[media] v4l2: add const to argument of write-only s_tuner ioctl
[linux-3.10.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/module.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@perex.cz>");
32 MODULE_DESCRIPTION("Generic i2c interface for ALSA");
33 MODULE_LICENSE("GPL");
34
35 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
36                                  unsigned char *bytes, int count);
37 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
38                                  unsigned char *bytes, int count);
39 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus,
40                                  unsigned short addr);
41
42 static struct snd_i2c_ops snd_i2c_bit_ops = {
43         .sendbytes = snd_i2c_bit_sendbytes,
44         .readbytes = snd_i2c_bit_readbytes,
45         .probeaddr = snd_i2c_bit_probeaddr,
46 };
47
48 static int snd_i2c_bus_free(struct snd_i2c_bus *bus)
49 {
50         struct snd_i2c_bus *slave;
51         struct snd_i2c_device *device;
52
53         if (snd_BUG_ON(!bus))
54                 return -EINVAL;
55         while (!list_empty(&bus->devices)) {
56                 device = snd_i2c_device(bus->devices.next);
57                 snd_i2c_device_free(device);
58         }
59         if (bus->master)
60                 list_del(&bus->buses);
61         else {
62                 while (!list_empty(&bus->buses)) {
63                         slave = snd_i2c_slave_bus(bus->buses.next);
64                         snd_device_free(bus->card, slave);
65                 }
66         }
67         if (bus->private_free)
68                 bus->private_free(bus);
69         kfree(bus);
70         return 0;
71 }
72
73 static int snd_i2c_bus_dev_free(struct snd_device *device)
74 {
75         struct snd_i2c_bus *bus = device->device_data;
76         return snd_i2c_bus_free(bus);
77 }
78
79 int snd_i2c_bus_create(struct snd_card *card, const char *name,
80                        struct snd_i2c_bus *master, struct snd_i2c_bus **ri2c)
81 {
82         struct snd_i2c_bus *bus;
83         int err;
84         static struct snd_device_ops ops = {
85                 .dev_free =     snd_i2c_bus_dev_free,
86         };
87
88         *ri2c = NULL;
89         bus = kzalloc(sizeof(*bus), GFP_KERNEL);
90         if (bus == NULL)
91                 return -ENOMEM;
92         mutex_init(&bus->lock_mutex);
93         INIT_LIST_HEAD(&bus->devices);
94         INIT_LIST_HEAD(&bus->buses);
95         bus->card = card;
96         bus->ops = &snd_i2c_bit_ops;
97         if (master) {
98                 list_add_tail(&bus->buses, &master->buses);
99                 bus->master = master;
100         }
101         strlcpy(bus->name, name, sizeof(bus->name));
102         err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops);
103         if (err < 0) {
104                 snd_i2c_bus_free(bus);
105                 return err;
106         }
107         *ri2c = bus;
108         return 0;
109 }
110
111 EXPORT_SYMBOL(snd_i2c_bus_create);
112
113 int snd_i2c_device_create(struct snd_i2c_bus *bus, const char *name,
114                           unsigned char addr, struct snd_i2c_device **rdevice)
115 {
116         struct snd_i2c_device *device;
117
118         *rdevice = NULL;
119         if (snd_BUG_ON(!bus))
120                 return -EINVAL;
121         device = kzalloc(sizeof(*device), GFP_KERNEL);
122         if (device == NULL)
123                 return -ENOMEM;
124         device->addr = addr;
125         strlcpy(device->name, name, sizeof(device->name));
126         list_add_tail(&device->list, &bus->devices);
127         device->bus = bus;
128         *rdevice = device;
129         return 0;
130 }
131
132 EXPORT_SYMBOL(snd_i2c_device_create);
133
134 int snd_i2c_device_free(struct snd_i2c_device *device)
135 {
136         if (device->bus)
137                 list_del(&device->list);
138         if (device->private_free)
139                 device->private_free(device);
140         kfree(device);
141         return 0;
142 }
143
144 EXPORT_SYMBOL(snd_i2c_device_free);
145
146 int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
147 {
148         return device->bus->ops->sendbytes(device, bytes, count);
149 }
150
151 EXPORT_SYMBOL(snd_i2c_sendbytes);
152
153 int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
154 {
155         return device->bus->ops->readbytes(device, bytes, count);
156 }
157
158 EXPORT_SYMBOL(snd_i2c_readbytes);
159
160 int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
161 {
162         return bus->ops->probeaddr(bus, addr);
163 }
164
165 EXPORT_SYMBOL(snd_i2c_probeaddr);
166
167 /*
168  *  bit-operations
169  */
170
171 static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus)
172 {
173         if (bus->hw_ops.bit->start)
174                 bus->hw_ops.bit->start(bus);
175 }
176
177 static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus)
178 {
179         if (bus->hw_ops.bit->stop)
180                 bus->hw_ops.bit->stop(bus);
181 }
182
183 static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data)
184 {
185         if (bus->hw_ops.bit->direction)
186                 bus->hw_ops.bit->direction(bus, clock, data);
187 }
188
