i2c-mux-pca954x: Add support for "i2c-mux-idle-disconnect" ...

Add support for "i2c-mux-idle-disconnect" binding to match the
behavior, already present in upstream kernel driver. This feature is a
must have for I2C bus topologies with multiple muxes connected to
child segments containing slaves with identical addresses (e.g. ZII's
SCU4)

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

i2c/pca954x: Initialize the mux to disconnected state ...

Port of a Linux kernel commit cd823db

    pca954x power-on default is channel 0 connected. If multiple pca954x
    muxes are connected to the same physical I2C bus, the parent bus will
    see channel 0 devices behind both muxes by default. This is bad.

    Scenario:
                -- pca954x @ 0x70 -- ch 0 (I2C-bus-101) -- EEPROM @ 0x50
                |
    I2C-bus-1 ---
                |
                -- pca954x @ 0x71 -- ch 0 (I2C-bus-111) -- EEPROM @ 0x50

    1. Load I2C bus driver: creates I2C-bus-1
    2. Load pca954x driver: creates virtual I2C-bus-101 and I2C-bus-111
    3. Load eeprom driver
    4. Try to read EEPROM @ 0x50 on I2C-bus-101. The transaction will also bleed
       onto I2C-bus-111 because pca954x @ 0x71 channel 0 is connected by default.

    Fix: Initialize pca954x to disconnected state in pca954x_probe()

    Signed-off-by: Petri Gynther <pgynther@google.com>
    Signed-off-by: Jean Delvare <khali@linux-fr.org>
    Cc: stable@kernel.org

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

i2c-mux-pca954x: remove use of uninitialized variable ...

force isn't used except to print its uninitialized value in an error
path. Drop it.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

i2c: introduce device_i2c_driver() macro ...

Add macro and dependency to avoid boilerplate code. Since now simple
i2c drivers only have to include the i2c.h header and call the
device_i2c_driver() macro to register a i2c device driver.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

i2c-mux-pca954x: fix out-of-bounds write for 64 bit systems ...

get_drv_data(..., &data->type) overwrites memory beyond data->type member due
to mismatch of sizeof(enum pca_type) and sizeof(void *) on 64 bit systems.

Signed-off-by: Peter Mamonov <pmamonov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

i2c-mux-pca954x: Add code to control reset line ...

Most recent device tree binding for that mux support specifying a GPIO
connected to a reset line of that chip. Add code to handle that binding
in order to be able to use the chip on boards that leverage
aforementioned functionality.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

i2c: add pca954x bus multiplexer driver ...

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>