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* i2c-mux.h - functions for the i2c-bus mux support
* Copyright (c) 2008-2009 Rodolfo Giometti <>
* Copyright (c) 2008-2009 Eurotech S.p.A. <>
* Michael Lawnick <>
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301 USA.
#ifndef _LINUX_I2C_MUX_H
#define _LINUX_I2C_MUX_H
#ifdef __KERNEL__
#include <linux/bitops.h>
struct i2c_mux_core {
struct i2c_adapter *parent;
struct device *dev;
unsigned int mux_locked:1;
unsigned int arbitrator:1;
unsigned int gate:1;
void *priv;
int (*select)(struct i2c_mux_core *, u32 chan_id);
int (*deselect)(struct i2c_mux_core *, u32 chan_id);
int num_adapters;
int max_adapters;
struct i2c_adapter *adapter[0];
struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent,
struct device *dev, int max_adapters,
int sizeof_priv, u32 flags,
int (*select)(struct i2c_mux_core *, u32),
int (*deselect)(struct i2c_mux_core *, u32));
/* flags for i2c_mux_alloc */
#define I2C_MUX_LOCKED BIT(0)
#define I2C_MUX_GATE BIT(2)
static inline void *i2c_mux_priv(struct i2c_mux_core *muxc)
return muxc->priv;
struct i2c_adapter *i2c_root_adapter(struct device *dev);
* Called to create an i2c bus on a multiplexed bus segment.
* The chan_id parameter is passed to the select and deselect
* callback functions to perform hardware-specific mux control.
int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
u32 force_nr, u32 chan_id,
unsigned int class);
void i2c_mux_del_adapters(struct i2c_mux_core *muxc);
#endif /* __KERNEL__ */
#endif /* _LINUX_I2C_MUX_H */