(+), 93 deletions(-)
> 
> diff --git a/drivers/media/platform/rcar-vin/rcar-core.c b/drivers/media/platform/rcar-vin/rcar-core.c
> index 142de447aaaa..4378806be1d4 100644
> --- a/drivers/media/platform/rcar-vin/rcar-core.c
> +++ b/drivers/media/platform/rcar-vin/rcar-core.c
> @@ -21,6 +21,7 @@
>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
>  
> +#include <media/v4l2-async.h>
>  #include <media/v4l2-fwnode.h>
>  
>  #include "rcar-vin.h"
> @@ -77,14 +78,14 @@ static int rvin_digital_notify_complete(struct v4l2_async_notifier *notifier)
>  	int ret;
>  
>  	/* Verify subdevices mbus format */
> -	if (!rvin_mbus_supported(&vin->digital)) {
> +	if (!rvin_mbus_supported(vin->digital)) {
>  		vin_err(vin, "Unsupported media bus format for %s\n",
> -			vin->digital.subdev->name);
> +			vin->digital->subdev->name);
>  		return -EINVAL;
>  	}
>  
>  	vin_dbg(vin, "Found media bus format for %s: %d\n",
> -		vin->digital.subdev->name, vin->digital.code);
> +		vin->digital->subdev->name, vin->digital->code);
>  
>  	ret = v4l2_device_register_subdev_nodes(&vin->v4l2_dev);
>  	if (ret < 0) {
> @@ -103,7 +104,7 @@ static void rvin_digital_notify_unbind(struct v4l2_async_notifier *notifier,
>  
>  	vin_dbg(vin, "unbind digital subdev %s\n", subdev->name);
>  	rvin_v4l2_remove(vin);
> -	vin->digital.subdev = NULL;
> +	vin->digital->subdev = NULL;
>  }
>  
>  static int rvin_digital_notify_bound(struct v4l2_async_notifier *notifier,
> @@ -120,117 +121,67 @@ static int rvin_digital_notify_bound(struct v4l2_async_notifier *notifier,
>  	ret = rvin_find_pad(subdev, MEDIA_PAD_FL_SOURCE);
>  	if (ret < 0)
>  		return ret;
> -	vin->digital.source_pad = ret;
> +	vin->digital->source_pad = ret;
>  
>  	ret = rvin_find_pad(subdev, MEDIA_PAD_FL_SINK);
> -	vin->digital.sink_pad = ret < 0 ? 0 : ret;
> +	vin->digital->sink_pad = ret < 0 ? 0 : ret;
>  
> -	vin->digital.subdev = subdev;
> +	vin->digital->subdev = subdev;
>  
>  	vin_dbg(vin, "bound subdev %s source pad: %u sink pad: %u\n",
> -		subdev->name, vin->digital.source_pad,
> -		vin->digital.sink_pad);
> +		subdev->name, vin->digital->source_pad,
> +		vin->digital->sink_pad);
>  
>  	return 0;
>  }
>  
> -static int rvin_digitial_parse_v4l2(struct rvin_dev *vin,
> -				    struct device_node *ep,
> -				    struct v4l2_mbus_config *mbus_cfg)
> +static int rvin_digital_parse_v4l2(struct device *dev,
> +				   struct v4l2_fwnode_endpoint *vep,
> +				   struct v4l2_async_subdev *asd)
>  {
> -	struct v4l2_fwnode_endpoint v4l2_ep;
> -	int ret;
> -
> -	ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(ep), &v4l2_ep);
> -	if (ret) {
> -		vin_err(vin, "Could not parse v4l2 endpoint\n");
> -		return -EINVAL;
> -	}
> +	struct rvin_dev *vin = dev_get_drvdata(dev);
> +	struct rvin_graph_entity *rvge =
> +		container_of(asd, struct rvin_graph_entity, asd);
>  
> -	mbus_cfg->type = v4l2_ep.bus_type;
> +	rvge->mbus_cfg.type = vep->bus_type;
>  
> -	switch (mbus_cfg->type) {
> +	switch (rvge->mbus_cfg.type) {
>  	case V4L2_MBUS_PARALLEL:
>  		vin_dbg(vin, "Found PARALLEL media bus\n");
> -		mbus_cfg->flags = v4l2_ep.bus.parallel.flags;
> +		rvge->mbus_cfg.flags = vep->bus.parallel.flags;
>  		break;
>  	case V4L2_MBUS_BT656:
>  		vin_dbg(vin, "Found BT656 media bus\n");
> -		mbus_cfg->flags = 0;
> +		rvge->mbus_cfg.flags = 0;
>  		break;
>  	default:
>  		vin_err(vin, "Unknown media bus type\n");
>  		return -EINVAL;
>  	}
>  
> -	return 0;
> -}
> -
> -static int rvin_digital_graph_parse(struct rvin_dev *vin)
> -{
> -	struct device_node *ep, *np;
> -	int ret;
> -
> -	vin->digital.asd.match.fwnode.fwnode = NULL;
> -	vin->digital.subdev = NULL;
> -
> -	/*
> -	 * Port 0 id 0 is local digital input, try to get it.
> -	 * Not all instances can or will have this, that is OK
> -	 */
> -	ep = of_graph_get_endpoint_by_regs(vin->dev->of_node, 0, 0);
> -	if (!ep)
> -		return 0;
> -
> -	np = of_graph_get_remote_port_parent(ep);
> -	if (!np) {
> -		vin_err(vin, "No remote parent for digital input\n");
> -		of_node_put(ep);
> -		return -EINVAL;
> -	}
> -	of_node_put(np);
> -
> -	ret = rvin_digitial_parse_v4l2(vin, ep, &vin->digital.mbus_cfg);
> -	of_node_put(ep);
> -	if (ret)
> -		return ret;
> -
> -	vin->digital.asd.match.fwnode.fwnode = of_fwnode_handle(np);
> -	vin->digital.asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
> +	vin->digital = rvge;
>  
>  	return 0;
>  }
>  
>  static int rvin_digital_graph_init(struct rvin_dev *vin)
>  {
> -	struct v4l2_async_subdev **subdevs = NULL;
>  	int ret;
>  
> -	ret = rvin_digital_graph_parse(vin);
> +	ret = v4l2_async_notifier_parse_fwnode_endpoint(
> +		vin->dev, &vin->notifier, 0, 0,
> +		sizeof(struct rvin_graph_entity), rvin_digital_parse_v4l2);
>  	if (ret)
>  		return ret;
>  
> -	if (!vin->digital.asd.match.fwnode.fwnode) {
> -		vin_dbg(vin, "No digital subdevice found\n");
> -		return -ENODEV;
> -	}
> -
> -	/* Register the subdevices notifier. */
> -	subdevs = devm_kzalloc(vin->dev, sizeof(*subdevs), GFP_KERNEL);
> -	if (subdevs == NULL)
> -		return -ENOMEM;
> +	if (vin->notifier.num_subdevs > 0)
> +		vin_dbg(vin, "Found digital subdevice %pOF\n",
> +			to_of_node(
> +				vin->notifier.subdevs[0]->match.fwnode.fwnode));
>  
> -	subdevs[0] = &vin->digital.asd;
> -
> -	vin_dbg(vin, "Found digital subdevice %pOF\n",
> -		to_of_node(subdevs[0]->match.fwnode.fwnode));
> -
> -	vin->notifier.num_subdevs = 1;
> -	vin->notifier.subdevs = subdevs;
>  	vin->notifier.bound = rvin_digital_notify_bound;
>  	vin->notifier.unbind = rvin_digital_notify_unbind;
>  	vin->notifier.complete = rvin_digital_notify_complete;
> -
>  	ret = v4l2_async_notifier_register(&vin->v4l2_dev, &vin->notifier);
>  	if (ret < 0) {
>  		vin_err(vin, "Notifier registration failed\n");
> @@ -290,6 +241,8 @@ static int rcar_vin_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> +	platform_set_drvdata(pdev, vin);
> +
>  	ret = rvin_digital_graph_init(vin);
>  	if (ret < 0)
>  		goto error;
> @@ -297,11 +250,10 @@ static int rcar_vin_probe(struct platform_device *pdev)
>  	pm_suspend_ignore_children(&pdev->dev, true);
>  	pm_runtime_enable(&pdev->dev);
>  
> -	platform_set_drvdata(pdev, vin);
> -
>  	return 0;
>  error:
>  	rvin_dma_remove(vin);
> +	v4l2_async_notifier_release(&vin->notifier);
>  
>  	return ret;
>  }
> @@ -313,6 +265,7 @@ static int rcar_vin_remove(struct platform_device *pdev)
>  	pm_runtime_disable(&pdev->dev);
>  
>  	v4l2_async_notifier_unregister(&vin->notifier);
> +	v4l2_async_notifier_release(&vin->notifier);
>  
>  	rvin_dma_remove(vin);
>  
> diff --git a/drivers/media/platform/rcar-vin/rcar-dma.c b/drivers/media/platform/rcar-vin/rcar-dma.c
> index b136844499f6..23fdff7a7370 100644
> --- a/drivers/media/platform/rcar-vin/rcar-dma.c
> +++ b/drivers/media/platform/rcar-vin/rcar-dma.c
> @@ -183,7 +183,7 @@ static int rvin_setup(struct rvin_dev *vin)
>  	/*
>  	 * Input interface
>  	 */
> -	switch (vin->digital.code) {
> +	switch (vin->digital->code) {
>  	case MEDIA_BUS_FMT_YUYV8_1X16:
>  		/* BT.601/BT.1358 16bit YCbCr422 */
>  		vnmc |= VNMC_INF_YUV16;
> @@ -191,7 +191,7 @@ static int rvin_setup(struct rvin_dev *vin)
>  		break;
>  	case MEDIA_BUS_FMT_UYVY8_2X8:
>  		/* BT.656 8bit YCbCr422 or BT.601 8bit YCbCr422 */
> -		vnmc |= vin->digital.mbus_cfg.type == V4L2_MBUS_BT656 ?
> +		vnmc |= vin->digital->mbus_cfg.type == V4L2_MBUS_BT656 ?
>  			VNMC_INF_YUV8_BT656 : VNMC_INF_YUV8_BT601;
>  		input_is_yuv = true;
>  		break;
> @@ -200,7 +200,7 @@ static int rvin_setup(struct rvin_dev *vin)
>  		break;
>  	case MEDIA_BUS_FMT_UYVY10_2X10:
>  		/* BT.656 10bit YCbCr422 or BT.601 10bit YCbCr422 */
> -		vnmc |= vin->digital.mbus_cfg.type == V4L2_MBUS_BT656 ?
> +		vnmc |= vin->digital->mbus_cfg.type == V4L2_MBUS_BT656 ?
>  			VNMC_INF_YUV10_BT656 : VNMC_INF_YUV10_BT601;
>  		input_is_yuv = true;
>  		break;
> @@ -212,11 +212,11 @@ static int rvin_setup(struct rvin_dev *vin)
>  	dmr2 = VNDMR2_FTEV | VNDMR2_VLV(1);
>  
>  	/* Hsync Signal Polarity Select */
> -	if (!(vin->digital.mbus_cfg.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW))
> +	if (!(vin->digital->mbus_cfg.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW))
>  		dmr2 |= VNDMR2_HPS;
>  
>  	/* Vsync Signal Polarity Select */
> -	if (!(vin->digital.mbus_cfg.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW))
> +	if (!(vin->digital->mbus_cfg.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW))
>  		dmr2 |= VNDMR2_VPS;
>  
>  	/*
> diff --git a/drivers/media/platform/rcar-vin/rcar-v4l2.c b/drivers/media/platform/rcar-vin/rcar-v4l2.c
> index dd37ea811680..b479b882da12 100644
> --- a/drivers/media/platform/rcar-vin/rcar-v4l2.c
> +++ b/drivers/media/platform/rcar-vin/rcar-v4l2.c
> @@ -111,7 +111,7 @@ static int rvin_reset_format(struct rvin_dev *vin)
>  	struct v4l2_mbus_framefmt *mf = &fmt.format;
>  	int ret;
>  
> -	fmt.pad = vin->digital.source_pad;
> +	fmt.pad = vin->digital->source_pad;
>  
>  	ret = v4l2_subdev_call(vin_to_source(vin), pad, get_fmt, NULL, &fmt);
>  	if (ret)
> @@ -172,13 +172,13 @@ static int __rvin_try_format_source(struct rvin_dev *vin,
>  
>  	sd = vin_to_source(vin);
>  
> -	v4l2_fill_mbus_format(&format.format, pix, vin->digital.code);
> +	v4l2_fill_mbus_format(&format.format, pix, vin->digital->code);
>  
>  	pad_cfg = v4l2_subdev_alloc_pad_config(sd);
>  	if (pad_cfg == NULL)
>  		return -ENOMEM;
>  
> -	format.pad = vin->digital.source_pad;
> +	format.pad = vin->digital->source_pad;
>  
>  	field = pix->field;
>  
> @@ -555,7 +555,7 @@ static int rvin_enum_dv_timings(struct file *file, void *priv_fh,
>  	if (timings->pad)
>  		return -EINVAL;
>  
> -	timings->pad = vin->digital.sink_pad;
> +	timings->pad = vin->digital->sink_pad;
>  
>  	ret = v4l2_subdev_call(sd, pad, enum_dv_timings, timings);
>  
> @@ -607,7 +607,7 @@ static int rvin_dv_timings_cap(struct file *file, void *priv_fh,
>  	if (cap->pad)
>  		return -EINVAL;
>  
> -	cap->pad = vin->digital.sink_pad;
> +	cap->pad = vin->digital->sink_pad;
>  
>  	ret = v4l2_subdev_call(sd, pad, dv_timings_cap, cap);
>  
> @@ -625,7 +625,7 @@ static int rvin_g_edid(struct file *file, void *fh, struct v4l2_edid *edid)
>  	if (edid->pad)
>  		return -EINVAL;
>  
> -	edid->pad = vin->digital.sink_pad;
> +	edid->pad = vin->digital->sink_pad;
>  
>  	ret = v4l2_subdev_call(sd, pad, get_edid, edid);
>  
> @@ -643,7 +643,7 @@ static int rvin_s_edid(struct file *file, void *fh, struct v4l2_edid *edid)
>  	if (edid->pad)
>  		return -EINVAL;
>  
> -	edid->pad = vin->digital.sink_pad;
> +	edid->pad = vin->digital->sink_pad;
>  
>  	ret = v4l2_subdev_call(sd, pad, set_edid, edid);
>  
> diff --git a/drivers/media/platform/rcar-vin/rcar-vin.h b/drivers/media/platform/rcar-vin/rcar-vin.h
> index 9bfb5a7c4dc4..5382078143fb 100644
> --- a/drivers/media/platform/rcar-vin/rcar-vin.h
> +++ b/drivers/media/platform/rcar-vin/rcar-vin.h
> @@ -126,7 +126,7 @@ struct rvin_dev {
>  	struct v4l2_device v4l2_dev;
>  	struct v4l2_ctrl_handler ctrl_handler;
>  	struct v4l2_async_notifier notifier;
> -	struct rvin_graph_entity digital;
> +	struct rvin_graph_entity *digital;
>  
>  	struct mutex lock;
>  	struct vb2_queue queue;
> @@ -145,7 +145,7 @@ struct rvin_dev {
>  	struct v4l2_rect compose;
>  };
>  
> -#define vin_to_source(vin)		vin->digital.subdev
> +#define vin_to_source(vin)		((vin)->digital->subdev)
>  
>  /* Debug */
>  #define vin_dbg(d, fmt, arg...)		dev_dbg(d->dev, fmt, ##arg)
> diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
> index 2496d76eef4b..4720e8a043cf 100644
> --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> @@ -444,6 +444,53 @@ int v4l2_async_notifier_parse_fwnode_endpoints(
>  }
>  EXPORT_SYMBOL_GPL(v4l2_async_notifier_parse_fwnode_endpoints);
>  
> +int v4l2_async_notifier_parse_fwnode_endpoint(
> +	struct device *dev, struct v4l2_async_notifier *notifier,
> +	unsigned int port_id, unsigned int endpoint_id, size_t asd_struct_size,
> +	int (*parse_single)(struct device *dev,
> +			    struct v4l2_fwnode_endpoint *vep,
> +			    struct v4l2_async_subdev *asd))
> +{
> +	struct fwnode_handle *fwnode = NULL;
> +	int ret;
> +
> +	while ((fwnode = fwnode_graph_get_next_endpoint(
> +			dev_fwnode(dev), fwnode))) {
> +		struct fwnode_endpoint ep;
> +
> +		ret = fwnode_graph_parse_endpoint(fwnode, &ep);
> +		if (ret < 0)
> +			continue;
> +
> +		if (!fwnode_device_is_available(
> +			    fwnode_graph_get_port_parent(fwnode)))
> +			continue;
> +
> +		if (ep.port == port_id && ep.id == endpoint_id)
> +			break;
> +	}
> +
> +	if (!fwnode)
> +		return -ENOENT;
> +
> +	ret = v4l2_async_notifier_realloc(notifier, notifier->num_subdevs + 1);
> +	if (ret)
> +		goto out_err;
> +
> +	ret = v4l2_async_notifier_fwnode_parse_endpoint(
> +		dev, notifier, fwnode, asd_struct_size, parse_single);
> +	if (ret)
> +		goto out_err;
> +
> +	return 0;
> +
> +out_err:
> +	fwnode_handle_put(fwnode);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(v4l2_async_notifier_parse_fwnode_endpoint);
> +
>  MODULE_LICENSE("GPL");
>  MODULE_AUTHOR("Sakari Ailus <sakari.ailus@linux.intel.com>");
>  MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@samsung.com>");
> diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
> index d063ab4ff67b..dd13604178b4 100644
> --- a/include/media/v4l2-fwnode.h
> +++ b/include/media/v4l2-fwnode.h
> @@ -249,4 +249,53 @@ int v4l2_async_notifier_parse_fwnode_endpoints(
>  			    struct v4l2_fwnode_endpoint *vep,
>  			    struct v4l2_async_subdev *asd));
>  
> +/**
> + * v4l2_async_notifier_parse_fwnode_endpoint - Set up async notifier for an
> + *					       fwnode based sub-device
> + * @dev: @struct device pointer
> + * @notifier: pointer to &struct v4l2_async_notifier
> + * @port_id: port number
> + * @endpoint_id: endpoint number
> + * @asd_struct_size: size of the driver's async sub-device struct, including
> + *		     sizeof(struct v4l2_async_subdev). The &struct
> + *		     v4l2_async_subdev shall be the first member of
> + *		     the driver's async sub-device struct, i.e. both
> + *		     begin at the same memory address.
> + * @parse_single: driver's callback function called on each V4L2 fwnode endpoint
> + *
> + * Parse the fwnode endpoint of the @dev device corresponding to the given port
> + * and endpoint numbres and populate the async sub- devices array of the

