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 */ mux_chip_priv(struct mux_chip * mux_chip)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 */ mux_control_get_index(struct mux_control * mux)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 */ 106