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i2c: Multiplexed I2C bus core support

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Add multiplexed bus core support. I2C multiplexer and switches
like pca954x get instantiated as new adapters per port.

Signed-off-by: Michael Lawnick <ml.lawnick@gmx.de>
Acked-by: Rodolfo Giometti <giometti@linux.it>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
This commit is contained in:
Michael Lawnick
2010-08-11 18:21:02 +02:00
committed by Jean Delvare
parent dafc50d141
commit 0826374bff
7 changed files with 327 additions and 8 deletions
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46
include/linux/i2c-mux.h Normal file
View File

@@ -0,0 +1,46 @@
/*
*
* i2c-mux.h - functions for the i2c-bus mux support
*
* Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
* Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
* Michael Lawnick <michael.lawnick.ext@nsn.com>
*
* 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
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef _LINUX_I2C_MUX_H
#define _LINUX_I2C_MUX_H
#ifdef __KERNEL__
/*
* Called to create a i2c bus on a multiplexed bus segment.
* The mux_dev and chan_id parameters are passed to the select
* and deselect callback functions to perform hardware-specific
* mux control.
*/
struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
void *mux_dev, u32 force_nr, u32 chan_id,
int (*select) (struct i2c_adapter *,
void *mux_dev, u32 chan_id),
int (*deselect) (struct i2c_adapter *,
void *mux_dev, u32 chan_id));
int i2c_del_mux_adapter(struct i2c_adapter *adap);
#endif /* __KERNEL__ */
#endif /* _LINUX_I2C_MUX_H */

8
include/linux/i2c.h
View File

@@ -37,6 +37,7 @@
#include <linux/of.h> /* for struct device_node */
extern struct bus_type i2c_bus_type;
extern struct device_type i2c_adapter_type;
/* --- General options ------------------------------------------------ */
@@ -383,6 +384,13 @@ static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data)
dev_set_drvdata(&dev->dev, data);
}
static inline int i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
{
return adapter->dev.parent != NULL
&& adapter->dev.parent->bus == &i2c_bus_type
&& adapter->dev.parent->type == &i2c_adapter_type;
}
/* Adapter locking functions, exported for shared pin cases */
void i2c_lock_adapter(struct i2c_adapter *);
void i2c_unlock_adapter(struct i2c_adapter *);