b1e74e40cba050656879dbe529a72adb218397c3
[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@perex.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 <linux/init.h>
24 #include <linux/slab.h>
25 #include <linux/string.h>
26 #include <linux/errno.h>
27 #include <sound/core.h>
28 #include <sound/i2c.h>
29
30 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
31 MODULE_DESCRIPTION("Generic i2c interface for ALSA");
32 MODULE_LICENSE("GPL");
33
34 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
35                                  unsigned char *bytes, int count);
36 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
37                                  unsigned char *bytes, int count);
38 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus,
39                                  unsigned short addr);
40
41 static struct snd_i2c_ops snd_i2c_bit_ops = {
42         .sendbytes = snd_i2c_bit_sendbytes,
43         .readbytes = snd_i2c_bit_readbytes,
44         .probeaddr = snd_i2c_bit_probeaddr,
45 };
46
47 static int snd_i2c_bus_free(struct snd_i2c_bus *bus)
48 {
49         struct snd_i2c_bus *slave;
50         struct snd_i2c_device *device;
51
52         snd_assert(bus != NULL, return -EINVAL);
53         while (!list_empty(&bus->devices)) {
54                 device = snd_i2c_device(bus->devices.next);
55                 snd_i2c_device_free(device);
56         }
57         if (bus->master)
58                 list_del(&bus->buses);
59         else {
60                 while (!list_empty(&bus->buses)) {
61                         slave = snd_i2c_slave_bus(bus->buses.next);
62                         snd_device_free(bus->card, slave);
63                 }
64         }
65         if (bus->private_free)
66                 bus->private_free(bus);
67         kfree(bus);
68         return 0;
69 }
70
71 static int snd_i2c_bus_dev_free(struct snd_device *device)
72 {
73         struct snd_i2c_bus *bus = device->device_data;
74         return snd_i2c_bus_free(bus);
75 }
76
77 int snd_i2c_bus_create(struct snd_card *card, const char *name,
78                        struct snd_i2c_bus *master, struct snd_i2c_bus **ri2c)
79 {
80         struct snd_i2c_bus *bus;
81         int err;
82         static struct snd_device_ops ops = {
83                 .dev_free =     snd_i2c_bus_dev_free,
84         };
85
86         *ri2c = NULL;
87         bus = kzalloc(sizeof(*bus), GFP_KERNEL);
88         if (bus == NULL)
89                 return -ENOMEM;
90         mutex_init(&bus->lock_mutex);
91         INIT_LIST_HEAD(&bus->devices);
92         INIT_LIST_HEAD(&bus->buses);
93         bus->card = card;
94         bus->ops = &snd_i2c_bit_ops;
95         if (master) {
96                 list_add_tail(&bus->buses, &master->buses);
97                 bus->master = master;
98         }
99         strlcpy(bus->name, name, sizeof(bus->name));
100         if ((err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops)) < 0) {
101                 snd_i2c_bus_free(bus);
102                 return err;
103         }
104         *ri2c = bus;
105         return 0;
106 }
107
108 EXPORT_SYMBOL(snd_i2c_bus_create);
109
110 int snd_i2c_device_create(struct snd_i2c_bus *bus, const char *name,
111                           unsigned char addr, struct snd_i2c_device **rdevice)
112 {
113         struct snd_i2c_device *device;
114
115         *rdevice = NULL;
116         snd_assert(bus != NULL, return -EINVAL);
117         device = kzalloc(sizeof(*device), GFP_KERNEL);
118         if (device == NULL)
119                 return -ENOMEM;
120         device->addr = addr;
121         strlcpy(device->name, name, sizeof(device->name));
122         list_add_tail(&device->list, &bus->devices);
123         device->bus = bus;
124         *rdevice = device;
125         return 0;
126 }
127
128 EXPORT_SYMBOL(snd_i2c_device_create);
129
130 int snd_i2c_device_free(struct snd_i2c_device *device)
131 {
132         if (device->bus)
133                 list_del(&device->list);
134         if (device->private_free)
135                 device->private_free(device);
136         kfree(device);
137         return 0;
138 }
139
140 EXPORT_SYMBOL(snd_i2c_device_free);
141
142 int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
143 {
144         return device->bus->ops->sendbytes(device, bytes, count);
145 }
146
147 EXPORT_SYMBOL(snd_i2c_sendbytes);
148
149 int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
150 {
151         return device->bus->ops->readbytes(device, bytes, count);
152 }
153
154 EXPORT_SYMBOL(snd_i2c_readbytes);
155
156 int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
157 {
158         return bus->ops->probeaddr(bus, addr);
159 }
160
161 EXPORT_SYMBOL(snd_i2c_probeaddr);
162
163 /*
164  *  bit-operations
165  */
166
167 static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus)
168 {
169         if (bus->hw_ops.bit->start)
170                 bus->hw_ops.bit->start(bus);
171 }
172
173 static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus)
174 {
175         if (bus->hw_ops.bit->stop)
176                 bus->hw_ops.bit->stop(bus);
177 }
178
179 static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data)
180 {
181         if (bus->hw_ops.bit->direction)
