use 5.010;
use warnings;
use strict;
my $port_name = quotemeta 'sdm_yout_i[1]';
while (<DATA>) {
    if (/\.([0-9a-z_]*?) \(.*?${port_name} .*?,/ ) {
        print '$port_name = ';
        say $port_name;
        print 'cell name = ';
        say $1;
    }
}

__DATA__
 .dout_sar ( dout_sar ) , .dcoc_status ( dcoc_status ) ,     .sdm_yout_i ( {sdm_yout_i[1] , n145 } ) , .sdm_yout_q ( sdm_yout_q ) ,