Device properties framework updates for 5.2-rc1

- Fix the handling of data nodes in the ACPI properties support
    code for devices with child devices and hierarchical _DSD
    properties (Pierre-Louis Bossart).
 
  - Add fwnode_graph_get_endpoint_by_id() helper for endpoint lookup
    in device property graphs (Sakari Ailus).
 
  - Restore the _DSD data subnodes GUID comment inadvertently removed
    by one of previous changes (Shunyong Yang).
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Merge tag 'devprop-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull device properties framework updates from Rafael Wysocki:
 "These fix the handling of data nodes in the ACPI properties support
  code, add a new helper for endpoint lookup in property graphs and
  restore a comment inadvertently removed by one of previous changes.

  Specifics:

   - Fix the handling of data nodes in the ACPI properties support code
     for devices with child devices and hierarchical _DSD properties
     (Pierre-Louis Bossart).

   - Add fwnode_graph_get_endpoint_by_id() helper for endpoint lookup in
     device property graphs (Sakari Ailus).

   - Restore the _DSD data subnodes GUID comment inadvertently removed
     by one of previous changes (Shunyong Yang)"

* tag 'devprop-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / property: fix handling of data_nodes in acpi_get_next_subnode()
  device property: Add fwnode_graph_get_endpoint_by_id()
  ACPI: property: restore _DSD data subnodes GUID comment

drivers/acpi/property.c

@@ -44,6 +44,7 @@ static const guid_t prp_guids[] = {
 		  0xbf, 0xf0, 0x76, 0x14, 0x38, 0x07, 0xc3, 0x89),
 };
 
+/* ACPI _DSD data subnodes GUID: dbb8e3e6-5886-4ba6-8795-1319f52a966b */
 static const guid_t ads_guid =
 	GUID_INIT(0xdbb8e3e6, 0x5886, 0x4ba6,
 		  0x87, 0x95, 0x13, 0x19, 0xf5, 0x2a, 0x96, 0x6b);
@@ -1031,6 +1032,14 @@ struct fwnode_handle *acpi_get_next_subnode(const struct fwnode_handle *fwnode,
 		const struct acpi_data_node *data = to_acpi_data_node(fwnode);
 		struct acpi_data_node *dn;
 
+		/*
+		 * We can have a combination of device and data nodes, e.g. with
+		 * hierarchical _DSD properties. Make sure the adev pointer is
+		 * restored before going through data nodes, otherwise we will
+		 * be looking for data_nodes below the last device found instead
+		 * of the common fwnode shared by device_nodes and data_nodes.
+		 */
+		adev = to_acpi_device_node(fwnode);
 		if (adev)
 			head = &adev->data.subnodes;
 		else if (data)

drivers/base/property.c

@@ -983,6 +983,81 @@ fwnode_graph_get_remote_node(const struct fwnode_handle *fwnode, u32 port_id,
 }
 EXPORT_SYMBOL_GPL(fwnode_graph_get_remote_node);
 
+/**
+ * fwnode_graph_get_endpoint_by_id - get endpoint by port and endpoint numbers
+ * @fwnode: parent fwnode_handle containing the graph
+ * @port: identifier of the port node
+ * @endpoint: identifier of the endpoint node under the port node
+ * @flags: fwnode lookup flags
+ *
+ * Return the fwnode handle of the local endpoint corresponding the port and
+ * endpoint IDs or NULL if not found.
+ *
+ * If FWNODE_GRAPH_ENDPOINT_NEXT is passed in @flags and the specified endpoint
+ * has not been found, look for the closest endpoint ID greater than the
+ * specified one and return the endpoint that corresponds to it, if present.
+ *
+ * Do not return endpoints that belong to disabled devices, unless
+ * FWNODE_GRAPH_DEVICE_DISABLED is passed in @flags.
+ *
+ * The returned endpoint needs to be released by calling fwnode_handle_put() on
+ * it when it is not needed any more.
+ */
+struct fwnode_handle *
+fwnode_graph_get_endpoint_by_id(const struct fwnode_handle *fwnode,
+				u32 port, u32 endpoint, unsigned long flags)
+{
+	struct fwnode_handle *ep = NULL, *best_ep = NULL;
+	unsigned int best_ep_id = 0;
+	bool endpoint_next = flags & FWNODE_GRAPH_ENDPOINT_NEXT;
+	bool enabled_only = !(flags & FWNODE_GRAPH_DEVICE_DISABLED);
+
+	while ((ep = fwnode_graph_get_next_endpoint(fwnode, ep))) {
+		struct fwnode_endpoint fwnode_ep = { 0 };
+		int ret;
+
+		if (enabled_only) {
+			struct fwnode_handle *dev_node;
+			bool available;
+
+			dev_node = fwnode_graph_get_remote_port_parent(ep);
+			available = fwnode_device_is_available(dev_node);
+			fwnode_handle_put(dev_node);
+			if (!available)
+				continue;
+		}
+
+		ret = fwnode_graph_parse_endpoint(ep, &fwnode_ep);
+		if (ret < 0)
+			continue;
+
+		if (fwnode_ep.port != port)
+			continue;
+
+		if (fwnode_ep.id == endpoint)
+			return ep;
+
+		if (!endpoint_next)
+			continue;
+
+		/*
+		 * If the endpoint that has just been found is not the first
+		 * matching one and the ID of the one found previously is closer
+		 * to the requested endpoint ID, skip it.
+		 */
+		if (fwnode_ep.id < endpoint ||
+		    (best_ep && best_ep_id < fwnode_ep.id))
+			continue;
+
+		fwnode_handle_put(best_ep);
+		best_ep = fwnode_handle_get(ep);
+		best_ep_id = fwnode_ep.id;
+	}
+
+	return best_ep;
+}
+EXPORT_SYMBOL_GPL(fwnode_graph_get_endpoint_by_id);
+
 /**
  * fwnode_graph_parse_endpoint - parse common endpoint node properties
  * @fwnode: pointer to endpoint fwnode_handle

include/linux/property.h

@@ -13,6 +13,7 @@
 #ifndef _LINUX_PROPERTY_H_
 #define _LINUX_PROPERTY_H_
 
+#include <linux/bits.h>
 #include <linux/fwnode.h>
 #include <linux/types.h>
 
@@ -304,6 +305,23 @@ struct fwnode_handle *
 fwnode_graph_get_remote_node(const struct fwnode_handle *fwnode, u32 port,
 			     u32 endpoint);
 
+/*
+ * Fwnode lookup flags
+ *
+ * @FWNODE_GRAPH_ENDPOINT_NEXT: In the case of no exact match, look for the
+ *				closest endpoint ID greater than the specified
+ *				one.
+ * @FWNODE_GRAPH_DEVICE_DISABLED: That the device to which the remote
+ *				  endpoint of the given endpoint belongs to,
+ *				  may be disabled.
+ */
+#define FWNODE_GRAPH_ENDPOINT_NEXT	BIT(0)
+#define FWNODE_GRAPH_DEVICE_DISABLED	BIT(1)
+
+struct fwnode_handle *
+fwnode_graph_get_endpoint_by_id(const struct fwnode_handle *fwnode,
+				u32 port, u32 endpoint, unsigned long flags);
+
 #define fwnode_graph_for_each_endpoint(fwnode, child)			\
 	for (child = NULL;						\
 	     (child = fwnode_graph_get_next_endpoint(fwnode, child)); )