[mirror_ubuntu-zesty-kernel.git] / drivers / i2c / muxes / i2c-mux-pca9541.c

/*
 * I2C multiplexer driver for PCA9541 bus master selector
 *
 * Copyright (c) 2010 Ericsson AB.
 *
 * Author: Guenter Roeck <linux@roeck-us.net>
 *
 * Derived from:
 *  pca954x.c
 *
 *  Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
 *  Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/module.h>
#include <linux/jiffies.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/i2c.h>
#include <linux/i2c-mux.h>

#include <linux/i2c/pca954x.h>

/*
 * The PCA9541 is a bus master selector. It supports two I2C masters connected
 * to a single slave bus.
 *
 * Before each bus transaction, a master has to acquire bus ownership. After the
 * transaction is complete, bus ownership has to be released. This fits well
 * into the I2C multiplexer framework, which provides select and release
 * functions for this purpose. For this reason, this driver is modeled as
 * single-channel I2C bus multiplexer.
 *
 * This driver assumes that the two bus masters are controlled by two different
 * hosts. If a single host controls both masters, platform code has to ensure
 * that only one of the masters is instantiated at any given time.
 */

#define PCA9541_CONTROL		0x01
#define PCA9541_ISTAT		0x02

#define PCA9541_CTL_MYBUS	(1 << 0)
#define PCA9541_CTL_NMYBUS	(1 << 1)
#define PCA9541_CTL_BUSON	(1 << 2)
#define PCA9541_CTL_NBUSON	(1 << 3)
#define PCA9541_CTL_BUSINIT	(1 << 4)
#define PCA9541_CTL_TESTON	(1 << 6)
#define PCA9541_CTL_NTESTON	(1 << 7)

#define PCA9541_ISTAT_INTIN	(1 << 0)
#define PCA9541_ISTAT_BUSINIT	(1 << 1)
#define PCA9541_ISTAT_BUSOK	(1 << 2)
#define PCA9541_ISTAT_BUSLOST	(1 << 3)
#define PCA9541_ISTAT_MYTEST	(1 << 6)
#define PCA9541_ISTAT_NMYTEST	(1 << 7)

#define BUSON		(PCA9541_CTL_BUSON | PCA9541_CTL_NBUSON)
#define MYBUS		(PCA9541_CTL_MYBUS | PCA9541_CTL_NMYBUS)
#define mybus(x)	(!((x) & MYBUS) || ((x) & MYBUS) == MYBUS)
#define busoff(x)	(!((x) & BUSON) || ((x) & BUSON) == BUSON)

/* arbitration timeouts, in jiffies */
#define ARB_TIMEOUT	(HZ / 8)	/* 125 ms until forcing bus ownership */
#define ARB2_TIMEOUT	(HZ / 4)	/* 250 ms until acquisition failure */

/* arbitration retry delays, in us */
#define SELECT_DELAY_SHORT	50
#define SELECT_DELAY_LONG	1000

struct pca9541 {
	struct i2c_adapter *mux_adap;
	unsigned long select_timeout;
	unsigned long arb_timeout;
};

static const struct i2c_device_id pca9541_id[] = {
	{"pca9541", 0},
	{}
};

MODULE_DEVICE_TABLE(i2c, pca9541_id);

/*
 * Write to chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
 * as they will try to lock the adapter a second time.
 */
static int pca9541_reg_write(struct i2c_client *client, u8 command, u8 val)
{
	struct i2c_adapter *adap = client->adapter;
	int ret;

	if (adap->algo->master_xfer) {
		struct i2c_msg msg;
		char buf[2];

		msg.addr = client->addr;
		msg.flags = 0;
		msg.len = 2;
		buf[0] = command;
		buf[1] = val;
		msg.buf = buf;
		ret = adap->algo->master_xfer(adap, &msg, 1);
	} else {
		union i2c_smbus_data data;

		data.byte = val;
		ret = adap->algo->smbus_xfer(adap, client->addr,
					     client->flags,
					     I2C_SMBUS_WRITE,
					     command,
					     I2C_SMBUS_BYTE_DATA, &data);
	}

	return ret;
}

/*
 * Read from chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
 * as they will try to lock adapter a second time.
 */
static int pca9541_reg_read(struct i2c_client *client, u8 command)
{
	struct i2c_adapter *adap = client->adapter;
	int ret;
	u8 val;

