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