fixup! doc: Document various LwM2M

Co-authored-by: Pekka Niskanen <73991005+peknis@users.noreply.github.com>

doc/connectivity/networking/api/lwm2m.rst

@@ -370,37 +370,38 @@ LwM2M security modes
 ********************
 
 The Zephyr LwM2M library can be used either without security or use DTLS to secure the communication channel.
-When using DTLS with LwM2M engine, PSK (Pre-Shared Key) and X.509 certificates are two security modes that can be used to secure the communication.
-The engine uses LwM2M Security object (Id 0) to read stored credentials and feed keys from security object into
+When using DTLS with the LwM2M engine, PSK (Pre-Shared Key) and X.509 certificates are the security modes that can be used to secure the communication.
+The engine uses LwM2M Security object (Id 0) to read the stored credentials and feed keys from the security object into
 the TLS credential subsystem, see :ref:`secure sockets documentation <secure_sockets_interface>`.
-When security is used :kconfig:option:`CONFIG_LWM2M_DTLS_SUPPORT` Kconfig option must be enabled.
+Enable the :kconfig:option:`CONFIG_LWM2M_DTLS_SUPPORT` Kconfig option to use the security.
 
-Depending on the selected mode, security object should contain following data:
+Depending on the selected mode, the security object must contain following data:
 
 PSK
-  Security Mode (Resource ID 2) should be set to zero (Pre-Shared Key mode).
+  Security Mode (Resource ID 2) set to zero (Pre-Shared Key mode).
   Identity (Resource ID 3) contains PSK ID in binary form.
   Secret key (Resource ID 5) contains the PSK key in binary form.
-  If key or identity is provided as a hex string, it must be converted to binary before storing into security object.
+  If the key or identity is provided as a hex string, it must be converted to binary before storing into the security object.
 
 X509
-  When X509 certificates are used, Security Mode (ID 2) should be set to 2 (Certificate mode).
+  When X509 certificates are used, set Security Mode (ID 2) to ``2`` (Certificate mode).
   Identity (ID 3) is used to store the client certificate and Secret key (ID 5) must have a private key associated with the certificate.
   Server Public Key resource (ID 4) must contain a server certificate or CA certificate used to sign the certificate chain.
-  If :kconfig:option:`CONFIG_MBEDTLS_PEM_CERTIFICATE_FORMAT` is enabled, certificates and private key can be fed as a PEM format. Otherwise they must be in binary DER format.
+  If the :kconfig:option:`CONFIG_MBEDTLS_PEM_CERTIFICATE_FORMAT` Kconfig option is enabled, certificates and private key can be entered in PEM format.
+  Otherwise, they must be in binary DER format.
 
 NoSec
-  When no security is used, Security Mode (Resource ID 2) should be set to value 3 (NoSec).
+  When no security is used, set Security Mode (Resource ID 2) to ``3`` (NoSec).
 
-In all modes above, Server URI resource (ID 0) should contain full URI for the target server.
-When DNS names are used, DNS resolver should be enabled.
+In all modes, Server URI resource (ID 0) must contain the full URI for the target server.
+When DNS names are used, the DNS resolver must be enabled.
 
-LwM2M stack provides callbacks in :c:struct:`lwm2m_ctx` structure that are used to feed keys from
-LwM2M security object into the TLS credential subsystem. By default, these callbacks can be left
-as NULL pointers, in which case default callbacks are used. When external TLS stack, or non default
-socket options are required, user may overwrite the :c:func:`lwm2m_ctx.load_credentials` or :c:func:`lwm2m_ctx.set_socketoptions` callbacks.
+LwM2M stack provides callbacks in the :c:struct:`lwm2m_ctx` structure.
+They are used to feed keys from the LwM2M security object into the TLS credential subsystem.
+By default, these callbacks can be left as NULL pointers, in which case default callbacks are used.
+When an external TLS stack, or non-default socket options are required, you can overwrite the :c:func:`lwm2m_ctx.load_credentials` or :c:func:`lwm2m_ctx.set_socketoptions` callbacks.
 
-Example of setting up the security object for PSK mode:
+An example of setting up the security object for PSK mode:
 
 .. code-block:: c
 
@@ -419,7 +420,7 @@ Example of setting up the security object for PSK mode:
 	/* Set the client pre-shared key (PSK) */
 	lwm2m_set_opaque(&LWM2M_OBJ(LWM2M_OBJECT_SECURITY_ID, 0, 5), client_psk, sizeof(client_psk));
 
-Example of setting up the security object for X509 certificate mode:
+An example of setting up the security object for X509 certificate mode:
 
 .. code-block:: c
 

include/zephyr/net/lwm2m.h

@@ -2253,7 +2253,7 @@ enum lwm2m_security_mode_e {
 /**
  * @brief Read security mode from selected security object instance.
  *
- * This data is only valid if RD client is running.
+ * This data is valid only if RD client is running.
  *
  * @param ctx Pointer to client context.
  * @return int Positive values are @ref lwm2m_security_mode_e, negative error codes otherwise.
@@ -2263,8 +2263,8 @@ int lwm2m_security_mode(struct lwm2m_ctx *ctx);
 /**
  * @brief Set default socket options for DTLS connections.
  *
- * Engine calls this when @ref lwm2m_ctx::set_socketoptions is not overwritten.
- * You may call this from overwritten callback to set extra options after or
+ * The engine calls this when @ref lwm2m_ctx::set_socketoptions is not overwritten.
+ * You can call this from the overwritten callback to set extra options after or
  * before defaults.
  *
  * @param ctx Client context