This is useful for SoCs whose I2C module's signals can be routed to
different sets of pins at run-time, using the pinctrl API.
+-----+ +-----+
| dev | | dev |
+------------------------+ +-----+ +-----+
| SoC | | |
| /----|------+--------+
| +---+ +------+ | child bus A, on first set of pins
| |I2C|---|Pinmux| |
| +---+ +------+ | child bus B, on second set of pins
| \----|------+--------+--------+
| | | | |
+------------------------+ +-----+ +-----+ +-----+
| dev | | dev | | dev |
+-----+ +-----+ +-----+
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Update the MAINTAINERS entry and all other references accordingly.
Based on an original patch by Wolfram Sang.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Peter Korsgaard <peter.korsgaard@barco.com>
[wsa: fixed merge conflict due to rework in i2c_add_mux_adapter()]
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Apply a naming pattern like in the rest of the subsystem to a first set
of mux drivers. Those drivers are the low-hanging fruit; we want to pick
them to motivate upcoming drivers to follow the new pattern. The missing
GPIO driver will be converted in a later patch.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com> (pca9541)
Acked-by: Jean Delvare <khali@linux-fr.org>
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: David Daney <david.daney@cavium.com>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
This patch converts the drivers in drivers/i2c/muxes/* to use the
module_i2c_driver() macro which makes the code smaller and a bit simpler.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: Michael Lawnick <ml.lawnick@gmx.de>
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Convert gpio-i2cmux to use the module_platform_driver() macro which
makes the code smaller and a bit simpler.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Peter Korsgaard <peter.korsgaard@barco.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
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
Add an i2c mux driver providing access to i2c bus segments using a
hardware MUX sitting on a master bus and controlled through gpio pins.
E.G. something like:
---------- ---------- Bus segment 1 - - - - -
| | SCL/SDA | |-------------- | |
| |------------| |
| | | | Bus segment 2 | |
| Linux | GPIO 1..N | MUX |--------------- Devices
| |------------| | | |
| | | | Bus segment M
| | | |---------------| |
---------- ---------- - - - - -
SCL/SDA of the master I2C bus is multiplexed to bus segment 1..M
according to the settings of the GPIO pins 1..N.
Signed-off-by: Peter Korsgaard <peter.korsgaard@barco.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The underlying I2C adapter may or may not be present when this driver
gets initialized, and may disappear later, so there is no safe time at
which the probe and remove functions can be discarded.
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
This patch adds support for PCA9541, an I2C Bus Master Selector.
The driver is modeled as single channel I2C Multiplexer to be able to utilize
the I2C multiplexer framework.
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Tom Grennan <tom.grennan@ericsson.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
