FMC: add a software mezzanine driver

This simple do-nothing mezzanine driver shows how to write a mezzanine
driver, that can also handle interrupts reported by the carrier.

Signed-off-by: Alessandro Rubini <[email protected]>
Acked-by: Juan David Gonzalez Cobas <[email protected]>
Acked-by: Emilio G. Cota <[email protected]>
Acked-by: Samuel Iglesias Gonsalvez <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Documentation/fmc/00-INDEX

@@ -27,3 +27,6 @@ identifiers.txt
 
 fmc-fakedev.txt
 	- about drivers/fmc/fmc-fakedev.ko
+
+fmc-trivial.txt
+	- about drivers/fmc/fmc-trivial.ko

Documentation/fmc/fmc-trivial.txt

@@ -0,0 +1,17 @@
+fmc-trivial
+===========
+
+The simple module fmc-trivial is just a simple client that registers an
+interrupt handler. I used it to verify the basic mechanism of the FMC
+bus and how interrupts worked.
+
+The module implements the generic FMC parameters, so it can program a
+different gateware file in each card. The whole list of parameters it
+accepts are:
+
+`busid='
+`gateware='
+     Generic parameters. See mezzanine.txt
+
+
+This driver is worth reading, in my opinion.