/* *  i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters                 *    Copyright (C) 2004 Arcom Control Systems * *  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/slab.h>#include <linux/init.h>#include <linux/errno.h>#include <linux/i2c.h>#include <linux/i2c-algo-pca.h>#include "i2c-algo-pca.h"#define DRIVER "i2c-algo-pca"#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=0;#define pca_outw(adap, reg, val) adap->write_byte(adap, reg, val)#define pca_inw(adap, reg) adap->read_byte(adap, reg)#define pca_status(adap) pca_inw(adap, I2C_PCA_STA)#define pca_clock(adap) adap->get_clock(adap)#define pca_own(adap) adap->get_own(adap)#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_interrupt(adap)/* * 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);}/*  * Reset the i2c bus / SIO  */static void pca_reset(struct i2c_algo_pca_data *adap){	/* apparently only an external reset will do it. not a lot can be done */	printk(KERN_ERR DRIVER ": Haven't figured out how to do a reset yet\n");}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 = 100;	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:			printk(KERN_ERR DRIVER ": 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 int pca_init(struct i2c_algo_pca_data *adap){	static int freqs[] = {330,288,217,146,88,59,44,36};	int own, clock;	own = pca_own(adap);	clock = pca_clock(adap);	DEB1(KERN_INFO DRIVER ": own address is %#04x\n", own);	DEB1(KERN_INFO DRIVER ": clock freqeuncy is %dkHz\n", freqs[clock]);	pca_outw(adap, I2C_PCA_ADR, own << 1);	pca_set_con(adap, I2C_PCA_CON_ENSIO | clock);	udelay(500); /* 500 祍 for oscilator to stabilise */	return 0;}static struct i2c_algorithm pca_algo = {	.master_xfer	= pca_xfer,	.functionality	= pca_func,};/*  * registering functions to load algorithms at runtime  */int i2c_pca_add_bus(struct i2c_adapter *adap){	struct i2c_algo_pca_data *pca_adap = adap->algo_data;	int rval;	/* register new adapter to i2c module... */	adap->algo = &pca_algo;	adap->timeout = 100;		/* default values, should	*/	adap->retries = 3;		/* be replaced by defines	*/	rval = pca_init(pca_adap);	if (!rval)		i2c_add_adapter(adap);	return rval;}int i2c_pca_del_bus(struct i2c_adapter *adap){	return i2c_del_adapter(adap);}EXPORT_SYMBOL(i2c_pca_add_bus);EXPORT_SYMBOL(i2c_pca_del_bus);MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");MODULE_DESCRIPTION("I2C-Bus PCA9564 algorithm");MODULE_LICENSE("GPL");module_param(i2c_debug, int, 0);