linux/drivers/i2c
Petri Gynther cd823db8b1 i2c/pca954x: Initialize the mux to disconnected state
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
2011-06-29 11:36:11 +02:00
..
algos i2c-algo-bit: Call pre/post_xfer for bit_test 2011-04-17 10:20:19 +02:00
busses i2c-taos-evm: Fix log messages 2011-06-29 11:36:10 +02:00
muxes i2c/pca954x: Initialize the mux to disconnected state 2011-06-29 11:36:11 +02:00
Kconfig Revert "i2c: Fix Kconfig dependencies" 2010-11-22 11:27:33 -02:00
Makefile i2c: Deprecate i2c_driver.attach_adapter and .detach_adapter 2011-03-20 14:50:53 +01:00
i2c-boardinfo.c i2c-boardinfo: Fix typo in comment 2011-03-20 14:50:52 +01:00
i2c-core.c i2c: Improve deprecation warnings 2011-04-17 10:20:19 +02:00
i2c-core.h i2c: Use rwsem instead of mutex for board info 2009-06-19 16:58:20 +02:00
i2c-dev.c i2c-dev: Use standard bus notification mechanism 2011-03-20 14:50:52 +01:00
i2c-mux.c i2c: Mark i2c_adapter.id as deprecated 2010-11-15 22:40:38 +01:00
i2c-smbus.c i2c: Remove all i2c_set_clientdata(client, NULL) in drivers 2010-06-03 11:33:58 +02:00