How to create post buttons from model objects?

I have the following starting point code where I want clicking on the the button to update a content object by doing something like doubling its value field. It looks like the typical thing with a form is to have a changeset to get the form working. But is there a way to make this work without introducing a changeset and a form?

<%= for content <- @contents do %>
      <td><%= content.value %></td>
        <%= link "Update content", to: Routes.content_path(@conn, :update, content), class:  "button", method: :post %>
<% end %>