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@suse.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 <sound/driver.h>
24#include <linux/init.h>
25#include <linux/slab.h>
26#include <linux/string.h>
27#include <linux/errno.h>
28#include <sound/core.h>
29#include <sound/i2c.h>
30
31MODULE_AUTHOR("Jaroslav Kysela <perex@suse.cz>");
32MODULE_DESCRIPTION("Generic i2c interface for ALSA");
33MODULE_LICENSE("GPL");
34
35static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
36				 unsigned char *bytes, int count);
37static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
38				 unsigned char *bytes, int count);
39static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus,
40				 unsigned short addr);
41
42static 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
48static 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	snd_assert(bus != NULL, 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	if ((err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops)) < 0) {
102		snd_i2c_bus_free(bus);
103		return err;
104	}
105	*ri2c = bus;
106	return 0;
107}
108
109EXPORT_SYMBOL(snd_i2c_bus_create);
110
111int snd_i2c_device_create(struct snd_i2c_bus *bus, const char *name,
112			  unsigned char addr, struct snd_i2c_device **rdevice)
113{
114	struct snd_i2c_device *device;
115
116	*rdevice = NULL;
117	snd_assert(bus != NULL, return -EINVAL);
118	device = kzalloc(sizeof(*device), GFP_KERNEL);
119	if (device == NULL)
120		return -ENOMEM;
121	device->addr = addr;
122	strlcpy(device->name, name, sizeof(device->name));
123	list_add_tail(&device->list, &bus->devices);
124	device->bus = bus;
125	*rdevice = device;
126	return 0;
127}
128
129EXPORT_SYMBOL(snd_i2c_device_create);
130
131int snd_i2c_device_free(struct snd_i2c_device *device)
132{
133	if (device->bus)
134		list_del(&device->list);
135	if (device->private_free)
136		device->private_free(device);
137	kfree(device);
138	return 0;
139}
140
141EXPORT_SYMBOL(snd_i2c_device_free);
142
143int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
144{
145	return device->bus->ops->sendbytes(device, bytes, count);
146}
147
148EXPORT_SYMBOL(snd_i2c_sendbytes);
149
150int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
151{
152	return device->bus->ops->readbytes(device, bytes, count);
153}
154
155EXPORT_SYMBOL(snd_i2c_readbytes);
156
157int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
158{
159	return bus->ops->probeaddr(bus, addr);
160}
161
162EXPORT_SYMBOL(snd_i2c_probeaddr);
163
164/*
165 *  bit-operations
166 */
167
168static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus)
169{
170	if (bus->hw_ops.bit->start)
171		bus->hw_ops.bit->start(bus);
172}
173
174static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus)
175{
176	if (bus->hw_ops.bit->stop)
177		bus->hw_ops.bit->stop(bus);
178}
179
180static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data)
181{
182	if (bus->hw_ops.bit->direction)
183		bus->hw_ops.bit->direction(bus, clock, data);
184}
185
186static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data)
187{
188	bus->hw_ops.bit->setlines(bus, clock, data);
189}
190
191
192static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
193{
194	return bus->hw_ops.bit->getdata(bus, ack);
195}
196
197static void snd_i2c_bit_start(struct snd_i2c_bus *bus)
198{
199	snd_i2c_bit_hw_start(bus);
200	snd_i2c_bit_direction(bus, 1, 1);	/* SCL - wr, SDA - wr */
201	snd_i2c_bit_set(bus, 1, 1);
202	snd_i2c_bit_set(bus, 1, 0);
203	snd_i2c_bit_set(bus, 0, 0);
204}
205
206static void snd_i2c_bit_stop(struct snd_i2c_bus *bus)
207{
208	snd_i2c_bit_set(bus, 0, 0);
209	snd_i2c_bit_set(bus, 1, 0);
210	snd_i2c_bit_set(bus, 1, 1);
211	snd_i2c_bit_hw_stop(bus);
212}
213
214static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data)
215{
216	snd_i2c_bit_set(bus, 0, data);
217	snd_i2c_bit_set(bus, 1, data);
218	snd_i2c_bit_set(bus, 0, data);
219}
220
221static int snd_i2c_bit_ack(struct snd_i2c_bus *bus)
222{
223	int ack;
224
225	snd_i2c_bit_set(bus, 0, 1);
226	snd_i2c_bit_set(bus, 1, 1);
227	snd_i2c_bit_direction(bus, 1, 0);	/* SCL - wr, SDA - rd */
228	ack = snd_i2c_bit_data(bus, 1);
229	snd_i2c_bit_direction(bus, 1, 1);	/* SCL - wr, SDA - wr */
230	snd_i2c_bit_set(bus, 0, 1);
231	return ack ? -EIO : 0;
232}
233
234static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data)
235{
236	int i, err;
237
238	for (i = 7; i >= 0; i--)
239		snd_i2c_bit_send(bus, !!(data & (1 << i)));
240	if ((err = snd_i2c_bit_ack(bus)) < 0)
241		return err;
242	return 0;
243}
244
245static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
246{
247	int i;
248	unsigned char data = 0;
249
250	snd_i2c_bit_set(bus, 0, 1);
251	snd_i2c_bit_direction(bus, 1, 0);	/* SCL - wr, SDA - rd */
252	for (i = 7; i >= 0; i--) {
253		snd_i2c_bit_set(bus, 1, 1);
254		if (snd_i2c_bit_data(bus, 0))
255			data |= (1 << i);
256		snd_i2c_bit_set(bus, 0, 1);
257	}
258	snd_i2c_bit_direction(bus, 1, 1);	/* SCL - wr, SDA - wr */
259	snd_i2c_bit_send(bus, !!last);
260	return data;
261}
262
263static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
264				 unsigned char *bytes, int count)
265{
266	struct snd_i2c_bus *bus = device->bus;
267	int err, res = 0;
268
269	if (device->flags & SND_I2C_DEVICE_ADDRTEN)
270		return -EIO;		/* not yet implemented */
271	snd_i2c_bit_start(bus);
272	if ((err = snd_i2c_bit_sendbyte(bus, device->addr << 1)) < 0) {
273		snd_i2c_bit_hw_stop(bus);
274		return err;
275	}
276	while (count-- > 0) {
277		if ((err = snd_i2c_bit_sendbyte(bus, *bytes++)) < 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
287static 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	if ((err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1)) < 0) {
297		snd_i2c_bit_hw_stop(bus);
298		return err;
299	}
300	while (count-- > 0) {
301		if ((err = snd_i2c_bit_readbyte(bus, count == 0)) < 0) {
302			snd_i2c_bit_hw_stop(bus);
303			return err;
304		}
305		*bytes++ = (unsigned char)err;
306		res++;
307	}
308	snd_i2c_bit_stop(bus);
309	return res;
310}
311
312static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
313{
314	int err;
315
316	if (addr & 0x8000)	/* 10-bit address */
317		return -EIO;	/* not yet implemented */
318	if (addr & 0x7f80)	/* invalid address */
319		return -EINVAL;
320	snd_i2c_bit_start(bus);
321	err = snd_i2c_bit_sendbyte(bus, addr << 1);
322	snd_i2c_bit_stop(bus);
323	return err;
324}
325
326
327static int __init alsa_i2c_init(void)
328{
329	return 0;
330}
331
332static void __exit alsa_i2c_exit(void)
333{
334}
335
336module_init(alsa_i2c_init)
337module_exit(alsa_i2c_exit)
338