diff --git a/drivers/atmodem/sim.c b/drivers/atmodem/sim.c
index b6f34c20..775ce60e 100644
--- a/drivers/atmodem/sim.c
+++ b/drivers/atmodem/sim.c
@@ -399,24 +399,24 @@ error:
 }
 
 static struct {
-	enum ofono_passwd_type type;
+	enum ofono_sim_password_type type;
 	const char *name;
 } const at_sim_name[] = {
-	{ OFONO_PASSWD_SIM_PIN, "SIM PIN" },
-	{ OFONO_PASSWD_SIM_PUK, "SIM PUK" },
-	{ OFONO_PASSWD_PHSIM_PIN, "PH-SIM PIN" },
-	{ OFONO_PASSWD_PHFSIM_PIN, "PH-FSIM PIN" },
-	{ OFONO_PASSWD_PHFSIM_PUK, "PH-FSIM PUK" },
-	{ OFONO_PASSWD_SIM_PIN2, "SIM PIN2" },
-	{ OFONO_PASSWD_SIM_PUK2, "SIM PUK2" },
-	{ OFONO_PASSWD_PHNET_PIN, "PH-NET PIN" },
-	{ OFONO_PASSWD_PHNET_PUK, "PH-NET PUK" },
-	{ OFONO_PASSWD_PHNETSUB_PIN, "PH-NETSUB PIN" },
-	{ OFONO_PASSWD_PHNETSUB_PUK, "PH-NETSUB PUK" },
-	{ OFONO_PASSWD_PHSP_PIN, "PH-SP PIN" },
-	{ OFONO_PASSWD_PHSP_PUK, "PH-SP PUK" },
-	{ OFONO_PASSWD_PHCORP_PIN, "PH-CORP PIN" },
-	{ OFONO_PASSWD_PHCORP_PUK, "PH-CORP PUK" },
+	{ OFONO_SIM_PASSWORD_SIM_PIN, "SIM PIN" },
+	{ OFONO_SIM_PASSWORD_SIM_PUK, "SIM PUK" },
+	{ OFONO_SIM_PASSWORD_PHSIM_PIN, "PH-SIM PIN" },
+	{ OFONO_SIM_PASSWORD_PHFSIM_PIN, "PH-FSIM PIN" },
+	{ OFONO_SIM_PASSWORD_PHFSIM_PUK, "PH-FSIM PUK" },
+	{ OFONO_SIM_PASSWORD_SIM_PIN2, "SIM PIN2" },
+	{ OFONO_SIM_PASSWORD_SIM_PUK2, "SIM PUK2" },
+	{ OFONO_SIM_PASSWORD_PHNET_PIN, "PH-NET PIN" },
+	{ OFONO_SIM_PASSWORD_PHNET_PUK, "PH-NET PUK" },
+	{ OFONO_SIM_PASSWORD_PHNETSUB_PIN, "PH-NETSUB PIN" },
+	{ OFONO_SIM_PASSWORD_PHNETSUB_PUK, "PH-NETSUB PUK" },
+	{ OFONO_SIM_PASSWORD_PHSP_PIN, "PH-SP PIN" },
+	{ OFONO_SIM_PASSWORD_PHSP_PUK, "PH-SP PUK" },
+	{ OFONO_SIM_PASSWORD_PHCORP_PIN, "PH-CORP PIN" },
+	{ OFONO_SIM_PASSWORD_PHCORP_PUK, "PH-CORP PUK" },
 };
 
 static void at_cpin_cb(gboolean ok, GAtResult *result, gpointer user_data)
@@ -426,7 +426,7 @@ static void at_cpin_cb(gboolean ok, GAtResult *result, gpointer user_data)
 	ofono_sim_passwd_cb_t cb = cbd->cb;
 	struct ofono_error error;
 	const char *pin_required;
-	int pin_type;
+	int pin_type = OFONO_SIM_PASSWORD_INVALID;
 	int i;
 	int len = sizeof(at_sim_name) / sizeof(*at_sim_name);
 
