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