drivers/i2c/algos/i2c-algo-pca.c - kernel/msm-4.9 - Gitiles

 /*
  *  i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters
  *    Copyright (C) 2004 Arcom Control Systems
  *    Copyright (C) 2008 Pengutronix
  *
  *  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., 675 Mass Ave, Cambridge, MA 02139, USA.
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/i2c.h>
 #include <linux/i2c-algo-pca.h>

 #define DEB1(fmt, args...) do { if (i2c_debug>=1) printk(fmt, ## args); } while(0)
 #define DEB2(fmt, args...) do { if (i2c_debug>=2) printk(fmt, ## args); } while(0)
 #define DEB3(fmt, args...) do { if (i2c_debug>=3) printk(fmt, ## args); } while(0)

 static int i2c_debug;

 #define pca_outw(adap, reg, val) adap->write_byte(adap->data, reg, val)
 #define pca_inw(adap, reg) adap->read_byte(adap->data, reg)

 #define pca_status(adap) pca_inw(adap, I2C_PCA_STA)
 #define pca_clock(adap) adap->i2c_clock
 #define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val)
 #define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON)
 #define pca_wait(adap) adap->wait_for_completion(adap->data)
 #define pca_reset(adap) adap->reset_chip(adap->data)

 /*
  * Generate a start condition on the i2c bus.
  *
  * returns after the start condition has occurred
  */
 static void pca_start(struct i2c_algo_pca_data *adap)
 {
 	int sta = pca_get_con(adap);
 	DEB2("=== START\n");
 	sta |= I2C_PCA_CON_STA;
 	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
 	pca_set_con(adap, sta);
 	pca_wait(adap);
 }

 /*
  * Generate a repeated start condition on the i2c bus
  *
  * return after the repeated start condition has occurred
  */
 static void pca_repeated_start(struct i2c_algo_pca_data *adap)
 {
 	int sta = pca_get_con(adap);
 	DEB2("=== REPEATED START\n");
 	sta |= I2C_PCA_CON_STA;
 	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
 	pca_set_con(adap, sta);
 	pca_wait(adap);
 }

 /*
  * Generate a stop condition on the i2c bus
  *
  * returns after the stop condition has been generated
  *
  * STOPs do not generate an interrupt or set the SI flag, since the
  * part returns the idle state (0xf8). Hence we don't need to
  * pca_wait here.
  */
 static void pca_stop(struct i2c_algo_pca_data *adap)
 {
 	int sta = pca_get_con(adap);
 	DEB2("=== STOP\n");
 	sta |= I2C_PCA_CON_STO;
 	sta &= ~(I2C_PCA_CON_STA|I2C_PCA_CON_SI);
 	pca_set_con(adap, sta);
 }

 /*
  * Send the slave address and R/W bit
  *
  * returns after the address has been sent
  */
 static void pca_address(struct i2c_algo_pca_data *adap,
 			struct i2c_msg *msg)
 {
 	int sta = pca_get_con(adap);
 	int addr;

 	addr = ( (0x7f & msg->addr) << 1 );
 	if (msg->flags & I2C_M_RD )
 		addr |= 1;
 	DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n",
 	     msg->addr, msg->flags & I2C_M_RD ? 'R' : 'W', addr);

 	pca_outw(adap, I2C_PCA_DAT, addr);

 	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
 	pca_set_con(adap, sta);

 	pca_wait(adap);
 }

 /*
  * Transmit a byte.
  *
  * Returns after the byte has been transmitted
  */
 static void pca_tx_byte(struct i2c_algo_pca_data *adap,
 			__u8 b)
 {
 	int sta = pca_get_con(adap);
 	DEB2("=== WRITE %#04x\n", b);
 	pca_outw(adap, I2C_PCA_DAT, b);

