You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
160 lines
4.5 KiB
160 lines
4.5 KiB
/* 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 CONFIG_IS_ENABLED(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
|