Add setting for SNTP server

components/settings/settings.c

@@ -23,6 +23,7 @@ typedef enum {
 	SSID,
 	PSK,
 	TIMEZONE,
+	SNTP_SERVER,
 	ITEM_COUNT,
 } ItemIndex;
 
@@ -53,6 +54,10 @@ static Item state[ITEM_COUNT] = {
 		.id = "timezone",
 		.default_value = CONFIG_DEFAULT_TIMEZONE,
 	},
+	[SNTP_SERVER] = {
+		.id = "sntp-server",
+		.default_value = CONFIG_DEFAULT_SNTP_SERVER,
+	},
 };
 
 static bool load(ItemIndex item)
@@ -281,3 +286,18 @@ void settings_add_timezone_callback(SettingsCallback callback)
 {
 	add_callback(TIMEZONE, callback);
 }
+
+void settings_set_sntp_server(const char *sntp_server)
+{
+	set(SNTP_SERVER, sntp_server);
+}
+
+size_t settings_get_sntp_server(char *buffer, size_t buffer_size)
+{
+	return get(SNTP_SERVER, buffer, buffer_size);
+}
+
+void settings_add_sntp_server_callback(SettingsCallback callback)
+{
+	add_callback(SNTP_SERVER, callback);
+}

components/settings/settings.h

@@ -136,4 +136,32 @@ size_t settings_get_timezone(char *buffer, size_t buffer_size);
  */
 void settings_add_timezone_callback(SettingsCallback callback);
 
+/**
+ * Set the SNTP server URL.
+ *
+ * The argument should be a null-terminated string, containing a valid
+ * domain name for an SNTP server. If the maximum length is exceeded,
+ * the value will still be used, but will be truncated.
+ */
+void settings_set_sntp_server(const char *sntp_server);
+
+/**
+ * Write the SNTP server URL into the given buffer.
+ *
+ * The length of the SNTP server domain is returned. If the value's
+ * size exceeds the size of the buffer, nothing will be written to the
+ * buffer but the length is still returned.
+ */
+size_t settings_get_sntp_server(char *buffer, size_t buffer_size);
+
+/**
+ * Add a callback for SNTP server URL updates.
+ *
+ * The function specified in the argument will be invoked whenever the
+ * SNTP server is updated, with the new value as its argument. The
+ * lifetime of the passed argument will be static, but the value may
+ * be modified once the callback returns.
+ */
+void settings_add_sntp_server_callback(SettingsCallback callback);
+
 #endif

main/Kconfig.projbuild

@@ -11,6 +11,9 @@ menu "Bedside clock settings"
      config DEFAULT_TIMEZONE
             string "Default timezone"
             default "Europe/London"
+     config DEFAULT_SNTP_SERVER
+            string "Default SNTP server domain"
+            default "pool.ntp.org"
      config WIFI_MAX_RETRIES
             int "Maximum number of times to retry connecting to WiFi network"
             default 10