lopper: assists: gen_domain_dts: Generate rtc-counter wrapper for xlnx,zynqmp-rtc

Create a zephyr,rtc-counter child node under the generated
xlnx,zynqmp-rtc node and update the rtc alias to point to the
wrapper node used by the Zephyr RTC framework.

Also correct the fallback RTC clock frequency from 32767 Hz to
32768 Hz.

This enables RTC samples and tests to access the Xilinx RTC
through the upstream rtc-counter based architecture.

Signed-off-by: Vivek Nagamalla <vivek.nagamalla@amd.com>

Author: VivekNagamalla

lopper/assists/gen_domain_dts.py

@@ -851,7 +851,7 @@ def xlnx_generate_zephyr_domain_dts_arm(tgt_node, sdt, options, machine):
                 # Set clock frequency for RTC
                 # Revert this snippet once the clock support is added in sdtgen
                 if node.propval('clock-frequency') == ['']:
-                    node["clock-frequency"] = 32767
+                    node["clock-frequency"] = 32768
             elif compatible == "cdns,ttc":
                 # TTC: Convert 3-cell interrupts to 4-cell GIC format by adding 0xa0 priority
                 intr_list = node["interrupts"].value
@@ -910,9 +910,17 @@ def xlnx_generate_zephyr_domain_dts_arm(tgt_node, sdt, options, machine):
     if ufs_nodes:
         ufs_node = sdt.tree.pnode(ufs_nodes[0].phandle)
         sdt.tree['/aliases'] + LopperProp(name="ufs0", value = ufs_node.abs_path)
+    # Add a zephyr,rtc-counter child node for the RTC counter framework.
+    # update the "rtc" alias to reference the wrapper node used by RTC APIs.
     if rtc_nodes:
         rtc_node = sdt.tree.pnode(rtc_nodes[0].phandle)
-        sdt.tree['/aliases'] + LopperProp(name="rtc", value = rtc_node.abs_path)
+        sdt.tree['/aliases'] + LopperProp(name="rtc", value = rtc_node.abs_path + "/rtc-counter")
+        rtc_counter_node = LopperNode()
+        rtc_counter_node.name = "rtc-counter"
+        rtc_counter_node['compatible'] = "zephyr,rtc-counter"
+        rtc_counter_node['status'] = "okay"
+        rtc_counter_node['alarms-count'] = 1
+        rtc_node.add(rtc_counter_node)
 
     for node in root_sub_nodes:
         if node.propval("compatible") != ['']: