Ember handlebars template access deep object property

In my Ember app, I have the following code

Component JS

row = {};
Ember.set(row[my.constants.fieldKey], "cssType", 'leftPadding')

Component HBS

So I want to pass 'cssType' property of my-field as 'leftPadding' in my component.

The hbs code above does not work.

Essentially I am trying to access a deep/nested object property in my hbs template I even tried with lookup, but did not work. Please suggest.