How To Fill The Addon Setting From Database In Cs Cart

I new to cscart. I need to fill the settings from database for my new addon.
I have below code in my addon.xml
        
            
                
                    
                        header
                    
                    
                        info
                        fn_add_setting_info
                    
                
                    selectbox
                    fn_add_setting_info
                
            
        
    

In func.php
function fn_add_setting_info()
{
$all_datas=get_feature_description();
foreach($all_datas as $val){
$arr_sett[$val[‘feature_id’]]=$val[‘description’];
}
Registry::get(‘view’)->assign(‘option_details’,@$arr_sett);

 }
Here the select box does not fill fn_add_setting_info() data. How can I do . Please help me.
Thanks & Regards
Amelia

Please check reference addon: Email marketing

Check file : app/addons/email_marketing/schemas/settings/actions.functions.post.php
Function Name: fn_settings_variants_addons_email_marketing_em_madmimi_list() // fn_settings_variants_addons_ + addon_id +_+ item_id

For item id:
em_madmimi_list (app/addons/email_marketing/addon.xml)

    selectbox

Please take a look

http://docs.cs-cart.com/4.7.x/developer_guide/addons/scheme/scheme3.0_structure.html