182                 bus->hw_ops.bit->direction(bus, clock, data);
183 }
184
185 static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data)
186 {
187         bus->hw_ops.bit->setlines(bus, clock, data);
188 }
189
190 #if 0
191 static int snd_i2c_bit_clock(struct snd_i2c_bus *bus)
192 {
193         if (bus->hw_ops.bit->getclock)
194                 return bus->hw_ops.bit->getclock(bus);
195         return -ENXIO;
196 }
197 #endif
198
199 static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
200 {
201         return bus->hw_ops.bit->getdata(bus, ack);
202 }
203
204 static void snd_i2c_bit_start(struct snd_i2c_bus *bus)
205 {
206         snd_i2c_bit_hw_start(bus);
207         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
208         snd_i2c_bit_set(bus, 1, 1);
209         snd_i2c_bit_set(bus, 1, 0);
210         snd_i2c_bit_set(bus, 0, 0);
211 }
212
213 static void snd_i2c_bit_stop(struct snd_i2c_bus *bus)
214 {
215         snd_i2c_bit_set(bus, 0, 0);
216         snd_i2c_bit_set(bus, 1, 0);
217         snd_i2c_bit_set(bus, 1, 1);
218         snd_i2c_bit_hw_stop(bus);
219 }
220
221 static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data)
222 {
223         snd_i2c_bit_set(bus, 0, data);
224         snd_i2c_bit_set(bus, 1, data);
225         snd_i2c_bit_set(bus, 0, data);
226 }
227
228 static int snd_i2c_bit_ack(struct snd_i2c_bus *bus)
229 {
230         int ack;
231
232         snd_i2c_bit_set(bus, 0, 1);
233         snd_i2c_bit_set(bus, 1, 1);
234         snd_i2c_bit_direction(bus, 1, 0);       /* SCL - wr, SDA - rd */
235         ack = snd_i2c_bit_data(bus, 1);
236         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
237         snd_i2c_bit_set(bus, 0, 1);
238         return ack ? -EIO : 0;
239 }
240
241 static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data)
242 {
243         int i, err;
244
245         for (i = 7; i >= 0; i--)
246                 snd_i2c_bit_send(bus, !!(data & (1 << i)));
247         if ((err = snd_i2c_bit_ack(bus)) < 0)
248                 return err;
249         return 0;
250 }
251
252 static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
253 {
254         int i;
255         unsigned char data = 0;
256
257         snd_i2c_bit_set(bus, 0, 1);
258         snd_i2c_bit_direction(bus, 1, 0);       /* SCL - wr, SDA - rd */
259         for (i = 7; i >= 0; i--) {
260                 snd_i2c_bit_set(bus, 1, 1);
261                 if (snd_i2c_bit_data(bus, 0))
262                         data |= (1 << i);
263                 snd_i2c_bit_set(bus, 0, 1);
264         }
265         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
266         snd_i2c_bit_send(bus, !!last);
267         return data;
268 }
269
270 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
271                                  unsigned char *bytes, int count)
272 {
273         struct snd_i2c_bus *bus = device->bus;
274         int err, res = 0;
275
276         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
277                 return -EIO;            /* not yet implemented */
278         snd_i2c_bit_start(bus);
279         if ((err = snd_i2c_bit_sendbyte(bus, device->addr << 1)) < 0) {
280                 snd_i2c_bit_hw_stop(bus);
281                 return err;
282         }
283         while (count-- > 0) {
284                 if ((err = snd_i2c_bit_sendbyte(bus, *bytes++)) < 0) {
285                         snd_i2c_bit_hw_stop(bus);
286                         return err;
287                 }
288                 res++;
289         }
290         snd_i2c_bit_stop(bus);
291         return res;
292 }
293
294 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
295                                  unsigned char *bytes, int count)
296 {
297         struct snd_i2c_bus *bus = device->bus;
298         int err, res = 0;
299
300         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
301                 return -EIO;            /* not yet implemented */
302         snd_i2c_bit_start(bus);
303         if ((err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1)) < 0) {
304                 snd_i2c_bit_hw_stop(bus);
305                 return err;
306         }
307         while (count-- > 0) {
308                 if ((err = snd_i2c_bit_readbyte(bus, count == 0)) < 0) {
309                         snd_i2c_bit_hw_stop(bus);
310                         return err;
311                 }
312                 *bytes++ = (unsigned char)err;
313                 res++;
314         }
315         snd_i2c_bit_stop(bus);
316         return res;
317 }
318
319 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
320 {
321         int err;
322
323         if (addr & 0x8000)      /* 10-bit address */
324                 return -EIO;    /* not yet implemented */
325         if (addr & 0x7f80)      /* invalid address */
326                 return -EINVAL;
327         snd_i2c_bit_start(bus);
328         err = snd_i2c_bit_sendbyte(bus, addr << 1);
329         snd_i2c_bit_stop(bus);
330         return err;
331 }
332
333
334 static int __init alsa_i2c_init(void)
335 {
336         return 0;
337 }
338
339 static void __exit alsa_i2c_exit(void)
340 {
341 }
342
343 module_init(alsa_i2c_init)
344 module_exit(alsa_i2c_exit)