linux-stable/include/linux/i2c-mux.h
Peter Rosin b2d57b5604 i2c: mux: add support for 'i2c-mux', 'i2c-arb' and 'i2c-gate' DT subnodes
Backwards compatibility is preserved; the subnodes are in practice
optional.

However, the mux core needs to know what subnode it should examine, so add
a couple of new flags for i2c_mux_alloc for this purpose.

The rule is that if the mux core finds a 'reg' property in the appropriate
subnode, e.g. if 'reg' exists in the 'i2c-mux' subnode, then the mux core
will assume that this is an old style entry and not an i2c-mux subnode
(correspondingly for arbitrators and gates with 'i2c-arb' and 'i2c-gate').

Reviewed-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Peter Rosin <peda@axentia.se>
2016-08-25 22:11:02 +02:00

80 lines
2.3 KiB
C

/*
*
* 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., 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_ARBITRATOR BIT(1)
#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 */