On Sat, Sep 07, 2019 at 05:03:14PM -0700, Andrey Smirnov wrote: > Port of a Linux kernel commit cd823db8b1161ef0d756514d280715a576d65cc3 > > 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@xxxxxxxxxx> > Signed-off-by: Jean Delvare <khali@xxxxxxxxxxxx> > Cc: stable@xxxxxxxxxx > > Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx> > --- > drivers/i2c/muxes/i2c-mux-pca954x.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) Applied with whitespace cleanup, thanks Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
