Linux-2.6.12-rc2
[linux-2.6.git] / sound / i2c / i2c.c
1 /*
2  *   Generic i2c interface for ALSA
3  *
4  *   (c) 1998 Gerd Knorr <kraxel@cs.tu-berlin.de>
5  *   Modified for the ALSA driver by Jaroslav Kysela <perex@suse.cz>
6  *
7  *   This program is free software; you can redistribute it and/or modify
8  *   it under the terms of the GNU General Public License as published by
9  *   the Free Software Foundation; either version 2 of the License, or
10  *   (at your option) any later version.
11  *
12  *   This program is distributed in the hope that it will be useful,
13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  *   GNU General Public License for more details.
16  *
17  *   You should have received a copy of the GNU General Public License
18  *   along with this program; if not, write to the Free Software
19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
20  *
21  */
22
23 #include <sound/driver.h>
24 #include <linux/init.h>
25 #include <linux/slab.h>
26 #include <linux/string.h>
27 #include <linux/errno.h>
28 #include <sound/core.h>
29 #include <sound/i2c.h>
30
31 MODULE_AUTHOR("Jaroslav Kysela <perex@suse.cz>");
32 MODULE_DESCRIPTION("Generic i2c interface for ALSA");
33 MODULE_LICENSE("GPL");
34
35 static int snd_i2c_bit_sendbytes(snd_i2c_device_t *device, unsigned char *bytes, int count);
36 static int snd_i2c_bit_readbytes(snd_i2c_device_t *device, unsigned char *bytes, int count);
37 static int snd_i2c_bit_probeaddr(snd_i2c_bus_t *bus, unsigned short addr);
38
39 static snd_i2c_ops_t snd_i2c_bit_ops = {
40         .sendbytes = snd_i2c_bit_sendbytes,
41         .readbytes = snd_i2c_bit_readbytes,
42         .probeaddr = snd_i2c_bit_probeaddr,
43 };
44
45 static int snd_i2c_bus_free(snd_i2c_bus_t *bus)
46 {
47         snd_i2c_bus_t *slave;
48         snd_i2c_device_t *device;
49
50         snd_assert(bus != NULL, return -EINVAL);
51         while (!list_empty(&bus->devices)) {
52                 device = snd_i2c_device(bus->devices.next);
53                 snd_i2c_device_free(device);
54         }
55         if (bus->master)
56                 list_del(&bus->buses);
57         else {
58                 while (!list_empty(&bus->buses)) {
59                         slave = snd_i2c_slave_bus(bus->buses.next);
60                         snd_device_free(bus->card, slave);
61                 }
62         }
63         if (bus->private_free)
64                 bus->private_free(bus);
65         kfree(bus);
66         return 0;
67 }
68
69 static int snd_i2c_bus_dev_free(snd_device_t *device)
70 {
71         snd_i2c_bus_t *bus = device->device_data;
72         return snd_i2c_bus_free(bus);
73 }
74
75 int snd_i2c_bus_create(snd_card_t *card, const char *name, snd_i2c_bus_t *master, snd_i2c_bus_t **ri2c)
76 {
77         snd_i2c_bus_t *bus;
78         int err;
79         static snd_device_ops_t ops = {
80                 .dev_free =     snd_i2c_bus_dev_free,
81         };
82
83         *ri2c = NULL;
84         bus = kcalloc(1, sizeof(*bus), GFP_KERNEL);
85         if (bus == NULL)
86                 return -ENOMEM;
87         init_MUTEX(&bus->lock_mutex);
88         INIT_LIST_HEAD(&bus->devices);
89         INIT_LIST_HEAD(&bus->buses);
90         bus->card = card;
91         bus->ops = &snd_i2c_bit_ops;
92         if (master) {
93                 list_add_tail(&bus->buses, &master->buses);
94                 bus->master = master;
95         }
96         strlcpy(bus->name, name, sizeof(bus->name));
97         if ((err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops)) < 0) {
98                 snd_i2c_bus_free(bus);
99                 return err;
100         }
