Based on i2c-mux-gpio driver, similarly the register-based mux
switch from one bus to another by setting a single register.
The register can be on PCIe bus, local bus, or any memory-mapped
address. The endianness of such register can be specified in device
tree if used, or in platform data.
Signed-off-by: York Sun <yorksun@freescale.com>
Acked-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The GPIO subsystem provides dummy GPIO consumer functions if GPIOLIB is
not enabled. Hence drivers that depend on GPIOLIB, but use GPIO consumer
functionality only, can still be compiled if GPIOLIB is not enabled.
Relax the dependency on GPIOLIB if COMPILE_TEST is enabled, where
appropriate.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This driver causes the following randconfig build error:
drivers/i2c/muxes/i2c-mux-pca954x.c: In function ‘pca954x_probe’:
drivers/i2c/muxes/i2c-mux-pca954x.c:204:2: error: implicit declaration
of function ‘devm_gpiod_get’ [-Werror=implicit-function-declaration]
gpio = devm_gpiod_get(&client->dev, "reset");
^
drivers/i2c/muxes/i2c-mux-pca954x.c:204:7: warning: assignment makes
pointer from integer without a cast [enabled by default]
gpio = devm_gpiod_get(&client->dev, "reset");
^
drivers/i2c/muxes/i2c-mux-pca954x.c:206:3: error: implicit declaration
of function ‘gpiod_direction_output’
[-Werror=implicit-function-declaration]
gpiod_direction_output(gpio, 0);
^
cc1: some warnings being treated as errors
make[3]: *** [drivers/i2c/muxes/i2c-mux-pca954x.o] Error 1
This is because it is getting compiled without gpiolib, so
introduce an explicit dependency.
Reported-by: Jim Davis <jim.epost@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
GENERIC_GPIO now synonymous with GPIOLIB. There are no longer any valid
cases for enableing GENERIC_GPIO without GPIOLIB, even though it is
possible to do so which has been causing confusion and breakage. This
branch does the work to completely eliminate GENERIC_GPIO.
However, it is not trivial to just create a branch to remove it. Over
the course of the v3.9 cycle more code referencing GENERIC_GPIO has been
added to linux-next that conflicts with this branch. The following must
be done to resolve the conflicts when merging this branch into mainline:
* "git grep CONFIG_GENERIC_GPIO" should return 0 hits. Matches should be
replaced with CONFIG_GPIOLIB
* "git grep '\bGENERIC_GPIO\b'" should return 1 hit in the Chinese
documentation.
* Selectors of GENERIC_GPIO should be turned into selectors of GPIOLIB
* definitions of the option in architecture Kconfig code should be deleted.
Stephen has 3 merge fixup patches[1] that do the above. They are currently
applicable on mainline as of May 2nd.
[1] http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg428056.html
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Merge tag 'gpio-for-linus' of git://git.secretlab.ca/git/linux
Pull removal of GENERIC_GPIO from Grant Likely:
"GENERIC_GPIO now synonymous with GPIOLIB. There are no longer any
valid cases for enableing GENERIC_GPIO without GPIOLIB, even though it
is possible to do so which has been causing confusion and breakage.
This branch does the work to completely eliminate GENERIC_GPIO."
* tag 'gpio-for-linus' of git://git.secretlab.ca/git/linux:
gpio: update gpio Chinese documentation
Remove GENERIC_GPIO config option
Convert selectors of GENERIC_GPIO to GPIOLIB
blackfin: force use of gpiolib
m68k: coldfire: use gpiolib
mips: pnx833x: remove requirement for GENERIC_GPIO
openrisc: default GENERIC_GPIO to false
avr32: default GENERIC_GPIO to false
xtensa: remove explicit selection of GENERIC_GPIO
sh: replace CONFIG_GENERIC_GPIO by CONFIG_GPIOLIB
powerpc: remove redundant GENERIC_GPIO selection
unicore32: default GENERIC_GPIO to false
unicore32: remove unneeded select GENERIC_GPIO
arm: plat-orion: use GPIO driver on CONFIG_GPIOLIB
arm: remove redundant GENERIC_GPIO selection
mips: alchemy: require gpiolib
mips: txx9: change GENERIC_GPIO to GPIOLIB
mips: loongson: use GPIO driver on CONFIG_GPIOLIB
mips: remove redundant GENERIC_GPIO select
The i2c-arb-gpio-challenge driver implements an I2C arbitration scheme
where masters need to claim the bus with a GPIO before they can start
a transaction. This should generally only be used when standard I2C
multimaster isn't appropriate for some reason (errata/bugs).
This driver is based on code that Simon Glass added to the i2c-s3c2410
driver in the Chrome OS kernel 3.4 tree. The current incarnation as a
mux driver is as suggested by Grant Likely. See
<https://patchwork.kernel.org/patch/1877311/> for some history.
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
GENERIC_GPIO is now equivalent to GPIOLIB and features that depended on
GENERIC_GPIO can now depend on GPIOLIB to allow removal of this option.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
while now and is almost always enabled by default. As agreed during the
Linux kernel summit, remove it from any "depends on" lines in Kconfigs.
CC: Stephen Warren <swarren@nvidia.com>
CC: Peter Korsgaard <peter.korsgaard@barco.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Peter Korsgaard <peter.korsgaard@barco.com>
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>
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>
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>
