xref: /openbmc/linux/include/linux/i2c-mux.h (revision 8695e0b1)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  *
4  * i2c-mux.h - functions for the i2c-bus mux support
5  *
6  * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
7  * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
8  * Michael Lawnick <michael.lawnick.ext@nsn.com>
9  */
10 
11 #ifndef _LINUX_I2C_MUX_H
12 #define _LINUX_I2C_MUX_H
13 
14 #ifdef __KERNEL__
15 
16 #include <linux/bitops.h>
17 
18 struct i2c_mux_core {
19 	struct i2c_adapter *parent;
20 	struct device *dev;
21 	unsigned int mux_locked:1;
22 	unsigned int arbitrator:1;
23 	unsigned int gate:1;
24 
25 	void *priv;
26 
27 	int (*select)(struct i2c_mux_core *, u32 chan_id);
28 	int (*deselect)(struct i2c_mux_core *, u32 chan_id);
29 
30 	int num_adapters;
31 	int max_adapters;
32 	struct i2c_adapter *adapter[];
33 };
34 
35 struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent,
36 				   struct device *dev, int max_adapters,
37 				   int sizeof_priv, u32 flags,
38 				   int (*select)(struct i2c_mux_core *, u32),
39 				   int (*deselect)(struct i2c_mux_core *, u32));
40 
41 /* flags for i2c_mux_alloc */
42 #define I2C_MUX_LOCKED     BIT(0)
43 #define I2C_MUX_ARBITRATOR BIT(1)
44 #define I2C_MUX_GATE       BIT(2)
45 
i2c_mux_priv(struct i2c_mux_core * muxc)46 static inline void *i2c_mux_priv(struct i2c_mux_core *muxc)
47 {
48 	return muxc->priv;
49 }
50 
51 struct i2c_adapter *i2c_root_adapter(struct device *dev);
52 
53 /*
54  * Called to create an i2c bus on a multiplexed bus segment.
55  * The chan_id parameter is passed to the select and deselect
56  * callback functions to perform hardware-specific mux control.
57  */
58 int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
59 			u32 force_nr, u32 chan_id,
60 			unsigned int class);
61 
62 void i2c_mux_del_adapters(struct i2c_mux_core *muxc);
63 
64 #endif /* __KERNEL__ */
65 
66 #endif /* _LINUX_I2C_MUX_H */
67