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2026-03-09mux: Add helper functions for getting optional and selected mux-stateJosua Mayer
In-tree phy-can-transceiver and phy_rcar_gen3_usb2 have already implemented local versions of devm_mux_state_get_optional. The omap-i2c driver gets and selects an optional mux in its probe function without using any helper. Add new helper functions covering both aforementioned use-cases: - mux_control_get_optional: Get a mux-control if specified in dt, return NULL otherwise. - devm_mux_state_get_optional: Get a mux-state if specified in dt, return NULL otherwise. - devm_mux_state_get_selected: Get and select a mux-state specified in dt, return error otherwise. - devm_mux_state_get_optional_selected: Get and select a mux-state if specified in dt, return error or NULL. Existing mux_get helper function is changed to take an extra argument indicating whether the mux is optional. In this case no error is printed, and NULL returned in case of ENOENT. Calling code is adapted to handle NULL return case, and to pass optional argument as required. To support automatic deselect for _selected helper, a new structure is created storing an exit pointer similar to clock core which is called on release. To facilitate code sharing between optional/mandatory/selected helpers, a new internal helper function is added to handle quiet (optional) and verbose (mandatory) errors, as well as storing the correct callback for devm release: __devm_mux_state_get Due to this structure devm_mux_state_get_*_selected can no longer print a useful error message when select fails. Instead callers should print errors where needed. Commit e153fdea9db04 ("phy: can-transceiver: Re-instate "mux-states" property presence check") noted that "mux_get() always prints an error message in case of an error, including when the property is not present, confusing the user." The first error message covers the case that a mux name is not matched in dt. The second error message is based on of_parse_phandle_with_args return value. In optional case no error is printed and NULL is returned. This ensures that the new helper functions will not confuse the user either. With the addition of optional helper functions it became clear that drivers should compile and link even if CONFIG_MULTIPLEXER was not enabled. Add stubs for all symbols exported by mux core. Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Josua Mayer <josua@solid-run.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
2025-06-18mux: Convert mux_control_ops to a flex array member in mux_chipThorsten Blum
Convert mux_control_ops to a flexible array member at the end of the mux_chip struct and add the __counted_by() compiler attribute to improve access bounds-checking via CONFIG_UBSAN_BOUNDS and CONFIG_FORTIFY_SOURCE. Use struct_size() to calculate the number of bytes to allocate for a new mux chip and to remove the following Coccinelle/coccicheck warning: WARNING: Use struct_size Use size_add() to safely add any extra bytes. No functional changes intended. Link: https://github.com/KSPP/linux/issues/83 Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev> Link: https://lore.kernel.org/r/20250610104106.1948-2-thorsten.blum@linux.dev Signed-off-by: Kees Cook <kees@kernel.org>
2022-02-04mux: Add support for reading mux state from consumer DT nodeAswath Govindraju
In some cases, we might need to provide the state of the mux to be set for the operation of a given peripheral. Therefore, pass this information using mux-states property. Link: https://lore.kernel.org/lkml/20211123081222.27979-1-a-govindraju@ti.com Signed-off-by: Aswath Govindraju <a-govindraju@ti.com> Signed-off-by: Peter Rosin <peda@axentia.se> (minor edits) Link: https://lore.kernel.org/r/aac25be8-9515-a980-f7cb-709938c84822@axentia.se Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21mux: add support for delay after muxingVincent Whitchurch
Hardware may require some time for the muxed analog signals to settle after the muxing is changed. Allow users of the mux subsystem to specify this delay with the new mux_control_select_delay() function (and the _try equivalent). Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Reviewed-by: Lars-Peter Clausen <lars@metafoo.de> Tested-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Peter Rosin <peda@axentia.se> Link: https://lore.kernel.org/r/20211007134641.13417-2-vincent.whitchurch@axis.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2018-01-09mux: add SPDX identifiers to all mux source filesPeter Rosin
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 <pombredanne@nexb.com> Acked-by: Philipp Zabel <p.zabel@pengutronix.de> Signed-off-by: Peter Rosin <peda@axentia.se> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-28mux: include compiler.h from mux/consumer.hUlrich Hecht
Required for __must_check. Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com> Signed-off-by: Peter Rosin <peda@axentia.se> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-03mux: minimal mux subsystemPeter Rosin
Add a new minimalistic subsystem that handles multiplexer controllers. When multiplexers are used in various places in the kernel, and the same multiplexer controller can be used for several independent things, there should be one place to implement support for said multiplexer controller. A single multiplexer controller can also be used to control several parallel multiplexers, that are in turn used by different subsystems in the kernel, leading to a need to coordinate multiplexer accesses. The multiplexer subsystem handles this coordination. Thanks go out to Lars-Peter Clausen, Jonathan Cameron, Rob Herring, Wolfram Sang, Paul Gortmaker, Dan Carpenter, Colin Ian King, Greg Kroah-Hartman and last but certainly not least to Philipp Zabel for helpful comments, reviews, patches and general encouragement! Reviewed-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Peter Rosin <peda@axentia.se> Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> Tested-by: Philipp Zabel <p.zabel@pengutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>