101         *ri2c = bus;
102         return 0;
103 }
104
105 int snd_i2c_device_create(snd_i2c_bus_t *bus, const char *name, unsigned char addr, snd_i2c_device_t **rdevice)
106 {
107         snd_i2c_device_t *device;
108
109         *rdevice = NULL;
110         snd_assert(bus != NULL, return -EINVAL);
111         device = kcalloc(1, sizeof(*device), GFP_KERNEL);
112         if (device == NULL)
113                 return -ENOMEM;
114         device->addr = addr;
115         strlcpy(device->name, name, sizeof(device->name));
116         list_add_tail(&device->list, &bus->devices);
117         device->bus = bus;
118         *rdevice = device;
119         return 0;
120 }
121
122 int snd_i2c_device_free(snd_i2c_device_t *device)
123 {
124         if (device->bus)
125                 list_del(&device->list);
126         if (device->private_free)
127                 device->private_free(device);
128         kfree(device);
129         return 0;
130 }
131
132 int snd_i2c_sendbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
133 {
134         return device->bus->ops->sendbytes(device, bytes, count);
135 }
136
137
138 int snd_i2c_readbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
139 {
140         return device->bus->ops->readbytes(device, bytes, count);
141 }
142
143 int snd_i2c_probeaddr(snd_i2c_bus_t *bus, unsigned short addr)
144 {
145         return bus->ops->probeaddr(bus, addr);
146 }
147
148 /*
149  *  bit-operations
150  */
151
152 static inline void snd_i2c_bit_hw_start(snd_i2c_bus_t *bus)
153 {
154         if (bus->hw_ops.bit->start)
155                 bus->hw_ops.bit->start(bus);
156 }
157
158 static inline void snd_i2c_bit_hw_stop(snd_i2c_bus_t *bus)
159 {
160         if (bus->hw_ops.bit->stop)
161                 bus->hw_ops.bit->stop(bus);
162 }
163
164 static void snd_i2c_bit_direction(snd_i2c_bus_t *bus, int clock, int data)
165 {
166         if (bus->hw_ops.bit->direction)
167                 bus->hw_ops.bit->direction(bus, clock, data);
168 }
169
170 static void snd_i2c_bit_set(snd_i2c_bus_t *bus, int clock, int data)
171 {
172         bus->hw_ops.bit->setlines(bus, clock, data);
173 }
174
175 #if 0
176 static int snd_i2c_bit_clock(snd_i2c_bus_t *bus)
177 {
178         if (bus->hw_ops.bit->getclock)
179                 return bus->hw_ops.bit->getclock(bus);
180         return -ENXIO;
181 }
182 #endif
183
184 static int snd_i2c_bit_data(snd_i2c_bus_t *bus, int ack)
185 {
186         return bus->hw_ops.bit->getdata(bus, ack);
187 }
188
189 static void snd_i2c_bit_start(snd_i2c_bus_t *bus)
190 {
191         snd_i2c_bit_hw_start(bus);
192         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
193         snd_i2c_bit_set(bus, 1, 1);
194         snd_i2c_bit_set(bus, 1, 0);
195         snd_i2c_bit_set(bus, 0, 0);
196 }
197
198 static void snd_i2c_bit_stop(snd_i2c_bus_t *bus)
199 {
200         snd_i2c_bit_set(bus, 0, 0);
201         snd_i2c_bit_set(bus, 1, 0);
202         snd_i2c_bit_set(bus, 1, 1);
203         snd_i2c_bit_hw_stop(bus);
204 }
205
206 static void snd_i2c_bit_send(snd_i2c_bus_t *bus, int data)
207 {
208         snd_i2c_bit_set(bus, 0, data);
209         snd_i2c_bit_set(bus, 1, data);
210         snd_i2c_bit_set(bus, 0, data);
211 }
212
213 static int snd_i2c_bit_ack(snd_i2c_bus_t *bus)
214 {
215         int ack;
216
217         snd_i2c_bit_set(bus, 0, 1);
218         snd_i2c_bit_set(bus, 1, 1);
219         snd_i2c_bit_direction(bus, 1, 0);       /* SCL - wr, SDA - rd */
220         ack = snd_i2c_bit_data(bus, 1);
221         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
222         snd_i2c_bit_set(bus, 0, 1);
223         return ack ? -EIO : 0;
