LXR linux/include/linux/mux/driver.h

   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
  20struct mux_chip;
  21struct 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 */
  27struct 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 */
  45struct 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 */
  63struct 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 */
  80static inline void *mux_chip_priv(struct mux_chip *mux_chip)
  81{
  82        return &mux_chip->mux[mux_chip->controllers];
  83}
  84
  85struct mux_chip *mux_chip_alloc(struct device *dev,
  86                                unsigned int controllers, size_t sizeof_priv);
  87int mux_chip_register(struct mux_chip *mux_chip);
  88void mux_chip_unregister(struct mux_chip *mux_chip);
  89void mux_chip_free(struct mux_chip *mux_chip);
  90
  91struct mux_chip *devm_mux_chip_alloc(struct device *dev,
  92                                     unsigned int controllers,
  93                                     size_t sizeof_priv);
  94int 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 */
 103static 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