1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * mux/driver.h - definitions for the multiplexer driver interface
4 *
5 * Copyright (C) 2017 Axentia Technologies AB
6 *
7 * Author: Peter Rosin <peda@axentia.se>
8 */
9
10 #ifndef _LINUX_MUX_DRIVER_H
11 #define _LINUX_MUX_DRIVER_H
12
13 #include <dt-bindings/mux/mux.h>
14 #include <linux/device.h>
15 #include <linux/ktime.h>
16 #include <linux/semaphore.h>
17
18 struct mux_chip;
19 struct mux_control;
20
21 /**
22 * struct mux_control_ops - Mux controller operations for a mux chip.
23 * @set: Set the state of the given mux controller.
24 */
25 struct mux_control_ops {
26 int (*set)(struct mux_control *mux, int state);
27 };
28
29 /**
30 * struct mux_control - Represents a mux controller.
31 * @lock: Protects the mux controller state.
32 * @chip: The mux chip that is handling this mux controller.
33 * @cached_state: The current mux controller state, or -1 if none.
34 * @states: The number of mux controller states.
35 * @idle_state: The mux controller state to use when inactive, or one
36 * of MUX_IDLE_AS_IS and MUX_IDLE_DISCONNECT.
37 * @last_change: Timestamp of last change
38 *
39 * Mux drivers may only change @states and @idle_state, and may only do so
40 * between allocation and registration of the mux controller. Specifically,
41 * @cached_state is internal to the mux core and should never be written by
42 * mux drivers.
43 */
44 struct mux_control {
45 struct semaphore lock; /* protects the state of the mux */
46
47 struct mux_chip *chip;
48 int cached_state;
49
50 unsigned int states;
51 int idle_state;
52
53 ktime_t last_change;
54 };
55
56 /**
57 * struct mux_chip - Represents a chip holding mux controllers.
58 * @controllers: Number of mux controllers handled by the chip.
59 * @mux: Array of mux controllers that are handled.
60 * @dev: Device structure.
61 * @id: Used to identify the device internally.
62 * @ops: Mux controller operations.
63 */
64 struct mux_chip {
65 unsigned int controllers;
66 struct mux_control *mux;
67 struct device dev;
68 int id;
69
70 const struct mux_control_ops *ops;
71 };
72
73 #define to_mux_chip(x) container_of((x), struct mux_chip, dev)
74
75 /**
76 * mux_chip_priv() - Get the extra memory reserved by mux_chip_alloc().
77 * @mux_chip: The mux-chip to get the private memory from.
78 *
79 * Return: Pointer to the private memory reserved by the allocator.
80 */
81 static inline void *mux_chip_priv(struct mux_chip *mux_chip)
82 {
83 return &mux_chip->mux[mux_chip->controllers];
84 }
85
86 struct mux_chip *mux_chip_alloc(struct device *dev,
87 unsigned int controllers, size_t sizeof_priv);
88 int mux_chip_register(struct mux_chip *mux_chip);
89 void mux_chip_unregister(struct mux_chip *mux_chip);
90 void mux_chip_free(struct mux_chip *mux_chip);
91
92 struct mux_chip *devm_mux_chip_alloc(struct device *dev,
93 unsigned int controllers,
94 size_t sizeof_priv);
95 int devm_mux_chip_register(struct device *dev, struct mux_chip *mux_chip);
96
97 /**
98 * mux_control_get_index() - Get the index of the given mux controller
99 * @mux: The mux-control to get the index for.
100 *
101 * Return: The index of the mux controller within the mux chip the mux
102 * controller is a part of.
103 */
104 static inline unsigned int mux_control_get_index(struct mux_control *mux)
105 {
106 return mux - mux->chip->mux;
107 }
108
109 #endif /* _LINUX_MUX_DRIVER_H */
110
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