| 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
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| 2 | /* |
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| 3 | * Copyright (c) 2025 Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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| 4 | * Copyright (c) 2025 The Linux Foundation |
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| 5 | * |
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| 6 | * A "simple" faux bus that allows devices to be created and added |
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| 7 | * automatically to it. This is to be used whenever you need to create a |
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| 8 | * device that is not associated with any "real" system resources, and do |
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| 9 | * not want to have to deal with a bus/driver binding logic. It is |
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| 10 | * intended to be very simple, with only a create and a destroy function |
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| 11 | * available. |
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| 12 | */ |
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| 13 | #ifndef _FAUX_DEVICE_H_ |
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| 14 | #define _FAUX_DEVICE_H_ |
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| 15 | |
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| 16 | #include <linux/container_of.h> |
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| 17 | #include <linux/device.h> |
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| 18 | |
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| 19 | /** |
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| 20 | * struct faux_device - a "faux" device |
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| 21 | * @dev: internal struct device of the object |
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| 22 | * |
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| 23 | * A simple faux device that can be created/destroyed. To be used when a |
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| 24 | * driver only needs to have a device to "hang" something off. This can be |
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| 25 | * used for downloading firmware or other basic tasks. Use this instead of |
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| 26 | * a struct platform_device if the device has no resources assigned to |
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| 27 | * it at all. |
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| 28 | */ |
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| 29 | struct faux_device { |
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| 30 | struct device dev; |
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| 31 | }; |
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| 32 | #define to_faux_device(x) container_of_const((x), struct faux_device, dev) |
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| 33 | |
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| 34 | /** |
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| 35 | * struct faux_device_ops - a set of callbacks for a struct faux_device |
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| 36 | * @probe: called when a faux device is probed by the driver core |
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| 37 | * before the device is fully bound to the internal faux bus |
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| 38 | * code. If probe succeeds, return 0, otherwise return a |
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| 39 | * negative error number to stop the probe sequence from |
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| 40 | * succeeding. |
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| 41 | * @remove: called when a faux device is removed from the system |
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| 42 | * |
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| 43 | * Both @probe and @remove are optional, if not needed, set to NULL. |
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| 44 | */ |
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| 45 | struct faux_device_ops { |
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| 46 | int (*probe)(struct faux_device *faux_dev); |
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| 47 | void (*remove)(struct faux_device *faux_dev); |
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| 48 | }; |
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| 49 | |
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| 50 | struct faux_device *faux_device_create(const char *name, |
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| 51 | struct device *parent, |
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| 52 | const struct faux_device_ops *faux_ops); |
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| 53 | struct faux_device *faux_device_create_with_groups(const char *name, |
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| 54 | struct device *parent, |
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| 55 | const struct faux_device_ops *faux_ops, |
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| 56 | const struct attribute_group **groups); |
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| 57 | void faux_device_destroy(struct faux_device *faux_dev); |
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| 58 | |
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| 59 | static inline void *faux_device_get_drvdata(const struct faux_device *faux_dev) |
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| 60 | { |
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| 61 | return dev_get_drvdata(dev: &faux_dev->dev); |
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| 62 | } |
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| 63 | |
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| 64 | static inline void faux_device_set_drvdata(struct faux_device *faux_dev, void *data) |
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| 65 | { |
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| 66 | dev_set_drvdata(dev: &faux_dev->dev, data); |
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| 67 | } |
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| 68 | |
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| 69 | #endif /* _FAUX_DEVICE_H_ */ |
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| 70 | |
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