TODO

 1This driver suffers from a bad initial design that results in various aspects
 2being intricated, making it difficult to scale to new codecs and to add encoding
 3support in the future.
 4
 5Before leaving the staging area, it should be reworked to clearly distinguish
 6between different aspects:
 7- platform, with resources management, interrupt handler, watchdog,
 8  v4l2 and m2m devices registration;
 9- proc, with video device registration and related operations;
10- context, with m2m context, queue and controls management;
11- engine, with each individual codec job execution and codec-specific
12  operation callbacks;
13
14This will make it possible to register two different procs (decoder and
15encoder) while sharing significant common infrastructure, common v4l2 and m2m
16devices but exposing distinct video devices.