1 /*
2  *
3  * i2c-mux.h - functions for the i2c-bus mux support
4  *
5  * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
6  * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
7  * Michael Lawnick <michael.lawnick.ext@nsn.com>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
22  * MA 02110-1301 USA.
23  */
24 
25 #ifndef _LINUX_I2C_MUX_H
26 #define _LINUX_I2C_MUX_H
27 
28 #ifdef __KERNEL__
29 
30 #include <linux/bitops.h>
31 
32 struct i2c_mux_core {
33 	struct i2c_adapter *parent;
34 	struct device *dev;
35 	unsigned int mux_locked:1;
36 	unsigned int arbitrator:1;
37 	unsigned int gate:1;
38 
39 	void *priv;
40 
41 	int (*select)(struct i2c_mux_core *, u32 chan_id);
42 	int (*deselect)(struct i2c_mux_core *, u32 chan_id);
43 
44 	int num_adapters;
45 	int max_adapters;
46 	struct i2c_adapter *adapter[0];
47 };
48 
49 struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent,
50 				   struct device *dev, int max_adapters,
51 				   int sizeof_priv, u32 flags,
52 				   int (*select)(struct i2c_mux_core *, u32),
53 				   int (*deselect)(struct i2c_mux_core *, u32));
54 
55 /* flags for i2c_mux_alloc */
56 #define I2C_MUX_LOCKED     BIT(0)
57 #define I2C_MUX_ARBITRATOR BIT(1)
58 #define I2C_MUX_GATE       BIT(2)
59 
i2c_mux_priv(struct i2c_mux_core * muxc)60 static inline void *i2c_mux_priv(struct i2c_mux_core *muxc)
61 {
62 	return muxc->priv;
63 }
64 
65 struct i2c_adapter *i2c_root_adapter(struct device *dev);
66 
67 /*
68  * Called to create an i2c bus on a multiplexed bus segment.
69  * The chan_id parameter is passed to the select and deselect
70  * callback functions to perform hardware-specific mux control.
71  */
72 int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
73 			u32 force_nr, u32 chan_id,
74 			unsigned int class);
75 
76 void i2c_mux_del_adapters(struct i2c_mux_core *muxc);
77 
78 #endif /* __KERNEL__ */
79 
80 #endif /* _LINUX_I2C_MUX_H */
81