KSH scripting: how to split on ',' when values have escaped commas?

NAME1 VALUE1,NAME2 VALUE2,NAME3 VALUE3, etc

read l
IFS=","
set -A nvls $l
echo "$nvls[2]"

NAME1 VALUE1,NAME2 VALUE2_1,VALUE2_2,NAME3 VALUE3, etc

read l
l=${l//\,/!!}
IFS=","
set -A nvls $l
unset IFS
echo ${nvls[2]/!!/,}

sed -e 's/([^]),/1
/g;s/$/
/

NAME1.1 VALUE1.1
NAME1.2 VALUE1.2_1,VALUE1.2_2
NAME1.3 VALUE1.3
<empty line>
NAME2.1 VALUE2.1
<second record continues>

while read name value ; do
  echo "$name => $value"
done