numbers
no space after sub-

> + * notifier. The @parse_endpoint callback function is called for the endpoint

parse_single, but (as in the previous patch) I actually prefer parse_endpoint.

> + * with the corresponding async sub-device pointer to let the caller initialize
> + * the driver-specific part of the async sub-device structure.
> + *
> + * The notifier memory shall be zeroed before this function is called on the
> + * notifier.

Should it? Doesn't this add additional subdevs?

I'm lost. What's the relationship between v4l2_async_notifier_parse_fwnode_endpoints
and this function? When do you use which? When you should zero the notifier?

Regards,

	Hans

> + *
> + * This function may not be called on a registered notifier and may be called on
> + * a notifier once or more times, but may not be called more than once on a
> + * given port / endpoint pair. When using this function, the user may not access
> + * the notifier's subdevs array nor change notifier's num_subdevs field, these
> + * are reserved for the framework's internal use only.
> + *
> + * The @struct v4l2_fwnode_endpoint passed to the callback function
> + * @parse_single is released once the function is finished. If there is a need
> + * to retain that configuration, the user needs to allocate memory for it.
> + *
> + * Any notifier populated using this function must be released with a call to
> + * v4l2_async_notifier_release() after it has been unregistered and the async
> + * sub-devices are no longer in use.
> + *
> + * Return: %0 on success, including when no async sub-devices are found
> + *	   %-ENOMEM if memory allocation failed
> + *	   %-EINVAL if graph or endpoint parsing failed
> + *	   Other error codes as returned by @parse_single
> + */
> +int v4l2_async_notifier_parse_fwnode_endpoint(
> +	struct device *dev, struct v4l2_async_notifier *notifier,
> +	unsigned int port_id, unsigned int endpoint_id, size_t asd_struct_size,
> +	int (*parse_single)(struct device *dev,
> +			    struct v4l2_fwnode_endpoint *vep,
> +			    struct v4l2_async_subdev *asd));
> +
>  #endif /* _V4L2_FWNODE_H */
> 

Re: [PATCH v6.1 4/5] v4l: fwnode: Support generic parsing of graph endpoints in a device

[Sakari Ailus]

Hi Hans,

Thanks for the review!

On Fri, Sep 01, 2017 at 01:18:55PM +0200, Hans Verkuil wrote:
> Hi Sakari,
> 
> On 30/08/17 14:45, Sakari Ailus wrote:
> > The current practice is that drivers iterate over their endpoints and
> > parse each endpoint separately. This is very similar in a number of
> > drivers, implement a generic function for the job. Driver specific matters
> > can be taken into account in the driver specific callback.
> > 
> > Convert the omap3isp as an example.
> 
> It would be much easier to review if the omap3isp conversion was done in a
> separate patch. Ditto for the rcar conversion, and I prefer to have both
> at the end of the patch series, after the core code patches.

Ack, I'll split them for v7.

