It appears that ReadData requires a file handle when using the csv parser. The following seems to work.

#!/usr/bin/env perl

use strict;
use warnings;
use v5.10;

use Data::Dumper;
use Spreadsheet::Read;

my $data_str = "A,B,C\na,b,c";
open (my $fh, '<', \$data_str ) or die 'Could not open file handle';

my $data = ReadData(
    $fh,
    parser=>"csv",
    debug => 9
);

close($fh);

say Dumper $data;

exit;
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