[mirror_ubuntu-focal-kernel.git] / sound / i2c / i2c.c

/*
 *   Generic i2c interface for ALSA
 *
 *   (c) 1998 Gerd Knorr <kraxel@cs.tu-berlin.de>
 *   Modified for the ALSA driver by Jaroslav Kysela <perex@perex.cz>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <sound/core.h>
#include <sound/i2c.h>

MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
MODULE_DESCRIPTION("Generic i2c interface for ALSA");
MODULE_LICENSE("GPL");

static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
				 unsigned char *bytes, int count);
static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
				 unsigned char *bytes, int count);
static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus,
				 unsigned short addr);

static struct snd_i2c_ops snd_i2c_bit_ops = {
	.sendbytes = snd_i2c_bit_sendbytes,
	.readbytes = snd_i2c_bit_readbytes,
	.probeaddr = snd_i2c_bit_probeaddr,
};

static int snd_i2c_bus_free(struct snd_i2c_bus *bus)
{
	struct snd_i2c_bus *slave;
	struct snd_i2c_device *device;

	snd_assert(bus != NULL, return -EINVAL);
	while (!list_empty(&bus->devices)) {
		device = snd_i2c_device(bus->devices.next);
		snd_i2c_device_free(device);
	}
	if (bus->master)
		list_del(&bus->buses);
	else {
		while (!list_empty(&bus->buses)) {
			slave = snd_i2c_slave_bus(bus->buses.next);
			snd_device_free(bus->card, slave);
		}
	}
	if (bus->private_free)
		bus->private_free(bus);
	kfree(bus);
	return 0;
}

static int snd_i2c_bus_dev_free(struct snd_device *device)
{
	struct snd_i2c_bus *bus = device->device_data;
	return snd_i2c_bus_free(bus);
}

int snd_i2c_bus_create(struct snd_card *card, const char *name,
		       struct snd_i2c_bus *master, struct snd_i2c_bus **ri2c)
{
	struct snd_i2c_bus *bus;
	int err;
	static struct snd_device_ops ops = {
		.dev_free =	snd_i2c_bus_dev_free,
	};

	*ri2c = NULL;
	bus = kzalloc(sizeof(*bus), GFP_KERNEL);
	if (bus == NULL)
		return -ENOMEM;
	mutex_init(&bus->lock_mutex);
	INIT_LIST_HEAD(&bus->devices);
	INIT_LIST_HEAD(&bus->buses);
	bus->card = card;
	bus->ops = &snd_i2c_bit_ops;
	if (master) {
		list_add_tail(&bus->buses, &master->buses);
		bus->master = master;
	}
	strlcpy(bus->name, name, sizeof(bus->name));
	if ((err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops)) < 0) {
		snd_i2c_bus_free(bus);
		return err;
	}
	*ri2c = bus;
	return 0;
}

EXPORT_SYMBOL(snd_i2c_bus_create);

int snd_i2c_device_create(struct snd_i2c_bus *bus, const char *name,
			  unsigned char addr, struct snd_i2c_device **rdevice)
{
	struct snd_i2c_device *device;

	*rdevice = NULL;
	snd_assert(bus != NULL, return -EINVAL);
	device = kzalloc(sizeof(*device), GFP_KERNEL);
	if (device == NULL)
		return -ENOMEM;
	device->addr = addr;
	strlcpy(device->name, name, sizeof(device->name));
	list_add_tail(&device->list, &bus->devices);
	device->bus = bus;
	*rdevice = device;
	return 0;
}

EXPORT_SYMBOL(snd_i2c_device_create);

int snd_i2c_device_free(struct snd_i2c_device *device)
{
	if (device->bus)
		list_del(&device->list);
	if (device->private_free)
		device->private_free(device);
	kfree(device);
	return 0;
}

EXPORT_SYMBOL(snd_i2c_device_free);

int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
{
	return device->bus->ops->sendbytes(device, bytes, count);
}

EXPORT_SYMBOL(snd_i2c_sendbytes);

int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
{
	return device->bus->ops->readbytes(device, bytes, count);
}

EXPORT_SYMBOL(snd_i2c_readbytes);

int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
{
	return bus->ops->probeaddr(bus, addr);
}

EXPORT_SYMBOL(snd_i2c_probeaddr);

