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
