i2c: tegra: remove support for I2C_M_REV_DIR_ADDR
[linux-2.6.git] / drivers / i2c / i2c-mux.c
1 /*
2  * Multiplexed I2C bus driver.
3  *
4  * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
5  * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
6  * Copyright (c) 2009-2010 NSN GmbH & Co KG <michael.lawnick.ext@nsn.com>
7  *
8  * Simplifies access to complex multiplexed I2C bus topologies, by presenting
9  * each multiplexed bus segment as an additional I2C adapter.
10  * Supports multi-level mux'ing (mux behind a mux).
11  *
12  * Based on:
13  *      i2c-virt.c from Kumar Gala <galak@kernel.crashing.org>
14  *      i2c-virtual.c from Ken Harrenstien, Copyright (c) 2004 Google, Inc.
15  *      i2c-virtual.c from Brian Kuschak <bkuschak@yahoo.com>
16  *
17  * This file is licensed under the terms of the GNU General Public
18  * License version 2. This program is licensed "as is" without any
19  * warranty of any kind, whether express or implied.
20  */
21
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/slab.h>
25 #include <linux/i2c.h>
26 #include <linux/i2c-mux.h>
27
28 /* multiplexer per channel data */
29 struct i2c_mux_priv {
30         struct i2c_adapter adap;
31         struct i2c_algorithm algo;
32
33         struct i2c_adapter *parent;
34         void *mux_dev;  /* the mux chip/device */
35         u32  chan_id;   /* the channel id */
36
37         int (*select)(struct i2c_adapter *, void *mux_dev, u32 chan_id);
38         int (*deselect)(struct i2c_adapter *, void *mux_dev, u32 chan_id);
39 };
40
41 static int i2c_mux_master_xfer(struct i2c_adapter *adap,
42                                struct i2c_msg msgs[], int num)
43 {
44         struct i2c_mux_priv *priv = adap->algo_data;
45         struct i2c_adapter *parent = priv->parent;
46         int ret;
47
48         /* Switch to the right mux port and perform the transfer. */
49
50         ret = priv->select(parent, priv->mux_dev, priv->chan_id);
51         if (ret >= 0)
52                 ret = parent->algo->master_xfer(parent, msgs, num);
53         if (priv->deselect)
54                 priv->deselect(parent, priv->mux_dev, priv->chan_id);
55
56         return ret;
57 }
58
59 static int i2c_mux_smbus_xfer(struct i2c_adapter *adap,
60                               u16 addr, unsigned short flags,
61                               char read_write, u8 command,
62                               int size, union i2c_smbus_data *data)
63 {
64         struct i2c_mux_priv *priv = adap->algo_data;
65         struct i2c_adapter *parent = priv->parent;
66         int ret;
67
68         /* Select the right mux port and perform the transfer. */
69
70         ret = priv->select(parent, priv->mux_dev, priv->chan_id);
71         if (ret >= 0)
72                 ret = parent->algo->smbus_xfer(parent, addr, flags,
73                                         read_write, command, size, data);
74         if (priv->deselect)
75                 priv->deselect(parent, priv->mux_dev, priv->chan_id);
76
77         return ret;
78 }
79
80 /* Return the parent's functionality */
81 static u32 i2c_mux_functionality(struct i2c_adapter *adap)
82 {
83         struct i2c_mux_priv *priv = adap->algo_data;
84         struct i2c_adapter *parent = priv->parent;
85
86         return parent->algo->functionality(parent);
87 }
88
89 struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
90                                 void *mux_dev, u32 force_nr, u32 chan_id,
91                                 int (*select) (struct i2c_adapter *,
92                                                void *, u32),
93                                 int (*deselect) (struct i2c_adapter *,
94                                                  void *, u32))
95 {
96         struct i2c_mux_priv *priv;
97         int ret;
98
99         priv = kzalloc(sizeof(struct i2c_mux_priv), GFP_KERNEL);
100         if (!priv)
101                 return NULL;
102
103         /* Set up private adapter data */
104         priv->parent = parent;
105         priv->mux_dev = mux_dev;
106         priv->chan_id = chan_id;
107         priv->select = select;
108         priv->deselect = deselect;
109
110         /* Need to do algo dynamically because we don't know ahead
111          * of time what sort of physical adapter we'll be dealing with.
112          */
113         if (parent->algo->master_xfer)
114                 priv->algo.master_xfer = i2c_mux_master_xfer;
115         if (parent->algo->smbus_xfer)
116                 priv->algo.smbus_xfer = i2c_mux_smbus_xfer;
117         priv->algo.functionality = i2c_mux_functionality;
118
119         /* Now fill out new adapter structure */
120         snprintf(priv->adap.name, sizeof(priv->adap.name),
121                  "i2c-%d-mux (chan_id %d)", i2c_adapter_id(parent), chan_id);
122         priv->adap.owner = THIS_MODULE;
123         priv->adap.algo = &priv->algo;
124         priv->adap.algo_data = priv;
125         priv->adap.dev.parent = &parent->dev;
126
127         if (force_nr) {
128                 priv->adap.nr = force_nr;
129                 ret = i2c_add_numbered_adapter(&priv->adap);
130         } else {
131                 ret = i2c_add_adapter(&priv->adap);
132         }
133         if (ret < 0) {
134                 dev_err(&parent->dev,
135                         "failed to add mux-adapter (error=%d)\n",
136                         ret);
137                 kfree(priv);
138                 return NULL;
139         }
140
141         dev_info(&parent->dev, "Added multiplexed i2c bus %d\n",
142                  i2c_adapter_id(&priv->adap));
143
144         return &priv->adap;
145 }
146 EXPORT_SYMBOL_GPL(i2c_add_mux_adapter);
147
148 int i2c_del_mux_adapter(struct i2c_adapter *adap)
149 {
150         struct i2c_mux_priv *priv = adap->algo_data;
151         int ret;
152
153         ret = i2c_del_adapter(adap);
154         if (ret < 0)
155                 return ret;
156         kfree(priv);
157
158         return 0;
159 }
160 EXPORT_SYMBOL_GPL(i2c_del_mux_adapter);
161
162 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
163 MODULE_DESCRIPTION("I2C driver for multiplexed I2C busses");
164 MODULE_LICENSE("GPL v2");