include/linux/mux/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/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  */
  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  */
 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 */