> 
> > 
> > Signed-off-by: Sakari Ailus <sakari.ailus-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> > ---
> > since v6:
> > 
> > - Set notifier->subdevs NULL and notifier->num_subdevs 0 in
> >   v4l2_async_notifier_release().
> > 
> >  drivers/media/platform/omap3isp/isp.c | 115 ++++++++++-------------------
> >  drivers/media/platform/omap3isp/isp.h |   5 +-
> >  drivers/media/v4l2-core/v4l2-async.c  |  16 +++++
> >  drivers/media/v4l2-core/v4l2-fwnode.c | 131 ++++++++++++++++++++++++++++++++++
> >  include/media/v4l2-async.h            |  24 ++++++-
> >  include/media/v4l2-fwnode.h           |  48 +++++++++++++
> >  6 files changed, 254 insertions(+), 85 deletions(-)
> > 
> > diff --git a/drivers/media/platform/omap3isp/isp.c b/drivers/media/platform/omap3isp/isp.c
> > index 1a428fe9f070..a546cf774d40 100644
> > --- a/drivers/media/platform/omap3isp/isp.c
> > +++ b/drivers/media/platform/omap3isp/isp.c
> > @@ -2001,6 +2001,7 @@ static int isp_remove(struct platform_device *pdev)
> >  	__omap3isp_put(isp, false);
> >  
> >  	media_entity_enum_cleanup(&isp->crashed);
> > +	v4l2_async_notifier_release(&isp->notifier);
> >  
> >  	return 0;
> >  }
> > @@ -2011,44 +2012,41 @@ enum isp_of_phy {
> >  	ISP_OF_PHY_CSIPHY2,
> >  };
> >  
> > -static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
> > -			    struct isp_async_subdev *isd)
> > +static int isp_fwnode_parse(struct device *dev,
> > +			    struct v4l2_fwnode_endpoint *vep,
> > +			    struct v4l2_async_subdev *asd)
> >  {
> > +	struct isp_async_subdev *isd =
> > +		container_of(asd, struct isp_async_subdev, asd);
> >  	struct isp_bus_cfg *buscfg = &isd->bus;
> > -	struct v4l2_fwnode_endpoint vep;
> > -	unsigned int i;
> > -	int ret;
> >  	bool csi1 = false;
> > -
> > -	ret = v4l2_fwnode_endpoint_parse(fwnode, &vep);
> > -	if (ret)
> > -		return ret;
> > +	unsigned int i;
> >  
> >  	dev_dbg(dev, "parsing endpoint %pOF, interface %u\n",
> > -		to_of_node(fwnode), vep.base.port);
> > +		to_of_node(vep->base.local_fwnode), vep->base.port);
> >  
> > -	switch (vep.base.port) {
> > +	switch (vep->base.port) {
> >  	case ISP_OF_PHY_PARALLEL:
> >  		buscfg->interface = ISP_INTERFACE_PARALLEL;
> >  		buscfg->bus.parallel.data_lane_shift =
> > -			vep.bus.parallel.data_shift;
> > +			vep->bus.parallel.data_shift;
> >  		buscfg->bus.parallel.clk_pol =
> > -			!!(vep.bus.parallel.flags
> > +			!!(vep->bus.parallel.flags
> >  			   & V4L2_MBUS_PCLK_SAMPLE_FALLING);
> >  		buscfg->bus.parallel.hs_pol =
> > -			!!(vep.bus.parallel.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW);
> > +			!!(vep->bus.parallel.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW);
> >  		buscfg->bus.parallel.vs_pol =
> > -			!!(vep.bus.parallel.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW);
> > +			!!(vep->bus.parallel.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW);
> >  		buscfg->bus.parallel.fld_pol =
> > -			!!(vep.bus.parallel.flags & V4L2_MBUS_FIELD_EVEN_LOW);
> > +			!!(vep->bus.parallel.flags & V4L2_MBUS_FIELD_EVEN_LOW);
> >  		buscfg->bus.parallel.data_pol =
> > -			!!(vep.bus.parallel.flags & V4L2_MBUS_DATA_ACTIVE_LOW);
> > -		buscfg->bus.parallel.bt656 = vep.bus_type == V4L2_MBUS_BT656;
> > +			!!(vep->bus.parallel.flags & V4L2_MBUS_DATA_ACTIVE_LOW);
> > +		buscfg->bus.parallel.bt656 = vep->bus_type == V4L2_MBUS_BT656;
> >  		break;
> >  
> >  	case ISP_OF_PHY_CSIPHY1:
> >  	case ISP_OF_PHY_CSIPHY2:
> > -		switch (vep.bus_type) {
> > +		switch (vep->bus_type) {
> >  		case V4L2_MBUS_CCP2:
> >  		case V4L2_MBUS_CSI1:
> >  			dev_dbg(dev, "CSI-1/CCP-2 configuration\n");
> > @@ -2060,11 +2058,11 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
> >  			break;
> >  		default:
> >  			dev_err(dev, "unsupported bus type %u\n",
> > -				vep.bus_type);
> > +				vep->bus_type);
> >  			return -EINVAL;
> >  		}
> >  
> > -		switch (vep.base.port) {
> > +		switch (vep->base.port) {
> >  		case ISP_OF_PHY_CSIPHY1:
> >  			if (csi1)
> >  				buscfg->interface = ISP_INTERFACE_CCP2B_PHY1;
> > @@ -2080,47 +2078,47 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
> >  		}
> >  		if (csi1) {
> >  			buscfg->bus.ccp2.lanecfg.clk.pos =
> > -				vep.bus.mipi_csi1.clock_lane;
> > +				vep->bus.mipi_csi1.clock_lane;
> >  			buscfg->bus.ccp2.lanecfg.clk.pol =
> > -				vep.bus.mipi_csi1.lane_polarity[0];
> > +				vep->bus.mipi_csi1.lane_polarity[0];
> >  			dev_dbg(dev, "clock lane polarity %u, pos %u\n",
> >  				buscfg->bus.ccp2.lanecfg.clk.pol,
> >  				buscfg->bus.ccp2.lanecfg.clk.pos);
> >  
> >  			buscfg->bus.ccp2.lanecfg.data[0].pos =
> > -				vep.bus.mipi_csi1.data_lane;
> > +				vep->bus.mipi_csi1.data_lane;
> >  			buscfg->bus.ccp2.lanecfg.data[0].pol =
> > -				vep.bus.mipi_csi1.lane_polarity[1];
> > +				vep->bus.mipi_csi1.lane_polarity[1];
> >  
> >  			dev_dbg(dev, "data lane polarity %u, pos %u\n",
> >  				buscfg->bus.ccp2.lanecfg.data[0].pol,
> >  				buscfg->bus.ccp2.lanecfg.data[0].pos);
> >  
> >  			buscfg->bus.ccp2.strobe_clk_pol =
> > -				vep.bus.mipi_csi1.clock_inv;
> > -			buscfg->bus.ccp2.phy_layer = vep.bus.mipi_csi1.strobe;
> > +				vep->bus.mipi_csi1.clock_inv;
> > +			buscfg->bus.ccp2.phy_layer = vep->bus.mipi_csi1.strobe;
> >  			buscfg->bus.ccp2.ccp2_mode =
> > -				vep.bus_type == V4L2_MBUS_CCP2;
> > +				vep->bus_type == V4L2_MBUS_CCP2;
> >  			buscfg->bus.ccp2.vp_clk_pol = 1;
> >  
> >  			buscfg->bus.ccp2.crc = 1;
> >  		} else {
> >  			buscfg->bus.csi2.lanecfg.clk.pos =
> > -				vep.bus.mipi_csi2.clock_lane;
> > +				vep->bus.mipi_csi2.clock_lane;
> >  			buscfg->bus.csi2.lanecfg.clk.pol =
> > -				vep.bus.mipi_csi2.lane_polarities[0];
> > +				vep->bus.mipi_csi2.lane_polarities[0];
> >  			dev_dbg(dev, "clock lane polarity %u, pos %u\n",
> >  				buscfg->bus.csi2.lanecfg.clk.pol,
> >  				buscfg->bus.csi2.lanecfg.clk.pos);
> >  
> >  			buscfg->bus.csi2.num_data_lanes =
> > -				vep.bus.mipi_csi2.num_data_lanes;
> > +				vep->bus.mipi_csi2.num_data_lanes;
> >  
> >  			for (i = 0; i < buscfg->bus.csi2.num_data_lanes; i++) {
> >  				buscfg->bus.csi2.lanecfg.data[i].pos =
> > -					vep.bus.mipi_csi2.data_lanes[i];
> > +					vep->bus.mipi_csi2.data_lanes[i];
> >  				buscfg->bus.csi2.lanecfg.data[i].pol =
> > -					vep.bus.mipi_csi2.lane_polarities[i + 1];
> > +					vep->bus.mipi_csi2.lane_polarities[i + 1];
> >  				dev_dbg(dev,
> >  					"data lane %u polarity %u, pos %u\n", i,
> >  					buscfg->bus.csi2.lanecfg.data[i].pol,
> > @@ -2137,57 +2135,13 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
> >  
> >  	default:
> >  		dev_warn(dev, "%pOF: invalid interface %u\n",
> > -			 to_of_node(fwnode), vep.base.port);
> > +			 to_of_node(vep->base.local_fwnode), vep->base.port);
> >  		return -EINVAL;
> >  	}
> >  
> >  	return 0;
> >  }
> >  
> > -static int isp_fwnodes_parse(struct device *dev,
> > -			     struct v4l2_async_notifier *notifier)
> > -{
> > -	struct fwnode_handle *fwnode = NULL;
> > -
> > -	notifier->subdevs = devm_kcalloc(
> > -		dev, ISP_MAX_SUBDEVS, sizeof(*notifier->subdevs), GFP_KERNEL);
> > -	if (!notifier->subdevs)
> > -		return -ENOMEM;
> > -
> > -	while (notifier->num_subdevs < ISP_MAX_SUBDEVS &&
> > -	       (fwnode = fwnode_graph_get_next_endpoint(
> > -			of_fwnode_handle(dev->of_node), fwnode))) {
> > -		struct isp_async_subdev *isd;
> > -
> > -		isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
> > -		if (!isd)
> > -			goto error;
> > -
> > -		if (isp_fwnode_parse(dev, fwnode, isd)) {
> > -			devm_kfree(dev, isd);
> > -			continue;
> > -		}
> > -
> > -		notifier->subdevs[notifier->num_subdevs] = &isd->asd;
> > -
> > -		isd->asd.match.fwnode.fwnode =
> > -			fwnode_graph_get_remote_port_parent(fwnode);
> > -		if (!isd->asd.match.fwnode.fwnode) {
> > -			dev_warn(dev, "bad remote port parent\n");
> > -			goto error;
> > -		}
> > -
> > -		isd->asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
> > -		notifier->num_subdevs++;
> > -	}
> > -
> > -	return notifier->num_subdevs;
> > -
> > -error:
> > -	fwnode_handle_put(fwnode);
> > -	return -EINVAL;
> > -}
> > -
> >  static int isp_subdev_notifier_complete(struct v4l2_async_notifier *async)
> >  {
> >  	struct isp_device *isp = container_of(async, struct isp_device,
> > @@ -2256,7 +2210,9 @@ static int isp_probe(struct platform_device *pdev)
> >  	if (ret)
> >  		return ret;
> >  
> > -	ret = isp_fwnodes_parse(&pdev->dev, &isp->notifier);
> > +	ret = v4l2_async_notifier_parse_fwnode_endpoints(
> > +		&pdev->dev, &isp->notifier, sizeof(struct isp_async_subdev),
> > +		isp_fwnode_parse);
> >  	if (ret < 0)
> >  		return ret;
> >  
> > @@ -2407,6 +2363,7 @@ static int isp_probe(struct platform_device *pdev)
> >  	__omap3isp_put(isp, false);
> >  error:
> >  	mutex_destroy(&isp->isp_mutex);
> > +	v4l2_async_notifier_release(&isp->notifier);
> >  
> >  	return ret;
> >  }
> > diff --git a/drivers/media/platform/omap3isp/isp.h b/drivers/media/platform/omap3isp/isp.h
> > index e528df6efc09..8b9043db94b3 100644
> > --- a/drivers/media/platform/omap3isp/isp.h
> > +++ b/drivers/media/platform/omap3isp/isp.h
> > @@ -220,14 +220,11 @@ struct isp_device {
> >  
> >  	unsigned int sbl_resources;
> >  	unsigned int subclk_resources;
> > -
> > -#define ISP_MAX_SUBDEVS		8
> > -	struct v4l2_subdev *subdevs[ISP_MAX_SUBDEVS];
> >  };
> >  
> >  struct isp_async_subdev {
> > -	struct isp_bus_cfg bus;
> >  	struct v4l2_async_subdev asd;
> > +	struct isp_bus_cfg bus;
> >  };
> >  
> >  #define v4l2_subdev_to_bus_cfg(sd) \
> > diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
> > index 851f128eba22..6740a241d4a1 100644
> > --- a/drivers/media/v4l2-core/v4l2-async.c
> > +++ b/drivers/media/v4l2-core/v4l2-async.c
> > @@ -22,6 +22,7 @@
> >  
> >  #include <media/v4l2-async.h>
> >  #include <media/v4l2-device.h>
> > +#include <media/v4l2-fwnode.h>
> >  #include <media/v4l2-subdev.h>
> >  
> >  static bool match_i2c(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
> > @@ -278,6 +279,21 @@ void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
> >  }
> >  EXPORT_SYMBOL(v4l2_async_notifier_unregister);
> >  
> > +void v4l2_async_notifier_release(struct v4l2_async_notifier *notifier)
> > +{
> > +	unsigned int i;
> > +
> > +	for (i = 0; i < notifier->num_subdevs; i++)
> > +		kfree(notifier->subdevs[i]);
> > +
> > +	notifier->max_subdevs = 0;
> > +	notifier->num_subdevs = 0;
> > +
> > +	kvfree(notifier->subdevs);
> > +	notifier->subdevs = NULL;
> > +}
> > +EXPORT_SYMBOL_GPL(v4l2_async_notifier_release);
> > +
> >  int v4l2_async_register_subdev(struct v4l2_subdev *sd)
> >  {
> >  	struct v4l2_async_notifier *notifier;
> > diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
> > index 706f9e7b90f1..2496d76eef4b 100644
> > --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> > +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> > @@ -19,6 +19,7 @@
> >   */
> >  #include <linux/acpi.h>
> >  #include <linux/kernel.h>
> > +#include <linux/mm.h>
> >  #include <linux/module.h>
> >  #include <linux/of.h>
> >  #include <linux/property.h>
> > @@ -26,6 +27,7 @@
> >  #include <linux/string.h>
> >  #include <linux/types.h>
> >  
> > +#include <media/v4l2-async.h>
> >  #include <media/v4l2-fwnode.h>
> >  
> >  enum v4l2_fwnode_bus_type {
> > @@ -313,6 +315,135 @@ void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link)
> >  }
> >  EXPORT_SYMBOL_GPL(v4l2_fwnode_put_link);
> >  
> > +static int v4l2_async_notifier_realloc(struct v4l2_async_notifier *notifier,
> > +				       unsigned int max_subdevs)
> > +{
> > +	struct v4l2_async_subdev **subdevs;
> > +
> > +	if (max_subdevs <= notifier->max_subdevs)
> > +		return 0;
> 
> Should probably be a WARN_ON. Or add a comment saying that this should
> never happen.

It could, if parsing of whichever endpoint fails after memory has been
allocated for it. No reallocation will be made for shorter array; it's just
a few bytes after all.

> 
> > +
> > +	subdevs = kvmalloc_array(
> > +		max_subdevs, sizeof(*notifier->subdevs),
> > +		GFP_KERNEL | __GFP_ZERO);
> > +	if (!subdevs)
> > +		return -ENOMEM;
> > +
> > +	if (notifier->subdevs) {
> > +		memcpy(subdevs, notifier->subdevs,
> > +		       sizeof(*subdevs) * notifier->num_subdevs);
> > +
> > +		kvfree(notifier->subdevs);
> > +	}
> > +
> > +	notifier->subdevs = subdevs;
> > +	notifier->max_subdevs = max_subdevs;
> > +
> > +	return 0;
> > +}
> > +
> > +static int v4l2_async_notifier_fwnode_parse_endpoint(
> > +	struct device *dev, struct v4l2_async_notifier *notifier,
> > +	struct fwnode_handle *endpoint, unsigned int asd_struct_size,
> > +	int (*parse_single)(struct device *dev,
> > +			    struct v4l2_fwnode_endpoint *vep,
> > +			    struct v4l2_async_subdev *asd))
> > +{
> > +	struct v4l2_async_subdev *asd;
> > +	struct v4l2_fwnode_endpoint *vep;
> > +	int ret = 0;
> > +
> > +	asd = kzalloc(asd_struct_size, GFP_KERNEL);
> > +	if (!asd)
> > +		return -ENOMEM;
> > +
> > +	asd->match.fwnode.fwnode =
> > +		fwnode_graph_get_remote_port_parent(endpoint);
> > +	if (!asd->match.fwnode.fwnode) {
> > +		dev_warn(dev, "bad remote port parent\n");
> > +		ret = -EINVAL;
> > +		goto out_err;
> > +	}
> > +
> > +	/* Ignore endpoints the parsing of which failed. */
> > +	vep = v4l2_fwnode_endpoint_alloc_parse(endpoint);
> > +	if (IS_ERR(vep)) {
> > +		ret = PTR_ERR(vep);
> > +		dev_warn(dev, "unable to parse V4L2 fwnode endpoint (%d)\n",
> > +			 ret);
> > +		goto out_err;
> > +	}
> > +
> > +	ret = parse_single(dev, vep, asd);
> > +	v4l2_fwnode_endpoint_free(vep);
> > +	if (ret) {
> > +		dev_warn(dev, "driver could not parse endpoint (%d)\n", ret);
> > +		goto out_err;
> > +	}
> > +
> > +	asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
> > +	notifier->subdevs[notifier->num_subdevs] = asd;
> > +	notifier->num_subdevs++;
> > +
> > +	return 0;
> > +
> > +out_err:
> > +	fwnode_handle_put(asd->match.fwnode.fwnode);
> 
> Just checking: the fwnode_handle_put argument can safely be NULL?

