kernel/linux.git/drivers/mux/Kconfig, branch master

mux: add visible config symbol to enable multiplexer subsystem

2026-03-09T12:44:45+00:00

The multiplexer subsystem was initially designed to be completely hidden, relying on consumers to "select MULTIPLEXER" explicitly. Drivers implementing multiplexers depend on this hidden symbol. This prevents users from manually enabling both the mux core and any of the multiplexer drivers. All multiplexer drivers in drivers/mux/ can operate standalone without a consumer. This is particularly useful in a device-tree, where a default state can be set through the idle-state property. Over time, several drivers have added "select MULTIPLEXER" dependencies, some of which require a mux and some consider it optional. v7.0-rc1 shows 15 such occurrences in Kconfig files, in a variety of subsystems. The natural step forward to allow enabling mux core and drivers would be adding a prompt and help text to the existing symbol. This violates the general Kbuild advice to avoid selecting visible symbols for all existing consumers of the mux core. Add the new config symbol MUX_CORE with a prompt and help text as a wrapper for users to enable manually. This avoids existing consumers automatically selecting a visible symbol. Change the MULTIPLEXER symbol from tristate to bool. This avoids complex dependencies if users were to attempt a configuration where the mux is a module but one of its consumers is built-in, as well as difficulties keeping the state of visible and invisible symbols in sync. Further convert the "menu ... depends on ..." structure to "if ... menu ... endmenu endif". These are functionally equivalent, but the new structure is more efficient and can support future source statements within the conditional block. Signed-off-by: Josua Mayer Signed-off-by: Ulf Hansson

mux: mmio: Fix missing CONFIG_REGMAP_MMIO

2025-07-04T14:27:08+00:00

MMIO mux uses now regmap_init_mmio(), so one way or another CONFIG_REGMAP_MMIO should be enabled, because there are no stubs for !REGMAP_MMIO case: ERROR: modpost: "__regmap_init_mmio_clk" [drivers/mux/mux-mmio.ko] undefined! Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202505150312.dYbBqUhG-lkp@intel.com/ Fixes: 61de83fd8256 ("mux: mmio: Do not use syscon helper to build regmap") Acked-by: Arnd Bergmann Link: https://lore.kernel.org/r/20250521152354.92720-2-krzysztof.kozlowski@linaro.org Signed-off-by: Krzysztof Kozlowski Link: https://lore.kernel.org/r/20250616093841.31985-2-krzysztof.kozlowski@linaro.org Signed-off-by: Greg Kroah-Hartman

mux: mmio: drop obsolete dependency on COMPILE_TEST

2023-06-01T06:19:51+00:00

Since commit 0166dc11be91 ("of: make CONFIG_OF user selectable"), it is possible to test-build any driver which depends on OF on any architecture by explicitly selecting OF. Therefore depending on COMPILE_TEST as an alternative is no longer needed. It is actually better to always build such drivers with OF enabled, so that the test builds are closer to how each driver will actually be built on its intended target. Building them without OF may not test much as the compiler will optimize out potentially large parts of the code. In the worst case, this could even pop false positive warnings. Dropping COMPILE_TEST here improves the quality of our testing and avoids wasting time on non-existent issues. As a minor optimization, this also lets us drop of_match_ptr(), as we now know what it will resolve to, we might as well save cpp some work. Signed-off-by: Jean Delvare Signed-off-by: Peter Rosin Link: https://lore.kernel.org/r/bc790b4e-1cb4-4ef5-3da8-9d0e6b613bc7@axentia.se Signed-off-by: Greg Kroah-Hartman

mux: mmio: add generic regmap bitfield-based multiplexer

2019-06-21T13:59:53+00:00

Generic register bitfield-based multiplexer that controls the multiplexer producer defined under a parent node. The driver corresponding to parent node provides register read/write capabilities. Signed-off-by: Pankaj Bansal Signed-off-by: Peter Rosin Signed-off-by: Greg Kroah-Hartman

mux: adgs1408: new driver for Analog Devices ADGS1408/1409 mux

2018-08-02T08:23:02+00:00

This patch adds basic support for Analog Device ADGS1408/09 SPI mux controller. The device is probed and set to a disabled state. It uses the new mux controller framework. Signed-off-by: Mircea Caprioru Signed-off-by: Peter Rosin Signed-off-by: Greg Kroah-Hartman

mux: add SPDX identifiers to all mux source files

2018-01-09T15:51:44+00:00

Remove all free-text license texts. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. No copyright headers or other non-license-description text was removed. Reviewed-by: Philippe Ombredanne Acked-by: Philipp Zabel Signed-off-by: Peter Rosin Signed-off-by: Greg Kroah-Hartman

mux: remove the Kconfig question for the subsystem

2017-07-17T14:37:30+00:00

The MULTIPLEXER question in the Kconfig might be confusing and is of dubious value. Remove it. This makes consumers responsible for selecting MULTIPLEXER, which they already do. Signed-off-by: Peter Rosin Reported-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mux: adg792a: always require I2C support

2017-06-09T10:45:05+00:00

COMPILE_TEST makes no sense when I2C is disabled, as the driver cannot compile in that configuration: drivers/mux/mux-adg792a.c: In function 'adg792a_write_cmd': drivers/mux/mux-adg792a.c:34:9: error: implicit declaration of function 'i2c_smbus_write_byte_data'; did you mean 'i2c_set_clientdata'? [-Werror=implicit-function-declaration] drivers/mux/mux-adg792a.o: In function `adg792a_driver_init': mux-adg792a.c:(.init.text+0x14): undefined reference to `i2c_register_driver' drivers/mux/mux-adg792a.o: In function `adg792a_probe': mux-adg792a.c:(.text.adg792a_probe+0x94): undefined reference to `i2c_smbus_write_byte_data' drivers/mux/mux-adg792a.o: In function `adg792a_set': mux-adg792a.c:(.text.adg792a_set+0x80): undefined reference to `i2c_smbus_write_byte_data' Fixes: afda08c4caa9 ("mux: adg792a: add mux controller driver for ADG792A/G") Signed-off-by: Arnd Bergmann Reviewed-by: Peter Rosin Signed-off-by: Greg Kroah-Hartman

mux: mmio-based syscon mux controller

2017-06-03T10:29:26+00:00

This adds a driver for mmio-based syscon multiplexers controlled by bitfields in a syscon register range. Signed-off-by: Philipp Zabel Signed-off-by: Peter Rosin Signed-off-by: Greg Kroah-Hartman

mux: adg792a: add mux controller driver for ADG792A/G

2017-06-03T10:29:26+00:00

Analog Devices ADG792A/G is a triple 4:1 mux. Reviewed-by: Jonathan Cameron Signed-off-by: Peter Rosin Signed-off-by: Greg Kroah-Hartman