Add editor toolbar to Metabox

I need to add a custom toolbar (cf. image below) to this Metaboxes

Do you want to add a custom TinyMCE toolbar to the TinyMCE/visual editor, or do you want to turn a textarea into a TinyMCE editor?

If it is the latter one, here’s a sample code for turning the champ_home textarea into a TinyMCE editor:

wp_editor( $val, 'champ_home', array(
    'textarea_name' => 'champ_home',
    'textarea_rows' => '10',
    // TRUE to output the minimal editor config, such as the Comment editor.
    'teeny'         => true,
) );

See:

• https://codex.wordpress.org/Function_Reference/wp_editor
• https://developer.wordpress.org/reference/functions/wp_editor/