1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Generic i2c interface for ALSA
4 *
5 * (c) 1998 Gerd Knorr <kraxel@cs.tu-berlin.de>
6 * Modified for the ALSA driver by Jaroslav Kysela <perex@perex.cz>
7 */
8
9 #include <linux/init.h>
10 #include <linux/slab.h>
11 #include <linux/module.h>
12 #include <linux/string.h>
13 #include <linux/errno.h>
14 #include <sound/core.h>
15 #include <sound/i2c.h>
16
17 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
18 MODULE_DESCRIPTION("Generic i2c interface for ALSA");
19 MODULE_LICENSE("GPL");
20
21 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
22 unsigned char *bytes, int count);
23 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
24 unsigned char *bytes, int count);
25 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus,
26 unsigned short addr);
27
28 static const struct snd_i2c_ops snd_i2c_bit_ops = {
29 .sendbytes = snd_i2c_bit_sendbytes,
30 .readbytes = snd_i2c_bit_readbytes,
31 .probeaddr = snd_i2c_bit_probeaddr,
32 };
33
34 static int snd_i2c_bus_free(struct snd_i2c_bus *bus)
35 {
36 struct snd_i2c_bus *slave;
37 struct snd_i2c_device *device;
38
39 if (snd_BUG_ON(!bus))
40 return -EINVAL;
41 while (!list_empty(&bus->devices)) {
42 device = snd_i2c_device(bus->devices.next);
43 snd_i2c_device_free(device);
44 }
45 if (bus->master)
46 list_del(&bus->buses);
47 else {
48 while (!list_empty(&bus->buses)) {
49 slave = snd_i2c_slave_bus(bus->buses.next);
50 snd_device_free(bus->card, slave);
51 }
52 }
53 if (bus->private_free)
54 bus->private_free(bus);
55 kfree(bus);
56 return 0;
57 }
58
59 static int snd_i2c_bus_dev_free(struct snd_device *device)
60 {
61 struct snd_i2c_bus *bus = device->device_data;
62 return snd_i2c_bus_free(bus);
63 }
64
65 int snd_i2c_bus_create(struct snd_card *card, const char *name,
66 struct snd_i2c_bus *master, struct snd_i2c_bus **ri2c)
67 {
68 struct snd_i2c_bus *bus;
69 int err;
70 static const struct snd_device_ops ops = {
71 .dev_free = snd_i2c_bus_dev_free,
72 };
73
74 *ri2c = NULL;
75 bus = kzalloc(sizeof(*bus), GFP_KERNEL);
76 if (bus == NULL)
77 return -ENOMEM;
78 mutex_init(&bus->lock_mutex);
79 INIT_LIST_HEAD(&bus->devices);
80 INIT_LIST_HEAD(&bus->buses);
81 bus->card = card;
82 bus->ops = &snd_i2c_bit_ops;
83 if (master) {
84 list_add_tail(&bus->buses, &master->buses);
85 bus->master = master;
86 }
87 strscpy(bus->name, name, sizeof(bus->name));
88 err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops);
89 if (err < 0) {
90 snd_i2c_bus_free(bus);
91 return err;
92 }
93 *ri2c = bus;
94 return 0;
95 }
96
97 EXPORT_SYMBOL(snd_i2c_bus_create);
98
99 int snd_i2c_device_create(struct snd_i2c_bus *bus, const char *name,
100 unsigned char addr, struct snd_i2c_device **rdevice)
101 {
102 struct snd_i2c_device *device;
103
104 *rdevice = NULL;
105 if (snd_BUG_ON(!bus))
106 return -EINVAL;
107 device = kzalloc(sizeof(*device), GFP_KERNEL);
108 if (device == NULL)
109 return -ENOMEM;
110 device->addr = addr;
111 strscpy(device->name, name, sizeof(device->name));
112 list_add_tail(&device->list, &bus->devices);
113 device->bus = bus;
114 *rdevice = device;
115 return 0;
116 }
117
118 EXPORT_SYMBOL(snd_i2c_device_create);
119
120 int snd_i2c_device_free(struct snd_i2c_device *device)
121 {
122 if (device->bus)
123 list_del(&device->list);
124 if (device->private_free)
125 device->private_free(device);
126 kfree(device);
127 return 0;
128 }
129
130 EXPORT_SYMBOL(snd_i2c_device_free);
131
132 int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
133 {
134 return device->bus->ops->sendbytes(device, bytes, count);
135 }
136
137 EXPORT_SYMBOL(snd_i2c_sendbytes);
138
139 int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
140 {
141 return device->bus->ops->readbytes(device, bytes, count);
142 }
143
144 EXPORT_SYMBOL(snd_i2c_readbytes);
145
146 int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
147 {
148 return bus->ops->probeaddr(bus, addr);
149 }
150
151 EXPORT_SYMBOL(snd_i2c_probeaddr);
152
153 /*
154 * bit-operations
155 */
156
157 static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus)
158 {
159 if (bus->hw_ops.bit->start)
160 bus->hw_ops.bit->start(bus);
161 }
162
163 static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus)