 	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
 	pca_set_con(adap, sta);

 	pca_wait(adap);
 }

 /*
  * Receive a byte
  *
  * returns immediately.
  */
 static void pca_rx_byte(struct i2c_algo_pca_data *adap,
 			__u8 *b, int ack)
 {
 	*b = pca_inw(adap, I2C_PCA_DAT);
 	DEB2("=== READ %#04x %s\n", *b, ack ? "ACK" : "NACK");
 }

 /*
  * Setup ACK or NACK for next received byte and wait for it to arrive.
  *
  * Returns after next byte has arrived.
  */
 static void pca_rx_ack(struct i2c_algo_pca_data *adap,
 		       int ack)
 {
 	int sta = pca_get_con(adap);

 	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI|I2C_PCA_CON_AA);

 	if ( ack )
 		sta |= I2C_PCA_CON_AA;

 	pca_set_con(adap, sta);
 	pca_wait(adap);
 }

 static int pca_xfer(struct i2c_adapter *i2c_adap,
                     struct i2c_msg *msgs,
                     int num)
 {
         struct i2c_algo_pca_data *adap = i2c_adap->algo_data;
         struct i2c_msg *msg = NULL;
         int curmsg;
 	int numbytes = 0;
 	int state;
 	int ret;
 	int timeout = i2c_adap->timeout;

 	while ((state = pca_status(adap)) != 0xf8 && timeout--) {
 		msleep(10);
 	}
 	if (state != 0xf8) {
 		dev_dbg(&i2c_adap->dev, "bus is not idle. status is %#04x\n", state);
 		return -EIO;
 	}

 	DEB1("{{{ XFER %d messages\n", num);

 	if (i2c_debug>=2) {
 		for (curmsg = 0; curmsg < num; curmsg++) {
 			int addr, i;
 			msg = &msgs[curmsg];

 			addr = (0x7f & msg->addr) ;

 			if (msg->flags & I2C_M_RD )
 				printk(KERN_INFO "    [%02d] RD %d bytes from %#02x [%#02x, ...]\n",
 				       curmsg, msg->len, addr, (addr<<1) | 1);
 			else {
 				printk(KERN_INFO "    [%02d] WR %d bytes to %#02x [%#02x%s",
 				       curmsg, msg->len, addr, addr<<1,
 				       msg->len == 0 ? "" : ", ");
 				for(i=0; i < msg->len; i++)
 					printk("%#04x%s", msg->buf[i], i == msg->len - 1 ? "" : ", ");
 				printk("]\n");
 			}
 		}
 	}

 	curmsg = 0;
 	ret = -EREMOTEIO;
 	while (curmsg < num) {
 		state = pca_status(adap);

 		DEB3("STATE is 0x%02x\n", state);
 		msg = &msgs[curmsg];

 		switch (state) {
 		case 0xf8: /* On reset or stop the bus is idle */
 			pca_start(adap);
 			break;

 		case 0x08: /* A START condition has been transmitted */
 		case 0x10: /* A repeated start condition has been transmitted */
 			pca_address(adap, msg);
 			break;

 		case 0x18: /* SLA+W has been transmitted; ACK has been received */
 		case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */
 			if (numbytes < msg->len) {
 				pca_tx_byte(adap, msg->buf[numbytes]);
 				numbytes++;
 				break;
 			}
 			curmsg++; numbytes = 0;
 			if (curmsg == num)
 				pca_stop(adap);
 			else
 				pca_repeated_start(adap);
 			break;

 		case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */
 			DEB2("NOT ACK received after SLA+W\n");
 			pca_stop(adap);
 			goto out;

 		case 0x40: /* SLA+R has been transmitted; ACK has been received */
 			pca_rx_ack(adap, msg->len > 1);
 			break;

 		case 0x50: /* Data bytes has been received; ACK has been returned */
 			if (numbytes < msg->len) {
 				pca_rx_byte(adap, &msg->buf[numbytes], 1);
 				numbytes++;
 				pca_rx_ack(adap, numbytes < msg->len - 1);
 				break;
 			}
 			curmsg++; numbytes = 0;
 			if (curmsg == num)
 				pca_stop(adap);
 			else
 				pca_repeated_start(adap);
 			break;

