logging: allow simplified logging of backend

This allows no timestamps and level prefixes in backend log output.

Signed-off-by: Shawn Huang <[email protected]>

Author: Shawn-Huang724

doc/services/logging/index.rst

@@ -181,6 +181,11 @@ with function name. Hexdump messages are not prepended.
 :kconfig:option:`CONFIG_LOG_FUNC_NAME_PREFIX_DBG`: Prepend standard DEBUG log messages
 with function name. Hexdump messages are not prepended.
 
+:kconfig:option:`CONFIG_LOG_BACKEND_SHOW_TIMESTAMP`: Enables backend to print timestamps
+with log.
+
+:kconfig:option:`CONFIG_LOG_BACKEND_SHOW_LEVEL`: Enables backend to print levels with log.
+
 :kconfig:option:`CONFIG_LOG_BACKEND_SHOW_COLOR`: Enables coloring of errors (red)
 and warnings (yellow).
 

include/zephyr/logging/log_backend_std.h

@@ -23,7 +23,15 @@ extern "C" {
 
 static inline uint32_t log_backend_std_get_flags(void)
 {
-	uint32_t flags = (LOG_OUTPUT_FLAG_LEVEL | LOG_OUTPUT_FLAG_TIMESTAMP);
+	uint32_t flags = 0;
+
+	if (IS_ENABLED(CONFIG_LOG_BACKEND_SHOW_TIMESTAMP)) {
+		flags |= LOG_OUTPUT_FLAG_TIMESTAMP;
+	}
+
+	if (IS_ENABLED(CONFIG_LOG_BACKEND_SHOW_LEVEL)) {
+		flags |= LOG_OUTPUT_FLAG_LEVEL;
+	}
 
 	if (IS_ENABLED(CONFIG_LOG_BACKEND_SHOW_COLOR)) {
 		flags |= LOG_OUTPUT_FLAG_COLORS;

subsys/logging/Kconfig.formatting

@@ -132,6 +132,18 @@ config LOG_IMMEDIATE_CLEAN_OUTPUT
 	  this option is causing interrupts locking for significant amount of
 	  time (up to multiple milliseconds).
 
+config LOG_BACKEND_SHOW_TIMESTAMP
+	bool "Timestamps in the backend"
+	default y
+	help
+	  When enabled, selected backend prints timestamps with log.
+
+config LOG_BACKEND_SHOW_LEVEL
+	bool "Levels in the backend"
+	default y
+	help
+	  When enabled, selected backend prints levels with log.
+
 config LOG_BACKEND_SHOW_COLOR
 	bool "Colors in the backend"
 	default y if LOG_BACKEND_UART || LOG_BACKEND_NATIVE_POSIX || LOG_BACKEND_RTT \
@@ -172,7 +184,7 @@ config LOG_BACKEND_SUPPORTS_FORMAT_TIMESTAMP
 config LOG_BACKEND_FORMAT_TIMESTAMP
 	bool "Timestamp formatting in the backend"
 	depends on LOG_BACKEND_SUPPORTS_FORMAT_TIMESTAMP
-	default y
+	default y if LOG_BACKEND_SHOW_TIMESTAMP
 	help
 	  When enabled timestamp is formatted.