164 {
165 if (bus->hw_ops.bit->stop)
166 bus->hw_ops.bit->stop(bus);
167 }
168
169 static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data)
170 {
171 if (bus->hw_ops.bit->direction)
172 bus->hw_ops.bit->direction(bus, clock, data);
173 }
174
175 static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data)
176 {
177 bus->hw_ops.bit->setlines(bus, clock, data);
178 }
179
180 #if 0
181 static int snd_i2c_bit_clock(struct snd_i2c_bus *bus)
182 {
183 if (bus->hw_ops.bit->getclock)
184 return bus->hw_ops.bit->getclock(bus);
185 return -ENXIO;
186 }
187 #endif
188
189 static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
190 {
191 return bus->hw_ops.bit->getdata(bus, ack);
192 }
193
194 static void snd_i2c_bit_start(struct snd_i2c_bus *bus)
195 {
196 snd_i2c_bit_hw_start(bus);
197 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
198 snd_i2c_bit_set(bus, 1, 1);
199 snd_i2c_bit_set(bus, 1, 0);
200 snd_i2c_bit_set(bus, 0, 0);
201 }
202
203 static void snd_i2c_bit_stop(struct snd_i2c_bus *bus)
204 {
205 snd_i2c_bit_set(bus, 0, 0);
206 snd_i2c_bit_set(bus, 1, 0);
207 snd_i2c_bit_set(bus, 1, 1);
208 snd_i2c_bit_hw_stop(bus);
209 }
210
211 static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data)
212 {
213 snd_i2c_bit_set(bus, 0, data);
214 snd_i2c_bit_set(bus, 1, data);
215 snd_i2c_bit_set(bus, 0, data);
216 }
217
218 static int snd_i2c_bit_ack(struct snd_i2c_bus *bus)
219 {
220 int ack;
221
222 snd_i2c_bit_set(bus, 0, 1);
223 snd_i2c_bit_set(bus, 1, 1);
224 snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
225 ack = snd_i2c_bit_data(bus, 1);
226 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
227 snd_i2c_bit_set(bus, 0, 1);
228 return ack ? -EIO : 0;
229 }
230
231 static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data)
232 {
233 int i, err;
234
235 for (i = 7; i >= 0; i--)
236 snd_i2c_bit_send(bus, !!(data & (1 << i)));
237 err = snd_i2c_bit_ack(bus);
238 if (err < 0)
239 return err;
240 return 0;
241 }
242
243 static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
244 {
245 int i;
246 unsigned char data = 0;
247
248 snd_i2c_bit_set(bus, 0, 1);
249 snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
250 for (i = 7; i >= 0; i--) {
251 snd_i2c_bit_set(bus, 1, 1);
252 if (snd_i2c_bit_data(bus, 0))
253 data |= (1 << i);
254 snd_i2c_bit_set(bus, 0, 1);
255 }
256 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
257 snd_i2c_bit_send(bus, !!last);
258 return data;
259 }
260
261 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
262 unsigned char *bytes, int count)
263 {
264 struct snd_i2c_bus *bus = device->bus;
265 int err, res = 0;
266
267 if (device->flags & SND_I2C_DEVICE_ADDRTEN)
268 return -EIO; /* not yet implemented */
269 snd_i2c_bit_start(bus);
270 err = snd_i2c_bit_sendbyte(bus, device->addr << 1);
271 if (err < 0) {
272 snd_i2c_bit_hw_stop(bus);
273 return err;
274 }
275 while (count-- > 0) {
276 err = snd_i2c_bit_sendbyte(bus, *bytes++);
277 if (err < 0) {
278 snd_i2c_bit_hw_stop(bus);
279 return err;
280 }
281 res++;
282 }
283 snd_i2c_bit_stop(bus);
284 return res;
285 }
286
287 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
288 unsigned char *bytes, int count)
289 {
290 struct snd_i2c_bus *bus = device->bus;
291 int err, res = 0;
292
293 if (device->flags & SND_I2C_DEVICE_ADDRTEN)
294 return -EIO; /* not yet implemented */
295 snd_i2c_bit_start(bus);
296 err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1);
297 if (err < 0) {
298 snd_i2c_bit_hw_stop(bus);
299 return err;
300 }
301 while (count-- > 0) {
302 err = snd_i2c_bit_readbyte(bus, count == 0);
303 if (err < 0) {
304 snd_i2c_bit_hw_stop(bus);
305 return err;
306 }
307 *bytes++ = (unsigned char)err;
308 res++;
309 }
310 snd_i2c_bit_stop(bus);
311 return res;
312 }
313
314 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
315 {
316 int err;
317
318 if (addr & 0x8000) /* 10-bit address */
319 return -EIO; /* not yet implemented */
320 if (addr & 0x7f80) /* invalid address */
321 return -EINVAL;
322 snd_i2c_bit_start(bus);
323 err = snd_i2c_bit_sendbyte(bus, addr << 1);
324 snd_i2c_bit_stop(bus);
325 return err;
326 }
327
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