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
31MODULE_AUTHOR("Jaroslav Kysela <perex@perex.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	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
73static 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
79int 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
111EXPORT_SYMBOL(snd_i2c_bus_create);
112
113int 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
132EXPORT_SYMBOL(snd_i2c_device_create);
133
134int 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
144EXPORT_SYMBOL(snd_i2c_device_free);
145
146int 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
151EXPORT_SYMBOL(snd_i2c_sendbytes);
152
153int 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
158EXPORT_SYMBOL(snd_i2c_readbytes);
159
160int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
161{
162	return bus->ops->probeaddr(bus, addr);
163}
164
165EXPORT_SYMBOL(snd_i2c_probeaddr);
166
167/*
168 *  bit-operations
169 */
170
171static 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
177static 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
183static 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
189static 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
195static 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
203static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
204{
205	return bus->hw_ops.bit->getdata(bus, ack);
206}
207
208static 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
217static 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
225static 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
232static 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
245static 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
257static 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
275static 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
301static 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
328static 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
343static int __init alsa_i2c_init(void)
344{
345	return 0;
346}
347
348static void __exit alsa_i2c_exit(void)
349{
350}
351
352module_init(alsa_i2c_init)
353module_exit(alsa_i2c_exit)
354