570 lines
15 KiB
C
570 lines
15 KiB
C
|
/* ------------------------------------------------------------------------- */
|
|||
|
|
/* i2c-algo-bit.c i2c driver algorithms for bit-shift adapters */
|
|||
|
|
/* ------------------------------------------------------------------------- */
|
|||
|
|
/* Copyright (C) 1995-2000 Simon G. Vogl
|
|||
|
|
|
|||
|
|
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. */
|
|||
|
|
/* ------------------------------------------------------------------------- */
|
|||
|
|
|
|||
|
|
/* With some changes from Frodo Looijaard <frodol@dds.nl>, Ky<4B>sti M<>lkki
|
|||
|
|
<kmalkki@cc.hut.fi> and Jean Delvare <khali@linux-fr.org> */
|
|||
|
|
|
|||
|
|
#include <linux/kernel.h>
|
|||
|
|
#include <linux/module.h>
|
|||
|
|
#include <linux/delay.h>
|
|||
|
|
#include <linux/slab.h>
|
|||
|
|
#include <linux/init.h>
|
|||
|
|
#include <linux/errno.h>
|
|||
|
|
#include <linux/sched.h>
|
|||
|
|
#include <linux/i2c.h>
|
|||
|
|
#include <linux/i2c-algo-bit.h>
|
|||
|
|
|
|||
|
|
|
|||
|
|
/* ----- global defines ----------------------------------------------- */
|
|||
|
|
#define DEB(x) if (i2c_debug>=1) x;
|
|||
|
|
#define DEB2(x) if (i2c_debug>=2) x;
|
|||
|
|
#define DEBSTAT(x) if (i2c_debug>=3) x; /* print several statistical values*/
|
|||
|
|
#define DEBPROTO(x) if (i2c_debug>=9) { x; }
|
|||
|
|
/* debug the protocol by showing transferred bits */
|
|||
|
|
|
|||
|
|
|
|||
|
|
/* ----- global variables --------------------------------------------- */
|
|||
|
|
|
|||
|
|
/* module parameters:
|
|||
|
|
*/
|
|||
|
|
static int i2c_debug;
|
|||
|
|
static int bit_test; /* see if the line-setting functions work */
|
|||
|
|
|
|||
|
|
/* --- setting states on the bus with the right timing: --------------- */
|
|||
|
|
|
|||
|
|
#define setsda(adap,val) adap->setsda(adap->data, val)
|
|||
|
|
#define setscl(adap,val) adap->setscl(adap->data, val)
|
|||
|
|
#define getsda(adap) adap->getsda(adap->data)
|
|||
|
|
#define getscl(adap) adap->getscl(adap->data)
|
|||
|
|
|
|||
|
|
static inline void sdalo(struct i2c_algo_bit_data *adap)
|
|||
|
|
{
|
|||
|
|
setsda(adap,0);
|
|||
|
|
udelay(adap->udelay);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
static inline void sdahi(struct i2c_algo_bit_data *adap)
|
|||
|
|
{
|
|||
|
|
setsda(adap,1);
|
|||
|
|
udelay(adap->udelay);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
static inline void scllo(struct i2c_algo_bit_data *adap)
|
|||
|
|
{
|
|||
|
|
setscl(adap,0);
|
|||
|
|
udelay(adap->udelay);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/*
|
|||
|
|
* Raise scl line, and do checking for delays. This is necessary for slower
|
|||
|
|
* devices.
|
|||
|
|
*/
|
|||
|
|
static inline int sclhi(struct i2c_algo_bit_data *adap)
|
|||
|
|
{
|
|||
|
|
unsigned long start;
|
|||
|
|
|
|||
|
|
setscl(adap,1);
|
|||
|
|
|
|||
|
|
/* Not all adapters have scl sense line... */
|
|||
|
|
if (adap->getscl == NULL ) {
|
|||
|
|
udelay(adap->udelay);
|
|||
|
|
return 0;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
start=jiffies;
|
|||
|
|
while (! getscl(adap) ) {
|
|||
|
|
/* the hw knows how to read the clock line,
|
|||
|
|
* so we wait until it actually gets high.
|
|||
|
|
* This is safer as some chips may hold it low
|
|||
|
|
* while they are processing data internally.
