diff --git a/include/mbedtls/pk.h b/include/mbedtls/pk.h
index b481e43..3f64093 100644
--- a/include/mbedtls/pk.h
+++ b/include/mbedtls/pk.h
@@ -249,7 +249,7 @@
  * \brief           Initialize a PK context to wrap a PSA key slot.
  *
  * \param ctx       Context to initialize. Must be empty (type NONE).
- * \param key       PSA key slot to wrap.
+ * \param key       PSA key slot to wrap - must hold an ECC keypair.
  *
  * \note            The wrapped key slot must remain valid as long as the
  *                  wrapping PK context is in use, that is at least between
@@ -257,13 +257,19 @@
  *                  mbedtls_pk_free() is called on this context. The wrapped
  *                  key slot might then be independently used or destroyed.
  *
- * \return          0 on success,
- *                  MBEDTLS_ERR_PK_BAD_INPUT_DATA on invalid input,
- *                  MBEDTLS_ERR_PK_ALLOC_FAILED on allocation failure.
+ * \return          \c 0 on success,
+ * \return          #MBEDTLS_ERR_PK_BAD_INPUT_DATA on invalid input
+ *                  (context already used, invalid key slot)
+ * \return          #MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE if the key is not an
+ *                  ECC keypair,
+ * \return          #MBEDTLS_ERR_PK_ALLOC_FAILED on allocation failure.
  *
  * \note            This function replaces mbedtls_pk_setup() for contexts
  *                  that wrap a (possibly opaque) PSA key slot instead of
  *                  storing and manipulating the key material directly.
+ *
+ * \note            This function is currently only available for ECC keypair.
+ *                  Support for other key types will be added later.
  */
 int mbedtls_pk_setup_psa( mbedtls_pk_context *ctx, const psa_key_slot_t key );
 #endif /* MBEDTLS_USE_PSA_CRYPTO */