3 files changed, 102 insertions, 0 deletions

diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
index 77abe0ec4043..9d460a859be0 100644
--- a/drivers/acpi/property.c
+++ b/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)
diff --git a/drivers/base/property.c b/drivers/base/property.c
index 8b91ab380d14..348b37e64944 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -984,6 +984,81 @@ 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
  * @endpoint: pointer to the fwnode endpoint data structure
diff --git a/include/linux/property.h b/include/linux/property.h
index 65d3420dd5d1..a29369c89e6e 100644
--- a/include/linux/property.h
+++ b/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)); )