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/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Based on the linux multiplexer framework
*
* At its core, a multiplexer (or mux), also known as a data selector, is a
* device that selects between several analog or digital input signals and
* forwards it to a single output line. This notion can be extended to work
* with buses, like a I2C bus multiplexer for example.
*
* Copyright (C) 2017 Axentia Technologies AB
* Author: Peter Rosin <peda@axentia.se>
*
* Copyright (C) 2017-2018 Texas Instruments Incorporated - http://www.ti.com/
* Jean-Jacques Hiblot <jjhiblot@ti.com>
*/
#ifndef _MUX_H_
#define _MUX_H_
#include <linux/errno.h>
#include <linux/types.h>
struct udevice;
struct mux_control;
#if IS_ENABLED(CONFIG_MULTIPLEXER)
/**
* mux_control_states() - Query the number of multiplexer states.
* @mux: The mux-control to query.
*
* Return: The number of multiplexer states.
*/
unsigned int mux_control_states(struct mux_control *mux);
/**
* mux_control_select() - Select the given multiplexer state.
* @mux: The mux-control to request a change of state from.
* @state: The new requested state.
*
* On successfully selecting the mux-control state, it will be locked until
* there is a call to mux_control_deselect(). If the mux-control is already
* selected when mux_control_select() is called, the function will indicate
* -EBUSY
*
* Therefore, make sure to call mux_control_deselect() when the operation is
* complete and the mux-control is free for others to use, but do not call
* mux_control_deselect() if mux_control_select() fails.
*
* Return: 0 when the mux-control state has the requested state or a negative
* errno on error.
*/
int __must_check mux_control_select(struct mux_control *mux,
unsigned int state);
#define mux_control_try_select(mux, state) mux_control_select(mux, state)
/**
* mux_control_deselect() - Deselect the previously selected multiplexer state.
* @mux: The mux-control to deselect.
*
* It is required that a single call is made to mux_control_deselect() for
* each and every successful call made to either of mux_control_select() or
* mux_control_try_select().
*
* Return: 0 on success and a negative errno on error. An error can only
* occur if the mux has an idle state. Note that even if an error occurs, the
* mux-control is unlocked and is thus free for the next access.
*/
int mux_control_deselect(struct mux_control *mux);
/**
* mux_get_by_index() = Get a mux by integer index.
* @dev: The client device.
* @index: The index of the mux to get.
* @mux: A pointer to the 'mux_control' struct to initialize.
*
* This looks up and initializes a mux. The index is relative to the client
* device.
*
* Return: 0 if OK, or a negative error code.
*/
int mux_get_by_index(struct udevice *dev, int index, struct mux_control **mux);
/**
* mux_control_get() - Get the mux-control for a device.
* @dev: The device that needs a mux-control.
* @mux_name: The name identifying the mux-control.
* @mux: A pointer to the mux-control pointer.
*
* Return: 0 of OK, or a negative error code.
*/
int mux_control_get(struct udevice *dev, const char *name,
struct mux_control **mux);
/**
* mux_control_put() - Put away the mux-control for good.
* @mux: The mux-control to put away.
*
* mux_control_put() reverses the effects of mux_control_get().
*/
void mux_control_put(struct mux_control *mux);
/**
* devm_mux_control_get() - Get the mux-control for a device, with resource
* management.
* @dev: The device that needs a mux-control.
* @mux_name: The name identifying the mux-control.
*
* Return: Pointer to the mux-control, or an ERR_PTR with a negative errno.
*/
struct mux_control *devm_mux_control_get(struct udevice *dev,
const char *mux_name);
/**
* dm_mux_init() - Initialize the multiplexer controls to their default state.
*
* Return: 0 if OK, -errno otherwise.
*/
int dm_mux_init(void);
#else
unsigned int mux_control_states(struct mux_control *mux)
{
return -ENOSYS;
}
int __must_check mux_control_select(struct mux_control *mux,
unsigned int state)
{
return -ENOSYS;
}
#define mux_control_try_select(mux, state) mux_control_select(mux, state)
int mux_control_deselect(struct mux_control *mux)
{
return -ENOSYS;
}
struct mux_control *mux_control_get(struct udevice *dev, const char *mux_name)
{
return NULL;
}
void mux_control_put(struct mux_control *mux)
{
}
struct mux_control *devm_mux_control_get(struct udevice *dev,
const char *mux_name)
{
return NULL;
}
int dm_mux_init(void)
{
return -ENOSYS;
}
#endif
#endif
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