 		case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */
 			DEB2("NOT ACK received after SLA+R\n");
 			pca_stop(adap);
 			goto out;

 		case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */
 			DEB2("NOT ACK received after data byte\n");
 			goto out;

 		case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */
 			DEB2("Arbitration lost\n");
 			goto out;

 		case 0x58: /* Data byte has been received; NOT ACK has been returned */
 			if ( numbytes == msg->len - 1 ) {
 				pca_rx_byte(adap, &msg->buf[numbytes], 0);
 				curmsg++; numbytes = 0;
 				if (curmsg == num)
 					pca_stop(adap);
 				else
 					pca_repeated_start(adap);
 			} else {
 				DEB2("NOT ACK sent after data byte received. "
 				     "Not final byte. numbytes %d. len %d\n",
 				     numbytes, msg->len);
 				pca_stop(adap);
 				goto out;
 			}
 			break;
 		case 0x70: /* Bus error - SDA stuck low */
 			DEB2("BUS ERROR - SDA Stuck low\n");
 			pca_reset(adap);
 			goto out;
 		case 0x90: /* Bus error - SCL stuck low */
 			DEB2("BUS ERROR - SCL Stuck low\n");
 			pca_reset(adap);
 			goto out;
 		case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */
 			DEB2("BUS ERROR - Illegal START or STOP\n");
 			pca_reset(adap);
 			goto out;
 		default:
 			dev_err(&i2c_adap->dev, "unhandled SIO state 0x%02x\n", state);
 			break;
 		}

 	}

 	ret = curmsg;
  out:
 	DEB1(KERN_CRIT "}}} transfered %d/%d messages. "
 	     "status is %#04x. control is %#04x\n",
 	     curmsg, num, pca_status(adap),
 	     pca_get_con(adap));
 	return ret;
 }

 static u32 pca_func(struct i2c_adapter *adap)
 {
         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 }

 static const struct i2c_algorithm pca_algo = {
 	.master_xfer	= pca_xfer,
 	.functionality	= pca_func,
 };

 static int pca_init(struct i2c_adapter *adap)
 {
 	static int freqs[] = {330,288,217,146,88,59,44,36};
 	int clock;
 	struct i2c_algo_pca_data *pca_data = adap->algo_data;

 	if (pca_data->i2c_clock > 7) {
 		printk(KERN_WARNING "%s: Invalid I2C clock speed selected. Trying default.\n",
 			adap->name);
 		pca_data->i2c_clock = I2C_PCA_CON_59kHz;
 	}

 	adap->algo = &pca_algo;

 	pca_reset(pca_data);

 	clock = pca_clock(pca_data);
 	DEB1(KERN_INFO "%s: Clock frequency is %dkHz\n", adap->name, freqs[clock]);

 	pca_set_con(pca_data, I2C_PCA_CON_ENSIO | clock);
 	udelay(500); /* 500 us for oscilator to stabilise */

 	return 0;
 }

 /*
  * registering functions to load algorithms at runtime
  */
 int i2c_pca_add_bus(struct i2c_adapter *adap)
 {
 	int rval;

 	rval = pca_init(adap);
 	if (rval)
 		return rval;

 	return i2c_add_adapter(adap);
 }
 EXPORT_SYMBOL(i2c_pca_add_bus);

 int i2c_pca_add_numbered_bus(struct i2c_adapter *adap)
 {
 	int rval;

 	rval = pca_init(adap);
 	if (rval)
 		return rval;

 	return i2c_add_numbered_adapter(adap);
 }
 EXPORT_SYMBOL(i2c_pca_add_numbered_bus);