|
|||
|
|
*/
|
|||
|
|
if (time_after_eq(jiffies, start+adap->timeout)) {
|
|||
|
|
return -ETIMEDOUT;
|
|||
|
|
}
|
|||
|
|
cond_resched();
|
|||
|
|
}
|
|||
|
|
DEBSTAT(printk(KERN_DEBUG "needed %ld jiffies\n", jiffies-start));
|
|||
|
|
udelay(adap->udelay);
|
|||
|
|
return 0;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
|
|||
|
|
/* --- other auxiliary functions -------------------------------------- */
|
|||
|
|
static void i2c_start(struct i2c_algo_bit_data *adap)
|
|||
|
|
{
|
|||
|
|
/* assert: scl, sda are high */
|
|||
|
|
DEBPROTO(printk("S "));
|
|||
|
|
sdalo(adap);
|
|||
|
|
scllo(adap);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
static void i2c_repstart(struct i2c_algo_bit_data *adap)
|
|||
|
|
{
|
|||
|
|
/* scl, sda may not be high */
|
|||
|
|
DEBPROTO(printk(" Sr "));
|
|||
|
|
setsda(adap,1);
|
|||
|
|
sclhi(adap);
|
|||
|
|
udelay(adap->udelay);
|
|||
|
|
|
|||
|
|
sdalo(adap);
|
|||
|
|
scllo(adap);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
|
|||
|
|
static void i2c_stop(struct i2c_algo_bit_data *adap)
|
|||
|
|
{
|
|||
|
|
DEBPROTO(printk("P\n"));
|
|||
|
|
/* assert: scl is low */
|
|||
|
|
sdalo(adap);
|
|||
|
|
sclhi(adap);
|
|||
|
|
sdahi(adap);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
/* send a byte without start cond., look for arbitration,
|
|||
|
|
check ackn. from slave */
|
|||
|
|
/* returns:
|
|||
|
|
* 1 if the device acknowledged
|
|||
|
|
* 0 if the device did not ack
|
|||
|
|
* -ETIMEDOUT if an error occurred (while raising the scl line)
|
|||
|
|
*/
|
|||
|
|
static int i2c_outb(struct i2c_adapter *i2c_adap, char c)
|
|||
|
|
{
|
|||
|
|
int i;
|
|||
|
|
int sb;
|
|||
|
|
int ack;
|
|||
|
|
struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
|
|||
|
|
|
|||
|
|
/* assert: scl is low */
|
|||
|
|
for ( i=7 ; i>=0 ; i-- ) {
|
|||
|
|
sb = c & ( 1 << i );
|
|||
|
|
setsda(adap,sb);
|
|||
|
|
udelay(adap->udelay);
|
|||
|
|
DEBPROTO(printk(KERN_DEBUG "%d",sb!=0));
|
|||
|
|
if (sclhi(adap)<0) { /* timed out */
|
|||
|
|
sdahi(adap); /* we don't want to block the net */
|
|||
|
|
DEB2(printk(KERN_DEBUG " i2c_outb: 0x%02x, timeout at bit #%d\n", c&0xff, i));
|
|||
|
|
return -ETIMEDOUT;
|
|||
|
|
};
|
|||
|
|
/* do arbitration here:
|
|||
|
|
* if ( sb && ! getsda(adap) ) -> ouch! Get out of here.
|
|||
|
|
*/
|
|||
|
|
setscl(adap, 0 );
|
|||
|
|
udelay(adap->udelay);
|
|||
|
|
}
|
|||
|
|
sdahi(adap);
|
|||
|
|
if (sclhi(adap)<0){ /* timeout */
|
|||
|
|
DEB2(printk(KERN_DEBUG " i2c_outb: 0x%02x, timeout at ack\n", c&0xff));
|
|||
|
|
return -ETIMEDOUT;
|
|||
|
|
};
|
|||
|
|
/* read ack: SDA should be pulled down by slave */
|
|||
|
|
ack=getsda(adap); /* ack: sda is pulled low ->success. */
|
|||
|
|
DEB2(printk(KERN_DEBUG " i2c_outb: 0x%02x , getsda() = %d\n", c & 0xff, ack));
|
|||
|
|
|
|||
|
|
DEBPROTO( printk(KERN_DEBUG "[%2.2x]",c&0xff) );
|
|||
|
|
DEBPROTO(if (0==ack){ printk(KERN_DEBUG " A ");} else printk(KERN_DEBUG " NA ") );
|
|||
|
|
scllo(adap);
|
|||
|
|
return 0==ack; /* return 1 if device acked */
