summaryrefslogtreecommitdiff
path: root/drivers/acpi/property.c
diff options
context:
space:
mode:
authorMika Westerberg <mika.westerberg@linux.intel.com>2017-03-28 10:52:20 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-03-29 01:00:28 +0300
commit79389a83bc3888a900191e3990cda5c76f2ca1ec (patch)
tree4b4276b07b604d56da9713bcb698e7b2191977be /drivers/acpi/property.c
parent21ea73f54c6d77f35381c79870160496c9e78b60 (diff)
downloadlinux-79389a83bc3888a900191e3990cda5c76f2ca1ec.tar.xz
ACPI / property: Add support for remote endpoints
DT has had concept of remote endpoints for some time already. It makes possible to reference another firmware node through a property called remote-endpoint. This is already used by some subsystems like v4l2 for parsing hardware properties related to camera. This patch adds ACPI support for remote endpoints utilizing _DSD hierarchical data extensions. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/property.c')
-rw-r--r--drivers/acpi/property.c138
1 files changed, 138 insertions, 0 deletions
diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
index 8730ce745b43..9eb7c13c5bb7 100644
--- a/drivers/acpi/property.c
+++ b/drivers/acpi/property.c
@@ -969,3 +969,141 @@ struct fwnode_handle *acpi_node_get_parent(struct fwnode_handle *fwnode)
return NULL;
}
+
+/**
+ * acpi_graph_get_next_endpoint - Get next endpoint ACPI firmware node
+ * @fwnode: Pointer to the parent firmware node
+ * @prev: Previous endpoint node or %NULL to get the first
+ *
+ * Looks up next endpoint ACPI firmware node below a given @fwnode. Returns
+ * %NULL if there is no next endpoint, ERR_PTR() in case of error. In case
+ * of success the next endpoint is returned.
+ */
+struct fwnode_handle *acpi_graph_get_next_endpoint(struct fwnode_handle *fwnode,
+ struct fwnode_handle *prev)
+{
+ struct fwnode_handle *port = NULL;
+ struct fwnode_handle *endpoint;
+
+ if (!prev) {
+ do {
+ port = fwnode_get_next_child_node(fwnode, port);
+ /* Ports must have port property */
+ if (fwnode_property_present(port, "port"))
+ break;
+ } while (port);
+ } else {
+ port = fwnode_get_parent(prev);
+ }
+
+ if (!port)
+ return NULL;
+
+ endpoint = fwnode_get_next_child_node(port, prev);
+ while (!endpoint) {
+ port = fwnode_get_next_child_node(fwnode, port);
+ if (!port)
+ break;
+ if (fwnode_property_present(port, "port"))
+ endpoint = fwnode_get_next_child_node(port, NULL);
+ }
+
+ if (endpoint) {
+ /* Endpoints must have "endpoint" property */
+ if (!fwnode_property_present(endpoint, "endpoint"))
+ return ERR_PTR(-EPROTO);
+ }
+
+ return endpoint;
+}
+
+/**
+ * acpi_graph_get_child_prop_value - Return a child with a given property value
+ * @fwnode: device fwnode
+ * @prop_name: The name of the property to look for
+ * @val: the desired property value
+ *
+ * Return the port node corresponding to a given port number. Returns
+ * the child node on success, NULL otherwise.
+ */
+static struct fwnode_handle *acpi_graph_get_child_prop_value(
+ struct fwnode_handle *fwnode, const char *prop_name, unsigned int val)
+{
+ struct fwnode_handle *child;
+
+ fwnode_for_each_child_node(fwnode, child) {
+ u32 nr;
+
+ if (!fwnode_property_read_u32(fwnode, prop_name, &nr))
+ continue;
+
+ if (val == nr)
+ return child;
+ }
+
+ return NULL;
+}
+
+
+/**
+ * acpi_graph_get_remote_enpoint - Parses and returns remote end of an endpoint
+ * @fwnode: Endpoint firmware node pointing to a remote device
+ * @parent: Firmware node of remote port parent is filled here if not %NULL
+ * @port: Firmware node of remote port is filled here if not %NULL
+ * @endpoint: Firmware node of remote endpoint is filled here if not %NULL
+ *
+ * Function parses remote end of ACPI firmware remote endpoint and fills in
+ * fields requested by the caller. Returns %0 in case of success and
+ * negative errno otherwise.
+ */
+int acpi_graph_get_remote_endpoint(struct fwnode_handle *fwnode,
+ struct fwnode_handle **parent,
+ struct fwnode_handle **port,
+ struct fwnode_handle **endpoint)
+{
+ unsigned int port_nr, endpoint_nr;
+ struct acpi_reference_args args;
+ int ret;
+
+ memset(&args, 0, sizeof(args));
+ ret = acpi_node_get_property_reference(fwnode, "remote-endpoint", 0,
+ &args);
+ if (ret)
+ return ret;
+
+ /*
+ * Always require two arguments with the reference: port and
+ * endpoint indices.
+ */
+ if (args.nargs != 2)
+ return -EPROTO;
+
+ fwnode = acpi_fwnode_handle(args.adev);
+ port_nr = args.args[0];
+ endpoint_nr = args.args[1];
+
+ if (parent)
+ *parent = fwnode;
+
+ if (!port && !endpoint)
+ return 0;
+
+ fwnode = acpi_graph_get_child_prop_value(fwnode, "port", port_nr);
+ if (!fwnode)
+ return -EPROTO;
+
+ if (port)
+ *port = fwnode;
+
+ if (!endpoint)
+ return 0;
+
+ fwnode = acpi_graph_get_child_prop_value(fwnode, "endpoint",
+ endpoint_nr);
+ if (!fwnode)
+ return -EPROTO;
+
+ *endpoint = fwnode;
+
+ return 0;
+}