 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>, "
 	"Wolfram Sang <w.sang@pengutronix.de>");
 MODULE_DESCRIPTION("I2C-Bus PCA9564 algorithm");
 MODULE_LICENSE("GPL");

 module_param(i2c_debug, int, 0);
	/*
	* i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters
	* Copyright (C) 2004 Arcom Control Systems
	* Copyright (C) 2008 Pengutronix
	*
	* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/delay.h>
	#include <linux/init.h>
	#include <linux/errno.h>
	#include <linux/i2c.h>
	#include <linux/i2c-algo-pca.h>

	#define DEB1(fmt, args...) do { if (i2c_debug>=1) printk(fmt, ## args); } while(0)
	#define DEB2(fmt, args...) do { if (i2c_debug>=2) printk(fmt, ## args); } while(0)
	#define DEB3(fmt, args...) do { if (i2c_debug>=3) printk(fmt, ## args); } while(0)

	static int i2c_debug;

	#define pca_outw(adap, reg, val) adap->write_byte(adap->data, reg, val)
	#define pca_inw(adap, reg) adap->read_byte(adap->data, reg)

	#define pca_status(adap) pca_inw(adap, I2C_PCA_STA)
	#define pca_clock(adap) adap->i2c_clock
	#define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val)
	#define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON)
	#define pca_wait(adap) adap->wait_for_completion(adap->data)
	#define pca_reset(adap) adap->reset_chip(adap->data)

	/*
	* Generate a start condition on the i2c bus.
	*
	* returns after the start condition has occurred
	*/
	static void pca_start(struct i2c_algo_pca_data *adap)
	{
	int sta = pca_get_con(adap);
	DEB2("=== START\n");
	sta \|= I2C_PCA_CON_STA;
	sta &= ~(I2C_PCA_CON_STO\|I2C_PCA_CON_SI);
	pca_set_con(adap, sta);
	pca_wait(adap);
	}

	/*
	* Generate a repeated start condition on the i2c bus
	*
	* return after the repeated start condition has occurred
	*/
	static void pca_repeated_start(struct i2c_algo_pca_data *adap)
	{
	int sta = pca_get_con(adap);
	DEB2("=== REPEATED START\n");
	sta \|= I2C_PCA_CON_STA;
	sta &= ~(I2C_PCA_CON_STO\|I2C_PCA_CON_SI);
	pca_set_con(adap, sta);
	pca_wait(adap);
	}

	/*
	* Generate a stop condition on the i2c bus
	*
	* returns after the stop condition has been generated
	*
	* STOPs do not generate an interrupt or set the SI flag, since the
	* part returns the idle state (0xf8). Hence we don't need to
	* pca_wait here.
	*/
	static void pca_stop(struct i2c_algo_pca_data *adap)
	{
	int sta = pca_get_con(adap);
	DEB2("=== STOP\n");
	sta \|= I2C_PCA_CON_STO;
	sta &= ~(I2C_PCA_CON_STA\|I2C_PCA_CON_SI);
	pca_set_con(adap, sta);
	}

	/*
	* Send the slave address and R/W bit
	*
	* returns after the address has been sent
	*/
	static void pca_address(struct i2c_algo_pca_data *adap,
	struct i2c_msg *msg)
	{
	int sta = pca_get_con(adap);
	int addr;

	addr = ( (0x7f & msg->addr) << 1 );
	if (msg->flags & I2C_M_RD )
	addr \|= 1;
	DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n",
	msg->addr, msg->flags & I2C_M_RD ? 'R' : 'W', addr);

	pca_outw(adap, I2C_PCA_DAT, addr);

	sta &= ~(I2C_PCA_CON_STO\|I2C_PCA_CON_STA\|I2C_PCA_CON_SI);
	pca_set_con(adap, sta);

	pca_wait(adap);
	}

	/*
	* Transmit a byte.
	*
	* Returns after the byte has been transmitted
	*/
	static void pca_tx_byte(struct i2c_algo_pca_data *adap,
	__u8 b)
	{
	int sta = pca_get_con(adap);
	DEB2("=== WRITE %#04x\n", b);
	pca_outw(adap, I2C_PCA_DAT, b);

	sta &= ~(I2C_PCA_CON_STO\|I2C_PCA_CON_STA\|I2C_PCA_CON_SI);
	pca_set_con(adap, sta);

	pca_wait(adap);
	}

	/*
	* Receive a byte
	*
	* returns immediately.
	*/
	static void pca_rx_byte(struct i2c_algo_pca_data *adap,
	__u8 *b, int ack)
	{
	*b = pca_inw(adap, I2C_PCA_DAT);
	DEB2("=== READ %#04x %s\n", *b, ack ? "ACK" : "NACK");
	}