	if (adap->algo->master_xfer) {
		struct i2c_msg msg[2] = {
			{
				.addr = client->addr,
				.flags = 0,
				.len = 1,
				.buf = &command
			},
			{
				.addr = client->addr,
				.flags = I2C_M_RD,
				.len = 1,
				.buf = &val
			}
		};
		ret = adap->algo->master_xfer(adap, msg, 2);
		if (ret == 2)
			ret = val;
		else if (ret >= 0)
			ret = -EIO;
	} else {
		union i2c_smbus_data data;

		ret = adap->algo->smbus_xfer(adap, client->addr,
					     client->flags,
					     I2C_SMBUS_READ,
					     command,
					     I2C_SMBUS_BYTE_DATA, &data);
		if (!ret)
			ret = data.byte;
	}
	return ret;
}

/*
 * Arbitration management functions
 */

/* Release bus. Also reset NTESTON and BUSINIT if it was set. */
static void pca9541_release_bus(struct i2c_client *client)
{
	int reg;

	reg = pca9541_reg_read(client, PCA9541_CONTROL);
	if (reg >= 0 && !busoff(reg) && mybus(reg))
		pca9541_reg_write(client, PCA9541_CONTROL,
				  (reg & PCA9541_CTL_NBUSON) >> 1);
}

/*
 * Arbitration is defined as a two-step process. A bus master can only activate
 * the slave bus if it owns it; otherwise it has to request ownership first.
 * This multi-step process ensures that access contention is resolved
 * gracefully.
 *
 * Bus	Ownership	Other master	Action
 * state		requested access
 * ----------------------------------------------------
 * off	-		yes		wait for arbitration timeout or
 *					for other master to drop request
 * off	no		no		take ownership
 * off	yes		no		turn on bus
 * on	yes		-		done
 * on	no		-		wait for arbitration timeout or
 *					for other master to release bus
 *
 * The main contention point occurs if the slave bus is off and both masters
 * request ownership at the same time. In this case, one master will turn on
 * the slave bus, believing that it owns it. The other master will request
 * bus ownership. Result is that the bus is turned on, and master which did
 * _not_ own the slave bus before ends up owning it.
 */

/* Control commands per PCA9541 datasheet */
static const u8 pca9541_control[16] = {
	4, 0, 1, 5, 4, 4, 5, 5, 0, 0, 1, 1, 0, 4, 5, 1
};

/*
 * Channel arbitration
 *
 * Return values:
 *  <0: error
 *  0 : bus not acquired
 *  1 : bus acquired
 */
static int pca9541_arbitrate(struct i2c_client *client)
{
	struct pca9541 *data = i2c_get_clientdata(client);
	int reg;

	reg = pca9541_reg_read(client, PCA9541_CONTROL);
	if (reg < 0)
		return reg;

	if (busoff(reg)) {
		int istat;
		/*
		 * Bus is off. Request ownership or turn it on unless
		 * other master requested ownership.
		 */
		istat = pca9541_reg_read(client, PCA9541_ISTAT);
		if (!(istat & PCA9541_ISTAT_NMYTEST)
		    || time_is_before_eq_jiffies(data->arb_timeout)) {
			/*
			 * Other master did not request ownership,
			 * or arbitration timeout expired. Take the bus.
			 */
			pca9541_reg_write(client,
					  PCA9541_CONTROL,
					  pca9541_control[reg & 0x0f]
					  | PCA9541_CTL_NTESTON);
			data->select_timeout = SELECT_DELAY_SHORT;
		} else {
			/*
			 * Other master requested ownership.
			 * Set extra long timeout to give it time to acquire it.
			 */
			data->select_timeout = SELECT_DELAY_LONG * 2;
		}
	} else if (mybus(reg)) {
		/*
		 * Bus is on, and we own it. We are done with acquisition.
		 * Reset NTESTON and BUSINIT, then return success.
		 */
		if (reg & (PCA9541_CTL_NTESTON | PCA9541_CTL_BUSINIT))
			pca9541_reg_write(client,
					  PCA9541_CONTROL,
					  reg & ~(PCA9541_CTL_NTESTON
						  | PCA9541_CTL_BUSINIT));
		return 1;
	} else {
		/*
		 * Other master owns the bus.
		 * If arbitration timeout has expired, force ownership.
		 * Otherwise request it.
		 */
		data->select_timeout = SELECT_DELAY_LONG;
		if (time_is_before_eq_jiffies(data->arb_timeout)) {
			/* Time is up, take the bus and reset it. */
			pca9541_reg_write(client,
					  PCA9541_CONTROL,
					  pca9541_control[reg & 0x0f]
					  | PCA9541_CTL_BUSINIT
					  | PCA9541_CTL_NTESTON);
		} else {
			/* Request bus ownership if needed */
			if (!(reg & PCA9541_CTL_NTESTON))
				pca9541_reg_write(client,
						  PCA9541_CONTROL,
						  reg | PCA9541_CTL_NTESTON);
		}
	}
	return 0;
}

