[PATCH v5 4/5] v4l: fwnode: Support generic parsing of graph endpoints in a device

[Sakari Ailus <sakari.ailus-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>]

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-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
---
 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 | 132 ++++++++++++++++++++++++++++++++++
 include/media/v4l2-async.h            |  20 +++++-
 include/media/v4l2-fwnode.h           |  39 ++++++++++
 6 files changed, 242 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..39a587c6992a 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 +315,136 @@ void v4l2_fwnode_put_link(struct v4l2_fwnode_link *link)
 }
 EXPORT_SYMBOL_GPL(v4l2_fwnode_put_link);
 
+static int notifier_realloc(struct v4l2_async_notifier *notifier,
+			    unsigned int max_subdevs)
+{
+	struct v4l2_async_subdev **subdevs;
+	unsigned int i;
+
+	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) {
+		for (i = 0; i < notifier->num_subdevs; i++)
+			subdevs[i] = notifier->subdevs[i];
+
+		kvfree(notifier->subdevs);
+	}
+
+	notifier->subdevs = subdevs;
+	notifier->max_subdevs = max_subdevs;
+
+	return 0;
+}
+
+static int 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 = 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 = 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..4a44ab47ab04 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
@@ -78,7 +77,8 @@ 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 +90,7 @@ 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 +122,21 @@ 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: pointer to &struct v4l2_async_notifier
+ *
+ * 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..46521e8c8872 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 +203,41 @@ 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: @struct device pointer
+ * @notifier: pointer to &struct v4l2_async_notifier
+ * @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
+ *
+ * Allocate async sub-device array and sub-devices for each fwnode endpoint,
+ * parse the related fwnode endpoints and finally call driver's callback
+ * function to that V4L2 fwnode endpoint.
+ *
+ * The function may not be called on a registered notifier.
+ *
+ * Once the user has called this function, the resources released by it need to
+ * be released by callin v4l2_async_notifier_release after the notifier has been
+ * unregistered and the sub-devices are no longer in use.
+ *
+ * A driver supporting fwnode (currently Devicetree and ACPI) should call this
+ * function as part of its probe function before it registers the notifier.
+ *
+ * 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

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