	/*
	* Setup ACK or NACK for next received byte and wait for it to arrive.
	*
	* Returns after next byte has arrived.
	*/
	static void pca_rx_ack(struct i2c_algo_pca_data *adap,
	int ack)
	{
	int sta = pca_get_con(adap);

	sta &= ~(I2C_PCA_CON_STO\|I2C_PCA_CON_STA\|I2C_PCA_CON_SI\|I2C_PCA_CON_AA);

	if ( ack )
	sta \|= I2C_PCA_CON_AA;

	pca_set_con(adap, sta);
	pca_wait(adap);
	}

	static int pca_xfer(struct i2c_adapter *i2c_adap,
	struct i2c_msg *msgs,
	int num)
	{
	struct i2c_algo_pca_data *adap = i2c_adap->algo_data;
	struct i2c_msg *msg = NULL;
	int curmsg;
	int numbytes = 0;
	int state;
	int ret;
	int timeout = i2c_adap->timeout;

	while ((state = pca_status(adap)) != 0xf8 && timeout--) {
	msleep(10);
	}
	if (state != 0xf8) {
	dev_dbg(&i2c_adap->dev, "bus is not idle. status is %#04x\n", state);
	return -EIO;
	}

	DEB1("{{{ XFER %d messages\n", num);

	if (i2c_debug>=2) {
	for (curmsg = 0; curmsg < num; curmsg++) {
	int addr, i;
	msg = &msgs[curmsg];

	addr = (0x7f & msg->addr) ;

	if (msg->flags & I2C_M_RD )
	printk(KERN_INFO " [%02d] RD %d bytes from %#02x [%#02x, ...]\n",
	curmsg, msg->len, addr, (addr<<1) \| 1);
	else {
	printk(KERN_INFO " [%02d] WR %d bytes to %#02x [%#02x%s",
	curmsg, msg->len, addr, addr<<1,
	msg->len == 0 ? "" : ", ");
	for(i=0; i < msg->len; i++)
	printk("%#04x%s", msg->buf[i], i == msg->len - 1 ? "" : ", ");
	printk("]\n");
	}
	}
	}

	curmsg = 0;
	ret = -EREMOTEIO;
	while (curmsg < num) {
	state = pca_status(adap);

	DEB3("STATE is 0x%02x\n", state);
	msg = &msgs[curmsg];

	switch (state) {
	case 0xf8: /* On reset or stop the bus is idle */
	pca_start(adap);
	break;

	case 0x08: /* A START condition has been transmitted */
	case 0x10: /* A repeated start condition has been transmitted */
	pca_address(adap, msg);
	break;

	case 0x18: /* SLA+W has been transmitted; ACK has been received */
	case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */
	if (numbytes < msg->len) {
	pca_tx_byte(adap, msg->buf[numbytes]);
	numbytes++;
	break;
	}
	curmsg++; numbytes = 0;
	if (curmsg == num)
	pca_stop(adap);
	else
	pca_repeated_start(adap);
	break;

	case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */
	DEB2("NOT ACK received after SLA+W\n");
	pca_stop(adap);
	goto out;

	case 0x40: /* SLA+R has been transmitted; ACK has been received */
	pca_rx_ack(adap, msg->len > 1);
	break;

	case 0x50: /* Data bytes has been received; ACK has been returned */
	if (numbytes < msg->len) {
	pca_rx_byte(adap, &msg->buf[numbytes], 1);
	numbytes++;
	pca_rx_ack(adap, numbytes < msg->len - 1);
	break;
	}
	curmsg++; numbytes = 0;
	if (curmsg == num)
	pca_stop(adap);
	else
	pca_repeated_start(adap);
	break;

