Merge pull request #17165 from leandrolanzieri/pr/sys/ztimer_kconfig_entry

sys/ztimer: rework Kconfig

To eliminate circular dependencies based in periph_rtc and xtimer_ztimer_compatibility the following changes are applied:
- Change entrypoint of ztimer as a specific backend is always required
- Add a non-module symbol for ztimer_usec that bring in the ztimer and ztimer_usec module which allows the xtimer ztimer compatibility layer to only select the ztimer_usec module preventing circular dependency issues

examples/twr_aloha/app.config.test

@@ -9,4 +9,4 @@ CONFIG_MODULE_SHELL=y
 CONFIG_MODULE_PS=y
 CONFIG_MODULE_SHELL_COMMANDS=y
 CONFIG_MODULE_ZTIMER=y
-CONFIG_MODULE_ZTIMER_USEC=y
+CONFIG_ZTIMER_USEC=y

sys/xtimer/Kconfig

@@ -7,7 +7,7 @@
 
 menuconfig MODULE_XTIMER
     bool "xtimer"
-    depends on HAS_PERIPH_TIMER || MODULE_XTIMER_ON_ZTIMER || MODULE_ZTIMER_XTIMER_COMPAT
+    depends on HAS_PERIPH_TIMER
     depends on TEST_KCONFIG
 
     # use timer peripheral unless ztimer compatibility module is used

sys/ztimer/Kconfig

@@ -5,15 +5,7 @@
 # directory for more details.
 #
 
-menuconfig MODULE_ZTIMER
-    bool "ztimer - High level timer abstraction layer"
-    depends on TEST_KCONFIG
-    select MODULE_ZTIMER_CORE
-    select MODULE_ZTIMER_CONVERT_FRAC
-    select MODULE_ZTIMER_CONVERT_SHIFT
-    select MODULE_ZTIMER_EXTEND
-
-if MODULE_ZTIMER
+menu "ztimer - High level timer abstraction layer"
 
 config ZTIMER_CUSTOM_BACKEND_CONFIGURATION
     bool "Override default backend selection"
@@ -45,12 +37,21 @@ endmenu # Backends
 
 menu "Clocks"
 
-config MODULE_ZTIMER_USEC
+# TODO: this extra indirection in the entry point for ztimer_usec is required
+# to allow xtimer compatibility modules to depend on ztimer being there while
+# still selecting ztimer_usec.
+config ZTIMER_USEC
     bool "Microseconds"
+    select MODULE_ZTIMER_USEC
+    select MODULE_ZTIMER
+
+config MODULE_ZTIMER_USEC
+    bool
     select MODULE_ZTIMER_PERIPH_TIMER
 
 config MODULE_ZTIMER_MSEC
     bool "Milliseconds"
+    select MODULE_ZTIMER
 
 choice
     bool "Backend"
@@ -70,6 +71,7 @@ endchoice
 
 config MODULE_ZTIMER_SEC
     bool "Seconds"
+    select MODULE_ZTIMER
 
 choice
     bool "Backend"
@@ -95,6 +97,7 @@ endchoice
 endmenu # Clocks
 
 menu "Frequency conversion"
+    depends on MODULE_ZTIMER
 
 config MODULE_ZTIMER_CONVERT_MULDIV64
     bool "64-bits arithmetic conversion"
@@ -132,15 +135,16 @@ menu "xtimer and evtimer compatibility"
 
 choice
     bool "xtimer compatibility"
-    optional
-    depends on MODULE_ZTIMER_USEC
+    depends on MODULE_XTIMER && MODULE_ZTIMER
 
 config MODULE_XTIMER_ON_ZTIMER
     bool "ztimer_usec as timer backend for xtimer"
+    select MODULE_ZTIMER_USEC
 
 config MODULE_ZTIMER_XTIMER_COMPAT
     bool "map xtimer calls to ztimer"
     select MODULE_DIV
+    select MODULE_ZTIMER_USEC
     help
         This is a wrapper of xtimer API on ztimer_usec and is currently
         incomplete. Unless doing testing, use xtimer on ztimer.
@@ -157,6 +161,15 @@ config MODULE_EVTIMER_ON_ZTIMER
 
 endmenu # xtimer compatibility
 
+config MODULE_ZTIMER
+    bool
+    depends on TEST_KCONFIG
+    select MODULE_ZTIMER_CORE
+    select MODULE_ZTIMER_CONVERT_FRAC
+    select MODULE_ZTIMER_CONVERT_SHIFT
+    select MODULE_ZTIMER_EXTEND
+
+if MODULE_ZTIMER
 
