Where to find manual for Cirrus Logic 7543

[Joseph Adams]

I'm new to driver development, but I managed to modify the cirrus
driver so that my Cirrus Logic 7543 on my Compaq LTE 5100 shows the X
cursor and background (it was movable for a few seconds) until X
freezes a few seconds later without successfully launching the
programs in ~/.xsession (I did this by adding cases for 7543 every
time I saw 7548 in the source).  I noticed that in the cirrus source,
it mentions a manual for the 7548.  Does anybody happen to know where
I could find a manual for the 7543?  I googled for it, but I couldn't
find it, and searching for "7543" at cirrus.com yields absolutely no
results.  Thanks!