Correct.

> 
> > +	kfree(asd);
> > +
> > +	return ret;
> > +}
> > +
> > +int v4l2_async_notifier_parse_fwnode_endpoints(
> > +	struct device *dev, struct v4l2_async_notifier *notifier,
> > +	size_t asd_struct_size,
> > +	int (*parse_single)(struct device *dev,
> > +			    struct v4l2_fwnode_endpoint *vep,
> > +			    struct v4l2_async_subdev *asd))
> > +{
> > +	struct fwnode_handle *fwnode = NULL;
> > +	unsigned int max_subdevs = notifier->max_subdevs;
> 
> I thought the notifier was supposed to be zeroed?

Well, yes. That part actually will be mostly useful for the next patch: the
function for parsing endpoints will be called separately for each endpoint.

> 
> > +	int ret;
> > +
> > +	if (asd_struct_size < sizeof(struct v4l2_async_subdev) ||
> > +	    notifier->v4l2_dev)
> 
> This could use a comment why you check for notifier->v4l2_dev. That's not
> obvious.

Hmm. Good point. I think it's been left there during development and the
purpose of the function changed. I'll remove it.

The other check is actually missing from the second version, I'll add it
there as well.

> 
> > +		return -EINVAL;
> 
> Since we have the requirement that the notifier should be zeroed,
> why not do that here?

This is the first function parsing endpoints but there will be more to
come, also in addition to what's in the next patch. In that case zeroing
the notifier would erase what was parsed previously.

> 
> > +
> > +	for (fwnode = NULL; (fwnode = fwnode_graph_get_next_endpoint(
> > +				     dev_fwnode(dev), fwnode)); )
> > +		if (fwnode_device_is_available(
> > +			    fwnode_graph_get_port_parent(fwnode)))
> > +			max_subdevs++;
> > +
> > +	/* No subdevs to add? Return here. */
> > +	if (max_subdevs == notifier->max_subdevs)
> > +		return 0;
> > +
> > +	ret = v4l2_async_notifier_realloc(notifier, max_subdevs);
> > +	if (ret)
> > +		return ret;
> 
> I think this is confusing. There is nothing to realloc here. Only in the
> next patch (5/5) do you add support for recursively walking the graph and
> adding more subdevs.
> 
> I would just call kvmalloc_array here.

Not yet, but with future patches, yes.

Actually, I got forward with my lens / flash phandle parsing and I'll see
if I could add those patches to this set. They should make the goal more
obvious.

> 
> > +
> > +	for (fwnode = NULL; (fwnode = fwnode_graph_get_next_endpoint(
> > +				     dev_fwnode(dev), fwnode)); ) {
> > +		if (!fwnode_device_is_available(
> > +			    fwnode_graph_get_port_parent(fwnode)))
> > +			continue;
> > +
> > +		if (WARN_ON(notifier->num_subdevs >= notifier->max_subdevs))
> > +			break;
> > +
> > +		ret = v4l2_async_notifier_fwnode_parse_endpoint(
> > +			dev, notifier, fwnode, asd_struct_size, parse_single);
> > +		if (ret < 0)
> > +			break;
> > +	}
> > +
> > +	fwnode_handle_put(fwnode);
> > +
> > +	return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(v4l2_async_notifier_parse_fwnode_endpoints);
> > +
> >  MODULE_LICENSE("GPL");
> >  MODULE_AUTHOR("Sakari Ailus <sakari.ailus-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>");
> >  MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>");
> > diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
> > index c69d8c8a66d0..cf13c7311a1c 100644
> > --- a/include/media/v4l2-async.h
> > +++ b/include/media/v4l2-async.h
> > @@ -18,7 +18,6 @@ struct device;
> >  struct device_node;
> >  struct v4l2_device;
> >  struct v4l2_subdev;
> > -struct v4l2_async_notifier;
> >  
> >  /* A random max subdevice number, used to allocate an array on stack */
> >  #define V4L2_MAX_SUBDEVS 128U
> > @@ -50,6 +49,10 @@ enum v4l2_async_match_type {
> >   * @match:	union of per-bus type matching data sets
> >   * @list:	used to link struct v4l2_async_subdev objects, waiting to be
> >   *		probed, to a notifier->waiting list
> > + *
> > + * When the struct is used as the first member of a driver specific
> 
> Just replace "the first member" by "part"...

Yes.

> 
> > + * struct, the driver specific struct shall contain the @struct
> > + * v4l2_async_subdev as its first member.
> 
> ...since you mention in the second part that it has to be the first member.
> No need to mention that twice.
> 
> >   */
> >  struct v4l2_async_subdev {
> >  	enum v4l2_async_match_type match_type;
> > @@ -78,7 +81,8 @@ struct v4l2_async_subdev {
> >  /**
> >   * struct v4l2_async_notifier - v4l2_device notifier data
> >   *
> > - * @num_subdevs: number of subdevices
> > + * @num_subdevs: number of subdevices used in subdevs array
> 
> in the
> 
> > + * @max_subdevs: number of subdevices allocated in subdevs array
> 
> in the

Will fix.

> 
> >   * @subdevs:	array of pointers to subdevice descriptors
> >   * @v4l2_dev:	pointer to struct v4l2_device
> >   * @waiting:	list of struct v4l2_async_subdev, waiting for their drivers
> > @@ -90,6 +94,7 @@ struct v4l2_async_subdev {
> >   */
> >  struct v4l2_async_notifier {
> >  	unsigned int num_subdevs;
> > +	unsigned int max_subdevs;
> >  	struct v4l2_async_subdev **subdevs;
> >  	struct v4l2_device *v4l2_dev;
> >  	struct list_head waiting;
> > @@ -121,6 +126,21 @@ int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
> >  void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier);
> >  
> >  /**
> > + * v4l2_async_notifier_release - release notifier resources
> > + * @notifier: the notifier the resources of which are to be released
> 
> Just say: @notifier: pointer to &struct v4l2_async_notifier

I used the above text on Laurent's suggestion. :-)

I don't really have an opinion either way myself.

> 
> > + *
> > + * Release memory resources related to a notifier, including the async
> 
> s/a/the/
> 
> > + * sub-devices allocated for the purposes of the notifier. The user is
> > + * responsible for releasing the notifier's resources after calling
> > + * @v4l2_async_notifier_parse_fwnode_endpoints.
> > + *
> > + * There is no harm from calling v4l2_async_notifier_release in other
> > + * cases as long as its memory has been zeroed after it has been
> > + * allocated.
> > + */
> > +void v4l2_async_notifier_release(struct v4l2_async_notifier *notifier);
> > +
> > +/**
> >   * v4l2_async_register_subdev - registers a sub-device to the asynchronous
> >   * 	subdevice framework
> >   *
> > diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
> > index 68eb22ba571b..d063ab4ff67b 100644
> > --- a/include/media/v4l2-fwnode.h
> > +++ b/include/media/v4l2-fwnode.h
> > @@ -25,6 +25,8 @@
> >  #include <media/v4l2-mediabus.h>
> >  
> >  struct fwnode_handle;
> > +struct v4l2_async_notifier;
> > +struct v4l2_async_subdev;
> >  
> >  #define V4L2_FWNODE_CSI2_MAX_DATA_LANES	4
> >  
> > @@ -201,4 +203,50 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,
> >   */
> >  void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link);
> >  
> > +/**
> > + * v4l2_async_notifier_parse_fwnode_endpoints - Parse V4L2 fwnode endpoints in a
> > + *						device node
> > + * @dev: the device the endpoints of which are to be parsed
> > + * @notifier: notifier for @dev
> > + * @asd_struct_size: size of the driver's async sub-device struct, including
> > + *		     sizeof(struct v4l2_async_subdev). The &struct
> > + *		     v4l2_async_subdev shall be the first member of
> > + *		     the driver's async sub-device struct, i.e. both
> > + *		     begin at the same memory address.
> > + * @parse_single: driver's callback function called on each V4L2 fwnode endpoint
> > + *
> > + * Parse the fwnode endpoints of the @dev device and populate the async sub-
> > + * devices array of the notifier. The @parse_endpoint callback function is
> 
> parse_endpoint -> parse_single
> 
> (Actually, I like the name parse_endpoint better)

I'll change that.

> 
> > + * called for each endpoint with the corresponding async sub-device pointer to
> > + * let the caller initialize the driver-specific part of the async sub-device
> > + * structure.
> > + *
> > + * The notifier memory shall be zeroed before this function is called on the
> > + * notifier.
> > + *
> > + * This function may not be called on a registered notifier and may be called on
> > + * a notifier only once. When using this function, the user may not access the
> > + * notifier's subdevs array nor change notifier's num_subdevs field, these are
> > + * reserved for the framework's internal use only.
> 
> Ditto for the max_subdevs field, I think.

Yes, but max_subdevs was added by this patch and there never was (and
isn't) a purpose to change that by drivers directly. The current users of
the V4L2 async in the kernel do exactly that, as the gather the contents of
the subdevs array themselves.

So I doubt it'd be useful to mention that in the documentation.

> 
> > + *
> > + * The @struct v4l2_fwnode_endpoint passed to the callback function
> > + * @parse_single is released once the function is finished. If there is a need
> > + * to retain that configuration, the user needs to allocate memory for it.
> > + *
> > + * Any notifier populated using this function must be released with a call to
> > + * v4l2_async_notifier_release() after it has been unregistered and the async
> > + * sub-devices are no longer in use.
> > + *
> > + * Return: %0 on success, including when no async sub-devices are found
> > + *	   %-ENOMEM if memory allocation failed
> > + *	   %-EINVAL if graph or endpoint parsing failed
> > + *	   Other error codes as returned by @parse_single
> > + */
> > +int v4l2_async_notifier_parse_fwnode_endpoints(
> > +	struct device *dev, struct v4l2_async_notifier *notifier,
> > +	size_t asd_struct_size,
> > +	int (*parse_single)(struct device *dev,
> > +			    struct v4l2_fwnode_endpoint *vep,
> > +			    struct v4l2_async_subdev *asd));
> > +
> >  #endif /* _V4L2_FWNODE_H */
> > 
> 

-- 
Regards,

Sakari Ailus
e-mail: sakari.ailus-X3B1VOXEql0@public.gmane.org
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Re: [PATCH v6.1 4/5] v4l: fwnode: Support generic parsing of graph endpoints in a device

[Sakari Ailus]

Hi Hans,

Thanks for the review!

On Fri, Sep 01, 2017 at 01:18:55PM +0200, Hans Verkuil wrote:
> Hi Sakari,
> 
> On 30/08/17 14:45, Sakari Ailus wrote:
> > The current practice is that drivers iterate over their endpoints and
> > parse each endpoint separately. This is very similar in a number of
> > drivers, implement a generic function for the job. Driver specific matters
> > can be taken into account in the driver specific callback.
> > 
> > Convert the omap3isp as an example.
> 
> It would be much easier to review if the omap3isp conversion was done in a
> separate patch. Ditto for the rcar conversion, and I prefer to have both
> at the end of the patch series, after the core code patches.

Ack, I'll split them for v7.

