net: lwm2m: Adds semantics for handling time

This far time values have been synonymous to integer values. Content
formats like CBOR do use different representation.

Signed-off-by: Veijo Pesonen <veijo.pesonen@nordicsemi.no>

subsys/net/lib/lwm2m/lwm2m_engine.c

@@ -2375,7 +2375,6 @@ static int lwm2m_read_handler(struct lwm2m_engine_obj_inst *obj_inst,
 			break;
 
 		case LWM2M_RES_TYPE_U32:
-		case LWM2M_RES_TYPE_TIME:
 			ret = engine_put_s64(&msg->out, &msg->path,
 					     (int64_t)*(uint32_t *)data_ptr);
 			break;
@@ -2410,6 +2409,11 @@ static int lwm2m_read_handler(struct lwm2m_engine_obj_inst *obj_inst,
 					    *(int8_t *)data_ptr);
 			break;
 
+		case LWM2M_RES_TYPE_TIME:
+			ret = engine_put_time(&msg->out, &msg->path,
+					       (int64_t)*(uint32_t *)data_ptr);
+			break;
+
 		case LWM2M_RES_TYPE_BOOL:
 			ret = engine_put_bool(&msg->out, &msg->path,
 					      *(bool *)data_ptr);
@@ -2661,8 +2665,16 @@ int lwm2m_write_handler(struct lwm2m_engine_obj_inst *obj_inst,
 			len = strlen((char *)write_buf);
 			break;
 
-		case LWM2M_RES_TYPE_U32:
 		case LWM2M_RES_TYPE_TIME:
+			ret = engine_get_time(&msg->in, &temp64);
+			if (ret < 0) {
+				break;
+			}
+			*(uint32_t *)write_buf = temp64;
+			len = 4;
+			break;
+
+		case LWM2M_RES_TYPE_U32:
 			ret = engine_get_s64(&msg->in, &temp64);
 			if (ret < 0) {
 				break;

subsys/net/lib/lwm2m/lwm2m_object.h

@@ -500,6 +500,8 @@ struct lwm2m_writer {
 		       struct lwm2m_obj_path *path, int32_t value);
 	int (*put_s64)(struct lwm2m_output_context *out,
 		       struct lwm2m_obj_path *path, int64_t value);
+	int (*put_time)(struct lwm2m_output_context *out,
+		       struct lwm2m_obj_path *path, int64_t value);
 	int (*put_string)(struct lwm2m_output_context *out,
 			  struct lwm2m_obj_path *path, char *buf,
 			  size_t buflen);
@@ -520,6 +522,7 @@ struct lwm2m_writer {
 struct lwm2m_reader {
 	int (*get_s32)(struct lwm2m_input_context *in, int32_t *value);
 	int (*get_s64)(struct lwm2m_input_context *in, int64_t *value);
+	int (*get_time)(struct lwm2m_input_context *in, int64_t *value);
 	int (*get_string)(struct lwm2m_input_context *in, uint8_t *buf,
 			  size_t buflen);
 	int (*get_float)(struct lwm2m_input_context *in, double *value);
@@ -686,6 +689,12 @@ static inline int engine_put_float(struct lwm2m_output_context *out,
 	return out->writer->put_float(out, path, value);
 }
 
+static inline int engine_put_time(struct lwm2m_output_context *out,
+				  struct lwm2m_obj_path *path, int64_t value)
+{
+	return out->writer->put_time(out, path, value);
+}
+
 static inline int engine_put_bool(struct lwm2m_output_context *out,
 				  struct lwm2m_obj_path *path, bool value)
 {
@@ -736,6 +745,11 @@ static inline int engine_get_string(struct lwm2m_input_context *in,
 	return in->reader->get_string(in, buf, buflen);
 }
 
+static inline int engine_get_time(struct lwm2m_input_context *in, int64_t *value)
+{
+	return in->reader->get_time(in, value);
+}
+
 static inline int engine_get_float(struct lwm2m_input_context *in,
 				   double *value)
 {

subsys/net/lib/lwm2m/lwm2m_rw_json.c

@@ -827,6 +827,7 @@ const struct lwm2m_writer json_writer = {
 	.put_s64 = put_s64,
 	.put_string = put_string,
 	.put_float = put_float,
+	.put_time = put_s64,
 	.put_bool = put_bool,
 	.put_objlnk = put_objlnk,
 };
@@ -835,6 +836,7 @@ const struct lwm2m_reader json_reader = {
 	.get_s32 = get_s32,
 	.get_s64 = get_s64,
 	.get_string = get_string,
+	.get_time = get_s64,
 	.get_float = get_float,
 	.get_bool = get_bool,
 	.get_opaque = get_opaque,

subsys/net/lib/lwm2m/lwm2m_rw_oma_tlv.c

@@ -757,6 +757,7 @@ const struct lwm2m_writer oma_tlv_writer = {
 	.put_s64 = put_s64,
 	.put_string = put_string,
 	.put_float = put_float,
+	.put_time = put_s64,
 	.put_bool = put_bool,
 	.put_opaque = put_opaque,
 	.put_objlnk = put_objlnk,
@@ -766,6 +767,7 @@ const struct lwm2m_reader oma_tlv_reader = {
 	.get_s32 = get_s32,
 	.get_s64 = get_s64,
 	.get_string = get_string,
+	.get_time = get_s64,
 	.get_float = get_float,
 	.get_bool = get_bool,
 	.get_opaque = get_opaque,

subsys/net/lib/lwm2m/lwm2m_rw_plain_text.c

@@ -403,6 +403,7 @@ const struct lwm2m_writer plain_text_writer = {
 	.put_s64 = put_s64,
 	.put_string = put_string,
 	.put_float = plain_text_put_float,
+	.put_time = put_s64,
 	.put_bool = put_bool,
 	.put_objlnk = put_objlnk,
 };
@@ -411,6 +412,7 @@ const struct lwm2m_reader plain_text_reader = {
 	.get_s32 = get_s32,
 	.get_s64 = get_s64,
 	.get_string = get_string,
+	.get_time = get_s64,
 	.get_float = get_float,
 	.get_bool = get_bool,
 	.get_opaque = get_opaque,