@@ -449,7 +449,7 @@ static void at_cpin_cb(gboolean ok, GAtResult *result, gpointer user_data)
 
 	pin_type = -1;
 	if (!strcmp(pin_required, "READY"))
-		pin_type = OFONO_PASSWD_NONE;
+		pin_type = OFONO_SIM_PASSWD_NONE;
 	else
 		for (i = 0; i < len; i++)
 			if (!strcmp(pin_required, at_sim_name[i].name)) {
@@ -457,7 +457,7 @@ static void at_cpin_cb(gboolean ok, GAtResult *result, gpointer user_data)
 				break;
 			}
 
-	if (pin_type == -1) {
+	if (pin_type == OFONO_SIM_PASSWORD_INVALID) {
 		CALLBACK_WITH_FAILURE(cb, -1, cbd->data);
 		return;
 	}
@@ -556,14 +556,14 @@ error:
 }
 
 static const char *const at_clck_cpwd_fac[] = {
-	[OFONO_PASSWD_SIM_PIN] = "SC",
-	[OFONO_PASSWD_SIM_PIN2] = "P2",
-	[OFONO_PASSWD_PHSIM_PIN] = "PS",
-	[OFONO_PASSWD_PHFSIM_PIN] = "PF",
-	[OFONO_PASSWD_PHNET_PIN] = "PN",
-	[OFONO_PASSWD_PHNETSUB_PIN] = "PU",
-	[OFONO_PASSWD_PHSP_PIN] = "PP",
-	[OFONO_PASSWD_PHCORP_PIN] = "PC",
+	[OFONO_SIM_PASSWORD_SIM_PIN] = "SC",
+	[OFONO_SIM_PASSWORD_SIM_PIN2] = "P2",
+	[OFONO_SIM_PASSWORD_PHSIM_PIN] = "PS",
+	[OFONO_SIM_PASSWORD_PHFSIM_PIN] = "PF",
+	[OFONO_SIM_PASSWORD_PHNET_PIN] = "PN",
+	[OFONO_SIM_PASSWORD_PHNETSUB_PIN] = "PU",
+	[OFONO_SIM_PASSWORD_PHSP_PIN] = "PP",
+	[OFONO_SIM_PASSWORD_PHCORP_PIN] = "PC",
 };
 
 static void at_pin_enable(struct ofono_sim *sim, int passwd_type, int enable,
@@ -600,7 +600,8 @@ error:
 	CALLBACK_WITH_FAILURE(cb, data);
 }
 
-static void at_change_passwd(struct ofono_sim *sim, int passwd_type,
+static void at_change_passwd(struct ofono_sim *sim,
+			enum ofono_sim_password_type passwd_type,
 			const char *old, const char *new,
 			ofono_sim_lock_unlock_cb_t cb, void *data)
 {
@@ -608,12 +609,12 @@ static void at_change_passwd(struct ofono_sim *sim, int passwd_type,
 	struct cb_data *cbd = cb_data_new(cb, data);
 	char buf[64];
 	int ret;
-	int len = sizeof(at_clck_cpwd_fac) / sizeof(*at_clck_cpwd_fac);
+	unsigned int len = sizeof(at_clck_cpwd_fac) / sizeof(*at_clck_cpwd_fac);
 
 	if (!cbd)
 		goto error;
 
-	if (passwd_type < 0 || passwd_type >= len ||
+	if (passwd_type >= len ||
 			!at_clck_cpwd_fac[passwd_type])
 		goto error;
 
diff --git a/include/sim.h b/include/sim.h
index eaa227dd..3d618270 100644
--- a/include/sim.h
+++ b/include/sim.h
@@ -37,23 +37,24 @@ enum ofono_sim_file_structure {
 	OFONO_SIM_FILE_STRUCTURE_CYCLIC = 3
 };
 
