i2c_del_mux_adapter always returns 0 and none of it current users check its
return value anyway. It is also an essential requirement of the Linux device
driver model, that functions which may be called from a device's remove callback
to free resources provided by the device, are not allowed to fail. This is the
case for i2c_del_mux_adapter(), so make its return type void to make the
fact that it won't fail explicit.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Reviewed-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Let I2C bus segments behind multiplexers have a class. This allows for
device auto-detection on these segments. As long as parent segments
don't share the same class, it should be fine.

I implemented support in drivers i2c-mux-gpio and i2c-mux-pca954x. I
left i2c-mux-pca9541 and i2c-mux-pinctrl alone for the moment as I
don't know if this feature makes sense for the use cases of these
drivers.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Cc: Peter Korsgaard <peter.korsgaard@barco.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Michael Lawnick <ml.lawnick@gmx.de>
Cc: Rodolfo Giometti <giometti@linux.it>

And adjust all callers.

The new device parameter is used in the next patch to initialize the
mux's of_node so that its children may be automatically populated.
Signed-off-by: NDavid Daney <david.daney@cavium.com>
Tested-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>

Signed-off-by: NJean Delvare <khali@linux-fr.org>

Add multiplexed bus core support. I2C multiplexer and switches
like pca954x get instantiated as new adapters per port.
Signed-off-by: NMichael Lawnick <ml.lawnick@gmx.de>
Acked-by: NRodolfo Giometti <giometti@linux.it>
Signed-off-by: NJean Delvare <khali@linux-fr.org>