From 76dcec8f4b2c21342e4514a07fd4138ccca8e7eb Mon Sep 17 00:00:00 2001
From: wangchengdong <wangchengdong@lixiang.com>
Date: Fri, 31 Oct 2025 09:33:52 +0800
Subject: [PATCH] Documentation: Add description for early_syslog()

   Add documentation describing the purpose and behavior of early_syslog(),
   which provides a minimal logging facility available during early system
   initialization or system down.

Signed-off-by: Chengdong Wang wangchengdong@lixiang.com
---
 .../components/drivers/special/syslog.rst     | 20 +++++++++++++++++++
 drivers/syslog/Make.defs                      |  2 +-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/Documentation/components/drivers/special/syslog.rst b/Documentation/components/drivers/special/syslog.rst
index 914b7db7d42..d53639bddfb 100644
--- a/Documentation/components/drivers/special/syslog.rst
+++ b/Documentation/components/drivers/special/syslog.rst
@@ -67,6 +67,26 @@ The above are all standard interfaces as defined at
 Those interfaces are available for use by application software.
 The remaining interfaces discussed in this section are non-standard, OS-internal interfaces.
 
+Early Syslog Interfaces
+-----------------------
+
+Provides a minimal SYSLOG output facility that can be used during the
+very early boot phase or when the system is in a down state, before the
+full SYSLOG subsystem or scheduler becomes available.
+
+.. c::function:: void early_syslog(FAR const char *fmt, ...);
+
+  See ``include/nuttx/syslog/syslog.h``.
+  This function provides basic formatted output similar to printf(),
+  and writes the resulting characters directly to the low-level output
+  device via up_putc(). It is primarily intended for debugging or
+  diagnostic messages in early system contexts, where interrupts may
+  be disabled and locking mechanisms are not yet available.
+
+  The function automatically appends a newline character ('\n') if
+  the formatted message does not already end with one, ensuring proper
+  alignment of log output in serial consoles or early boot traces.
+
 Debug Interfaces
 ----------------
 
diff --git a/drivers/syslog/Make.defs b/drivers/syslog/Make.defs
index 45e4d6bfa65..127f96d0eac 100644
--- a/drivers/syslog/Make.defs
+++ b/drivers/syslog/Make.defs
@@ -23,7 +23,7 @@
 ############################################################################
 # Include SYSLOG Infrastructure
 
-if(CONFIG_ARCH_LOWPUTC)
+ifeq ($(CONFIG_ARCH_LOWPUTC),y)
   CSRCS += syslog_early.c
 endif