static int pca9541_select_chan(struct i2c_adapter *adap, void *client, u32 chan)
{
	struct pca9541 *data = i2c_get_clientdata(client);
	int ret;
	unsigned long timeout = jiffies + ARB2_TIMEOUT;
		/* give up after this time */

	data->arb_timeout = jiffies + ARB_TIMEOUT;
		/* force bus ownership after this time */

	do {
		ret = pca9541_arbitrate(client);
		if (ret)
			return ret < 0 ? ret : 0;

		if (data->select_timeout == SELECT_DELAY_SHORT)
			udelay(data->select_timeout);
		else
			msleep(data->select_timeout / 1000);
	} while (time_is_after_eq_jiffies(timeout));

	return -ETIMEDOUT;
}

static int pca9541_release_chan(struct i2c_adapter *adap,
				void *client, u32 chan)
{
	pca9541_release_bus(client);
	return 0;
}

/*
 * I2C init/probing/exit functions
 */
static int pca9541_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct i2c_adapter *adap = client->adapter;
	struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
	struct pca9541 *data;
	int force;
	int ret = -ENODEV;

	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE_DATA))
		goto err;

	data = kzalloc(sizeof(struct pca9541), GFP_KERNEL);
	if (!data) {
		ret = -ENOMEM;
		goto err;
	}

	i2c_set_clientdata(client, data);

	/*
	 * I2C accesses are unprotected here.
	 * We have to lock the adapter before releasing the bus.
	 */
	i2c_lock_adapter(adap);
	pca9541_release_bus(client);
	i2c_unlock_adapter(adap);

	/* Create mux adapter */

	force = 0;
	if (pdata)
		force = pdata->modes[0].adap_id;
	data->mux_adap = i2c_add_mux_adapter(adap, &client->dev, client,
					     force, 0, 0,
					     pca9541_select_chan,
					     pca9541_release_chan);

	if (data->mux_adap == NULL) {
		dev_err(&client->dev, "failed to register master selector\n");
		goto exit_free;
	}

	dev_info(&client->dev, "registered master selector for I2C %s\n",
		 client->name);

	return 0;

exit_free:
	kfree(data);
err:
	return ret;
}

static int pca9541_remove(struct i2c_client *client)
{
	struct pca9541 *data = i2c_get_clientdata(client);

	i2c_del_mux_adapter(data->mux_adap);

	kfree(data);
	return 0;
}

static struct i2c_driver pca9541_driver = {
	.driver = {
		   .name = "pca9541",
		   .owner = THIS_MODULE,
		   },
	.probe = pca9541_probe,
	.remove = pca9541_remove,
	.id_table = pca9541_id,
};

module_i2c_driver(pca9541_driver);

MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
MODULE_DESCRIPTION("PCA9541 I2C master selector driver");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
ae63b13b GR	1	/*
	2	* I2C multiplexer driver for PCA9541 bus master selector
	3	*
	4	* Copyright (c) 2010 Ericsson AB.
	5	*
b104153e	6	* Author: Guenter Roeck <linux@roeck-us.net>
ae63b13b GR	7	*
	8	* Derived from:
	9	* pca954x.c
	10	*
	11	* Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
	12	* Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
	13	*
	14	* This file is licensed under the terms of the GNU General Public
	15	* License version 2. This program is licensed "as is" without any
	16	* warranty of any kind, whether express or implied.
	17	*/
	18
	19	#include <linux/module.h>
ae63b13b GR	20	#include <linux/jiffies.h>
	21	#include <linux/delay.h>
	22	#include <linux/slab.h>
	23	#include <linux/device.h>
	24	#include <linux/i2c.h>
	25	#include <linux/i2c-mux.h>
	26
	27	#include <linux/i2c/pca954x.h>
	28
	29	/*
	30	* The PCA9541 is a bus master selector. It supports two I2C masters connected
	31	* to a single slave bus.
	32	*
	33	* Before each bus transaction, a master has to acquire bus ownership. After the
	34	* transaction is complete, bus ownership has to be released. This fits well
	35	* into the I2C multiplexer framework, which provides select and release
	36	* functions for this purpose. For this reason, this driver is modeled as
	37	* single-channel I2C bus multiplexer.
	38	*
	39	* This driver assumes that the two bus masters are controlled by two different
	40	* hosts. If a single host controls both masters, platform code has to ensure
	41	* that only one of the masters is instantiated at any given time.
	42	*/
	43
	44	#define PCA9541_CONTROL 0x01
	45	#define PCA9541_ISTAT 0x02
	46
	47	#define PCA9541_CTL_MYBUS (1 << 0)
	48	#define PCA9541_CTL_NMYBUS (1 << 1)
	49	#define PCA9541_CTL_BUSON (1 << 2)
	50	#define PCA9541_CTL_NBUSON (1 << 3)
	51	#define PCA9541_CTL_BUSINIT (1 << 4)
	52	#define PCA9541_CTL_TESTON (1 << 6)
	53	#define PCA9541_CTL_NTESTON (1 << 7)
	54
	55	#define PCA9541_ISTAT_INTIN (1 << 0)
	56	#define PCA9541_ISTAT_BUSINIT (1 << 1)
	57	#define PCA9541_ISTAT_BUSOK (1 << 2)
	58	#define PCA9541_ISTAT_BUSLOST (1 << 3)
	59	#define PCA9541_ISTAT_MYTEST (1 << 6)
	60	#define PCA9541_ISTAT_NMYTEST (1 << 7)
	61
	62	#define BUSON (PCA9541_CTL_BUSON \| PCA9541_CTL_NBUSON)
	63	#define MYBUS (PCA9541_CTL_MYBUS \| PCA9541_CTL_NMYBUS)
	64	#define mybus(x) (!((x) & MYBUS) \|\| ((x) & MYBUS) == MYBUS)
	65	#define busoff(x) (!((x) & BUSON) \|\| ((x) & BUSON) == BUSON)
	66
	67	/* arbitration timeouts, in jiffies */
	68	#define ARB_TIMEOUT (HZ / 8) /* 125 ms until forcing bus ownership */
	69	#define ARB2_TIMEOUT (HZ / 4) /* 250 ms until acquisition failure */
	70
	71	/* arbitration retry delays, in us */
	72	#define SELECT_DELAY_SHORT 50
	73	#define SELECT_DELAY_LONG 1000
	74
	75	struct pca9541 {
	76	struct i2c_adapter *mux_adap;
	77	unsigned long select_timeout;
	78	unsigned long arb_timeout;
	79	};
	80
	81	static const struct i2c_device_id pca9541_id[] = {
	82	{"pca9541", 0},
	83	{}
84	};
85
86	MODULE_DEVICE_TABLE(i2c, pca9541_id);
87
88	/*
89	* Write to chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
90	* as they will try to lock the adapter a second time.
91	*/
92	static int pca9541_reg_write(struct i2c_client *client, u8 command, u8 val)
93	{
94	struct i2c_adapter *adap = client->adapter;
95	int ret;
96
97	if (adap->algo->master_xfer) {
98	struct i2c_msg msg;
99	char buf[2];
100
101	msg.addr = client->addr;
102	msg.flags = 0;
103	msg.len = 2;
104	buf[0] = command;
105	buf[1] = val;
106	msg.buf = buf;
107	ret = adap->algo->master_xfer(adap, &msg, 1);
108	} else {
109	union i2c_smbus_data data;
110
111	data.byte = val;
112	ret = adap->algo->smbus_xfer(adap, client->addr,
