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* mux/driver.h - definitions for the multiplexer driver interface
* Copyright (C) 2017 Axentia Technologies AB
* Author: Peter Rosin <>
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
#include <dt-bindings/mux/mux.h>
#include <linux/device.h>
#include <linux/semaphore.h>
struct mux_chip;
struct mux_control;
* struct mux_control_ops - Mux controller operations for a mux chip.
* @set: Set the state of the given mux controller.
struct mux_control_ops {
int (*set)(struct mux_control *mux, int state);
* struct mux_control - Represents a mux controller.
* @lock: Protects the mux controller state.
* @chip: The mux chip that is handling this mux controller.
* @cached_state: The current mux controller state, or -1 if none.
* @states: The number of mux controller states.
* @idle_state: The mux controller state to use when inactive, or one
* Mux drivers may only change @states and @idle_state, and may only do so
* between allocation and registration of the mux controller. Specifically,
* @cached_state is internal to the mux core and should never be written by
* mux drivers.
struct mux_control {
struct semaphore lock; /* protects the state of the mux */
struct mux_chip *chip;
int cached_state;
unsigned int states;
int idle_state;
* struct mux_chip - Represents a chip holding mux controllers.
* @controllers: Number of mux controllers handled by the chip.
* @mux: Array of mux controllers that are handled.
* @dev: Device structure.
* @id: Used to identify the device internally.
* @ops: Mux controller operations.
struct mux_chip {
unsigned int controllers;
struct mux_control *mux;
struct device dev;
int id;
const struct mux_control_ops *ops;
#define to_mux_chip(x) container_of((x), struct mux_chip, dev)
* mux_chip_priv() - Get the extra memory reserved by mux_chip_alloc().
* @mux_chip: The mux-chip to get the private memory from.
* Return: Pointer to the private memory reserved by the allocator.
static inline void *mux_chip_priv(struct mux_chip *mux_chip)
return &mux_chip->mux[mux_chip->controllers];
struct mux_chip *mux_chip_alloc(struct device *dev,
unsigned int controllers, size_t sizeof_priv);
int mux_chip_register(struct mux_chip *mux_chip);
void mux_chip_unregister(struct mux_chip *mux_chip);
void mux_chip_free(struct mux_chip *mux_chip);
struct mux_chip *devm_mux_chip_alloc(struct device *dev,
unsigned int controllers,
size_t sizeof_priv);
int devm_mux_chip_register(struct device *dev, struct mux_chip *mux_chip);
* mux_control_get_index() - Get the index of the given mux controller
* @mux: The mux-control to get the index for.
* Return: The index of the mux controller within the mux chip the mux
* controller is a part of.
static inline unsigned int mux_control_get_index(struct mux_control *mux)
return mux - mux->chip->mux;
#endif /* _LINUX_MUX_DRIVER_H */