driver.h

  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
 18struct mux_chip;
 19struct 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 */
 25struct 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 */
 44struct 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 * @dev:		Device structure.
 60 * @id:			Used to identify the device internally.
 61 * @ops:		Mux controller operations.
 62 * @mux:		Array of mux controllers that are handled.
 63 */
 64struct mux_chip {
 65	unsigned int controllers;
 66	struct device dev;
 67	int id;
 68
 69	const struct mux_control_ops *ops;
 70	struct mux_control mux[] __counted_by(controllers);
 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 */
 81static inline void *mux_chip_priv(struct mux_chip *mux_chip)
 82{
 83	return &mux_chip->mux[mux_chip->controllers];
 84}
 85
 86struct mux_chip *mux_chip_alloc(struct device *dev,
 87				unsigned int controllers, size_t sizeof_priv);
 88int mux_chip_register(struct mux_chip *mux_chip);
 89void mux_chip_unregister(struct mux_chip *mux_chip);
 90void mux_chip_free(struct mux_chip *mux_chip);
 91
 92struct mux_chip *devm_mux_chip_alloc(struct device *dev,
 93				     unsigned int controllers,
 94				     size_t sizeof_priv);
 95int 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 */
104static 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 */