113	client->flags,
114	I2C_SMBUS_WRITE,
115	command,
116	I2C_SMBUS_BYTE_DATA, &data);
117	}
118
119	return ret;
120	}
121
122	/*
123	* Read from chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
124	* as they will try to lock adapter a second time.
125	*/
126	static int pca9541_reg_read(struct i2c_client *client, u8 command)
127	{
128	struct i2c_adapter *adap = client->adapter;
129	int ret;
130	u8 val;
131
132	if (adap->algo->master_xfer) {
133	struct i2c_msg msg[2] = {
134	{
135	.addr = client->addr,
136	.flags = 0,
137	.len = 1,
138	.buf = &command
139	},
140	{
141	.addr = client->addr,
142	.flags = I2C_M_RD,
143	.len = 1,
144	.buf = &val
145	}
146	};
147	ret = adap->algo->master_xfer(adap, msg, 2);
148	if (ret == 2)
149	ret = val;
150	else if (ret >= 0)
151	ret = -EIO;
152	} else {
153	union i2c_smbus_data data;
154
155	ret = adap->algo->smbus_xfer(adap, client->addr,
156	client->flags,
157	I2C_SMBUS_READ,
158	command,
159	I2C_SMBUS_BYTE_DATA, &data);
160	if (!ret)
161	ret = data.byte;
162	}
163	return ret;
164	}
165
166	/*
167	* Arbitration management functions
168	*/
169
170	/* Release bus. Also reset NTESTON and BUSINIT if it was set. */
171	static void pca9541_release_bus(struct i2c_client *client)
172	{
173	int reg;
174
175	reg = pca9541_reg_read(client, PCA9541_CONTROL);
176	if (reg >= 0 && !busoff(reg) && mybus(reg))
177	pca9541_reg_write(client, PCA9541_CONTROL,
178	(reg & PCA9541_CTL_NBUSON) >> 1);
179	}
180
181	/*
182	* Arbitration is defined as a two-step process. A bus master can only activate
183	* the slave bus if it owns it; otherwise it has to request ownership first.
184	* This multi-step process ensures that access contention is resolved
185	* gracefully.
186	*
187	* Bus Ownership Other master Action
188	* state requested access
189	* ----------------------------------------------------
190	* off - yes wait for arbitration timeout or
191	* for other master to drop request
192	* off no no take ownership
193	* off yes no turn on bus
194	* on yes - done
195	* on no - wait for arbitration timeout or
196	* for other master to release bus
197	*
198	* The main contention point occurs if the slave bus is off and both masters
199	* request ownership at the same time. In this case, one master will turn on
200	* the slave bus, believing that it owns it. The other master will request
201	* bus ownership. Result is that the bus is turned on, and master which did
202	* _not_ own the slave bus before ends up owning it.
203	*/
204
205	/* Control commands per PCA9541 datasheet */
206	static const u8 pca9541_control[16] = {
207	4, 0, 1, 5, 4, 4, 5, 5, 0, 0, 1, 1, 0, 4, 5, 1
208	};
209
210	/*
211	* Channel arbitration
212	*
213	* Return values:
214	* <0: error
215	* 0 : bus not acquired
216	* 1 : bus acquired
217	*/
218	static int pca9541_arbitrate(struct i2c_client *client)
219	{
220	struct pca9541 *data = i2c_get_clientdata(client);
221	int reg;
222
223	reg = pca9541_reg_read(client, PCA9541_CONTROL);
224	if (reg < 0)
225	return reg;
226
227	if (busoff(reg)) {
228	int istat;
229	/*
230	* Bus is off. Request ownership or turn it on unless
231	* other master requested ownership.
232	*/
233	istat = pca9541_reg_read(client, PCA9541_ISTAT);
234	if (!(istat & PCA9541_ISTAT_NMYTEST)
235	\|\| time_is_before_eq_jiffies(data->arb_timeout)) {
236	/*
237	* Other master did not request ownership,
238	* or arbitration timeout expired. Take the bus.
239	*/
240	pca9541_reg_write(client,
241	PCA9541_CONTROL,
242	pca9541_control[reg & 0x0f]
243	\| PCA9541_CTL_NTESTON);
244	data->select_timeout = SELECT_DELAY_SHORT;
245	} else {
246	/*
247	* Other master requested ownership.
248	* Set extra long timeout to give it time to acquire it.
249	*/
250	data->select_timeout = SELECT_DELAY_LONG * 2;
251	}
252	} else if (mybus(reg)) {
253	/*
254	* Bus is on, and we own it. We are done with acquisition.
