[linux.git] / sound / i2c / i2c.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *   Generic i2c interface for ALSA
 *
 *   (c) 1998 Gerd Knorr <[email protected]>
 *   Modified for the ALSA driver by Jaroslav Kysela <[email protected]>
 */

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

MODULE_AUTHOR("Jaroslav Kysela <[email protected]>");
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 const 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;

	if (snd_BUG_ON(!bus))
		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 const 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));
	err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops);
	if (err < 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;
	if (snd_BUG_ON(!bus))
		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)));
	err = snd_i2c_bit_ack(bus);
	if (err < 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);
	err = snd_i2c_bit_sendbyte(bus, device->addr << 1);
	if (err < 0) {
		snd_i2c_bit_hw_stop(bus);
		return err;
	}
	while (count-- > 0) {
		err = snd_i2c_bit_sendbyte(bus, *bytes++);
		if (err < 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);
	err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1);
	if (err < 0) {
		snd_i2c_bit_hw_stop(bus);
		return err;
	}
	while (count-- > 0) {
		err = snd_i2c_bit_readbyte(bus, count == 0);
		if (err < 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;
}
Commit	Line	Data
1a59d1b8	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/*
	3	* Generic i2c interface for ALSA
	4	*
	5	* (c) 1998 Gerd Knorr <[email protected]>
c1017a4c	6	* Modified for the ALSA driver by Jaroslav Kysela <[email protected]>
1da177e4 LT	7	*/
1da177e4 LT	8
1da177e4 LT	9	#include <linux/init.h>
1da177e4 LT	10	#include <linux/slab.h>
da155d5b	11	#include <linux/module.h>
1da177e4 LT	12	#include <linux/string.h>
	13	#include <linux/errno.h>
	14	#include <sound/core.h>
	15	#include <sound/i2c.h>
	16
c1017a4c	17	MODULE_AUTHOR("Jaroslav Kysela <[email protected]>");
1da177e4 LT	18	MODULE_DESCRIPTION("Generic i2c interface for ALSA");
	19	MODULE_LICENSE("GPL");
	20
97f02e05 TI	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
5df29bca	28	static const struct snd_i2c_ops snd_i2c_bit_ops = {
1da177e4 LT	29	.sendbytes = snd_i2c_bit_sendbytes,
	30	.readbytes = snd_i2c_bit_readbytes,
	31	.probeaddr = snd_i2c_bit_probeaddr,
	32	};
	33
97f02e05	34	static int snd_i2c_bus_free(struct snd_i2c_bus *bus)
1da177e4	35	{
97f02e05 TI	36	struct snd_i2c_bus *slave;
97f02e05 TI	37	struct snd_i2c_device *device;
1da177e4	38
5e246b85 TI	39	if (snd_BUG_ON(!bus))
5e246b85 TI	40	return -EINVAL;
1da177e4 LT	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
97f02e05	59	static int snd_i2c_bus_dev_free(struct snd_device *device)
1da177e4	60	{
97f02e05	61	struct snd_i2c_bus *bus = device->device_data;
1da177e4 LT	62	return snd_i2c_bus_free(bus);
	63	}
	64
97f02e05 TI	65	int snd_i2c_bus_create(struct snd_card card, const char name,
97f02e05 TI	66	struct snd_i2c_bus master, struct snd_i2c_bus *ri2c)
1da177e4	67	{
97f02e05	68	struct snd_i2c_bus *bus;
1da177e4	69	int err;
d23015c1	70	static const struct snd_device_ops ops = {
1da177e4 LT	71	.dev_free = snd_i2c_bus_dev_free,
	72	};
	73
	74	*ri2c = NULL;
561b220a	75	bus = kzalloc(sizeof(*bus), GFP_KERNEL);
1da177e4 LT	76	if (bus == NULL)
1da177e4 LT	77	return -ENOMEM;
ef9f0a42	78	mutex_init(&bus->lock_mutex);
1da177e4 LT	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	strlcpy(bus->name, name, sizeof(bus->name));
1cff399e BW	88	err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops);
1cff399e BW	89	if (err < 0) {
1da177e4 LT	90	snd_i2c_bus_free(bus);
	91	return err;
	92	}
	93	*ri2c = bus;
	94	return 0;
	95	}
	96
57c65c11 TI	97	EXPORT_SYMBOL(snd_i2c_bus_create);
57c65c11 TI	98
97f02e05 TI	99	int snd_i2c_device_create(struct snd_i2c_bus bus, const char name,
97f02e05 TI	100	unsigned char addr, struct snd_i2c_device **rdevice)
1da177e4	101	{
97f02e05	102	struct snd_i2c_device *device;
1da177e4 LT	103
1da177e4 LT	104	*rdevice = NULL;
5e246b85 TI	105	if (snd_BUG_ON(!bus))
5e246b85 TI	106	return -EINVAL;
561b220a	107	device = kzalloc(sizeof(*device), GFP_KERNEL);
1da177e4 LT	108	if (device == NULL)
	109	return -ENOMEM;
	110	device->addr = addr;
	111	strlcpy(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
57c65c11 TI	118	EXPORT_SYMBOL(snd_i2c_device_create);
57c65c11 TI	119
