Johnson and his work seem to me to be entirely discredited. He had limited credentials to undertake the work in any case.The Truth, the Whole Truth, and Nothing but the Truth?In the first one, you will notice that there was every chance for Johnson to put his point of view in the face of criticism that renders his book largely worthless and he did not.
A Militant Dilettante in Judgment of Science
Critiques of Anti-Evolutionist Phillip Johnson's Views
Darwin on Trial: A Review
Origin of the Specious
Phillip Johnson's dishonest quote
Darwin on Trial, Johnson on Trial
Intelligent Design: An Ambiguous Assault on Evolution
The Newest Evolution of Creationism
In the second and third, there is a detailed criticism of Johnson's work. His bias is clear. He had a chance to answer this criticism but has not.
In the fourth, Johnson is criticised for redefining terms to suit his argument. Again, he has had a chance to rebutt this argument but has chosen not to discuss his work openly.
... and so on.