You'll have to modify the output formating to fit your needs but this is a very verbose way to list files for all filegroups and databases.

$sName = 'mysrr'

$server = new-object -TypeName Microsoft.SqlServer.Management.Smo.Server -ArgumentList $sName

foreach ($db in $server.Databases) {

$db.name

$fg = $db.FileGroups

foreach ($group in $fg) {

$group.Name

foreach ($file in $group.Files) {

$file.FileName

}

}

foreach ($log in $db.LogFiles) {

$log.FileName

}

}