97f02e05	120	int snd_i2c_device_free(struct snd_i2c_device *device)
1da177e4 LT	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
57c65c11 TI	130	EXPORT_SYMBOL(snd_i2c_device_free);
57c65c11 TI	131
97f02e05	132	int snd_i2c_sendbytes(struct snd_i2c_device device, unsigned char bytes, int count)
1da177e4 LT	133	{
	134	return device->bus->ops->sendbytes(device, bytes, count);
	135	}
	136
57c65c11	137	EXPORT_SYMBOL(snd_i2c_sendbytes);
1da177e4	138
97f02e05	139	int snd_i2c_readbytes(struct snd_i2c_device device, unsigned char bytes, int count)
1da177e4 LT	140	{
	141	return device->bus->ops->readbytes(device, bytes, count);
	142	}
	143
57c65c11 TI	144	EXPORT_SYMBOL(snd_i2c_readbytes);
57c65c11 TI	145
97f02e05	146	int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
1da177e4 LT	147	{
	148	return bus->ops->probeaddr(bus, addr);
	149	}
	150
57c65c11 TI	151	EXPORT_SYMBOL(snd_i2c_probeaddr);
57c65c11 TI	152
1da177e4 LT	153	/*
	154	* bit-operations
	155	*/
	156
97f02e05	157	static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus)
1da177e4 LT	158	{
	159	if (bus->hw_ops.bit->start)
	160	bus->hw_ops.bit->start(bus);
	161	}
	162
97f02e05	163	static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus)
1da177e4 LT	164	{
	165	if (bus->hw_ops.bit->stop)
	166	bus->hw_ops.bit->stop(bus);
	167	}
	168
97f02e05	169	static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data)
1da177e4 LT	170	{
	171	if (bus->hw_ops.bit->direction)
	172	bus->hw_ops.bit->direction(bus, clock, data);
	173	}
	174
97f02e05	175	static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data)
1da177e4 LT	176	{
	177	bus->hw_ops.bit->setlines(bus, clock, data);
	178	}
	179
	180	#if 0
97f02e05	181	static int snd_i2c_bit_clock(struct snd_i2c_bus *bus)
1da177e4 LT	182	{
	183	if (bus->hw_ops.bit->getclock)
	184	return bus->hw_ops.bit->getclock(bus);
	185	return -ENXIO;
	186	}
	187	#endif
	188
97f02e05	189	static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
1da177e4 LT	190	{
	191	return bus->hw_ops.bit->getdata(bus, ack);
	192	}
	193
97f02e05	194	static void snd_i2c_bit_start(struct snd_i2c_bus *bus)
1da177e4 LT	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
97f02e05	203	static void snd_i2c_bit_stop(struct snd_i2c_bus *bus)
1da177e4 LT	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
97f02e05	211	static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data)
1da177e4 LT	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
97f02e05	218	static int snd_i2c_bit_ack(struct snd_i2c_bus *bus)
1da177e4 LT	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
97f02e05	231	static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data)
1da177e4 LT	232	{
	233	int i, err;
	234
	235	for (i = 7; i >= 0; i--)
	236	snd_i2c_bit_send(bus, !!(data & (1 << i)));
1cff399e BW	237	err = snd_i2c_bit_ack(bus);
1cff399e BW	238	if (err < 0)
1da177e4 LT	239	return err;
	240	return 0;
	241	}
	242
97f02e05	243	static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
1da177e4 LT	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
97f02e05 TI	261	static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
97f02e05 TI	262	unsigned char *bytes, int count)
1da177e4	263	{
97f02e05	264	struct snd_i2c_bus *bus = device->bus;
1da177e4 LT	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);
1cff399e BW	270	err = snd_i2c_bit_sendbyte(bus, device->addr << 1);
1cff399e BW	271	if (err < 0) {
1da177e4 LT	272	snd_i2c_bit_hw_stop(bus);
	273	return err;
	274	}
	275	while (count-- > 0) {
1cff399e BW	276	err = snd_i2c_bit_sendbyte(bus, *bytes++);
1cff399e BW	277	if (err < 0) {
1da177e4 LT	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
97f02e05 TI	287	static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
97f02e05 TI	288	unsigned char *bytes, int count)
1da177e4	289	{
97f02e05	290	struct snd_i2c_bus *bus = device->bus;
1da177e4 LT	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);
1cff399e BW	296	err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) \| 1);
1cff399e BW	297	if (err < 0) {
1da177e4 LT	298	snd_i2c_bit_hw_stop(bus);
	299	return err;
	300	}
	301	while (count-- > 0) {
1cff399e BW	302	err = snd_i2c_bit_readbyte(bus, count == 0);
1cff399e BW	303	if (err < 0) {
1da177e4 LT	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
97f02e05	314	static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
1da177e4 LT	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	}