cellular: extend registration status definitions

Extend the registration status definitions and explicitly tie them to
the values defined in 3GPP TS 27.007. Definitions were copied from
version v18.6.0.

Signed-off-by: Jordan Yates <[email protected]>

Author: JordanYates

doc/releases/migration-guide-4.3.rst

@@ -225,6 +225,7 @@ Cellular
 ========
 
  * :c:enum:`cellular_access_technology` values have been redefined to align with 3GPP TS 27.007.
+ * :c:enum:`cellular_registration_status` values have been extended to align with 3GPP TS 27.007.
 
 Logging
 =======

include/zephyr/drivers/cellular.h

@@ -105,13 +105,32 @@ enum cellular_modem_info_type {
 	CELLULAR_MODEM_INFO_SIM_ICCID,
 };
 
+/** Cellular registration status (3GPP TS 27.007) */
 enum cellular_registration_status {
+	/** Not registered, not searching */
 	CELLULAR_REGISTRATION_NOT_REGISTERED = 0,
-	CELLULAR_REGISTRATION_REGISTERED_HOME,
-	CELLULAR_REGISTRATION_SEARCHING,
-	CELLULAR_REGISTRATION_DENIED,
-	CELLULAR_REGISTRATION_UNKNOWN,
-	CELLULAR_REGISTRATION_REGISTERED_ROAMING,
+	/** Registered, home network */
+	CELLULAR_REGISTRATION_REGISTERED_HOME = 1,
+	/** Not registered, searching for an operator */
+	CELLULAR_REGISTRATION_SEARCHING = 2,
+	/** Registration denied */
+	CELLULAR_REGISTRATION_DENIED = 3,
+	/** Unknown (e.g. out of coverage) */
+	CELLULAR_REGISTRATION_UNKNOWN = 4,
+	/** Registered, roaming */
+	CELLULAR_REGISTRATION_REGISTERED_ROAMING = 5,
+	/** Registered for "SMS only", home network */
+	CELLULAR_REGISTRATION_SMS_ONLY_HOME = 6,
+	/** Registered for "SMS only", roaming network */
+	CELLULAR_REGISTRATION_SMS_ONLY_ROAMING = 7,
+	/** Attached for emergency bearer services only */
+	CELLULAR_REGISTRATION_EMERGENCY_ONLY = 8,
+	/** Registered for "CSFB not preferred", home network */
+	CELLULAR_REGISTRATION_CSFB_NOT_PREFERRED_HOME = 9,
+	/** Registered for "CSFB not preferred", roaming network */
+	CELLULAR_REGISTRATION_CSFB_NOT_PREFERRED_ROAMING = 10,
+	/** Attached for access to "Restricted Local Operator Services" */
+	CELLULAR_REGISTRATION_RLOS = 11,
 };
 
 /** Events emitted asynchronously by a cellular driver */