> 
> > 
> > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > ---
> > since v6:
> > 
> > - Set notifier->subdevs NULL and notifier->num_subdevs 0 in
> >   v4l2_async_notifier_release().
> > 
> >  drivers/media/platform/omap3isp/isp.c | 115 ++++++++++-------------------
> >  drivers/media/platform/omap3isp/isp.h |   5 +-
> >  drivers/media/v4l2-core/v4l2-async.c  |  16 +++++
> >  drivers/media/v4l2-core/v4l2-fwnode.c | 131 ++++++++++++++++++++++++++++++++++
> >  include/media/v4l2-async.h            |  24 ++++++-
> >  include/media/v4l2-fwnode.h           |  48 +++++++++++++
> >  6 files changed, 254 insertions(+), 85 deletions(-)
> > 
> > diff --git a/drivers/media/platform/omap3isp/isp.c b/drivers/media/platform/omap3isp/isp.c
> > index 1a428fe9f070..a546cf774d40 100644
> > --- a/drivers/media/platform/omap3isp/isp.c
> > +++ b/drivers/media/platform/omap3isp/isp.c
> > @@ -2001,6 +2001,7 @@ static int isp_remove(struct platform_device *pdev)
> >  	__omap3isp_put(isp, false);
> >  
> >  	media_entity_enum_cleanup(&isp->crashed);
> > +	v4l2_async_notifier_release(&isp->notifier);
> >  
> >  	return 0;
> >  }
> > @@ -2011,44 +2012,41 @@ enum isp_of_phy {
> >  	ISP_OF_PHY_CSIPHY2,
> >  };
> >  
> > -static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
> > -			    struct isp_async_subdev *isd)
> > +static int isp_fwnode_parse(struct device *dev,
> > +			    struct v4l2_fwnode_endpoint *vep,
> > +			    struct v4l2_async_subdev *asd)
> >  {
> > +	struct isp_async_subdev *isd =
> > +		container_of(asd, struct isp_async_subdev, asd);
> >  	struct isp_bus_cfg *buscfg = &isd->bus;
> > -	struct v4l2_fwnode_endpoint vep;
> > -	unsigned int i;
> > -	int ret;
> >  	bool csi1 = false;
> > -
> > -	ret = v4l2_fwnode_endpoint_parse(fwnode, &vep);
> > -	if (ret)
> > -		return ret;
> > +	unsigned int i;
> >  
> >  	dev_dbg(dev, "parsing endpoint %pOF, interface %u\n",
> > -		to_of_node(fwnode), vep.base.port);
> > +		to_of_node(vep->base.local_fwnode), vep->base.port);
> >  
> > -	switch (vep.base.port) {
> > +	switch (vep->base.port) {
> >  	case ISP_OF_PHY_PARALLEL:
> >  		buscfg->interface = ISP_INTERFACE_PARALLEL;
> >  		buscfg->bus.parallel.data_lane_shift =
> > -			vep.bus.parallel.data_shift;
> > +			vep->bus.parallel.data_shift;
> >  		buscfg->bus.parallel.clk_pol =
> > -			!!(vep.bus.parallel.flags
> > +			!!(vep->bus.parallel.flags
> >  			   & V4L2_MBUS_PCLK_SAMPLE_FALLING);
> >  		buscfg->bus.parallel.hs_pol =
> > -			!!(vep.bus.parallel.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW);
> > +			!!(vep->bus.parallel.flags & V4L2_MBUS_VSYNC_ACTIVE_LOW);
> >  		buscfg->bus.parallel.vs_pol =
> > -			!!(vep.bus.parallel.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW);
> > +			!!(vep->bus.parallel.flags & V4L2_MBUS_HSYNC_ACTIVE_LOW);
> >  		buscfg->bus.parallel.fld_pol =
> > -			!!(vep.bus.parallel.flags & V4L2_MBUS_FIELD_EVEN_LOW);
> > +			!!(vep->bus.parallel.flags & V4L2_MBUS_FIELD_EVEN_LOW);
> >  		buscfg->bus.parallel.data_pol =
> > -			!!(vep.bus.parallel.flags & V4L2_MBUS_DATA_ACTIVE_LOW);
> > -		buscfg->bus.parallel.bt656 = vep.bus_type == V4L2_MBUS_BT656;
> > +			!!(vep->bus.parallel.flags & V4L2_MBUS_DATA_ACTIVE_LOW);
> > +		buscfg->bus.parallel.bt656 = vep->bus_type == V4L2_MBUS_BT656;
> >  		break;
> >  
> >  	case ISP_OF_PHY_CSIPHY1:
> >  	case ISP_OF_PHY_CSIPHY2:
> > -		switch (vep.bus_type) {
> > +		switch (vep->bus_type) {
> >  		case V4L2_MBUS_CCP2:
> >  		case V4L2_MBUS_CSI1:
> >  			dev_dbg(dev, "CSI-1/CCP-2 configuration\n");
> > @@ -2060,11 +2058,11 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
> >  			break;
> >  		default:
> >  			dev_err(dev, "unsupported bus type %u\n",
> > -				vep.bus_type);
> > +				vep->bus_type);
> >  			return -EINVAL;
> >  		}
> >  
> > -		switch (vep.base.port) {
> > +		switch (vep->base.port) {
> >  		case ISP_OF_PHY_CSIPHY1:
> >  			if (csi1)
> >  				buscfg->interface = ISP_INTERFACE_CCP2B_PHY1;
> > @@ -2080,47 +2078,47 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
> >  		}
> >  		if (csi1) {
> >  			buscfg->bus.ccp2.lanecfg.clk.pos =
> > -				vep.bus.mipi_csi1.clock_lane;
> > +				vep->bus.mipi_csi1.clock_lane;
> >  			buscfg->bus.ccp2.lanecfg.clk.pol =
> > -				vep.bus.mipi_csi1.lane_polarity[0];
> > +				vep->bus.mipi_csi1.lane_polarity[0];
> >  			dev_dbg(dev, "clock lane polarity %u, pos %u\n",
> >  				buscfg->bus.ccp2.lanecfg.clk.pol,
> >  				buscfg->bus.ccp2.lanecfg.clk.pos);
> >  
> >  			buscfg->bus.ccp2.lanecfg.data[0].pos =
> > -				vep.bus.mipi_csi1.data_lane;
> > +				vep->bus.mipi_csi1.data_lane;
> >  			buscfg->bus.ccp2.lanecfg.data[0].pol =
> > -				vep.bus.mipi_csi1.lane_polarity[1];
> > +				vep->bus.mipi_csi1.lane_polarity[1];
> >  
> >  			dev_dbg(dev, "data lane polarity %u, pos %u\n",
> >  				buscfg->bus.ccp2.lanecfg.data[0].pol,
> >  				buscfg->bus.ccp2.lanecfg.data[0].pos);
> >  
> >  			buscfg->bus.ccp2.strobe_clk_pol =
> > -				vep.bus.mipi_csi1.clock_inv;
> > -			buscfg->bus.ccp2.phy_layer = vep.bus.mipi_csi1.strobe;
> > +				vep->bus.mipi_csi1.clock_inv;
> > +			buscfg->bus.ccp2.phy_layer = vep->bus.mipi_csi1.strobe;
> >  			buscfg->bus.ccp2.ccp2_mode =
> > -				vep.bus_type == V4L2_MBUS_CCP2;
> > +				vep->bus_type == V4L2_MBUS_CCP2;
> >  			buscfg->bus.ccp2.vp_clk_pol = 1;
> >  
> >  			buscfg->bus.ccp2.crc = 1;
> >  		} else {
> >  			buscfg->bus.csi2.lanecfg.clk.pos =
> > -				vep.bus.mipi_csi2.clock_lane;
> > +				vep->bus.mipi_csi2.clock_lane;
> >  			buscfg->bus.csi2.lanecfg.clk.pol =
> > -				vep.bus.mipi_csi2.lane_polarities[0];
> > +				vep->bus.mipi_csi2.lane_polarities[0];
> >  			dev_dbg(dev, "clock lane polarity %u, pos %u\n",
> >  				buscfg->bus.csi2.lanecfg.clk.pol,
> >  				buscfg->bus.csi2.lanecfg.clk.pos);
> >  
> >  			buscfg->bus.csi2.num_data_lanes =
> > -				vep.bus.mipi_csi2.num_data_lanes;
> > +				vep->bus.mipi_csi2.num_data_lanes;
> >  
> >  			for (i = 0; i < buscfg->bus.csi2.num_data_lanes; i++) {
> >  				buscfg->bus.csi2.lanecfg.data[i].pos =
> > -					vep.bus.mipi_csi2.data_lanes[i];
> > +					vep->bus.mipi_csi2.data_lanes[i];
> >  				buscfg->bus.csi2.lanecfg.data[i].pol =
> > -					vep.bus.mipi_csi2.lane_polarities[i + 1];
> > +					vep->bus.mipi_csi2.lane_polarities[i + 1];
> >  				dev_dbg(dev,
> >  					"data lane %u polarity %u, pos %u\n", i,
> >  					buscfg->bus.csi2.lanecfg.data[i].pol,
> > @@ -2137,57 +2135,13 @@ static int isp_fwnode_parse(struct device *dev, struct fwnode_handle *fwnode,
> >  
> >  	default:
> >  		dev_warn(dev, "%pOF: invalid interface %u\n",
> > -			 to_of_node(fwnode), vep.base.port);
> > +			 to_of_node(vep->base.local_fwnode), vep->base.port);
> >  		return -EINVAL;
> >  	}
> >  
> >  	return 0;
> >  }
> >  
> > -static int isp_fwnodes_parse(struct device *dev,
> > -			     struct v4l2_async_notifier *notifier)
> > -{
> > -	struct fwnode_handle *fwnode = NULL;
> > -
> > -	notifier->subdevs = devm_kcalloc(
> > -		dev, ISP_MAX_SUBDEVS, sizeof(*notifier->subdevs), GFP_KERNEL);
> > -	if (!notifier->subdevs)
> > -		return -ENOMEM;
> > -
> > -	while (notifier->num_subdevs < ISP_MAX_SUBDEVS &&
> > -	       (fwnode = fwnode_graph_get_next_endpoint(
> > -			of_fwnode_handle(dev->of_node), fwnode))) {
> > -		struct isp_async_subdev *isd;
> > -
> > -		isd = devm_kzalloc(dev, sizeof(*isd), GFP_KERNEL);
> > -		if (!isd)
> > -			goto error;
> > -
> > -		if (isp_fwnode_parse(dev, fwnode, isd)) {
> > -			devm_kfree(dev, isd);
> > -			continue;
> > -		}
> > -
> > -		notifier->subdevs[notifier->num_subdevs] = &isd->asd;
> > -
> > -		isd->asd.match.fwnode.fwnode =
> > -			fwnode_graph_get_remote_port_parent(fwnode);
> > -		if (!isd->asd.match.fwnode.fwnode) {
> > -			dev_warn(dev, "bad remote port parent\n");
> > -			goto error;
> > -		}
> > -
> > -		isd->asd.match_type = V4L2_ASYNC_MATCH_FWNODE;
> > -		notifier->num_subdevs++;
> > -	}
> > -
> > -	return notifier->num_subdevs;
> > -
> > -error:
> > -	fwnode_handle_put(fwnode);
> > -	return -EINVAL;
> > -}
> > -
> >  static int isp_subdev_notifier_complete(struct v4l2_async_notifier *async)
> >  {
> >  	struct isp_device *isp = container_of(async, struct isp_device,
> > @@ -2256,7 +2210,9 @@ static int isp_probe(struct platform_device *pdev)
> >  	if (ret)
> >  		return ret;
> >  
> > -	ret = isp_fwnodes_parse(&pdev->dev, &isp->notifier);
> > +	ret = v4l2_async_notifier_parse_fwnode_endpoints(
> > +		&pdev->dev, &isp->notifier, sizeof(struct isp_async_subdev),
> > +		isp_fwnode_parse);
> >  	if (ret < 0)
> >  		return ret;
> >  
> > @@ -2407,6 +2363,7 @@ static int isp_probe(struct platform_device *pdev)
> >  	__omap3isp_put(isp, false);
> >  error:
> >  	mutex_destroy(&isp->isp_mutex);
> > +	v4l2_async_notifier_release(&isp->notifier);
> >  
> >  	return ret;
> >  }
> > diff --git a/drivers/media/platform/omap3isp/isp.h b/drivers/media/platform/omap3isp/isp.h
> > index e528df6efc09..8b9043db94b3 100644
> > --- a/drivers/media/platform/omap3isp/isp.h
> > +++ b/drivers/media/platform/omap3isp/isp.h
> > @@ -220,14 +220,11 @@ struct isp_device {
> >  
> >  	unsigned int sbl_resources;
> >  	unsigned int subclk_resources;
> > -
> > -#define ISP_MAX_SUBDEVS		8
> > -	struct v4l2_subdev *subdevs[ISP_MAX_SUBDEVS];
> >  };
> >  
> >  struct isp_async_subdev {
> > -	struct isp_bus_cfg bus;
> >  	struct v4l2_async_subdev asd;
> > +	struct isp_bus_cfg bus;
> >  };
> >  
> >  #define v4l2_subdev_to_bus_cfg(sd) \
> > diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
> > index 851f128eba22..6740a241d4a1 100644
> > --- a/drivers/media/v4l2-core/v4l2-async.c
> > +++ b/drivers/media/v4l2-core/v4l2-async.c
> > @@ -22,6 +22,7 @@
> >  
> >  #include <media/v4l2-async.h>
> >  #include <media/v4l2-device.h>
> > +#include <media/v4l2-fwnode.h>
> >  #include <media/v4l2-subdev.h>
> >  
> >  static bool match_i2c(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
> > @@ -278,6 +279,21 @@ void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
> >  }
> >  EXPORT_SYMBOL(v4l2_async_notifier_unregister);
> >  
> > +void v4l2_async_notifier_release(struct v4l2_async_notifier *notifier)
> > +{
> > +	unsigned int i;
> > +
> > +	for (i = 0; i < notifier->num_subdevs; i++)
> > +		kfree(notifier->subdevs[i]);
> > +
> > +	notifier->max_subdevs = 0;
> > +	notifier->num_subdevs = 0;
> > +
> > +	kvfree(notifier->subdevs);
> > +	notifier->subdevs = NULL;
> > +}
> > +EXPORT_SYMBOL_GPL(v4l2_async_notifier_release);
> > +
> >  int v4l2_async_register_subdev(struct v4l2_subdev *sd)
> >  {
> >  	struct v4l2_async_notifier *notifier;
> > diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
> > index 706f9e7b90f1..2496d76eef4b 100644
> > --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> > +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> > @@ -19,6 +19,7 @@
> >   */
> >  #include <linux/acpi.h>
> >  #include <linux/kernel.h>
> > +#include <linux/mm.h>
> >  #include <linux/module.h>
> >  #include <linux/of.h>
> >  #include <linux/property.h>
> > @@ -26,6 +27,7 @@
> >  #include <linux/string.h>
> >  #include <linux/types.h>
> >  
> > +#include <media/v4l2-async.h>
> >  #include <media/v4l2-fwnode.h>
> >  
> >  enum v4l2_fwnode_bus_type {
> > @@ -313,6 +315,135 @@ void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link)
> >  }
> >  EXPORT_SYMBOL_GPL(v4l2_fwnode_put_link);
> >  
> > +static int v4l2_async_notifier_realloc(struct v4l2_async_notifier *notifier,
> > +				       unsigned int max_subdevs)
> > +{
> > +	struct v4l2_async_subdev **subdevs;
> > +
> > +	if (max_subdevs <= notifier->max_subdevs)
> > +		return 0;
> 
> Should probably be a WARN_ON. Or add a comment saying that this should
> never happen.

