i2c/pca954x: Remove __devinit and __devexit from probe and remove functions
[linux-2.6.git] / drivers / i2c / muxes / pca954x.c
1 /*
2  * I2C multiplexer
3  *
4  * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
5  * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
6  *
7  * This module supports the PCA954x series of I2C multiplexer/switch chips
8  * made by Philips Semiconductors.
9  * This includes the:
10  *       PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547
11  *       and PCA9548.
12  *
13  * These chips are all controlled via the I2C bus itself, and all have a
14  * single 8-bit register. The upstream "parent" bus fans out to two,
15  * four, or eight downstream busses or channels; which of these
16  * are selected is determined by the chip type and register contents. A
17  * mux can select only one sub-bus at a time; a switch can select any
18  * combination simultaneously.
19  *
20  * Based on:
21  *      pca954x.c from Kumar Gala <galak@kernel.crashing.org>
22  * Copyright (C) 2006
23  *
24  * Based on:
25  *      pca954x.c from Ken Harrenstien
26  * Copyright (C) 2004 Google, Inc. (Ken Harrenstien)
27  *
28  * Based on:
29  *      i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com>
30  * and
31  *      pca9540.c from Jean Delvare <khali@linux-fr.org>.
32  *
33  * This file is licensed under the terms of the GNU General Public
34  * License version 2. This program is licensed "as is" without any
35  * warranty of any kind, whether express or implied.
36  */
37
38 #include <linux/module.h>
39 #include <linux/init.h>
40 #include <linux/slab.h>
41 #include <linux/device.h>
42 #include <linux/i2c.h>
43 #include <linux/i2c-mux.h>
44
45 #include <linux/i2c/pca954x.h>
46
47 #define PCA954X_MAX_NCHANS 8
48
49 enum pca_type {
50         pca_9540,
51         pca_9542,
52         pca_9543,
53         pca_9544,
54         pca_9545,
55         pca_9546,
56         pca_9547,
57         pca_9548,
58 };
59
60 struct pca954x {
61         enum pca_type type;
62         struct i2c_adapter *virt_adaps[PCA954X_MAX_NCHANS];
63
64         u8 last_chan;           /* last register value */
65 };
66
67 struct chip_desc {
68         u8 nchans;
69         u8 enable;      /* used for muxes only */
70         enum muxtype {
71                 pca954x_ismux = 0,
72                 pca954x_isswi
73         } muxtype;
74 };
75
76 /* Provide specs for the PCA954x types we know about */
77 static const struct chip_desc chips[] = {
78         [pca_9540] = {
79                 .nchans = 2,
80                 .enable = 0x4,
81                 .muxtype = pca954x_ismux,
82         },
83         [pca_9543] = {
84                 .nchans = 2,
85                 .muxtype = pca954x_isswi,
86         },
87         [pca_9544] = {
88                 .nchans = 4,
89                 .enable = 0x4,
90                 .muxtype = pca954x_ismux,
91         },
92         [pca_9545] = {
93                 .nchans = 4,
94                 .muxtype = pca954x_isswi,
95         },
96         [pca_9547] = {
97                 .nchans = 8,
98                 .enable = 0x8,
99                 .muxtype = pca954x_ismux,
100         },
101         [pca_9548] = {
102                 .nchans = 8,
103                 .muxtype = pca954x_isswi,
104         },
105 };
106
107 static const struct i2c_device_id pca954x_id[] = {
108         { "pca9540", pca_9540 },
109         { "pca9542", pca_9540 },
110         { "pca9543", pca_9543 },
111         { "pca9544", pca_9544 },
112         { "pca9545", pca_9545 },
113         { "pca9546", pca_9545 },
114         { "pca9547", pca_9547 },
115         { "pca9548", pca_9548 },
116         { }
117 };
118 MODULE_DEVICE_TABLE(i2c, pca954x_id);
119
120 /* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
121    for this as they will try to lock adapter a second time */
122 static int pca954x_reg_write(struct i2c_adapter *adap,
123                              struct i2c_client *client, u8 val)
124 {
125         int ret = -ENODEV;
126
127         if (adap->algo->master_xfer) {
128                 struct i2c_msg msg;
129                 char buf[1];
130
131                 msg.addr = client->addr;
132                 msg.flags = 0;
133                 msg.len = 1;
134                 buf[0] = val;
135                 msg.buf = buf;
136                 ret = adap->algo->master_xfer(adap, &msg, 1);
137         } else {
138                 union i2c_smbus_data data;
139                 ret = adap->algo->smbus_xfer(adap, client->addr,
140                                              client->flags,
141                                              I2C_SMBUS_WRITE,
142                                              val, I2C_SMBUS_BYTE, &data);
143         }
144
145         return ret;
146 }
147
148 static int pca954x_select_chan(struct i2c_adapter *adap,
149                                void *client, u32 chan)
150 {
151         struct pca954x *data = i2c_get_clientdata(client);
152         const struct chip_desc *chip = &chips[data->type];
153         u8 regval;
154         int ret = 0;
155
156         /* we make switches look like muxes, not sure how to be smarter */
