/* *  i2c-algo-pxa.c * *  I2C algorithm for the PXA I2C bus access. *  Byte driven algorithm similar to pcf. * *  Copyright (C) 2002 Intrinsyc Software Inc. * *  This program is free software; you can redistribute it and/or modify *  it under the terms of the GNU General Public License version 2 as *  published by the Free Software Foundation. * *  History: *    Apr 2002: Initial version [CS] *    Jun 2002: Properly seperated algo/adap [FB] *  */#include <linux/kernel.h>#include <linux/module.h>#include <linux/init.h>#include <linux/delay.h>#include <linux/i2c.h>          /* struct i2c_msg and others */#include <linux/i2c-id.h>#include "i2c-pxa.h"/* * Set this to zero to remove all the debug statements via dead code elimination. *///#define DEBUG       1#if DEBUGstatic unsigned int i2c_debug = DEBUG;#else#define i2c_debug	0#endifstatic int pxa_scan = 1;static int i2c_pxa_valid_messages( struct i2c_msg msgs[], int num){	int i;	if (num < 1 || num > MAX_MESSAGES){		if( i2c_debug) 			printk(KERN_INFO "Invalid number of messages (max=%d, num=%d)\n", 				MAX_MESSAGES, num);		return -EINVAL;	}	/* check consistency of our messages */	for (i=0;i<num;i++){		if (&msgs[i]==NULL){			if( i2c_debug) printk(KERN_INFO "Msgs is NULL\n");			return -EINVAL;		} else {			if (msgs[i].len < 0 || msgs[i].buf == NULL){				if( i2c_debug)printk(KERN_INFO "Length is less than zero");				return -EINVAL;			}			if (msgs[0].len == 0){  /* this is SMBUS_QUICK */				if( i2c_debug)printk(KERN_INFO "Message length is zero\n");				return 0;			}		}	}	return 1;}static int i2c_pxa_readbytes(struct i2c_adapter *i2c_adap, char *buf, 			int count, int last){        int i, timeout=0;        struct i2c_algo_pxa_data *adap = i2c_adap->algo_data;        /* increment number of bytes to read by one -- read dummy byte */        for (i = 0; i <= count; i++) {                if (i!=0){                        /* set ACK to NAK for last received byte ICR[ACKNAK] = 1                                only if not a repeated start */                        if ((i == count) && last) {				adap->transfer( last, I2C_RECEIVE, 0);			}else{				adap->transfer( 0, I2C_RECEIVE, 1);                        }			timeout = adap->wait_for_interrupt(I2C_RECEIVE);#ifdef DEBUG                        if (timeout==BUS_ERROR){				printk(KERN_INFO "i2c_pxa_readbytes: bus error -> forcing reset\n");                                adap->reset();                                return I2C_RETRY;                        }#endif                        if (timeout){                                adap->reset();                                return I2C_RETRY;                        }                }                if (i) {                        buf[i - 1] = adap->read_byte();                } else {                        adap->read_byte(); /* dummy read */                }        }        return (i - 1);}static int i2c_pxa_sendbytes(struct i2c_adapter *i2c_adap, const char *buf,                         int count, int last){        struct i2c_algo_pxa_data *adap = i2c_adap->algo_data;        int wrcount, timeout;        for (wrcount=0; wrcount<count; ++wrcount) {                adap->write_byte(buf[wrcount]);                if ((wrcount==(count-1)) && last) {			adap->transfer( last, I2C_TRANSMIT, 0);		}else{			adap->transfer( 0, I2C_TRANSMIT, 1);                }		timeout = adap->wait_for_interrupt(I2C_TRANSMIT);#ifdef DEBUG                if (timeout==BUS_ERROR) {			printk(KERN_INFO "i2c_pxa_sendbytes: bus error -> forcing reset.\n");                        adap->reset();                        return I2C_RETRY;                }#endif                if (timeout) {                        adap->reset();                        return I2C_RETRY;                }        }        return (wrcount);}static inline int i2c_pxa_set_ctrl_byte(struct i2c_algo_pxa_data * adap, struct i2c_msg *msg){	u16 flags = msg->flags; 	u8 addr;                            	addr = (u8) ( (0x7f & msg->addr) << 1 );	if (flags & I2C_M_RD ) 		addr |= 1;      	if (flags & I2C_M_REV_DIR_ADDR )		addr ^= 1;	adap->write_byte(addr);	return 0;}       static int i2c_pxa_do_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[], int