It could, if parsing of whichever endpoint fails after memory has been
allocated for it. No reallocation will be made for shorter array; it's just
a few bytes after all.

> 
> > +
> > +	subdevs = kvmalloc_array(
> > +		max_subdevs, sizeof(*notifier->subdevs),
> > +		GFP_KERNEL | __GFP_ZERO);
> > +	if (!subdevs)
> > +		return -ENOMEM;
> > +
> > +	if (notifier->subdevs) {
> > +		memcpy(subdevs, notifier->subdevs,
> > +		       sizeof(*subdevs) * notifier->num_subdevs);
> > +
> > +		kvfree(notifier->subdevs);
> > +	}
> > +
> > +	notifier->subdevs = subdevs;
> > +	notifier->max_subdevs = max_subdevs;
> > +
> > +	return 0;
> > +}
> > +
> > +static int v4l2_async_notifier_fwnode_parse_endpoint(
> > +	struct device *dev, struct v4l2_async_notifier *notifier,
> > +	struct fwnode_handle *endpoint, unsigned int asd_struct_size,
> > +	int (*parse_single)(struct device *dev,
> > +			    struct v4l2_fwnode_endpoint *vep,
> > +			    struct v4l2_async_subdev *asd))
> > +{
> > +	struct v4l2_async_subdev *asd;
> > +	struct v4l2_fwnode_endpoint *vep;
> > +	int ret = 0;
> > +
> > +	asd = kzalloc(asd_struct_size, GFP_KERNEL);
> > +	if (!asd)
> > +		return -ENOMEM;
> > +
> > +	asd->match.fwnode.fwnode =
> > +		fwnode_graph_get_remote_port_parent(endpoint);
> > +	if (!asd->match.fwnode.fwnode) {
> > +		dev_warn(dev, "bad remote port parent\n");
> > +		ret = -EINVAL;
> > +		goto out_err;
> > +	}
> > +
> > +	/* Ignore endpoints the parsing of which failed. */
> > +	vep = v4l2_fwnode_endpoint_alloc_parse(endpoint);
> > +	if (IS_ERR(vep)) {
> > +		ret = PTR_ERR(vep);
> > +		dev_warn(dev, "unable to parse V4L2 fwnode endpoint (%d)\n",
> > +			 ret);
> > +		goto out_err;
> > +	}
> > +
> > +	ret = parse_single(dev, vep, asd);
> > +	v4l2_fwnode_endpoint_free(vep);
> > +	if (ret) {
> > +		dev_warn(dev, "driver could not parse endpoint (%d)\n", ret);
> > +		goto out_err;
> > +	}
> > +
> > +	asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
> > +	notifier->subdevs[notifier->num_subdevs] = asd;
> > +	notifier->num_subdevs++;
> > +
> > +	return 0;
> > +
> > +out_err:
> > +	fwnode_handle_put(asd->match.fwnode.fwnode);
> 
> Just checking: the fwnode_handle_put argument can safely be NULL?

Correct.

> 
> > +	kfree(asd);
> > +
> > +	return ret;
> > +}
> > +
> > +int v4l2_async_notifier_parse_fwnode_endpoints(
> > +	struct device *dev, struct v4l2_async_notifier *notifier,
> > +	size_t asd_struct_size,
> > +	int (*parse_single)(struct device *dev,
> > +			    struct v4l2_fwnode_endpoint *vep,
> > +			    struct v4l2_async_subdev *asd))
> > +{
> > +	struct fwnode_handle *fwnode = NULL;
> > +	unsigned int max_subdevs = notifier->max_subdevs;
> 
> I thought the notifier was supposed to be zeroed?

Well, yes. That part actually will be mostly useful for the next patch: the
function for parsing endpoints will be called separately for each endpoint.

> 
> > +	int ret;
> > +
> > +	if (asd_struct_size < sizeof(struct v4l2_async_subdev) ||
> > +	    notifier->v4l2_dev)
> 
> This could use a comment why you check for notifier->v4l2_dev. That's not
> obvious.

Hmm. Good point. I think it's been left there during development and the
purpose of the function changed. I'll remove it.

The other check is actually missing from the second version, I'll add it
there as well.

> 
> > +		return -EINVAL;
> 
> Since we have the requirement that the notifier should be zeroed,
> why not do that here?

This is the first function parsing endpoints but there will be more to
come, also in addition to what's in the next patch. In that case zeroing
the notifier would erase what was parsed previously.

> 
> > +
> > +	for (fwnode = NULL; (fwnode = fwnode_graph_get_next_endpoint(
> > +				     dev_fwnode(dev), fwnode)); )
> > +		if (fwnode_device_is_available(
> > +			    fwnode_graph_get_port_parent(fwnode)))
> > +			max_subdevs++;
> > +
> > +	/* No subdevs to add? Return here. */
> > +	if (max_subdevs == notifier->max_subdevs)
> > +		return 0;
> > +
> > +	ret = v4l2_async_notifier_realloc(notifier, max_subdevs);
> > +	if (ret)
> > +		return ret;
> 
> I think this is confusing. There is nothing to realloc here. Only in the
> next patch (5/5) do you add support for recursively walking the graph and
> adding more subdevs.
> 
> I would just call kvmalloc_array here.

Not yet, but with future patches, yes.

Actually, I got forward with my lens / flash phandle parsing and I'll see
if I could add those patches to this set. They should make the goal more
obvious.

> 
> > +
> > +	for (fwnode = NULL; (fwnode = fwnode_graph_get_next_endpoint(
> > +				     dev_fwnode(dev), fwnode)); ) {
> > +		if (!fwnode_device_is_available(
> > +			    fwnode_graph_get_port_parent(fwnode)))
> > +			continue;
> > +
> > +		if (WARN_ON(notifier->num_subdevs >= notifier->max_subdevs))
> > +			break;
> > +
> > +		ret = v4l2_async_notifier_fwnode_parse_endpoint(
> > +			dev, notifier, fwnode, asd_struct_size, parse_single);
> > +		if (ret < 0)
> > +			break;
> > +	}
> > +
> > +	fwnode_handle_put(fwnode);
> > +
> > +	return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(v4l2_async_notifier_parse_fwnode_endpoints);
> > +
> >  MODULE_LICENSE("GPL");
> >  MODULE_AUTHOR("Sakari Ailus <sakari.ailus@linux.intel.com>");
> >  MODULE_AUTHOR("Sylwester Nawrocki <s.nawrocki@samsung.com>");
> > diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
> > index c69d8c8a66d0..cf13c7311a1c 100644
> > --- a/include/media/v4l2-async.h
> > +++ b/include/media/v4l2-async.h
> > @@ -18,7 +18,6 @@ struct device;
> >  struct device_node;
> >  struct v4l2_device;
> >  struct v4l2_subdev;
> > -struct v4l2_async_notifier;
> >  
> >  /* A random max subdevice number, used to allocate an array on stack */
> >  #define V4L2_MAX_SUBDEVS 128U
> > @@ -50,6 +49,10 @@ enum v4l2_async_match_type {
> >   * @match:	union of per-bus type matching data sets
> >   * @list:	used to link struct v4l2_async_subdev objects, waiting to be
> >   *		probed, to a notifier->waiting list
> > + *
> > + * When the struct is used as the first member of a driver specific
> 
> Just replace "the first member" by "part"...

Yes.

> 
> > + * struct, the driver specific struct shall contain the @struct
> > + * v4l2_async_subdev as its first member.
> 
> ...since you mention in the second part that it has to be the first member.
> No need to mention that twice.
> 
> >   */
> >  struct v4l2_async_subdev {
> >  	enum v4l2_async_match_type match_type;
> > @@ -78,7 +81,8 @@ struct v4l2_async_subdev {
> >  /**
> >   * struct v4l2_async_notifier - v4l2_device notifier data
> >   *
> > - * @num_subdevs: number of subdevices
> > + * @num_subdevs: number of subdevices used in subdevs array
> 
> in the
> 
> > + * @max_subdevs: number of subdevices allocated in subdevs array
> 
> in the

Will fix.

> 
> >   * @subdevs:	array of pointers to subdevice descriptors
> >   * @v4l2_dev:	pointer to struct v4l2_device
> >   * @waiting:	list of struct v4l2_async_subdev, waiting for their drivers
> > @@ -90,6 +94,7 @@ struct v4l2_async_subdev {
> >   */
> >  struct v4l2_async_notifier {
> >  	unsigned int num_subdevs;
> > +	unsigned int max_subdevs;
> >  	struct v4l2_async_subdev **subdevs;
> >  	struct v4l2_device *v4l2_dev;
> >  	struct list_head waiting;
> > @@ -121,6 +126,21 @@ int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
> >  void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier);
> >  
> >  /**
> > + * v4l2_async_notifier_release - release notifier resources
> > + * @notifier: the notifier the resources of which are to be released
> 
> Just say: @notifier: pointer to &struct v4l2_async_notifier

I used the above text on Laurent's suggestion. :-)

I don't really have an opinion either way myself.

> 
> > + *
> > + * Release memory resources related to a notifier, including the async
> 
> s/a/the/
> 
> > + * sub-devices allocated for the purposes of the notifier. The user is
> > + * responsible for releasing the notifier's resources after calling
> > + * @v4l2_async_notifier_parse_fwnode_endpoints.
> > + *
> > + * There is no harm from calling v4l2_async_notifier_release in other
> > + * cases as long as its memory has been zeroed after it has been
> > + * allocated.
> > + */
> > +void v4l2_async_notifier_release(struct v4l2_async_notifier *notifier);
> > +
> > +/**
> >   * v4l2_async_register_subdev - registers a sub-device to the asynchronous
> >   * 	subdevice framework
> >   *
> > diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
> > index 68eb22ba571b..d063ab4ff67b 100644
> > --- a/include/media/v4l2-fwnode.h
> > +++ b/include/media/v4l2-fwnode.h
> > @@ -25,6 +25,8 @@
> >  #include <media/v4l2-mediabus.h>
> >  
> >  struct fwnode_handle;
> > +struct v4l2_async_notifier;
> > +struct v4l2_async_subdev;
> >  
> >  #define V4L2_FWNODE_CSI2_MAX_DATA_LANES	4
> >  
> > @@ -201,4 +203,50 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,
> >   */
> >  void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link);
> >  
> > +/**
> > + * v4l2_async_notifier_parse_fwnode_endpoints - Parse V4L2 fwnode endpoints in a
> > + *						device node
> > + * @dev: the device the endpoints of which are to be parsed
> > + * @notifier: notifier for @dev
> > + * @asd_struct_size: size of the driver's async sub-device struct, including
> > + *		     sizeof(struct v4l2_async_subdev). The &struct
> > + *		     v4l2_async_subdev shall be the first member of
> > + *		     the driver's async sub-device struct, i.e. both
> > + *		     begin at the same memory address.
> > + * @parse_single: driver's callback function called on each V4L2 fwnode endpoint
> > + *
> > + * Parse the fwnode endpoints of the @dev device and populate the async sub-
> > + * devices array of the notifier. The @parse_endpoint callback function is
> 
> parse_endpoint -> parse_single
> 
> (Actually, I like the name parse_endpoint better)

I'll change that.

> 
> > + * called for each endpoint with the corresponding async sub-device pointer to
> > + * let the caller initialize the driver-specific part of the async sub-device
> > + * structure.
> > + *
> > + * The notifier memory shall be zeroed before this function is called on the
> > + * notifier.
> > + *
> > + * This function may not be called on a registered notifier and may be called on
> > + * a notifier only once. When using this function, the user may not access the
> > + * notifier's subdevs array nor change notifier's num_subdevs field, these are
> > + * reserved for the framework's internal use only.
> 
> Ditto for the max_subdevs field, I think.

Yes, but max_subdevs was added by this patch and there never was (and
isn't) a purpose to change that by drivers directly. The current users of
the V4L2 async in the kernel do exactly that, as the gather the contents of
the subdevs array themselves.

So I doubt it'd be useful to mention that in the documentation.