157         if (chip->muxtype == pca954x_ismux)
158                 regval = chan | chip->enable;
159         else
160                 regval = 1 << chan;
161
162         /* Only select the channel if its different from the last channel */
163         if (data->last_chan != regval) {
164                 ret = pca954x_reg_write(adap, client, regval);
165                 data->last_chan = regval;
166         }
167
168         return ret;
169 }
170
171 static int pca954x_deselect_mux(struct i2c_adapter *adap,
172                                 void *client, u32 chan)
173 {
174         struct pca954x *data = i2c_get_clientdata(client);
175
176         /* Deselect active channel */
177         data->last_chan = 0;
178         return pca954x_reg_write(adap, client, data->last_chan);
179 }
180
181 /*
182  * I2C init/probing/exit functions
183  */
184 static int pca954x_probe(struct i2c_client *client,
185                          const struct i2c_device_id *id)
186 {
187         struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
188         struct pca954x_platform_data *pdata = client->dev.platform_data;
189         int num, force;
190         struct pca954x *data;
191         int ret = -ENODEV;
192
193         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
194                 goto err;
195
196         data = kzalloc(sizeof(struct pca954x), GFP_KERNEL);
197         if (!data) {
198                 ret = -ENOMEM;
199                 goto err;
200         }
201
202         i2c_set_clientdata(client, data);
203
204         /* Read the mux register at addr to verify
205          * that the mux is in fact present.
206          */
207         if (i2c_smbus_read_byte(client) < 0) {
208                 dev_warn(&client->dev, "probe failed\n");
209                 goto exit_free;
210         }
211
212         data->type = id->driver_data;
213         data->last_chan = 0;               /* force the first selection */
214
215         /* Now create an adapter for each channel */
216         for (num = 0; num < chips[data->type].nchans; num++) {
217                 force = 0;                        /* dynamic adap number */
218                 if (pdata) {
219                         if (num < pdata->num_modes)
220                                 /* force static number */
221                                 force = pdata->modes[num].adap_id;
222                         else
223                                 /* discard unconfigured channels */
224                                 break;
225                 }
226
227                 data->virt_adaps[num] =
228                         i2c_add_mux_adapter(adap, client,
229                                 force, num, pca954x_select_chan,
230                                 (pdata && pdata->modes[num].deselect_on_exit)
231                                         ? pca954x_deselect_mux : NULL);
232
233                 if (data->virt_adaps[num] == NULL) {
234                         ret = -ENODEV;
235                         dev_err(&client->dev,
236                                 "failed to register multiplexed adapter"
237                                 " %d as bus %d\n", num, force);
238                         goto virt_reg_failed;
239                 }
240         }
241
242         dev_info(&client->dev,
243                  "registered %d multiplexed busses for I2C %s %s\n",
244                  num, chips[data->type].muxtype == pca954x_ismux
245                                 ? "mux" : "switch", client->name);
246
247         return 0;
248
249 virt_reg_failed:
250         for (num--; num >= 0; num--)
251                 i2c_del_mux_adapter(data->virt_adaps[num]);
252 exit_free:
253         kfree(data);
254 err:
255         return ret;
256 }
257
258 static int pca954x_remove(struct i2c_client *client)
259 {
260         struct pca954x *data = i2c_get_clientdata(client);
261         const struct chip_desc *chip = &chips[data->type];
262         int i, err;
263
264         for (i = 0; i < chip->nchans; ++i)
265                 if (data->virt_adaps[i]) {
266                         err = i2c_del_mux_adapter(data->virt_adaps[i]);
267                         if (err)
268                                 return err;
269                         data->virt_adaps[i] = NULL;
270                 }
271
272         kfree(data);
273         return 0;
274 }
275
276 static struct i2c_driver pca954x_driver = {
277         .driver         = {
278                 .name   = "pca954x",
279                 .owner  = THIS_MODULE,
280         },
281         .probe          = pca954x_probe,
282         .remove         = pca954x_remove,
283         .id_table       = pca954x_id,
284 };
285
286 static int __init pca954x_init(void)
287 {
288         return i2c_add_driver(&pca954x_driver);
289 }
290
291 static void __exit pca954x_exit(void)
292 {
293         i2c_del_driver(&pca954x_driver);
294 }
295
296 module_init(pca954x_init);
297 module_exit(pca954x_exit);
298
299 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
300 MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
301 MODULE_LICENSE("GPL v2");