/*
 *  bit-operations
 */

static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus)
{
	if (bus->hw_ops.bit->start)
		bus->hw_ops.bit->start(bus);
}

static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus)
{
	if (bus->hw_ops.bit->stop)
		bus->hw_ops.bit->stop(bus);
}

static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data)
{
	if (bus->hw_ops.bit->direction)
		bus->hw_ops.bit->direction(bus, clock, data);
}

static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data)
{
	bus->hw_ops.bit->setlines(bus, clock, data);
}

#if 0
static int snd_i2c_bit_clock(struct snd_i2c_bus *bus)
{
	if (bus->hw_ops.bit->getclock)
		return bus->hw_ops.bit->getclock(bus);
	return -ENXIO;
}
#endif

static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
{
	return bus->hw_ops.bit->getdata(bus, ack);
}

static void snd_i2c_bit_start(struct snd_i2c_bus *bus)
{
	snd_i2c_bit_hw_start(bus);
	snd_i2c_bit_direction(bus, 1, 1);	/* SCL - wr, SDA - wr */
	snd_i2c_bit_set(bus, 1, 1);
	snd_i2c_bit_set(bus, 1, 0);
	snd_i2c_bit_set(bus, 0, 0);
}

static void snd_i2c_bit_stop(struct snd_i2c_bus *bus)
{
	snd_i2c_bit_set(bus, 0, 0);
	snd_i2c_bit_set(bus, 1, 0);
	snd_i2c_bit_set(bus, 1, 1);
	snd_i2c_bit_hw_stop(bus);
}

static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data)
{
	snd_i2c_bit_set(bus, 0, data);
	snd_i2c_bit_set(bus, 1, data);
	snd_i2c_bit_set(bus, 0, data);
}

static int snd_i2c_bit_ack(struct snd_i2c_bus *bus)
{
	int ack;

	snd_i2c_bit_set(bus, 0, 1);
	snd_i2c_bit_set(bus, 1, 1);
	snd_i2c_bit_direction(bus, 1, 0);	/* SCL - wr, SDA - rd */
	ack = snd_i2c_bit_data(bus, 1);
	snd_i2c_bit_direction(bus, 1, 1);	/* SCL - wr, SDA - wr */
	snd_i2c_bit_set(bus, 0, 1);
	return ack ? -EIO : 0;
}

static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data)
{
	int i, err;

	for (i = 7; i >= 0; i--)
		snd_i2c_bit_send(bus, !!(data & (1 << i)));
	if ((err = snd_i2c_bit_ack(bus)) < 0)
		return err;
	return 0;
}

static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
{
	int i;
	unsigned char data = 0;

	snd_i2c_bit_set(bus, 0, 1);
	snd_i2c_bit_direction(bus, 1, 0);	/* SCL - wr, SDA - rd */
	for (i = 7; i >= 0; i--) {
		snd_i2c_bit_set(bus, 1, 1);
		if (snd_i2c_bit_data(bus, 0))
			data |= (1 << i);
		snd_i2c_bit_set(bus, 0, 1);
	}
	snd_i2c_bit_direction(bus, 1, 1);	/* SCL - wr, SDA - wr */
	snd_i2c_bit_send(bus, !!last);
	return data;
}

static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
				 unsigned char *bytes, int count)
{
	struct snd_i2c_bus *bus = device->bus;
	int err, res = 0;

	if (device->flags & SND_I2C_DEVICE_ADDRTEN)
		return -EIO;		/* not yet implemented */
	snd_i2c_bit_start(bus);
	if ((err = snd_i2c_bit_sendbyte(bus, device->addr << 1)) < 0) {
		snd_i2c_bit_hw_stop(bus);
		return err;
	}
	while (count-- > 0) {
		if ((err = snd_i2c_bit_sendbyte(bus, *bytes++)) < 0) {
			snd_i2c_bit_hw_stop(bus);
			return err;
		}
		res++;
	}
	snd_i2c_bit_stop(bus);
	return res;
}

static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
				 unsigned char *bytes, int count)
{
	struct snd_i2c_bus *bus = device->bus;
	int err, res = 0;

	if (device->flags & SND_I2C_DEVICE_ADDRTEN)
		return -EIO;		/* not yet implemented */
	snd_i2c_bit_start(bus);
	if ((err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1)) < 0) {
		snd_i2c_bit_hw_stop(bus);
		return err;
	}
	while (count-- > 0) {
		if ((err = snd_i2c_bit_readbyte(bus, count == 0)) < 0) {
			snd_i2c_bit_hw_stop(bus);
			return err;
		}
		*bytes++ = (unsigned char)err;
		res++;
	}
	snd_i2c_bit_stop(bus);
	return res;
}