> 
> > + *
> > + * The @struct v4l2_fwnode_endpoint passed to the callback function
> > + * @parse_single is released once the function is finished. If there is a need
> > + * to retain that configuration, the user needs to allocate memory for it.
> > + *
> > + * Any notifier populated using this function must be released with a call to
> > + * v4l2_async_notifier_release() after it has been unregistered and the async
> > + * sub-devices are no longer in use.
> > + *
> > + * Return: %0 on success, including when no async sub-devices are found
> > + *	   %-ENOMEM if memory allocation failed
> > + *	   %-EINVAL if graph or endpoint parsing failed
> > + *	   Other error codes as returned by @parse_single
> > + */
> > +int v4l2_async_notifier_parse_fwnode_endpoints(
> > +	struct device *dev, struct v4l2_async_notifier *notifier,
> > +	size_t asd_struct_size,
> > +	int (*parse_single)(struct device *dev,
> > +			    struct v4l2_fwnode_endpoint *vep,
> > +			    struct v4l2_async_subdev *asd));
> > +
> >  #endif /* _V4L2_FWNODE_H */
> > 
> 

-- 
Regards,

Sakari Ailus
e-mail: sakari.ailus@iki.fi

Re: [PATCH v6 5/5] v4l: fwnode: Support generic parsing of graph endpoints in a single port

[Sakari Ailus]

Hi Hans,

Thanks for the review.

On Fri, Sep 01, 2017 at 01:28:40PM +0200, Hans Verkuil wrote:
> > diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
> > index d063ab4ff67b..dd13604178b4 100644
> > --- a/include/media/v4l2-fwnode.h
> > +++ b/include/media/v4l2-fwnode.h
> > @@ -249,4 +249,53 @@ int v4l2_async_notifier_parse_fwnode_endpoints(
> >  			    struct v4l2_fwnode_endpoint *vep,
> >  			    struct v4l2_async_subdev *asd));
> >  
> > +/**
> > + * v4l2_async_notifier_parse_fwnode_endpoint - Set up async notifier for an
> > + *					       fwnode based sub-device
> > + * @dev: @struct device pointer
> > + * @notifier: pointer to &struct v4l2_async_notifier
> > + * @port_id: port number
> > + * @endpoint_id: endpoint number
> > + * @asd_struct_size: size of the driver's async sub-device struct, including
> > + *		     sizeof(struct v4l2_async_subdev). The &struct
> > + *		     v4l2_async_subdev shall be the first member of
> > + *		     the driver's async sub-device struct, i.e. both
> > + *		     begin at the same memory address.
> > + * @parse_single: driver's callback function called on each V4L2 fwnode endpoint
> > + *
> > + * Parse the fwnode endpoint of the @dev device corresponding to the given port
> > + * and endpoint numbres and populate the async sub- devices array of the
> 
> numbers
> no space after sub-
> 
> > + * notifier. The @parse_endpoint callback function is called for the endpoint
> 
> parse_single, but (as in the previous patch) I actually prefer parse_endpoint.
> 
> > + * with the corresponding async sub-device pointer to let the caller initialize
> > + * the driver-specific part of the async sub-device structure.
> > + *
> > + * The notifier memory shall be zeroed before this function is called on the
> > + * notifier.
> 
> Should it? Doesn't this add additional subdevs?
> 
> I'm lost. What's the relationship between v4l2_async_notifier_parse_fwnode_endpoints
> and this function? When do you use which? When you should zero the notifier?

I thought there would be advantages in this approach as it lets you to
choose which endpoints specifically you want to parse. That said, the
expectation is that the device has no endpoints that aren't supported in
hardware either.

Some drivers currently iterate over all the endpoints and then validate
them whereas others poke for some endpoints only (port 0, endpoint 0, for
the rcar-vin driver, for instance). In DT binding documentation the
endpoint numbers are currently not specified nor drivers have checked them.
Common sense tells to use zero if there's no reason to do otherwise, but
still this hasn't been documented nor validated in the past. So if we add
that now, there could be a chance of breaking something.

Additionally, specifying the endpoints to parse explicitly has been seen
beneficial (or even necessary) in parsing endpoints for devices that have
both input and output interfaces. Perhaps Niklas can comment on that.

What I though was to introduce a specific error code (EPERM, better
suggestions are taken) for the driver callback function (parse_endpoint) to
silently skip endpoints the driver doesn't like for reason or another. This
lets drivers to use the endpoint parser function added by the previous
patch and still maintain the old behaviour, i.e. ignore endpoints that
aren't explicitly recognised by the driver.

I'll drop this patch from the next version.

-- 
Regards,

Sakari Ailus
e-mail: sakari.ailus-X3B1VOXEql0@public.gmane.org
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Re: [PATCH v6 5/5] v4l: fwnode: Support generic parsing of graph endpoints in a single port

[Sakari Ailus]

Hi Hans,

Thanks for the review.

On Fri, Sep 01, 2017 at 01:28:40PM +0200, Hans Verkuil wrote:
> > diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
> > index d063ab4ff67b..dd13604178b4 100644
> > --- a/include/media/v4l2-fwnode.h
> > +++ b/include/media/v4l2-fwnode.h
> > @@ -249,4 +249,53 @@ int v4l2_async_notifier_parse_fwnode_endpoints(
> >  			    struct v4l2_fwnode_endpoint *vep,
> >  			    struct v4l2_async_subdev *asd));
> >  
> > +/**
> > + * v4l2_async_notifier_parse_fwnode_endpoint - Set up async notifier for an
> > + *					       fwnode based sub-device
> > + * @dev: @struct device pointer
> > + * @notifier: pointer to &struct v4l2_async_notifier
> > + * @port_id: port number
> > + * @endpoint_id: endpoint number
> > + * @asd_struct_size: size of the driver's async sub-device struct, including
> > + *		     sizeof(struct v4l2_async_subdev). The &struct
> > + *		     v4l2_async_subdev shall be the first member of
> > + *		     the driver's async sub-device struct, i.e. both
> > + *		     begin at the same memory address.
> > + * @parse_single: driver's callback function called on each V4L2 fwnode endpoint
> > + *
> > + * Parse the fwnode endpoint of the @dev device corresponding to the given port
> > + * and endpoint numbres and populate the async sub- devices array of the
> 
> numbers
> no space after sub-
> 
> > + * notifier. The @parse_endpoint callback function is called for the endpoint
> 
> parse_single, but (as in the previous patch) I actually prefer parse_endpoint.
> 
> > + * with the corresponding async sub-device pointer to let the caller initialize
> > + * the driver-specific part of the async sub-device structure.
> > + *
> > + * The notifier memory shall be zeroed before this function is called on the
> > + * notifier.
> 
> Should it? Doesn't this add additional subdevs?
> 
> I'm lost. What's the relationship between v4l2_async_notifier_parse_fwnode_endpoints
> and this function? When do you use which? When you should zero the notifier?

I thought there would be advantages in this approach as it lets you to
choose which endpoints specifically you want to parse. That said, the
expectation is that the device has no endpoints that aren't supported in
hardware either.

Some drivers currently iterate over all the endpoints and then validate
them whereas others poke for some endpoints only (port 0, endpoint 0, for
the rcar-vin driver, for instance). In DT binding documentation the
endpoint numbers are currently not specified nor drivers have checked them.
Common sense tells to use zero if there's no reason to do otherwise, but
still this hasn't been documented nor validated in the past. So if we add
that now, there could be a chance of breaking something.

Additionally, specifying the endpoints to parse explicitly has been seen
beneficial (or even necessary) in parsing endpoints for devices that have
both input and output interfaces. Perhaps Niklas can comment on that.

What I though was to introduce a specific error code (EPERM, better
suggestions are taken) for the driver callback function (parse_endpoint) to
silently skip endpoints the driver doesn't like for reason or another. This
lets drivers to use the endpoint parser function added by the previous
patch and still maintain the old behaviour, i.e. ignore endpoints that
aren't explicitly recognised by the driver.

I'll drop this patch from the next version.

-- 
Regards,

Sakari Ailus
e-mail: sakari.ailus@iki.fi

Re: [PATCH v6.1 4/5] v4l: fwnode: Support generic parsing of graph endpoints in a device

[Laurent Pinchart]

Hi Hans,

On Friday, 1 September 2017 14:18:55 EEST Hans Verkuil wrote:
> On 30/08/17 14:45, Sakari Ailus wrote:
> > The current practice is that drivers iterate over their endpoints and
> > parse each endpoint separately. This is very similar in a number of
> > drivers, implement a generic function for the job. Driver specific matters
> > can be taken into account in the driver specific callback.
> > 
> > Convert the omap3isp as an example.
> 
> It would be much easier to review if the omap3isp conversion was done in a
> separate patch. Ditto for the rcar conversion, and I prefer to have both
> at the end of the patch series, after the core code patches.
> 
> > Signed-off-by: Sakari Ailus <sakari.ailus-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> > ---
> > since v6:
> > 
> > - Set notifier->subdevs NULL and notifier->num_subdevs 0 in
> > 
> >   v4l2_async_notifier_release().
> >  
> >  drivers/media/platform/omap3isp/isp.c | 115 ++++++++++-------------------
> >  drivers/media/platform/omap3isp/isp.h |   5 +-
> >  drivers/media/v4l2-core/v4l2-async.c  |  16 +++++
> >  drivers/media/v4l2-core/v4l2-fwnode.c | 131 +++++++++++++++++++++++++++++
> >  include/media/v4l2-async.h            |  24 ++++++-
> >  include/media/v4l2-fwnode.h           |  48 +++++++++++++
> >  6 files changed, 254 insertions(+), 85 deletions(-)

[snip]

> > diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
> > index c69d8c8a66d0..cf13c7311a1c 100644
> > --- a/include/media/v4l2-async.h
> > +++ b/include/media/v4l2-async.h
> > @@ -18,7 +18,6 @@ struct device;
> >  struct device_node;
> >  struct v4l2_device;
> >  struct v4l2_subdev;
> > -struct v4l2_async_notifier;
> > 
> >  /* A random max subdevice number, used to allocate an array on stack */
> >  #define V4L2_MAX_SUBDEVS 128U
> > @@ -50,6 +49,10 @@ enum v4l2_async_match_type {
> >   * @match:	union of per-bus type matching data sets
> >   * @list:	used to link struct v4l2_async_subdev objects, waiting to be
> >   *		probed, to a notifier->waiting list
> > + *
> > + * When the struct is used as the first member of a driver specific
> 
> Just replace "the first member" by "part"...

I'd say "When the structure is embedded in a driver-specific structure, ...".

> > + * struct, the driver specific struct shall contain the @struct
> > + * v4l2_async_subdev as its first member.
> 
> ...since you mention in the second part that it has to be the first member.
> No need to mention that twice.
> 
> >   */

[snip]

> >  /**
> > + * v4l2_async_notifier_release - release notifier resources
> > + * @notifier: the notifier the resources of which are to be released
> 
> Just say: @notifier: pointer to &struct v4l2_async_notifier

I asked Sakari to be more explicit. Documenting an argument as "pointer to 
struct foo" is quite pointless, C is a typed language so it's evident from the 
function declaration. What pointer to pass to the function is a much more 
useful piece of information. This specific case is pretty trivial anyway, but 
in other cases, such as the dev pointer passed to the parse function, we need 
more than just documenting the variable type.

> > + *
> > + * Release memory resources related to a notifier, including the async
> 
> s/a/the/
> 
> > + * sub-devices allocated for the purposes of the notifier. The user is
> > + * responsible for releasing the notifier's resources after calling
> > + * @v4l2_async_notifier_parse_fwnode_endpoints.
> > + *
> > + * There is no harm from calling v4l2_async_notifier_release in other
> > + * cases as long as its memory has been zeroed after it has been
> > + * allocated.
> > + */
> > +void v4l2_async_notifier_release(struct v4l2_async_notifier *notifier);

[snip]

-- 
Regards,

Laurent Pinchart

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Re: [PATCH v6.1 4/5] v4l: fwnode: Support generic parsing of graph endpoints in a device

[Laurent Pinchart]

Hi Hans,

On Friday, 1 September 2017 14:18:55 EEST Hans Verkuil wrote:
> On 30/08/17 14:45, Sakari Ailus wrote:
> > The current practice is that drivers iterate over their endpoints and
> > parse each endpoint separately. This is very similar in a number of
> > drivers, implement a generic function for the job. Driver specific matters
> > can be taken into account in the driver specific callback.
> > 
> > Convert the omap3isp as an example.
> 
> It would be much easier to review if the omap3isp conversion was done in a
> separate patch. Ditto for the rcar conversion, and I prefer to have both
> at the end of the patch series, after the core code patches.
> 
> > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > ---
> > since v6:
> > 
> > - Set notifier->subdevs NULL and notifier->num_subdevs 0 in
> > 
> >   v4l2_async_notifier_release().
> >  
> >  drivers/media/platform/omap3isp/isp.c | 115 ++++++++++-------------------
> >  drivers/media/platform/omap3isp/isp.h |   5 +-
> >  drivers/media/v4l2-core/v4l2-async.c  |  16 +++++
> >  drivers/media/v4l2-core/v4l2-fwnode.c | 131 +++++++++++++++++++++++++++++
> >  include/media/v4l2-async.h            |  24 ++++++-
> >  include/media/v4l2-fwnode.h           |  48 +++++++++++++
> >  6 files changed, 254 insertions(+), 85 deletions(-)

[snip]

> > diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
> > index c69d8c8a66d0..cf13c7311a1c 100644
> > --- a/include/media/v4l2-async.h
> > +++ b/include/media/v4l2-async.h
> > @@ -18,7 +18,6 @@ struct device;
> >  struct device_node;
> >  struct v4l2_device;
> >  struct v4l2_subdev;
> > -struct v4l2_async_notifier;
> > 
> >  /* A random max subdevice number, used to allocate an array on stack */
> >  #define V4L2_MAX_SUBDEVS 128U
> > @@ -50,6 +49,10 @@ enum v4l2_async_match_type {
> >   * @match:	union of per-bus type matching data sets
> >   * @list:	used to link struct v4l2_async_subdev objects, waiting to be
> >   *		probed, to a notifier->waiting list
> > + *
> > + * When the struct is used as the first member of a driver specific
> 
> Just replace "the first member" by "part"...