num){	struct i2c_algo_pxa_data * adap;	struct i2c_msg *pmsg=NULL;	int i;	int ret=0, timeout;	adap = i2c_adap->algo_data;	timeout = adap->wait_bus_not_busy();	if (timeout) {		return I2C_RETRY;	}	for (i = 0;ret >= 0 && i < num; i++) {		int last = i + 1 == num;		pmsg = &msgs[i];		ret = i2c_pxa_set_ctrl_byte(adap,pmsg);		/* Send START */		if (i == 0) {			adap->start();		}else{			adap->repeat_start();		}		adap->transfer(0, I2C_TRANSMIT, 0);		/* Wait for ITE (transmit empty) */		timeout = adap->wait_for_interrupt(I2C_TRANSMIT);#ifdef DEBUG		/* Check for ACK (bus error) */		if (timeout==BUS_ERROR){			printk(KERN_INFO "i2c_pxa_do_xfer: bus error -> forcing reset\n");			adap->reset();			return I2C_RETRY;		}#endif		if (timeout) {			adap->abort();			adap->reset();			return I2C_RETRY;		}/* FIXME: handle arbitration... */#if 0		/* Check for bus arbitration loss */		if (adap->arbitration_loss()){			printk("Arbitration loss detected \n");			adap->reset();			return I2C_RETRY;		}#endif		/* Read */		if (pmsg->flags & I2C_M_RD) {			/* read bytes into buffer*/			ret = i2c_pxa_readbytes(i2c_adap, pmsg->buf, pmsg->len, last);#if DEBUG > 2			if (ret != pmsg->len) {				printk(KERN_INFO"i2c_pxa_do_xfer: read %d/%d bytes.\n",					ret, pmsg->len);			} else {				printk(KERN_INFO"i2c_pxa_do_xfer: read %d bytes.\n",ret);			}#endif		} else { /* Write */			ret = i2c_pxa_sendbytes(i2c_adap, pmsg->buf, pmsg->len, last);#if DEBUG > 2			if (ret != pmsg->len) {				printk(KERN_INFO"i2c_pxa_do_xfer: wrote %d/%d bytes.\n",					ret, pmsg->len);			} else {				printk(KERN_INFO"i2c_pxa_do_xfer: wrote %d bytes.\n",ret);			}#endif		}	}	if (ret<0){		return ret;	}else{		return i;	}}static int i2c_pxa_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[], int num){	int retval = i2c_pxa_valid_messages( msgs, num);	if( retval > 0)	{		int i;		for (i=i2c_adap->retries; i>=0; i--){			int retval = i2c_pxa_do_xfer(i2c_adap,msgs,num);			if (retval!=I2C_RETRY){				return retval;			}			if( i2c_debug)printk(KERN_INFO"Retrying transmission \n");			udelay(100);		}   		if( i2c_debug)printk(KERN_INFO"Retried %i times\n",i2c_adap->retries);		return -EREMOTEIO;	}	return retval;}struct i2c_algorithm i2c_pxa_algorithm  = {        name:                   "PXA-I2C-Algorithm",        id:                     I2C_ALGO_PXA,        master_xfer:            i2c_pxa_xfer,        smbus_xfer:             NULL,        slave_send:             NULL,        slave_recv:             NULL,        algo_control:           NULL,};/*  * registering functions to load algorithms at runtime  */int i2c_pxa_add_bus(struct i2c_adapter *i2c_adap){        struct i2c_algo_pxa_data *adap = i2c_adap->algo_data;        printk(KERN_INFO"I2C: Adding %s.\n", i2c_adap->name);        i2c_adap->algo = &i2c_pxa_algorithm;        MOD_INC_USE_COUNT;        /* register new adapter to i2c module... */        i2c_add_adapter(i2c_adap);	adap->reset();	/* scan bus */	if (pxa_scan) {		int i;		printk(KERN_INFO "I2C: Scanning bus ");		for (i = 0x02; i < 0xff; i+=2) {			if( i==(I2C_PXA_SLAVE_ADDR<<1)) continue;			if (adap->wait_bus_not_busy()) {				printk(KERN_INFO "I2C: scanning bus %s - TIMEOUTed.\n",						i2c_adap->name);                                return -EIO;			}			adap->write_byte(i);			adap->start();			adap->transfer(0, I2C_TRANSMIT, 0);			if ((adap->wait_for_interrupt(I2C_TRANSMIT) != BUS_ERROR)) {				printk("(%02x)",i>>1);				adap->abort();			} else {//				printk(".");			}			adap->stop();			udelay(adap->udelay);		}		printk("\n");	}        return 0;}int i2c_pxa_del_bus(struct i2c_adapter *i2c_adap){        int res;        if ((res = i2c_del_adapter(i2c_adap)) < 0)                return res;        MOD_DEC_USE_COUNT;        printk(KERN_INFO "I2C: Removing %s.\n", i2c_adap->name);        return 0;}static int __init i2c_algo_pxa_init (void){        printk(KERN_INFO "I2C: PXA algorithm module loaded.\n");        return 0;}EXPORT_SYMBOL(i2c_pxa_add_bus);EXPORT_SYMBOL(i2c_pxa_del_bus);MODULE_PARM(pxa_scan, "i");MODULE_PARM_DESC(pxa_scan, "Scan for active chips on the bus");MODULE_AUTHOR("Intrinsyc Software Inc.");MODULE_LICENSE("GPL");module_init(i2c_algo_pxa_init);