[RFC PATCH 0/8] component helper improvements

[Russell King - ARM Linux]

A while back, Laurent raised some comments about the component helper,
which this patch set starts to address.

The first point it addresses is the repeated parsing inefficiency when
deferred probing occurs.  When DT is used, the structure of the
component helper today means that masters end up parsing the device
tree for each attempt to re-bind the driver.

We remove this inefficiency by creating an array of matching data and
functions, which the component helper can use internally to match up
components to their master.

The second point was the inefficiency of destroying the list of
components each time we saw a failure.  We did this to ensure that
we kept things correctly ordered: component bind order matters.
As we have an array instead, the array is already ordered, so we
use this array to store the component pointers instead of a list,
and remember which are duplicates (and thus should be avoided.)
Avoiding the right duplicates matters as we walk the array in the
opposite direction at tear down.

I would like to see patches 1-5 scheduled for the next merge window,
with 6-8 for the following window - this gives us grace of one kernel
cycle to ensure that any new component helper users are properly
converted.

 drivers/base/component.c               | 248 ++++++++++++++++++++++-----------
 drivers/gpu/drm/msm/msm_drv.c          |  81 +++++------
 drivers/staging/imx-drm/imx-drm-core.c |  57 +-------
 include/linux/component.h              |   8 +-
 4 files changed, 206 insertions(+), 188 deletions(-)

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