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Linux/sound/i2c/i2c.c

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  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 const 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 

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