ACPI: property: graph: Update graph documentation to use generic references

Instead of port and endpoint properties for representing ports and
endpoints, use the keys of the hierarchical data extension references
when referring to the port and endpoint nodes. Additionally, use "reg"
properties as in Device Tree to specify the number of the port or the
endpoint.

The keys of the port nodes begin with "port" and the keys of the endpoint
nodes begin with "endpoint", both followed by "@" character and the number
of the port or the endpoint.

These changes have the advantage that no ACPI specific properties need to
be added to refer to non-device nodes. Additionally, using the name of the
node instead of an integer property inside the node is easier to parse in
code and easier for humans to understand.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

2 files changed, 36 insertions, 30 deletions

diff --git a/Documentation/acpi/dsd/data-node-references.txt b/Documentation/acpi/dsd/data-node-references.txt
index 6e9a5f925edd..c3871565c8cf 100644
--- a/Documentation/acpi/dsd/data-node-references.txt
+++ b/Documentation/acpi/dsd/data-node-references.txt
@@ -75,6 +75,7 @@ Example
             })
         }
 
+Please also see a graph example in graph.txt .
 
 References
 ----------
diff --git a/Documentation/acpi/dsd/graph.txt b/Documentation/acpi/dsd/graph.txt
index 3131f457882b..b9ce910781dc 100644
--- a/Documentation/acpi/dsd/graph.txt
+++ b/Documentation/acpi/dsd/graph.txt
@@ -38,34 +38,39 @@ represents a connection to that interface.
 
 All port nodes are located under the device's "_DSD" node in the hierarchical
 data extension tree. The data extension related to each port node must begin
-with "port" and must be followed by the number of the port as its key. The
-target object it refers to should be called "PRTX", where "X" is the number of
-the port. An example of such a package would be:
+with "port" and must be followed by the "@" character and the number of the port
+as its key. The target object it refers to should be called "PRTX", where "X" is
+the number of the port. An example of such a package would be:
 
-    Package() { "port4", PRT4 }
+    Package() { "port@4", PRT4 }
 
-Further on, endpoints are located under the port nodes. The hierarchical data
-extension key of the endpoint nodes must begin with "endpoint" and must be
-followed by the number of the endpoint. The object it refers to should be called
-"EPXY", where "X" is the number of the port and "Y" is the number of the
-endpoint. An example of such a package would be:
+Further on, endpoints are located under the port nodes. The hierarchical
+data extension key of the endpoint nodes must begin with
+"endpoint" and must be followed by the "@" character and the number of the
+endpoint. The object it refers to should be called "EPXY", where "X" is the
+number of the port and "Y" is the number of the endpoint. An example of such a
+package would be:
 
-    Package() { "endpoint0", EP40 }
+    Package() { "endpoint@0", EP40 }
 
-Each port node contains a property extension key "port", the value of
-which is the number of the port. Each endpoint is similarly numbered
-with a property extension key "endpoint". Port numbers must be unique within a
-device and endpoint numbers must be unique within a port. If a device object
-may only has a single port, then the number of that port shall be zero.
-Similarly, if a port may only have a single endpoint, the number of that
-endpoint shall be zero.
+Each port node contains a property extension key "port", the value of which is
+the number of the port. Each endpoint is similarly numbered with a property
+extension key "reg", the value of which is the number of the endpoint. Port
+numbers must be unique within a device and endpoint numbers must be unique
+within a port. If a device object may only has a single port, then the number
+of that port shall be zero. Similarly, if a port may only have a single
+endpoint, the number of that endpoint shall be zero.
 
 The endpoint reference uses property extension with "remote-endpoint" property
 name followed by a reference in the same package. Such references consist of the
-the remote device reference, number of the port in the device and finally the
-number of the endpoint in that port. Individual references thus appear as:
+the remote device reference, the first package entry of the port data extension
+reference under the device and finally the first package entry of the endpoint
+data extension reference under the port. Individual references thus appear as:
 
-    Package() { device, port_number, endpoint_number }
+    Package() { device, "port@X", "endpoint@Y" }
+
+In the above example, "X" is the number of the port and "Y" is the number of the
+endpoint.
 
 The references to endpoints must be always done both ways, to the
 remote endpoint and back from the referred remote endpoint node.
@@ -83,24 +88,24 @@ A simple example of this is show below:
                 },
                 ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
                 Package () {
-                    Package () { "port0", PRT0 },
+                    Package () { "port@0", PRT0 },
                 }
             })
             Name (PRT0, Package() {
                 ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
                 Package () {
-                    Package () { "port", 0 },
+                    Package () { "reg", 0 },
                 },
                 ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
                 Package () {
-                    Package () { "endpoint0", EP00 },
+                    Package () { "endpoint@0", EP00 },
                 }
             })
             Name (EP00, Package() {
                 ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
                 Package () {
-                    Package () { "endpoint", 0 },
-                    Package () { "remote-endpoint", Package() { \_SB.PCI0.ISP, 4, 0 } },
+                    Package () { "reg", 0 },
+                    Package () { "remote-endpoint", Package() { \_SB.PCI0.ISP, "port@4", "endpoint@0" } },
                 }
             })
         }
@@ -113,26 +118,26 @@ A simple example of this is show below:
             Name (_DSD, Package () {
                 ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
                 Package () {
-                    Package () { "port4", PRT4 },
+                    Package () { "port@4", PRT4 },
                 }
             })
 
             Name (PRT4, Package() {
                 ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
                 Package () {
-                    Package () { "port", 4 }, /* CSI-2 port number */
+                    Package () { "reg", 4 }, /* CSI-2 port number */
                 },
                 ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
                 Package () {
-                    Package () { "endpoint0", EP40 },
+                    Package () { "endpoint@0", EP40 },
                 }
             })
 
             Name (EP40, Package() {
                 ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
                 Package () {
-                    Package () { "endpoint", 0 },
-                    Package () { "remote-endpoint", Package () { \_SB.PCI0.I2C2.CAM0, 0, 0 } },
+                    Package () { "reg", 0 },
+                    Package () { "remote-endpoint", Package () { \_SB.PCI0.I2C2.CAM0, "port@0", "endpoint@0" } },
                 }
             })
         }