net: lwm2m: add missing application type to IPSO Light Control

Per IPSO Light Control definition from the OMA LwM2M registry:
http://www.openmobilealliance.org/tech/profiles/lwm2m/3311.xml

There is an optional "Application Type" string resource (5750) in the
Light Control object.  This was missed in the initial implementation.

NOTE: sample will assign reference if needed.

Signed-off-by: Michael Scott <mike@foundries.io>

samples/net/lwm2m_client/src/lwm2m-client.c

@@ -46,6 +46,7 @@ LOG_MODULE_REGISTER(LOG_MODULE_NAME);
 #define CLIENT_DEVICE_TYPE	"OMA-LWM2M Client"
 #define CLIENT_HW_VER		"1.0.1"
 
+#define LIGHT_NAME		"Test light"
 #define TIMER_NAME		"Test timer"
 
 #define ENDPOINT_LEN		32
@@ -337,6 +338,9 @@ static int lwm2m_setup(void)
 		lwm2m_engine_create_obj_inst("3311/0");
 		lwm2m_engine_register_post_write_callback("3311/0/5850",
 				led_on_off_cb);
+		lwm2m_engine_set_res_data("3311/0/5750",
+					  LIGHT_NAME, sizeof(LIGHT_NAME),
+					  LWM2M_RES_DATA_FLAG_RO);
 	}
 
 	/* IPSO: Timer object */

subsys/net/lib/lwm2m/ipso_light_control.c

@@ -31,8 +31,9 @@ LOG_MODULE_REGISTER(LOG_MODULE_NAME);
 #define LIGHT_POWER_FACTOR_ID			5820
 #define LIGHT_COLOUR_ID				5706
 #define LIGHT_SENSOR_UNITS_ID			5701
+#define LIGHT_APPLICATION_TYPE_ID		5750
 
-#define LIGHT_MAX_ID		7
+#define LIGHT_MAX_ID		8
 
 #define MAX_INSTANCE_COUNT	CONFIG_LWM2M_IPSO_LIGHT_CONTROL_INSTANCE_COUNT
 
@@ -58,6 +59,7 @@ static struct lwm2m_engine_obj_field fields[] = {
 	OBJ_FIELD_DATA(LIGHT_POWER_FACTOR_ID, R_OPT, FLOAT32),
 	OBJ_FIELD_DATA(LIGHT_COLOUR_ID, RW_OPT, STRING),
 	OBJ_FIELD_DATA(LIGHT_SENSOR_UNITS_ID, R_OPT, STRING),
+	OBJ_FIELD_DATA(LIGHT_APPLICATION_TYPE_ID, RW_OPT, STRING),
 };
 
 static struct lwm2m_engine_obj_inst inst[MAX_INSTANCE_COUNT];
@@ -166,6 +168,7 @@ static struct lwm2m_engine_obj_inst *light_control_create(u16_t obj_inst_id)
 		colour[avail], LIGHT_STRING_LONG);
 	INIT_OBJ_RES_DATA(res[avail], i, LIGHT_SENSOR_UNITS_ID,
 		units[avail], LIGHT_STRING_SHORT);
+	INIT_OBJ_RES_DUMMY(res[avail], i, LIGHT_APPLICATION_TYPE_ID);
 
 	inst[avail].resources = res[avail];
 	inst[avail].resource_count = i;