scripts: gen_defines: re-work write_clocks() with augmented nodes

Mirror the change already done to write_regs().

Other than the order in which they appear and comments, the output
before and after this patch should be exactly the same.

Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>

scripts/dts/gen_defines.py

@@ -790,6 +790,8 @@ def write_phandle_val_list_entry(node, entry, i, ident):
 def write_clocks(node):
     # Writes clock information.
     #
+    # Like write_regs(), but for clocks.
+    #
     # Most of this ought to be handled in write_props(), but the identifiers
     # that get generated for 'clocks' are inconsistent with the with other
     # 'phandle-array' properties.
@@ -799,30 +801,87 @@ def write_clocks(node):
     if "clocks" not in node.props:
         return
 
-    for clock_i, clock in enumerate(node.props["clocks"].val):
-        controller = clock.controller
+    # Maps a clock_i to (primary_controller, primary_data,
+    # primary_frequency) macros for that clock index
+    clock_i2primary_cdf = {}
 
-        if controller.label is not None:
-            out_node_s(node, "CLOCK_CONTROLLER", controller.label)
-
-        for name, val in clock.data.items():
-            if clock_i == 0:
-                clk_name_alias = "CLOCK_" + str2ident(name)
+    def write_clocks_for_ident(node, ident):
+        clocks = node.props["clocks"].val
+        for clock_i, clock in enumerate(clocks):
+            primary_cdf = clock_i2primary_cdf.get(clock_i)
+            if primary_cdf is None:
+                # Print the primary macros and save them for future use
+                clock_i2primary_cdf[clock_i] = primary_cdf = \
+                    write_clock_primary(ident, clock_i, clock)
             else:
-                clk_name_alias = None
+                # Print other macros in terms of primary macros
+                write_clock_other(ident, clock_i, clock, primary_cdf)
 
-            out_node(node, f"CLOCK_{str2ident(name)}_{clock_i}", val,
-                     name_alias=clk_name_alias)
+    def write_clock_primary(ident, clock_i, clock):
+        # Write clock macros for the primary identifier 'ident'.
+        # Return a (primary_controller, primary_data,
+        # primary_frequency) tuple to use for other idents.
 
-        if "fixed-clock" not in controller.compats:
-            continue
+        controller = clock.controller
+        # If the clock controller has a label property:
+        # DT_<IDENT>_CLOCK_CONTROLLER <LABEL_PROPERTY>
+        if controller.label:
+            # FIXME this is replicating previous behavior that didn't
+            # generate an indexed controller bug-for-bug. There's a
+            # missing _{clock_i} at the end of the f-string.
+            prim_controller = out_s(f"{ident}_CLOCK_CONTROLLER",
+                                    controller.label)
+        else:
+            prim_controller = None
 
-        if "clock-frequency" not in controller.props:
-            err(f"{controller!r} is a 'fixed-clock' but lacks a "
-                "'clock-frequency' property")
+        # For each additional cell in the controller + data:
+        # DT_<IDENT>_CLOCK_<CELL_NAME>_<clock_i> <CELL_VALUE>
+        #
+        # Cell names are from the controller binding's "clock-cells".
+        prim_data = []
+        for name, val in clock.data.items():
+            prim_macro = out(f"{ident}_CLOCK_{str2ident(name)}_{clock_i}", val)
+            prim_data.append(prim_macro)
+            if clock_i == 0:
+                out(f"{ident}_CLOCK_{str2ident(name)}", prim_macro)
 
-        out_node(node, "CLOCKS_CLOCK_FREQUENCY",
-                 controller.props["clock-frequency"].val)
+        # If the clock has a "fixed-clock" compat:
+        # DT_<IDENT>_CLOCKS_CLOCK_FREQUENCY_{clock_i} <CLOCK'S_FREQ>
+        if "fixed-clock" in controller.compats:
+            if "clock-frequency" not in controller.props:
+                err(f"{controller!r} is a 'fixed-clock' but lacks a "
+                    "'clock-frequency' property")
+            # FIXME like the CLOCK_CONTROLLER, this is missing a clock_i.
+            # We need to go bug-for-bug with the previous implementation
+            # to make sure there are no differences before fixing.
+            prim_freq = out(f"{ident}_CLOCKS_CLOCK_FREQUENCY",
+                            controller.props["clock-frequency"].val)
+        else:
+            prim_freq = None
+
+        return (prim_controller, prim_data, prim_freq)
+
+    def write_clock_other(ident, clock_i, clock, primary_cdf):
+        # Write clock macros for a secondary identifier 'ident'
+
+        prim_controller, prim_data, prim_freq = primary_cdf
+        if prim_controller is not None:
+            # FIXME this is replicating previous behavior that didn't
+            # generate an indexed controller bug-for-bug. There's a
+            # missing _{clock_i} at the end of the f-string.
+            out(f"{ident}_CLOCK_CONTROLLER", prim_controller)
+        for name_i, name in enumerate(clock.data.keys()):
+            out(f"{ident}_CLOCK_{str2ident(name)}_{clock_i}", prim_data[name_i])
+            if clock_i == 0:
+                out(f"{ident}_CLOCK_{str2ident(name)}", prim_data[name_i])
+        if prim_freq is not None:
+            # FIXME this is also a bug-for-bug match with the previous
+            # implementation.
+            out(f"{ident}_CLOCKS_CLOCK_FREQUENCY", prim_freq)
+
+    out_comment("Clock gate macros from the 'clocks' property",
+                blank_before=False)
+    for_each_ident(node, write_clocks_for_ident)
 
 
 def str2ident(s):