 # TODO: only use MODULE_ZTIMER_AUTO_INIT, for now we try to get the same modules
 # as the Makefile dependency resolution. See sys/ztimer/Makefile.dep for more
@@ -191,3 +204,5 @@ config MODULE_ZTIMER_EXTEND
     bool
 
 endif # MODULE_ZTIMER
+
+endmenu

tests/driver_sm_pwm_01c/app.config.test

@@ -2,5 +2,5 @@
 # application configuration. This is only needed during migration.
 CONFIG_MODULE_SM_PWM_01C=y
 CONFIG_MODULE_ZTIMER=y
-CONFIG_MODULE_ZTIMER_USEC=y
+CONFIG_ZTIMER_USEC=y
 CONFIG_MODULE_PROGRESS_BAR=y

tests/pkg_umorse/app.config.test

@@ -1,5 +1,5 @@
 CONFIG_MODULE_POSIX_SLEEP=y
 CONFIG_MODULE_ZTIMER=y
-CONFIG_MODULE_ZTIMER_USEC=y
+CONFIG_ZTIMER_USEC=y
 CONFIG_MODULE_ZTIMER_MSEC=y
 CONFIG_PACKAGE_UMORSE=y

tests/posix_sleep/app.config.test

@@ -1,4 +1,4 @@
 CONFIG_MODULE_POSIX_SLEEP=y
 CONFIG_MODULE_ZTIMER=y
-CONFIG_MODULE_ZTIMER_USEC=y
+CONFIG_ZTIMER_USEC=y
 CONFIG_MODULE_ZTIMER_MSEC=y

tests/ztimer_msg/app.config.test

@@ -1,4 +1,4 @@
 # this file enables modules defined in Kconfig. Do not use this file for
 # application configuration. This is only needed during migration.
 CONFIG_MODULE_ZTIMER=y
-CONFIG_MODULE_ZTIMER_USEC=y
+CONFIG_ZTIMER_USEC=y

tests/ztimer_mutex_lock_timeout/app.config.test

@@ -1,4 +1,4 @@
 # this file enables modules defined in Kconfig. Do not use this file for
 # application configuration. This is only needed during migration.
 CONFIG_MODULE_ZTIMER=y
-CONFIG_MODULE_ZTIMER_USEC=y
+CONFIG_ZTIMER_USEC=y

tests/ztimer_overhead/app.config.test

@@ -1,5 +1,5 @@
 # this file enables modules defined in Kconfig. Do not use this file for
 # application configuration. This is only needed during migration.
 CONFIG_MODULE_ZTIMER=y
-CONFIG_MODULE_ZTIMER_USEC=y
+CONFIG_ZTIMER_USEC=y
 CONFIG_MODULE_ZTIMER_OVERHEAD=y

tests/ztimer_periodic/app.config.test

@@ -1,7 +1,7 @@
 # this file enables modules defined in Kconfig. Do not use this file for
 # application configuration. This is only needed during migration.
 CONFIG_MODULE_ZTIMER=y
-CONFIG_MODULE_ZTIMER_USEC=y
+CONFIG_ZTIMER_USEC=y
 CONFIG_MODULE_ZTIMER_MSEC=y
 
 CONFIG_MODULE_FMT=y

tests/ztimer_rmutex_lock_timeout/app.config.test

@@ -1,5 +1,5 @@
 # this file enables modules defined in Kconfig. Do not use this file for
 # application configuration. This is only needed during migration.
 CONFIG_MODULE_ZTIMER=y
-CONFIG_MODULE_ZTIMER_USEC=y
+CONFIG_ZTIMER_USEC=y
 CONFIG_MODULE_SHELL=y

tests/ztimer_underflow/app.config.test

@@ -1,4 +1,4 @@
 # this file enables modules defined in Kconfig. Do not use this file for
 # application configuration. This is only needed during migration.
 CONFIG_MODULE_ZTIMER=y
-CONFIG_MODULE_ZTIMER_USEC=y
+CONFIG_ZTIMER_USEC=y

tests/ztimer_xsec/app.config.test

@@ -1,7 +1,6 @@
 # this file enables modules defined in Kconfig. Do not use this file for
 # application configuration. This is only needed during migration.
-CONFIG_MODULE_ZTIMER=y
 CONFIG_MODULE_ZTIMER_PERIPH_TIMER=y
-CONFIG_MODULE_ZTIMER_USEC=y
+CONFIG_ZTIMER_USEC=y
 CONFIG_MODULE_ZTIMER_MSEC=y
 CONFIG_MODULE_ZTIMER_SEC=y