I'd say "When the structure is embedded in a driver-specific structure, ...".

> > + * struct, the driver specific struct shall contain the @struct
> > + * v4l2_async_subdev as its first member.
> 
> ...since you mention in the second part that it has to be the first member.
> No need to mention that twice.
> 
> >   */

[snip]

> >  /**
> > + * v4l2_async_notifier_release - release notifier resources
> > + * @notifier: the notifier the resources of which are to be released
> 
> Just say: @notifier: pointer to &struct v4l2_async_notifier

I asked Sakari to be more explicit. Documenting an argument as "pointer to 
struct foo" is quite pointless, C is a typed language so it's evident from the 
function declaration. What pointer to pass to the function is a much more 
useful piece of information. This specific case is pretty trivial anyway, but 
in other cases, such as the dev pointer passed to the parse function, we need 
more than just documenting the variable type.

> > + *
> > + * Release memory resources related to a notifier, including the async
> 
> s/a/the/
> 
> > + * sub-devices allocated for the purposes of the notifier. The user is
> > + * responsible for releasing the notifier's resources after calling
> > + * @v4l2_async_notifier_parse_fwnode_endpoints.
> > + *
> > + * There is no harm from calling v4l2_async_notifier_release in other
> > + * cases as long as its memory has been zeroed after it has been
> > + * allocated.
> > + */
> > +void v4l2_async_notifier_release(struct v4l2_async_notifier *notifier);

[snip]

-- 
Regards,

Laurent Pinchart

Re: [PATCH v6 5/5] v4l: fwnode: Support generic parsing of graph endpoints in a single port

[Laurent Pinchart]

Hi Sakari,

On Saturday, 2 September 2017 01:57:48 EEST Sakari Ailus wrote:
> On Fri, Sep 01, 2017 at 01:28:40PM +0200, Hans Verkuil wrote:
> >> diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
> >> index d063ab4ff67b..dd13604178b4 100644
> >> --- a/include/media/v4l2-fwnode.h
> >> +++ b/include/media/v4l2-fwnode.h
> >> @@ -249,4 +249,53 @@ int v4l2_async_notifier_parse_fwnode_endpoints(
> >>  			    struct v4l2_fwnode_endpoint *vep,
> >>  			    struct v4l2_async_subdev *asd));
> >> 
> >> +/**
> >> + * v4l2_async_notifier_parse_fwnode_endpoint - Set up async notifier
> >> for an
> >> + *					       fwnode based sub-device
> >> + * @dev: @struct device pointer
> >> + * @notifier: pointer to &struct v4l2_async_notifier
> >> + * @port_id: port number
> >> + * @endpoint_id: endpoint number
> >> + * @asd_struct_size: size of the driver's async sub-device struct,
> >> including
> >> + *		     sizeof(struct v4l2_async_subdev). The &struct
> >> + *		     v4l2_async_subdev shall be the first member of
> >> + *		     the driver's async sub-device struct, i.e. both
> >> + *		     begin at the same memory address.
> >> + * @parse_single: driver's callback function called on each V4L2 fwnode
> >> endpoint
> >> + *
> >> + * Parse the fwnode endpoint of the @dev device corresponding to the
> >> given port
> >> + * and endpoint numbres and populate the async sub- devices array of
> >> the
> > 
> > numbers
> > no space after sub-
> > 
> > > + * notifier. The @parse_endpoint callback function is called for the
> > > endpoint
> > 
> > parse_single, but (as in the previous patch) I actually prefer
> > parse_endpoint.
> > 
> >> + * with the corresponding async sub-device pointer to let the caller
> >> initialize
> >> + * the driver-specific part of the async sub-device structure.
> >> + *
> >> + * The notifier memory shall be zeroed before this function is called
> >> on the
> >> + * notifier.
> > 
> > Should it? Doesn't this add additional subdevs?
> > 
> > I'm lost. What's the relationship between
> > v4l2_async_notifier_parse_fwnode_endpoints and this function? When do you
> > use which? When you should zero the notifier?
> I thought there would be advantages in this approach as it lets you to
> choose which endpoints specifically you want to parse. That said, the
> expectation is that the device has no endpoints that aren't supported in
> hardware either.
> 
> Some drivers currently iterate over all the endpoints and then validate
> them whereas others poke for some endpoints only (port 0, endpoint 0, for
> the rcar-vin driver, for instance). In DT binding documentation the
> endpoint numbers are currently not specified nor drivers have checked them.
> Common sense tells to use zero if there's no reason to do otherwise, but
> still this hasn't been documented nor validated in the past. So if we add
> that now, there could be a chance of breaking something.
> 
> Additionally, specifying the endpoints to parse explicitly has been seen
> beneficial (or even necessary) in parsing endpoints for devices that have
> both input and output interfaces. Perhaps Niklas can comment on that.
> 
> What I though was to introduce a specific error code (EPERM, better
> suggestions are taken)

Maybe ENOTCONN ?

> for the driver callback function (parse_endpoint) to silently skip endpoints
> the driver doesn't like for reason or another. This lets drivers to use the
> endpoint parser function added by the previous patch and still maintain the
> old behaviour, i.e. ignore endpoints that aren't explicitly recognised by
> the driver.
> 
> I'll drop this patch from the next version.

Parsing a specific endpoint of a specific port is probably indeed a bit too 
fine-grained, but I think there are use cases for parsing at the port level 
instead of parsing all ports.

-- 
Regards,

Laurent Pinchart

Re: [PATCH v6 5/5] v4l: fwnode: Support generic parsing of graph endpoints in a single port

[Sakari Ailus]

Hi Laurent,

On Sat, Sep 02, 2017 at 12:52:47PM +0300, Laurent Pinchart wrote:
> Hi Sakari,
> 
> On Saturday, 2 September 2017 01:57:48 EEST Sakari Ailus wrote:
> > On Fri, Sep 01, 2017 at 01:28:40PM +0200, Hans Verkuil wrote:
> > >> diff --git a/include/media/v4l2-fwnode.h b/include/media/v4l2-fwnode.h
> > >> index d063ab4ff67b..dd13604178b4 100644
> > >> --- a/include/media/v4l2-fwnode.h
> > >> +++ b/include/media/v4l2-fwnode.h
> > >> @@ -249,4 +249,53 @@ int v4l2_async_notifier_parse_fwnode_endpoints(
> > >>  			    struct v4l2_fwnode_endpoint *vep,
> > >>  			    struct v4l2_async_subdev *asd));
> > >> 
> > >> +/**
> > >> + * v4l2_async_notifier_parse_fwnode_endpoint - Set up async notifier
> > >> for an
> > >> + *					       fwnode based sub-device
> > >> + * @dev: @struct device pointer
> > >> + * @notifier: pointer to &struct v4l2_async_notifier
> > >> + * @port_id: port number
> > >> + * @endpoint_id: endpoint number
> > >> + * @asd_struct_size: size of the driver's async sub-device struct,
> > >> including
> > >> + *		     sizeof(struct v4l2_async_subdev). The &struct
> > >> + *		     v4l2_async_subdev shall be the first member of
> > >> + *		     the driver's async sub-device struct, i.e. both
> > >> + *		     begin at the same memory address.
> > >> + * @parse_single: driver's callback function called on each V4L2 fwnode
> > >> endpoint
> > >> + *
> > >> + * Parse the fwnode endpoint of the @dev device corresponding to the
> > >> given port
> > >> + * and endpoint numbres and populate the async sub- devices array of
> > >> the
> > > 
> > > numbers
> > > no space after sub-
> > > 
> > > > + * notifier. The @parse_endpoint callback function is called for the
> > > > endpoint
> > > 
> > > parse_single, but (as in the previous patch) I actually prefer
> > > parse_endpoint.
> > > 
> > >> + * with the corresponding async sub-device pointer to let the caller
> > >> initialize
> > >> + * the driver-specific part of the async sub-device structure.
> > >> + *
> > >> + * The notifier memory shall be zeroed before this function is called
> > >> on the
> > >> + * notifier.
> > > 
> > > Should it? Doesn't this add additional subdevs?
> > > 
> > > I'm lost. What's the relationship between
> > > v4l2_async_notifier_parse_fwnode_endpoints and this function? When do you
> > > use which? When you should zero the notifier?
> > I thought there would be advantages in this approach as it lets you to
> > choose which endpoints specifically you want to parse. That said, the
> > expectation is that the device has no endpoints that aren't supported in
> > hardware either.
> > 
> > Some drivers currently iterate over all the endpoints and then validate
> > them whereas others poke for some endpoints only (port 0, endpoint 0, for
> > the rcar-vin driver, for instance). In DT binding documentation the
> > endpoint numbers are currently not specified nor drivers have checked them.
> > Common sense tells to use zero if there's no reason to do otherwise, but
> > still this hasn't been documented nor validated in the past. So if we add
> > that now, there could be a chance of breaking something.
> > 
> > Additionally, specifying the endpoints to parse explicitly has been seen
> > beneficial (or even necessary) in parsing endpoints for devices that have
> > both input and output interfaces. Perhaps Niklas can comment on that.
> > 
> > What I though was to introduce a specific error code (EPERM, better
> > suggestions are taken)
> 
> Maybe ENOTCONN ?

Sounds good to me.

> 
> > for the driver callback function (parse_endpoint) to silently skip endpoints
> > the driver doesn't like for reason or another. This lets drivers to use the
> > endpoint parser function added by the previous patch and still maintain the
> > old behaviour, i.e. ignore endpoints that aren't explicitly recognised by
> > the driver.
> > 
> > I'll drop this patch from the next version.
> 
> Parsing a specific endpoint of a specific port is probably indeed a bit too 
> fine-grained, but I think there are use cases for parsing at the port level 
> instead of parsing all ports.

Could you elaborate?

If a driver would be interested in skipping endpoints in a subset of ports,
in which case only a single port would be excluded from this?

-- 
Regards,

Sakari Ailus
e-mail: sakari.ailus@iki.fi

Re: [PATCH v6 5/5] v4l: fwnode: Support generic parsing of graph endpoints in a single port

[Laurent Pinchart]

Hi Sakari,

On Sunday, 3 September 2017 10:43:39 EEST Sakari Ailus wrote:
> On Sat, Sep 02, 2017 at 12:52:47PM +0300, Laurent Pinchart wrote:
> > On Saturday, 2 September 2017 01:57:48 EEST Sakari Ailus wrote:
> >> On Fri, Sep 01, 2017 at 01:28:40PM +0200, Hans Verkuil wrote:

[sinp]

> >>> I'm lost. What's the relationship between
> >>> v4l2_async_notifier_parse_fwnode_endpoints and this function? When do
> >>> you use which? When you should zero the notifier?
> >> 
> >> I thought there would be advantages in this approach as it lets you to
> >> choose which endpoints specifically you want to parse. That said, the
> >> expectation is that the device has no endpoints that aren't supported in
> >> hardware either.
> >> 
> >> Some drivers currently iterate over all the endpoints and then validate
> >> them whereas others poke for some endpoints only (port 0, endpoint 0,
> >> for the rcar-vin driver, for instance). In DT binding documentation the
> >> endpoint numbers are currently not specified nor drivers have checked
> >> them. Common sense tells to use zero if there's no reason to do
> >> otherwise, but still this hasn't been documented nor validated in the
> >> past. So if we add that now, there could be a chance of breaking
> >> something.
> >> 
> >> Additionally, specifying the endpoints to parse explicitly has been seen
> >> beneficial (or even necessary) in parsing endpoints for devices that
> >> have both input and output interfaces. Perhaps Niklas can comment on
> >> that.
> >> 
> >> What I though was to introduce a specific error code (EPERM, better
> >> suggestions are taken)
> > 
> > Maybe ENOTCONN ?
> 
> Sounds good to me.
> 
> >> for the driver callback function (parse_endpoint) to silently skip
> >> endpoints the driver doesn't like for reason or another. This lets
> >> drivers to use the endpoint parser function added by the previous patch
> >> and still maintain the old behaviour, i.e. ignore endpoints that aren't
> >> explicitly recognised by the driver.
> >> 
> >> I'll drop this patch from the next version.
> > 
> > Parsing a specific endpoint of a specific port is probably indeed a bit
> > too fine-grained, but I think there are use cases for parsing at the port
> > level instead of parsing all ports.
> 
> Could you elaborate?
> 
> If a driver would be interested in skipping endpoints in a subset of ports,
> in which case only a single port would be excluded from this?

I meant that I see use cases for parsing specific ports only (for instance in 
the R-Car case parsing only the sink ports in a CSI-2 receiver DT node), but 
not really for parsing specific endpoints only.

-- 
Regards,

Laurent Pinchart