Similar to the new optional 'i2c-bus' subnode from Jon Hunter, this
adds an optional 'i2c-mux' subnode, for similar reasons. I.e. it is
bad of the i2c mux core to assume that any subnode of an i2c mux device
is a potential (when the 'reg' property matches) i2c-mux child bus,
given that i2c mux devices might do more than mux i2c traffic.

So, if an 'i2c-mux' subnode is present, dictate that all i2c-mux child
buses exist beneath that subnode.
Acked-by: NRob Herring <robh@kernel.org>
Reviewed-by: NWolfram Sang <wsa@the-dreams.de>
Signed-off-by: NPeter Rosin <peda@axentia.se>

Filenames of devictree binding documentation seems to be arbitrary and
for me it is unneeded hazzle to find the corresponding documentation for
a specific driver.

Naming the description the same as the driver is a lot easier and makes
sense to me since the driver defines the binding it understands.

Also, remove a reference in one source to the binding documentation, since path
information easily gets stale.
Signed-off-by: NWolfram Sang <wolfram@the-dreams.de>
Cc: Rob Herring <robherring2@gmail.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

For 'normal' i2c bus drivers, we can call of_i2c_register_devices()
and have the device tree framework automatically populate the bus with
the devices specified in the device tree.

This patch adds a common code to the i2c mux framework to have the mux
sub-busses be populated by the of_i2c_register_devices() too.  If the
mux device has an of_node, we populate the sub-bus' of_node so that
the subsequent call to of_i2c_register_devices() will find the
corresponding devices.

It seemed better to put this logic in i2c_add_mux_adapter() rather
than the individual mux drivers, as they will all probably want to do
the same thing.
Signed-off-by: NDavid Daney <david.daney@cavium.com>
Acked-by: NStephen Warren <swarren@wwwdotorg.org>
Tested-by: NLars-Peter Clausen <lars@metafoo.de>

[wsa: removed superfluous ret-variable and fixed a typo in a comment]
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>