kernel/linux.git/drivers/base/faux.c, branch v6.19.11

driver core: faux: stop using static struct device

2026-03-04T12:20:27+00:00

[ Upstream commit 61b76d07d2b46a86ea91267d36449fc78f8a1f6e ] faux_bus_root should not have been a static struct device, but rather a dynamically created structure so that lockdep and other testing tools do not trip over it (as well as being the right thing overall to do.) Fix this up by making it properly dynamic. Reported-by: Gui-Dong Han Closes: https://lore.kernel.org/lkml/CALbr=LYKJsj6cbrDLA07qioKhWJcRj+gW8=bq5=4ZvpEe2c4Yg@mail.gmail.com/ Reviewed-by: Danilo Krummrich Link: https://patch.msgid.link/2026012145-lapping-countless-ef81@gregkh Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

driver core: faux: Set power.no_pm for faux devices

2025-09-06T11:58:00+00:00

Since faux devices are not supposed to be involved in any kind of power management, set the no_pm flag for all of them. Signed-off-by: Rafael J. Wysocki Cc: stable Reviewed-by: Sudeep Holla Link: https://lore.kernel.org/r/6206518.lOV4Wx5bFT@rafael.j.wysocki Signed-off-by: Greg Kroah-Hartman

driver core: faux: Quiet probe failures

2025-06-10T17:23:25+00:00

The acpi-einj conversion to faux_device_create() leads to a noisy error message when the error injection facility is disabled. Quiet the error as CXL error injection via ACPI expects the module to stay loaded even if the error injection facility is disabled. This situation arose because CXL knows proper kernel named objects to trigger errors against, but acpi-einj knows how to perform the error injection. The injection mechanism is shared with non-CXL use cases. The result is CXL now has a module dependency on einj-core.ko, and init/probe failures are handled at runtime. Fixes: 6cb9441bfe8d ("ACPI: APEI: EINJ: Transition to the faux device interface") Signed-off-by: Dan Williams Reviewed-by: Jonathan Cameron Acked-by: Greg Kroah-Hartman Link: https://patch.msgid.link/20250607033228.1475625-3-dan.j.williams@intel.com Signed-off-by: Rafael J. Wysocki

driver core: faux: Suppress bind attributes

2025-06-10T17:23:25+00:00

faux_device_create() is almost a suitable candidate to replace platform_driver_probe() if not for the fact that faux_device_create() supports dynamic attach/detach of the driver. Drop the bind attributes with the expectation that simple faux devices can always assume that the device is permanently bound at create, and only unbound at 'destroy'. The acpi-einj driver depends on static bind. Fixes: 6cb9441bfe8d ("ACPI: APEI: EINJ: Transition to the faux device interface") Signed-off-by: Dan Williams Reviewed-by: Jonathan Cameron Acked-by: Greg Kroah-Hartman Link: https://patch.msgid.link/20250607033228.1475625-2-dan.j.williams@intel.com Signed-off-by: Rafael J. Wysocki

driver core: faux: Add sysfs groups after probing

2025-04-15T12:16:08+00:00

Manually add sysfs groups after the faux_device_ops's probe succeeds. Likewise remove these groups just before calling the faux_devices_ops's remove callback. This approach approximates the order in which the driver core adds and removes the driver's .dev_groups of a device to avoid lifetime issues. This is done specifically to avoid using the device's .groups member, which adds groups before the device is even registered to the bus. This lets consumers of this API, initialize resources on the .probe callback and then use them inside is_visible/show/store methods, through dev_get_drvdata() without races. Cc: Rafael J. Wysocki Cc: Danilo Krummrich Signed-off-by: Kurt Borja Link: https://lore.kernel.org/r/20250327-faux-groups-v2-1-745a3cf0bc16@gmail.com Signed-off-by: Greg Kroah-Hartman

driver core: faux: only create the device if probe() succeeds

2025-02-28T02:03:53+00:00

It's really hard to know if a faux device properly passes the callback to probe() without having to poke around in the faux_device structure and then clean up. Instead of having to have every user of the api do this logic, just do it in the faux device core itself. This makes the use of a custom probe() callback for a faux device much simpler overall. Suggested-by: Kurt Borja Cc: Rafael J. Wysocki Reviewed-by: Kurt Borja Reviewed-by: Danilo Krummrich Link: https://lore.kernel.org/r/2025022545-unroasted-common-fa0e@gregkh Signed-off-by: Greg Kroah-Hartman

driver core: add a faux bus for use when a simple device/bus is needed

2025-02-13T15:58:51+00:00

Many drivers abuse the platform driver/bus system as it provides a simple way to create and bind a device to a driver-specific set of probe/release functions. Instead of doing that, and wasting all of the memory associated with a platform device, here is a "faux" bus that can be used instead. Reviewed-by: Jonathan Cameron Reviewed-by: Danilo Krummrich Reviewed-by: Lyude Paul Reviewed-by: Thomas Weißschuh Reviewed-by: Zijun Hu Link: https://lore.kernel.org/r/2025021026-atlantic-gibberish-3f0c@gregkh Signed-off-by: Greg Kroah-Hartman