static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
{
	int err;

	if (addr & 0x8000)	/* 10-bit address */
		return -EIO;	/* not yet implemented */
	if (addr & 0x7f80)	/* invalid address */
		return -EINVAL;
	snd_i2c_bit_start(bus);
	err = snd_i2c_bit_sendbyte(bus, addr << 1);
	snd_i2c_bit_stop(bus);
	return err;
}


static int __init alsa_i2c_init(void)
{
	return 0;
}

static void __exit alsa_i2c_exit(void)
{
}

module_init(alsa_i2c_init)
module_exit(alsa_i2c_exit)
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Generic i2c interface for ALSA
	3	*
	4	* (c) 1998 Gerd Knorr <kraxel@cs.tu-berlin.de>
c1017a4c	5	* Modified for the ALSA driver by Jaroslav Kysela <perex@perex.cz>
1da177e4 LT	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
1da177e4 LT	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
c1017a4c	30	MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
1da177e4 LT	31	MODULE_DESCRIPTION("Generic i2c interface for ALSA");
	32	MODULE_LICENSE("GPL");
	33
97f02e05 TI	34	static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
	35	unsigned char *bytes, int count);
	36	static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
	37	unsigned char *bytes, int count);
	38	static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus,
	39	unsigned short addr);
	40
	41	static struct snd_i2c_ops snd_i2c_bit_ops = {
1da177e4 LT	42	.sendbytes = snd_i2c_bit_sendbytes,
	43	.readbytes = snd_i2c_bit_readbytes,
	44	.probeaddr = snd_i2c_bit_probeaddr,
	45	};
	46
97f02e05	47	static int snd_i2c_bus_free(struct snd_i2c_bus *bus)
1da177e4	48	{
97f02e05 TI	49	struct snd_i2c_bus *slave;
97f02e05 TI	50	struct snd_i2c_device *device;
1da177e4 LT	51
	52	snd_assert(bus != NULL, return -EINVAL);
	53	while (!list_empty(&bus->devices)) {
	54	device = snd_i2c_device(bus->devices.next);
	55	snd_i2c_device_free(device);
	56	}
	57	if (bus->master)
	58	list_del(&bus->buses);
	59	else {
	60	while (!list_empty(&bus->buses)) {
	61	slave = snd_i2c_slave_bus(bus->buses.next);
	62	snd_device_free(bus->card, slave);
	63	}
	64	}
	65	if (bus->private_free)
	66	bus->private_free(bus);
	67	kfree(bus);
	68	return 0;
	69	}
	70
97f02e05	71	static int snd_i2c_bus_dev_free(struct snd_device *device)
1da177e4	72	{
97f02e05	73	struct snd_i2c_bus *bus = device->device_data;
1da177e4 LT	74	return snd_i2c_bus_free(bus);
	75	}
	76
97f02e05 TI	77	int snd_i2c_bus_create(struct snd_card card, const char name,
97f02e05 TI	78	struct snd_i2c_bus master, struct snd_i2c_bus *ri2c)
1da177e4	79	{
97f02e05	80	struct snd_i2c_bus *bus;
1da177e4	81	int err;
97f02e05	82	static struct snd_device_ops ops = {
1da177e4 LT	83	.dev_free = snd_i2c_bus_dev_free,
	84	};
	85
	86	*ri2c = NULL;
561b220a	87	bus = kzalloc(sizeof(*bus), GFP_KERNEL);
1da177e4 LT	88	if (bus == NULL)
1da177e4 LT	89	return -ENOMEM;
ef9f0a42	90	mutex_init(&bus->lock_mutex);
1da177e4 LT	91	INIT_LIST_HEAD(&bus->devices);
	92	INIT_LIST_HEAD(&bus->buses);
	93	bus->card = card;
	94	bus->ops = &snd_i2c_bit_ops;
	95	if (master) {
	96	list_add_tail(&bus->buses, &master->buses);
	97	bus->master = master;
	98	}
	99	strlcpy(bus->name, name, sizeof(bus->name));
	100	if ((err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops)) < 0) {
	101	snd_i2c_bus_free(bus);
	102	return err;
	103	}
	104	*ri2c = bus;
	105	return 0;
	106	}
	107
57c65c11 TI	108	EXPORT_SYMBOL(snd_i2c_bus_create);
57c65c11 TI	109
