1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright 2021 Google Inc.
4 *
5 * The DP AUX bus is used for devices that are connected over a DisplayPort
6 * AUX bus. The devices on the far side of the bus are referred to as
7 * endpoints in this code.
8 */
9
10#ifndef _DP_AUX_BUS_H_
11#define _DP_AUX_BUS_H_
12
13#include <linux/device.h>
14#include <linux/mod_devicetable.h>
15
16/**
17 * struct dp_aux_ep_device - Main dev structure for DP AUX endpoints
18 *
19 * This is used to instantiate devices that are connected via a DP AUX
20 * bus. Usually the device is a panel, but conceivable other devices could
21 * be hooked up there.
22 */
23struct dp_aux_ep_device {
24	/** @dev: The normal dev pointer */
25	struct device dev;
26	/** @aux: Pointer to the aux bus */
27	struct drm_dp_aux *aux;
28};
29
30struct dp_aux_ep_driver {
31	int (*probe)(struct dp_aux_ep_device *aux_ep);
32	void (*remove)(struct dp_aux_ep_device *aux_ep);
33	void (*shutdown)(struct dp_aux_ep_device *aux_ep);
34	struct device_driver driver;
35};
36
37static inline struct dp_aux_ep_device *to_dp_aux_ep_dev(struct device *dev)
38{
39	return container_of(dev, struct dp_aux_ep_device, dev);
40}
41
42static inline struct dp_aux_ep_driver *to_dp_aux_ep_drv(struct device_driver *drv)
43{
44	return container_of(drv, struct dp_aux_ep_driver, driver);
45}
46
47int of_dp_aux_populate_bus(struct drm_dp_aux *aux,
48			   int (*done_probing)(struct drm_dp_aux *aux));
49void of_dp_aux_depopulate_bus(struct drm_dp_aux *aux);
50int devm_of_dp_aux_populate_bus(struct drm_dp_aux *aux,
51				int (*done_probing)(struct drm_dp_aux *aux));
52
53/* Deprecated versions of the above functions. To be removed when no callers. */
54static inline int of_dp_aux_populate_ep_devices(struct drm_dp_aux *aux)
55{
56	int ret;
57
58	ret = of_dp_aux_populate_bus(aux, NULL);
59
60	/* New API returns -ENODEV for no child case; adapt to old assumption */
61	return (ret != -ENODEV) ? ret : 0;
62}
63
64static inline int devm_of_dp_aux_populate_ep_devices(struct drm_dp_aux *aux)
65{
66	int ret;
67
68	ret = devm_of_dp_aux_populate_bus(aux, NULL);
69
70	/* New API returns -ENODEV for no child case; adapt to old assumption */
71	return (ret != -ENODEV) ? ret : 0;
72}
73
74static inline void of_dp_aux_depopulate_ep_devices(struct drm_dp_aux *aux)
75{
76	of_dp_aux_depopulate_bus(aux);
77}
78
79#define dp_aux_dp_driver_register(aux_ep_drv) \
80	__dp_aux_dp_driver_register(aux_ep_drv, THIS_MODULE)
81int __dp_aux_dp_driver_register(struct dp_aux_ep_driver *aux_ep_drv,
82				struct module *owner);
83void dp_aux_dp_driver_unregister(struct dp_aux_ep_driver *aux_ep_drv);
84
85#endif /* _DP_AUX_BUS_H_ */
86