sub parse_csv {
my $text = shift; # record containing cs values
my @new = ();
push(@new, $+) while $text =~m{
#the first part groups the phrase inside the quotes
#see expl of this pattern in MRE
"([^\"\\]*(?:\\.[^\"\\]*)*)",?
|  ([^,]+),?
| ,
}gx;
push(@new,undef) if substr($text, -1,1) eq ',';
return @new; #list of values that were comma separated
}

or standard module
use Text::ParseWords; 
sub parse_csv { return quoteword(",",0,$_[0]); }