97f02e05 TI	110	int snd_i2c_device_create(struct snd_i2c_bus bus, const char name,
97f02e05 TI	111	unsigned char addr, struct snd_i2c_device **rdevice)
1da177e4	112	{
97f02e05	113	struct snd_i2c_device *device;
1da177e4 LT	114
	115	*rdevice = NULL;
	116	snd_assert(bus != NULL, return -EINVAL);
561b220a	117	device = kzalloc(sizeof(*device), GFP_KERNEL);
1da177e4 LT	118	if (device == NULL)
	119	return -ENOMEM;
	120	device->addr = addr;
	121	strlcpy(device->name, name, sizeof(device->name));
	122	list_add_tail(&device->list, &bus->devices);
	123	device->bus = bus;
	124	*rdevice = device;
	125	return 0;
	126	}
	127
57c65c11 TI	128	EXPORT_SYMBOL(snd_i2c_device_create);
57c65c11 TI	129
97f02e05	130	int snd_i2c_device_free(struct snd_i2c_device *device)
1da177e4 LT	131	{
	132	if (device->bus)
	133	list_del(&device->list);
	134	if (device->private_free)
	135	device->private_free(device);
	136	kfree(device);
	137	return 0;
	138	}
	139
57c65c11 TI	140	EXPORT_SYMBOL(snd_i2c_device_free);
57c65c11 TI	141
97f02e05	142	int snd_i2c_sendbytes(struct snd_i2c_device device, unsigned char bytes, int count)
1da177e4 LT	143	{
	144	return device->bus->ops->sendbytes(device, bytes, count);
	145	}
	146
57c65c11	147	EXPORT_SYMBOL(snd_i2c_sendbytes);
1da177e4	148
97f02e05	149	int snd_i2c_readbytes(struct snd_i2c_device device, unsigned char bytes, int count)
1da177e4 LT	150	{
	151	return device->bus->ops->readbytes(device, bytes, count);
	152	}
	153
57c65c11 TI	154	EXPORT_SYMBOL(snd_i2c_readbytes);
57c65c11 TI	155
97f02e05	156	int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
1da177e4 LT	157	{
	158	return bus->ops->probeaddr(bus, addr);
	159	}
	160
57c65c11 TI	161	EXPORT_SYMBOL(snd_i2c_probeaddr);
57c65c11 TI	162
1da177e4 LT	163	/*
	164	* bit-operations
	165	*/
	166
97f02e05	167	static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus)
1da177e4 LT	168	{
	169	if (bus->hw_ops.bit->start)
	170	bus->hw_ops.bit->start(bus);
	171	}
	172
97f02e05	173	static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus)
1da177e4 LT	174	{
	175	if (bus->hw_ops.bit->stop)
	176	bus->hw_ops.bit->stop(bus);
	177	}
	178
97f02e05	179	static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data)
1da177e4 LT	180	{
	181	if (bus->hw_ops.bit->direction)
	182	bus->hw_ops.bit->direction(bus, clock, data);
	183	}
	184
97f02e05	185	static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data)
1da177e4 LT	186	{
	187	bus->hw_ops.bit->setlines(bus, clock, data);
	188	}
	189
	190	#if 0
97f02e05	191	static int snd_i2c_bit_clock(struct snd_i2c_bus *bus)
1da177e4 LT	192	{
	193	if (bus->hw_ops.bit->getclock)
	194	return bus->hw_ops.bit->getclock(bus);
	195	return -ENXIO;
	196	}
	197	#endif
	198
97f02e05	199	static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
1da177e4 LT	200	{
	201	return bus->hw_ops.bit->getdata(bus, ack);
	202	}
	203
97f02e05	204	static void snd_i2c_bit_start(struct snd_i2c_bus *bus)
1da177e4 LT	205	{
	206	snd_i2c_bit_hw_start(bus);
	207	snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
	208	snd_i2c_bit_set(bus, 1, 1);
	209	snd_i2c_bit_set(bus, 1, 0);
	210	snd_i2c_bit_set(bus, 0, 0);
	211	}
	212
97f02e05	213	static void snd_i2c_bit_stop(struct snd_i2c_bus *bus)
1da177e4 LT	214	{
	215	snd_i2c_bit_set(bus, 0, 0);
	216	snd_i2c_bit_set(bus, 1, 0);
	217	snd_i2c_bit_set(bus, 1, 1);
	218	snd_i2c_bit_hw_stop(bus);
	219	}
	220
97f02e05	221	static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data)
