admin.py
class CaseNoteInline(admin.TabularInline):
    model = CaseNote
    form = CaseNoteInlineForm
    extra = 1
    max_num = 5
    readonly_fields = ['User']
    def formfield_for_foreignkey(self, db_field, request, **kwargs):
        if db_field.name == 'User':
            kwargs['initial'] = request.user.id
            return db_field.formfield(**kwargs)
        return super(CaseNoteInline, self).formfield_for_foreignkey(
            db_field, request, **kwargs
        )
i have a some column in CaseNote which is "User" and i want to set default value for that. 