224 }
225
226 static int snd_i2c_bit_sendbyte(snd_i2c_bus_t *bus, unsigned char data)
227 {
228         int i, err;
229
230         for (i = 7; i >= 0; i--)
231                 snd_i2c_bit_send(bus, !!(data & (1 << i)));
232         if ((err = snd_i2c_bit_ack(bus)) < 0)
233                 return err;
234         return 0;
235 }
236
237 static int snd_i2c_bit_readbyte(snd_i2c_bus_t *bus, int last)
238 {
239         int i;
240         unsigned char data = 0;
241
242         snd_i2c_bit_set(bus, 0, 1);
243         snd_i2c_bit_direction(bus, 1, 0);       /* SCL - wr, SDA - rd */
244         for (i = 7; i >= 0; i--) {
245                 snd_i2c_bit_set(bus, 1, 1);
246                 if (snd_i2c_bit_data(bus, 0))
247                         data |= (1 << i);
248                 snd_i2c_bit_set(bus, 0, 1);
249         }
250         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
251         snd_i2c_bit_send(bus, !!last);
252         return data;
253 }
254
255 static int snd_i2c_bit_sendbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
256 {
257         snd_i2c_bus_t *bus = device->bus;
258         int err, res = 0;
259
260         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
261                 return -EIO;            /* not yet implemented */
262         snd_i2c_bit_start(bus);
263         if ((err = snd_i2c_bit_sendbyte(bus, device->addr << 1)) < 0) {
264                 snd_i2c_bit_hw_stop(bus);
265                 return err;
266         }
267         while (count-- > 0) {
268                 if ((err = snd_i2c_bit_sendbyte(bus, *bytes++)) < 0) {
269                         snd_i2c_bit_hw_stop(bus);
270                         return err;
271                 }
272                 res++;
273         }
274         snd_i2c_bit_stop(bus);
275         return res;
276 }
277
278 static int snd_i2c_bit_readbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
279 {
280         snd_i2c_bus_t *bus = device->bus;
281         int err, res = 0;
282
283         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
284                 return -EIO;            /* not yet implemented */
285         snd_i2c_bit_start(bus);
286         if ((err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1)) < 0) {
287                 snd_i2c_bit_hw_stop(bus);
288                 return err;
289         }
290         while (count-- > 0) {
291                 if ((err = snd_i2c_bit_readbyte(bus, count == 0)) < 0) {
292                         snd_i2c_bit_hw_stop(bus);
293                         return err;
294                 }
295                 *bytes++ = (unsigned char)err;
296                 res++;
297         }
298         snd_i2c_bit_stop(bus);
299         return res;
300 }
301
302 static int snd_i2c_bit_probeaddr(snd_i2c_bus_t *bus, unsigned short addr)
303 {
304         int err;
305
306         if (addr & 0x8000)      /* 10-bit address */
307                 return -EIO;    /* not yet implemented */
308         if (addr & 0x7f80)      /* invalid address */
309                 return -EINVAL;
310         snd_i2c_bit_start(bus);
311         err = snd_i2c_bit_sendbyte(bus, addr << 1);
312         snd_i2c_bit_stop(bus);
313         return err;
314 }
315
316 EXPORT_SYMBOL(snd_i2c_bus_create);
317 EXPORT_SYMBOL(snd_i2c_device_create);
318 EXPORT_SYMBOL(snd_i2c_device_free);
319 EXPORT_SYMBOL(snd_i2c_sendbytes);
320 EXPORT_SYMBOL(snd_i2c_readbytes);
321 EXPORT_SYMBOL(snd_i2c_probeaddr);
322
323 static int __init alsa_i2c_init(void)
324 {
325         return 0;
326 }
327
328 static void __exit alsa_i2c_exit(void)
329 {
330 }
331
332 module_init(alsa_i2c_init)
333 module_exit(alsa_i2c_exit)