-enum ofono_passwd_type {
-	OFONO_PASSWD_NONE = 0,
-	OFONO_PASSWD_SIM_PIN,
-	OFONO_PASSWD_SIM_PUK,
-	OFONO_PASSWD_PHSIM_PIN,
-	OFONO_PASSWD_PHFSIM_PIN,
-	OFONO_PASSWD_PHFSIM_PUK,
-	OFONO_PASSWD_SIM_PIN2,
-	OFONO_PASSWD_SIM_PUK2,
-	OFONO_PASSWD_PHNET_PIN,
-	OFONO_PASSWD_PHNET_PUK,
-	OFONO_PASSWD_PHNETSUB_PIN,
-	OFONO_PASSWD_PHNETSUB_PUK,
-	OFONO_PASSWD_PHSP_PIN,
-	OFONO_PASSWD_PHSP_PUK,
-	OFONO_PASSWD_PHCORP_PIN,
-	OFONO_PASSWD_PHCORP_PUK,
+enum ofono_sim_password_type {
+	OFONO_SIM_PASSWORD_NONE = 0,
+	OFONO_SIM_PASSWORD_SIM_PIN,
+	OFONO_SIM_PASSWORD_PHSIM_PIN,
+	OFONO_SIM_PASSWORD_PHFSIM_PIN,
+	OFONO_SIM_PASSWORD_SIM_PIN2,
+	OFONO_SIM_PASSWORD_PHNET_PIN,
+	OFONO_SIM_PASSWORD_PHNETSUB_PIN,
+	OFONO_SIM_PASSWORD_PHSP_PIN,
+	OFONO_SIM_PASSWORD_PHCORP_PIN,
+	OFONO_SIM_PASSWORD_SIM_PUK,
+	OFONO_SIM_PASSWORD_PHFSIM_PUK,
+	OFONO_SIM_PASSWORD_SIM_PUK2,
+	OFONO_SIM_PASSWORD_PHNET_PUK,
+	OFONO_SIM_PASSWORD_PHNETSUB_PUK,
+	OFONO_SIM_PASSWORD_PHSP_PUK,
+	OFONO_SIM_PASSWORD_PHCORP_PUK,
+	OFONO_SIM_PASSWORD_INVALID,
 };
 
 typedef void (*ofono_sim_file_info_cb_t)(const struct ofono_error *error,
@@ -122,7 +123,8 @@ struct ofono_sim_driver {
 	void (*reset_passwd)(struct ofono_sim *sim, const char *puk,
 			const char *passwd,
 			ofono_sim_lock_unlock_cb_t cb, void *data);
-	void (*change_passwd)(struct ofono_sim *sim, int passwd_type,
+	void (*change_passwd)(struct ofono_sim *sim,
+			enum ofono_sim_password_type type,
 			const char *old, const char *new,
 			ofono_sim_lock_unlock_cb_t cb, void *data);
 	void (*lock)(struct ofono_sim *sim, int passwd_type, int enable,
diff --git a/src/sim.c b/src/sim.c
index 19be299a..d4a920b9 100644
--- a/src/sim.c
+++ b/src/sim.c
@@ -113,30 +113,30 @@ struct service_number {
 };
 
 static const char *const passwd_name[] = {
-	[OFONO_PASSWD_NONE] = "none",
-	[OFONO_PASSWD_SIM_PIN] = "pin",
-	[OFONO_PASSWD_SIM_PUK] = "puk",
-	[OFONO_PASSWD_PHSIM_PIN] = "phone",
-	[OFONO_PASSWD_PHFSIM_PIN] = "firstphone",
-	[OFONO_PASSWD_PHFSIM_PUK] = "firstphonepuk",
-	[OFONO_PASSWD_SIM_PIN2] = "pin2",
-	[OFONO_PASSWD_SIM_PUK2] = "puk2",
-	[OFONO_PASSWD_PHNET_PIN] = "network",
-	[OFONO_PASSWD_PHNET_PUK] = "networkpuk",
-	[OFONO_PASSWD_PHNETSUB_PIN] = "netsub",
-	[OFONO_PASSWD_PHNETSUB_PUK] = "netsubpuk",
-	[OFONO_PASSWD_PHSP_PIN] = "service",
-	[OFONO_PASSWD_PHSP_PUK] = "servicepuk",
-	[OFONO_PASSWD_PHCORP_PIN] = "corp",
-	[OFONO_PASSWD_PHCORP_PUK] = "corppuk",
+	[OFONO_SIM_PASSWORD_NONE] = "none",
+	[OFONO_SIM_PASSWORD_SIM_PIN] = "pin",
+	[OFONO_SIM_PASSWORD_SIM_PUK] = "puk",
+	[OFONO_SIM_PASSWORD_PHSIM_PIN] = "phone",
+	[OFONO_SIM_PASSWORD_PHFSIM_PIN] = "firstphone",
+	[OFONO_SIM_PASSWORD_PHFSIM_PUK] = "firstphonepuk",
+	[OFONO_SIM_PASSWORD_SIM_PIN2] = "pin2",
+	[OFONO_SIM_PASSWORD_SIM_PUK2] = "puk2",
+	[OFONO_SIM_PASSWORD_PHNET_PIN] = "network",
+	[OFONO_SIM_PASSWORD_PHNET_PUK] = "networkpuk",
+	[OFONO_SIM_PASSWORD_PHNETSUB_PIN] = "netsub",
+	[OFONO_SIM_PASSWORD_PHNETSUB_PUK] = "netsubpuk",
+	[OFONO_SIM_PASSWORD_PHSP_PIN] = "service",
+	[OFONO_SIM_PASSWORD_PHSP_PUK] = "servicepuk",
+	[OFONO_SIM_PASSWORD_PHCORP_PIN] = "corp",
+	[OFONO_SIM_PASSWORD_PHCORP_PUK] = "corppuk",
 };
 
