Merge tag 'driver-core-6.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core api addition from Greg KH:
 "Here is a driver core new api for 6.14-rc3 that is being added to
  allow platform devices from stop being abused.

  It adds a new 'faux_device' structure and bus and api to allow almost
  a straight or simpler conversion from platform devices that were not
  really a platform device. It also comes with a binding for rust, with
  an example driver in rust showing how it's used.

  I'm adding this now so that the patches that convert the different
  drivers and subsystems can all start flowing into linux-next now
  through their different development trees, in time for 6.15-rc1.

  We have a number that are already reviewed and tested, but adding
  those conversions now doesn't seem right. For now, no one is using
  this, and it passes all build tests from 0-day and linux-next, so all
  should be good"

* tag 'driver-core-6.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  rust/kernel: Add faux device bindings
  driver core: add a faux bus for use when a simple device/bus is needed

1 files changed, 69 insertions, 0 deletions

diff --git a/include/linux/device/faux.h b/include/linux/device/faux.h
new file mode 100644
index 000000000000..9f43c0e46aa4
--- /dev/null
+++ b/include/linux/device/faux.h
@@ -0,0 +1,69 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2025 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+ * Copyright (c) 2025 The Linux Foundation
+ *
+ * A "simple" faux bus that allows devices to be created and added
+ * automatically to it.  This is to be used whenever you need to create a
+ * device that is not associated with any "real" system resources, and do
+ * not want to have to deal with a bus/driver binding logic.  It is
+ * intended to be very simple, with only a create and a destroy function
+ * available.
+ */
+#ifndef _FAUX_DEVICE_H_
+#define _FAUX_DEVICE_H_
+
+#include <linux/container_of.h>
+#include <linux/device.h>
+
+/**
+ * struct faux_device - a "faux" device
+ * @dev:	internal struct device of the object
+ *
+ * A simple faux device that can be created/destroyed.  To be used when a
+ * driver only needs to have a device to "hang" something off.  This can be
+ * used for downloading firmware or other basic tasks.  Use this instead of
+ * a struct platform_device if the device has no resources assigned to
+ * it at all.
+ */
+struct faux_device {
+	struct device dev;
+};
+#define to_faux_device(x) container_of_const((x), struct faux_device, dev)
+
+/**
+ * struct faux_device_ops - a set of callbacks for a struct faux_device
+ * @probe:	called when a faux device is probed by the driver core
+ *		before the device is fully bound to the internal faux bus
+ *		code.  If probe succeeds, return 0, otherwise return a
+ *		negative error number to stop the probe sequence from
+ *		succeeding.
+ * @remove:	called when a faux device is removed from the system
+ *
+ * Both @probe and @remove are optional, if not needed, set to NULL.
+ */
+struct faux_device_ops {
+	int (*probe)(struct faux_device *faux_dev);
+	void (*remove)(struct faux_device *faux_dev);
+};
+
+struct faux_device *faux_device_create(const char *name,
+				       struct device *parent,
+				       const struct faux_device_ops *faux_ops);
+struct faux_device *faux_device_create_with_groups(const char *name,
+						   struct device *parent,
+						   const struct faux_device_ops *faux_ops,
+						   const struct attribute_group **groups);
+void faux_device_destroy(struct faux_device *faux_dev);
+
+static inline void *faux_device_get_drvdata(const struct faux_device *faux_dev)
+{
+	return dev_get_drvdata(&faux_dev->dev);
+}
+
+static inline void faux_device_set_drvdata(struct faux_device *faux_dev, void *data)
+{
+	dev_set_drvdata(&faux_dev->dev, data);
+}
+
+#endif /* _FAUX_DEVICE_H_ */