i2c port format?

[mzwtjp]

I am trying to use i2c, but I can see I have to pass ata like below as 'port' parameter to i2c functions.
(Not simply '/dev/i2c-1', etc.)

Trying to open /dev/i2c-1 and scan devices:

var x = [ '/dev/i2c-2', 0x20 ];

b.i2cOpen(x, { device: '/dev/i2c-1'}, function(err) {
...
}

b.i2cScan(x, function(err, data) {
...
}

Is this expected?
Sorry to be lazy but what exactly the format to be used here?
I can see below change that might have something to do with this..?

i2c: move address definition to port

c2bc109#diff-9f08fda3dc96b65b6bb787e899d80703