	case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */
	DEB2("NOT ACK received after SLA+R\n");
	pca_stop(adap);
	goto out;

	case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */
	DEB2("NOT ACK received after data byte\n");
	goto out;

	case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */
	DEB2("Arbitration lost\n");
	goto out;

	case 0x58: /* Data byte has been received; NOT ACK has been returned */
	if ( numbytes == msg->len - 1 ) {
	pca_rx_byte(adap, &msg->buf[numbytes], 0);
	curmsg++; numbytes = 0;
	if (curmsg == num)
	pca_stop(adap);
	else
	pca_repeated_start(adap);
	} else {
	DEB2("NOT ACK sent after data byte received. "
	"Not final byte. numbytes %d. len %d\n",
	numbytes, msg->len);
	pca_stop(adap);
	goto out;
	}
	break;
	case 0x70: /* Bus error - SDA stuck low */
	DEB2("BUS ERROR - SDA Stuck low\n");
	pca_reset(adap);
	goto out;
	case 0x90: /* Bus error - SCL stuck low */
	DEB2("BUS ERROR - SCL Stuck low\n");
	pca_reset(adap);
	goto out;
	case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */
	DEB2("BUS ERROR - Illegal START or STOP\n");
	pca_reset(adap);
	goto out;
	default:
	dev_err(&i2c_adap->dev, "unhandled SIO state 0x%02x\n", state);
	break;
	}

	}

	ret = curmsg;
	out:
	DEB1(KERN_CRIT "}}} transfered %d/%d messages. "
	"status is %#04x. control is %#04x\n",
	curmsg, num, pca_status(adap),
	pca_get_con(adap));
	return ret;
	}

	static u32 pca_func(struct i2c_adapter *adap)
	{
	return I2C_FUNC_I2C \| I2C_FUNC_SMBUS_EMUL;
	}

	static const struct i2c_algorithm pca_algo = {
	.master_xfer = pca_xfer,
	.functionality = pca_func,
	};

	static int pca_init(struct i2c_adapter *adap)
	{
	static int freqs[] = {330,288,217,146,88,59,44,36};
	int clock;
	struct i2c_algo_pca_data *pca_data = adap->algo_data;

	if (pca_data->i2c_clock > 7) {
	printk(KERN_WARNING "%s: Invalid I2C clock speed selected. Trying default.\n",
	adap->name);
	pca_data->i2c_clock = I2C_PCA_CON_59kHz;
	}

	adap->algo = &pca_algo;

	pca_reset(pca_data);

	clock = pca_clock(pca_data);
	DEB1(KERN_INFO "%s: Clock frequency is %dkHz\n", adap->name, freqs[clock]);

	pca_set_con(pca_data, I2C_PCA_CON_ENSIO \| clock);
	udelay(500); /* 500 us for oscilator to stabilise */

	return 0;
	}

	/*
	* registering functions to load algorithms at runtime
	*/
	int i2c_pca_add_bus(struct i2c_adapter *adap)
	{
	int rval;

	rval = pca_init(adap);
	if (rval)
	return rval;

	return i2c_add_adapter(adap);
	}
	EXPORT_SYMBOL(i2c_pca_add_bus);

	int i2c_pca_add_numbered_bus(struct i2c_adapter *adap)
	{
	int rval;

	rval = pca_init(adap);
	if (rval)
	return rval;

	return i2c_add_numbered_adapter(adap);
	}
	EXPORT_SYMBOL(i2c_pca_add_numbered_bus);

	MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>, "
	"Wolfram Sang <w.sang@pengutronix.de>");
	MODULE_DESCRIPTION("I2C-Bus PCA9564 algorithm");
	MODULE_LICENSE("GPL");

	module_param(i2c_debug, int, 0);