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
30MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
31MODULE_DESCRIPTION("Generic i2c interface for ALSA");
32MODULE_LICENSE("GPL");
33
34static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
35				 unsigned char *bytes, int count);
36static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
37				 unsigned char *bytes, int count);
38static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus,
39				 unsigned short addr);
40
41static 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
47static 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	if (snd_BUG_ON(!bus))
53		return -EINVAL;
54	while (!list_empty(&bus->devices)) {
55		device = snd_i2c_device(bus->devices.next);
56		snd_i2c_device_free(device);
57	}
58	if (bus->master)
59		list_del(&bus->buses);
60	else {
61		while (!list_empty(&bus->buses)) {
62			slave = snd_i2c_slave_bus(bus->buses.next);
63			snd_device_free(bus->card, slave);
64		}
65	}
66	if (bus->private_free)
67		bus->private_free(bus);
68	kfree(bus);
69	return 0;
70}
71
72static int snd_i2c_bus_dev_free(struct snd_device *device)
73{
74	struct snd_i2c_bus *bus = device->device_data;
75	return snd_i2c_bus_free(bus);
76}
77
78int snd_i2c_bus_create(struct snd_card *card, const char *name,
79		       struct snd_i2c_bus *master, struct snd_i2c_bus **ri2c)
80{
81	struct snd_i2c_bus *bus;
82	int err;
83	static struct snd_device_ops ops = {
84		.dev_free =	snd_i2c_bus_dev_free,
85	};
86
87	*ri2c = NULL;
88	bus = kzalloc(sizeof(*bus), GFP_KERNEL);
89	if (bus == NULL)
90		return -ENOMEM;
91	mutex_init(&bus->lock_mutex);
92	INIT_LIST_HEAD(&bus->devices);
93	INIT_LIST_HEAD(&bus->buses);
94	bus->card = card;
95	bus->ops = &snd_i2c_bit_ops;
96	if (master) {
97		list_add_tail(&bus->buses, &master->buses);
98		bus->master = master;
99	}
100	strlcpy(bus->name, name, sizeof(bus->name));
101	err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops);
102	if (err < 0) {
103		snd_i2c_bus_free(bus);
104		return err;
105	}
106	*ri2c = bus;
107	return 0;
108}
109
110EXPORT_SYMBOL(snd_i2c_bus_create);
111
112int snd_i2c_device_create(struct snd_i2c_bus *bus, const char *name,
113			  unsigned char addr, struct snd_i2c_device **rdevice)
114{
115	struct snd_i2c_device *device;
116
117	*rdevice = NULL;
118	if (snd_BUG_ON(!bus))
119		return -EINVAL;
120	device = kzalloc(sizeof(*device), GFP_KERNEL);
121	if (device == NULL)
122		return -ENOMEM;
123	device->addr = addr;
124	strlcpy(device->name, name, sizeof(device->name));
125	list_add_tail(&device->list, &bus->devices);
126	device->bus = bus;
127	*rdevice = device;
128	return 0;
129}
130
131EXPORT_SYMBOL(snd_i2c_device_create);
132
133int snd_i2c_device_free(struct snd_i2c_device *device)
134{
135	if (device->bus)
136		list_del(&device->list);
137	if (device->private_free)
138		device->private_free(device);
139	kfree(device);
140	return 0;
141}
142
143EXPORT_SYMBOL(snd_i2c_device_free);
144
145int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
146{
147	return device->bus->ops->sendbytes(device, bytes, count);
148}
149
150EXPORT_SYMBOL(snd_i2c_sendbytes);
151
152int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
153{
154	return device->bus->ops->readbytes(device, bytes, count);
155}
156
157EXPORT_SYMBOL(snd_i2c_readbytes);
158
159int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
160{
161	return bus->ops->probeaddr(bus, addr);
162}
163
164EXPORT_SYMBOL(snd_i2c_probeaddr);
165
166/*
167 *  bit-operations
168 */
169
170static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus)
171{
172	if (bus->hw_ops.bit->start)
173		bus->hw_ops.bit->start(bus);
174}
175
176static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus)
177{
178	if (bus->hw_ops.bit->stop)
179		bus->hw_ops.bit->stop(bus);
180}
181
182static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data)
183{
184	if (bus->hw_ops.bit->direction)
185		bus->hw_ops.bit->direction(bus, clock, data);
186}
187
188static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data)
189{