-static const char *sim_passwd_name(enum ofono_passwd_type type)
+static const char *sim_passwd_name(enum ofono_sim_password_type type)
 {
 	return passwd_name[type];
 }
 
-static enum ofono_passwd_type sim_string_to_passwd(const char *name)
+static enum ofono_sim_password_type sim_string_to_passwd(const char *name)
 {
 	int len = sizeof(passwd_name) / sizeof(*passwd_name);
 	int i;
@@ -145,7 +145,7 @@ static enum ofono_passwd_type sim_string_to_passwd(const char *name)
 		if (!strcmp(passwd_name[i], name))
 			return i;
 
-	return OFONO_PASSWD_NONE;
+	return OFONO_SIM_PASSWORD_INVALID;
 }
 
 static char **get_own_numbers(GSList *own_numbers)
@@ -450,7 +450,7 @@ static DBusMessage *sim_change_pin(DBusConnection *conn, DBusMessage *msg,
 	struct ofono_sim *sim = data;
 	struct pin_enable_request *req;
 	DBusMessageIter iter;
-	enum ofono_passwd_type type;
+	enum ofono_sim_password_type type;
 	const char *typestr;
 	const char *old;
 	const char *new;
@@ -467,7 +467,8 @@ static DBusMessage *sim_change_pin(DBusConnection *conn, DBusMessage *msg,
 	dbus_message_iter_get_basic(&iter, &typestr);
 
 	type = sim_string_to_passwd(typestr);
-	if (type == OFONO_PASSWD_NONE)
+	if (type == OFONO_SIM_PASSWORD_NONE ||
+			type == OFONO_SIM_PASSWORD_INVALID)
 		return __ofono_error_invalid_format(msg);
 
 	dbus_message_iter_next(&iter);
@@ -553,7 +554,7 @@ static DBusMessage *sim_enter_pin(DBusConnection *conn, DBusMessage *msg,
 	dbus_message_iter_get_basic(&iter, &typestr);
 
 	type = sim_string_to_passwd(typestr);
-	if (type == OFONO_PASSWD_NONE || type != sim->pin_type)
+	if (type == OFONO_SIM_PASSWORD_NONE || type != sim->pin_type)
 		return __ofono_error_invalid_format(msg);
 
 	dbus_message_iter_next(&iter);
@@ -596,7 +597,7 @@ static DBusMessage *sim_reset_pin(DBusConnection *conn, DBusMessage *msg,
 	dbus_message_iter_get_basic(&iter, &typestr);
 
 	type = sim_string_to_passwd(typestr);
-	if (type == OFONO_PASSWD_NONE || type != sim->pin_type)
+	if (type == OFONO_SIM_PASSWORD_NONE || type != sim->pin_type)
 		return __ofono_error_invalid_format(msg);
 
 	dbus_message_iter_next(&iter);
@@ -889,7 +890,7 @@ static void sim_retrieve_imsi(struct ofono_sim *sim)
 }
 
 static void sim_pin_query_cb(const struct ofono_error *error, int pin_type,
-		void *data)
+				void *data)
 {
 	struct ofono_sim *sim = data;
 	DBusConnection *conn = ofono_dbus_get_connection();
@@ -914,7 +915,7 @@ static void sim_pin_query_cb(const struct ofono_error *error, int pin_type,
 	}
 
 checkdone:
-	if (pin_type == OFONO_PASSWD_NONE)
+	if (pin_type == OFONO_SIM_PASSWORD_NONE)
 		sim_retrieve_imsi(sim);
 }