189 static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data)
190 {
191         bus->hw_ops.bit->setlines(bus, clock, data);
192 }
193
194 #if 0
195 static int snd_i2c_bit_clock(struct snd_i2c_bus *bus)
196 {
197         if (bus->hw_ops.bit->getclock)
198                 return bus->hw_ops.bit->getclock(bus);
199         return -ENXIO;
200 }
201 #endif
202
203 static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
204 {
205         return bus->hw_ops.bit->getdata(bus, ack);
206 }
207
208 static void snd_i2c_bit_start(struct snd_i2c_bus *bus)
209 {
210         snd_i2c_bit_hw_start(bus);
211         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
212         snd_i2c_bit_set(bus, 1, 1);
213         snd_i2c_bit_set(bus, 1, 0);
214         snd_i2c_bit_set(bus, 0, 0);
215 }
216
217 static void snd_i2c_bit_stop(struct snd_i2c_bus *bus)
218 {
219         snd_i2c_bit_set(bus, 0, 0);
220         snd_i2c_bit_set(bus, 1, 0);
221         snd_i2c_bit_set(bus, 1, 1);
222         snd_i2c_bit_hw_stop(bus);
223 }
224
225 static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data)
226 {
227         snd_i2c_bit_set(bus, 0, data);
228         snd_i2c_bit_set(bus, 1, data);
229         snd_i2c_bit_set(bus, 0, data);
230 }
231
232 static int snd_i2c_bit_ack(struct snd_i2c_bus *bus)
233 {
234         int ack;
235
236         snd_i2c_bit_set(bus, 0, 1);
237         snd_i2c_bit_set(bus, 1, 1);
238         snd_i2c_bit_direction(bus, 1, 0);       /* SCL - wr, SDA - rd */
239         ack = snd_i2c_bit_data(bus, 1);
240         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
241         snd_i2c_bit_set(bus, 0, 1);
242         return ack ? -EIO : 0;
243 }
244
245 static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data)
246 {
247         int i, err;
248
249         for (i = 7; i >= 0; i--)
250                 snd_i2c_bit_send(bus, !!(data & (1 << i)));
251         err = snd_i2c_bit_ack(bus);
252         if (err < 0)
253                 return err;
254         return 0;
255 }
256
257 static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
258 {
259         int i;
260         unsigned char data = 0;
261
262         snd_i2c_bit_set(bus, 0, 1);
263         snd_i2c_bit_direction(bus, 1, 0);       /* SCL - wr, SDA - rd */
264         for (i = 7; i >= 0; i--) {
265                 snd_i2c_bit_set(bus, 1, 1);
266                 if (snd_i2c_bit_data(bus, 0))
267                         data |= (1 << i);
268                 snd_i2c_bit_set(bus, 0, 1);
269         }
270         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
271         snd_i2c_bit_send(bus, !!last);
272         return data;
273 }
274
275 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
276                                  unsigned char *bytes, int count)
277 {
278         struct snd_i2c_bus *bus = device->bus;
279         int err, res = 0;
280
281         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
282                 return -EIO;            /* not yet implemented */
283         snd_i2c_bit_start(bus);
284         err = snd_i2c_bit_sendbyte(bus, device->addr << 1);
285         if (err < 0) {
286                 snd_i2c_bit_hw_stop(bus);
287                 return err;
288         }
289         while (count-- > 0) {
290                 err = snd_i2c_bit_sendbyte(bus, *bytes++);
291                 if (err < 0) {
292                         snd_i2c_bit_hw_stop(bus);
293                         return err;
294                 }
295                 res++;
296         }
297         snd_i2c_bit_stop(bus);
298         return res;
299 }
300
301 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
302                                  unsigned char *bytes, int count)
303 {
304         struct snd_i2c_bus *bus = device->bus;
305         int err, res = 0;
306
307         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
308                 return -EIO;            /* not yet implemented */
309         snd_i2c_bit_start(bus);
310         err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1);
311         if (err < 0) {
312                 snd_i2c_bit_hw_stop(bus);
313                 return err;
314         }
315         while (count-- > 0) {
316                 err = snd_i2c_bit_readbyte(bus, count == 0);
317                 if (err < 0) {
318                         snd_i2c_bit_hw_stop(bus);
319                         return err;
320                 }
321                 *bytes++ = (unsigned char)err;
322                 res++;
323         }
324         snd_i2c_bit_stop(bus);
325         return res;
326 }
327
328 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
329 {
330         int err;
331
332         if (addr & 0x8000)      /* 10-bit address */
333                 return -EIO;    /* not yet implemented */
334         if (addr & 0x7f80)      /* invalid address */
335                 return -EINVAL;
336         snd_i2c_bit_start(bus);
337         err = snd_i2c_bit_sendbyte(bus, addr << 1);
338         snd_i2c_bit_stop(bus);
339         return err;
340 }
341
342
343 static int __init alsa_i2c_init(void)
344 {
345         return 0;
346 }
347
348 static void __exit alsa_i2c_exit(void)
349 {
350 }
351
352 module_init(alsa_i2c_init)
353 module_exit(alsa_i2c_exit)