190	bus->hw_ops.bit->setlines(bus, clock, data);
191}
192
193#if 0
194static int snd_i2c_bit_clock(struct snd_i2c_bus *bus)
195{
196	if (bus->hw_ops.bit->getclock)
197		return bus->hw_ops.bit->getclock(bus);
198	return -ENXIO;
199}
200#endif
201
202static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
203{
204	return bus->hw_ops.bit->getdata(bus, ack);
205}
206
207static void snd_i2c_bit_start(struct snd_i2c_bus *bus)
208{
209	snd_i2c_bit_hw_start(bus);
210	snd_i2c_bit_direction(bus, 1, 1);	/* SCL - wr, SDA - wr */
211	snd_i2c_bit_set(bus, 1, 1);
212	snd_i2c_bit_set(bus, 1, 0);
213	snd_i2c_bit_set(bus, 0, 0);
214}
215
216static void snd_i2c_bit_stop(struct snd_i2c_bus *bus)
217{
218	snd_i2c_bit_set(bus, 0, 0);
219	snd_i2c_bit_set(bus, 1, 0);
220	snd_i2c_bit_set(bus, 1, 1);
221	snd_i2c_bit_hw_stop(bus);
222}
223
224static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data)
225{
226	snd_i2c_bit_set(bus, 0, data);
227	snd_i2c_bit_set(bus, 1, data);
228	snd_i2c_bit_set(bus, 0, data);
229}
230
231static int snd_i2c_bit_ack(struct snd_i2c_bus *bus)
232{
233	int ack;
234
235	snd_i2c_bit_set(bus, 0, 1);
236	snd_i2c_bit_set(bus, 1, 1);
237	snd_i2c_bit_direction(bus, 1, 0);	/* SCL - wr, SDA - rd */
238	ack = snd_i2c_bit_data(bus, 1);
239	snd_i2c_bit_direction(bus, 1, 1);	/* SCL - wr, SDA - wr */
240	snd_i2c_bit_set(bus, 0, 1);
241	return ack ? -EIO : 0;
242}
243
244static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data)
245{
246	int i, err;
247
248	for (i = 7; i >= 0; i--)
249		snd_i2c_bit_send(bus, !!(data & (1 << i)));
250	err = snd_i2c_bit_ack(bus);
251	if (err < 0)
252		return err;
253	return 0;
254}
255
256static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
257{
258	int i;
259	unsigned char data = 0;
260
261	snd_i2c_bit_set(bus, 0, 1);
262	snd_i2c_bit_direction(bus, 1, 0);	/* SCL - wr, SDA - rd */
263	for (i = 7; i >= 0; i--) {
264		snd_i2c_bit_set(bus, 1, 1);
265		if (snd_i2c_bit_data(bus, 0))
266			data |= (1 << i);
267		snd_i2c_bit_set(bus, 0, 1);
268	}
269	snd_i2c_bit_direction(bus, 1, 1);	/* SCL - wr, SDA - wr */
270	snd_i2c_bit_send(bus, !!last);
271	return data;
272}
273
274static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
275				 unsigned char *bytes, int count)
276{
277	struct snd_i2c_bus *bus = device->bus;
278	int err, res = 0;
279
280	if (device->flags & SND_I2C_DEVICE_ADDRTEN)
281		return -EIO;		/* not yet implemented */
282	snd_i2c_bit_start(bus);
283	err = snd_i2c_bit_sendbyte(bus, device->addr << 1);
284	if (err < 0) {
285		snd_i2c_bit_hw_stop(bus);
286		return err;
287	}
288	while (count-- > 0) {
289		err = snd_i2c_bit_sendbyte(bus, *bytes++);
290		if (err < 0) {
291			snd_i2c_bit_hw_stop(bus);
292			return err;
293		}
294		res++;
295	}
296	snd_i2c_bit_stop(bus);
297	return res;
298}
299
300static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
301				 unsigned char *bytes, int count)
302{
303	struct snd_i2c_bus *bus = device->bus;
304	int err, res = 0;
305
306	if (device->flags & SND_I2C_DEVICE_ADDRTEN)
307		return -EIO;		/* not yet implemented */
308	snd_i2c_bit_start(bus);
309	err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1);
310	if (err < 0) {
311		snd_i2c_bit_hw_stop(bus);
312		return err;
313	}
314	while (count-- > 0) {
315		err = snd_i2c_bit_readbyte(bus, count == 0);
316		if (err < 0) {
317			snd_i2c_bit_hw_stop(bus);
318			return err;
319		}
320		*bytes++ = (unsigned char)err;
321		res++;
322	}
323	snd_i2c_bit_stop(bus);
324	return res;
325}
326
327static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
328{
329	int err;
330
331	if (addr & 0x8000)	/* 10-bit address */
332		return -EIO;	/* not yet implemented */
333	if (addr & 0x7f80)	/* invalid address */
334		return -EINVAL;
335	snd_i2c_bit_start(bus);
336	err = snd_i2c_bit_sendbyte(bus, addr << 1);
337	snd_i2c_bit_stop(bus);
338	return err;
339}
340
341
342static int __init alsa_i2c_init(void)
343{
344	return 0;
345}
346
347static void __exit alsa_i2c_exit(void)
348{
349}
350
351module_init(alsa_i2c_init)
352module_exit(alsa_i2c_exit)
353