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 | |