255	* Reset NTESTON and BUSINIT, then return success.
256	*/
257	if (reg & (PCA9541_CTL_NTESTON \| PCA9541_CTL_BUSINIT))
258	pca9541_reg_write(client,
259	PCA9541_CONTROL,
260	reg & ~(PCA9541_CTL_NTESTON
261	\| PCA9541_CTL_BUSINIT));
262	return 1;
263	} else {
264	/*
265	* Other master owns the bus.
266	* If arbitration timeout has expired, force ownership.
267	* Otherwise request it.
268	*/
269	data->select_timeout = SELECT_DELAY_LONG;
270	if (time_is_before_eq_jiffies(data->arb_timeout)) {
271	/* Time is up, take the bus and reset it. */
272	pca9541_reg_write(client,
273	PCA9541_CONTROL,
274	pca9541_control[reg & 0x0f]
275	\| PCA9541_CTL_BUSINIT
276	\| PCA9541_CTL_NTESTON);
277	} else {
278	/* Request bus ownership if needed */
279	if (!(reg & PCA9541_CTL_NTESTON))
280	pca9541_reg_write(client,
281	PCA9541_CONTROL,
282	reg \| PCA9541_CTL_NTESTON);
283	}
284	}
285	return 0;
286	}
287
288	static int pca9541_select_chan(struct i2c_adapter adap, void client, u32 chan)
289	{
290	struct pca9541 *data = i2c_get_clientdata(client);
291	int ret;
292	unsigned long timeout = jiffies + ARB2_TIMEOUT;
293	/* give up after this time */
294
295	data->arb_timeout = jiffies + ARB_TIMEOUT;
296	/* force bus ownership after this time */
297
298	do {
299	ret = pca9541_arbitrate(client);
300	if (ret)
301	return ret < 0 ? ret : 0;
302
303	if (data->select_timeout == SELECT_DELAY_SHORT)
304	udelay(data->select_timeout);
305	else
306	msleep(data->select_timeout / 1000);
307	} while (time_is_after_eq_jiffies(timeout));
308
309	return -ETIMEDOUT;
310	}
311
312	static int pca9541_release_chan(struct i2c_adapter *adap,
313	void *client, u32 chan)
314	{
315	pca9541_release_bus(client);
316	return 0;
317	}
318
319	/*
320	* I2C init/probing/exit functions
321	*/
322	static int pca9541_probe(struct i2c_client *client,
323	const struct i2c_device_id *id)
324	{
325	struct i2c_adapter *adap = client->adapter;
6d4028c6	326	struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
ae63b13b GR	327	struct pca9541 *data;
	328	int force;
	329	int ret = -ENODEV;
	330
	331	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE_DATA))
	332	goto err;
	333
	334	data = kzalloc(sizeof(struct pca9541), GFP_KERNEL);
	335	if (!data) {
	336	ret = -ENOMEM;
	337	goto err;
	338	}
	339
	340	i2c_set_clientdata(client, data);
	341
	342	/*
	343	* I2C accesses are unprotected here.
	344	* We have to lock the adapter before releasing the bus.
	345	*/
	346	i2c_lock_adapter(adap);
	347	pca9541_release_bus(client);
	348	i2c_unlock_adapter(adap);
	349
	350	/* Create mux adapter */
	351
	352	force = 0;
	353	if (pdata)
	354	force = pdata->modes[0].adap_id;
5a3ecd5f	355	data->mux_adap = i2c_add_mux_adapter(adap, &client->dev, client,
eee543e8	356	force, 0, 0,
ae63b13b GR	357	pca9541_select_chan,
	358	pca9541_release_chan);
	359
	360	if (data->mux_adap == NULL) {
	361	dev_err(&client->dev, "failed to register master selector\n");
	362	goto exit_free;
	363	}
	364
	365	dev_info(&client->dev, "registered master selector for I2C %s\n",
	366	client->name);
	367
	368	return 0;
	369
	370	exit_free:
	371	kfree(data);
	372	err:
	373	return ret;
	374	}
	375
	376	static int pca9541_remove(struct i2c_client *client)
	377	{
	378	struct pca9541 *data = i2c_get_clientdata(client);
	379
	380	i2c_del_mux_adapter(data->mux_adap);
	381
	382	kfree(data);
	383	return 0;
	384	}
	385
	386	static struct i2c_driver pca9541_driver = {
	387	.driver = {
	388	.name = "pca9541",
	389	.owner = THIS_MODULE,
	390	},
	391	.probe = pca9541_probe,
	392	.remove = pca9541_remove,
	393	.id_table = pca9541_id,
	394	};
	395
de05497a	396	module_i2c_driver(pca9541_driver);
ae63b13b	397
83a638df	398	MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
ae63b13b GR	399	MODULE_DESCRIPTION("PCA9541 I2C master selector driver");
ae63b13b GR	400	MODULE_LICENSE("GPL v2");