1da177e4 LT	222	{
	223	snd_i2c_bit_set(bus, 0, data);
	224	snd_i2c_bit_set(bus, 1, data);
	225	snd_i2c_bit_set(bus, 0, data);
	226	}
	227
97f02e05	228	static int snd_i2c_bit_ack(struct snd_i2c_bus *bus)
1da177e4 LT	229	{
	230	int ack;
	231
	232	snd_i2c_bit_set(bus, 0, 1);
	233	snd_i2c_bit_set(bus, 1, 1);
	234	snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
	235	ack = snd_i2c_bit_data(bus, 1);
	236	snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
	237	snd_i2c_bit_set(bus, 0, 1);
	238	return ack ? -EIO : 0;
	239	}
	240
97f02e05	241	static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data)
1da177e4 LT	242	{
	243	int i, err;
	244
	245	for (i = 7; i >= 0; i--)
	246	snd_i2c_bit_send(bus, !!(data & (1 << i)));
	247	if ((err = snd_i2c_bit_ack(bus)) < 0)
	248	return err;
	249	return 0;
	250	}
	251
97f02e05	252	static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
1da177e4 LT	253	{
	254	int i;
	255	unsigned char data = 0;
	256
	257	snd_i2c_bit_set(bus, 0, 1);
	258	snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
	259	for (i = 7; i >= 0; i--) {
	260	snd_i2c_bit_set(bus, 1, 1);
	261	if (snd_i2c_bit_data(bus, 0))
	262	data \|= (1 << i);
	263	snd_i2c_bit_set(bus, 0, 1);
	264	}
	265	snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
	266	snd_i2c_bit_send(bus, !!last);
	267	return data;
	268	}
	269
97f02e05 TI	270	static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
97f02e05 TI	271	unsigned char *bytes, int count)
1da177e4	272	{
97f02e05	273	struct snd_i2c_bus *bus = device->bus;
1da177e4 LT	274	int err, res = 0;
	275
	276	if (device->flags & SND_I2C_DEVICE_ADDRTEN)
	277	return -EIO; /* not yet implemented */
	278	snd_i2c_bit_start(bus);
	279	if ((err = snd_i2c_bit_sendbyte(bus, device->addr << 1)) < 0) {
	280	snd_i2c_bit_hw_stop(bus);
	281	return err;
	282	}
	283	while (count-- > 0) {
	284	if ((err = snd_i2c_bit_sendbyte(bus, *bytes++)) < 0) {
	285	snd_i2c_bit_hw_stop(bus);
	286	return err;
	287	}
	288	res++;
	289	}
	290	snd_i2c_bit_stop(bus);
	291	return res;
	292	}
	293
97f02e05 TI	294	static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
97f02e05 TI	295	unsigned char *bytes, int count)
1da177e4	296	{
97f02e05	297	struct snd_i2c_bus *bus = device->bus;
1da177e4 LT	298	int err, res = 0;
	299
	300	if (device->flags & SND_I2C_DEVICE_ADDRTEN)
	301	return -EIO; /* not yet implemented */
	302	snd_i2c_bit_start(bus);
	303	if ((err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) \| 1)) < 0) {
	304	snd_i2c_bit_hw_stop(bus);
	305	return err;
	306	}
	307	while (count-- > 0) {
	308	if ((err = snd_i2c_bit_readbyte(bus, count == 0)) < 0) {
	309	snd_i2c_bit_hw_stop(bus);
	310	return err;
	311	}
	312	*bytes++ = (unsigned char)err;
	313	res++;
	314	}
	315	snd_i2c_bit_stop(bus);
	316	return res;
	317	}
	318
97f02e05	319	static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
1da177e4 LT	320	{
	321	int err;
	322
	323	if (addr & 0x8000) /* 10-bit address */
	324	return -EIO; /* not yet implemented */
	325	if (addr & 0x7f80) /* invalid address */
	326	return -EINVAL;
	327	snd_i2c_bit_start(bus);
	328	err = snd_i2c_bit_sendbyte(bus, addr << 1);
	329	snd_i2c_bit_stop(bus);
	330	return err;
	331	}
	332
1da177e4 LT	333
	334	static int __init alsa_i2c_init(void)
	335	{
	336	return 0;
	337	}
	338
	339	static void __exit alsa_i2c_exit(void)
	340	{
	341	}
	342
	343	module_init(alsa_i2c_init)
	344	module_exit(alsa_i2c_exit)