|
|||
|
|
/* assert: scl is low (sda undef) */
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
|
|||
|
|
static int i2c_inb(struct i2c_adapter *i2c_adap)
|
|||
|
|
{
|
|||
|
|
/* read byte via i2c port, without start/stop sequence */
|
|||
|
|
/* acknowledge is sent in i2c_read. */
|
|||
|
|
int i;
|
|||
|
|
unsigned char indata=0;
|
|||
|
|
struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
|
|||
|
|
|
|||
|
|
/* assert: scl is low */
|
|||
|
|
sdahi(adap);
|
|||
|
|
for (i=0;i<8;i++) {
|
|||
|
|
if (sclhi(adap)<0) { /* timeout */
|
|||
|
|
DEB2(printk(KERN_DEBUG " i2c_inb: timeout at bit #%d\n", 7-i));
|
|||
|
|
return -ETIMEDOUT;
|
|||
|
|
};
|
|||
|
|
indata *= 2;
|
|||
|
|
if ( getsda(adap) )
|
|||
|
|
indata |= 0x01;
|
|||
|
|
scllo(adap);
|
|||
|
|
}
|
|||
|
|
/* assert: scl is low */
|
|||
|
|
DEB2(printk(KERN_DEBUG "i2c_inb: 0x%02x\n", indata & 0xff));
|
|||
|
|
|
|||
|
|
DEBPROTO(printk(KERN_DEBUG " 0x%02x", indata & 0xff));
|
|||
|
|
return (int) (indata & 0xff);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/*
|
|||
|
|
* Sanity check for the adapter hardware - check the reaction of
|
|||
|
|
* the bus lines only if it seems to be idle.
|
|||
|
|
*/
|
|||
|
|
static int test_bus(struct i2c_algo_bit_data *adap, char* name) {
|
|||
|
|
int scl,sda;
|
|||
|
|
|
|||
|
|
if (adap->getscl==NULL)
|
|||
|
|
printk(KERN_INFO "i2c-algo-bit.o: Testing SDA only, "
|
|||
|
|
"SCL is not readable.\n");
|
|||
|
|
|
|||
|
|
sda=getsda(adap);
|
|||
|
|
scl=(adap->getscl==NULL?1:getscl(adap));
|
|||
|
|
printk(KERN_DEBUG "i2c-algo-bit.o: (0) scl=%d, sda=%d\n",scl,sda);
|
|||
|
|
if (!scl || !sda ) {
|
|||
|
|
printk(KERN_WARNING "i2c-algo-bit.o: %s seems to be busy.\n", name);
|
|||
|
|
goto bailout;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
sdalo(adap);
|
|||
|
|
sda=getsda(adap);
|
|||
|
|
scl=(adap->getscl==NULL?1:getscl(adap));
|
|||
|
|
printk(KERN_DEBUG "i2c-algo-bit.o: (1) scl=%d, sda=%d\n",scl,sda);
|
|||
|
|
if ( 0 != sda ) {
|
|||
|
|
printk(KERN_WARNING "i2c-algo-bit.o: SDA stuck high!\n");
|
|||
|
|
goto bailout;
|
|||
|
|
}
|
|||
|
|
if ( 0 == scl ) {
|
|||
|
|
printk(KERN_WARNING "i2c-algo-bit.o: SCL unexpected low "
|
|||
|
|
"while pulling SDA low!\n");
|
|||
|
|
goto bailout;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
sdahi(adap);
|
|||
|
|
sda=getsda(adap);
|
|||
|
|
scl=(adap->getscl==NULL?1:getscl(adap));
|
|||
|
|
printk(KERN_DEBUG "i2c-algo-bit.o: (2) scl=%d, sda=%d\n",scl,sda);
|
|||
|
|
if ( 0 == sda ) {
|
|||
|
|
printk(KERN_WARNING "i2c-algo-bit.o: SDA stuck low!\n");
|
|||
|
|
goto bailout;
|
|||
|
|
}
|
|||
|
|
if ( 0 == scl ) {
|
|||
|
|
printk(KERN_WARNING "i2c-algo-bit.o: SCL unexpected low "
|
|||
|
|
"while pulling SDA high!\n");
|
|||
|
|
goto bailout;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
scllo(adap);
|
|||
|
|
sda=getsda(adap);
|
|||
|
|
scl=(adap->getscl==NULL?0:getscl(adap));
|
|||
|
|
printk(KERN_DEBUG "i2c-algo-bit.o: (3) scl=%d, sda=%d\n",scl,sda);
|
|||
|
|
if ( 0 != scl ) {
|
|||
|
|
printk(KERN_WARNING "i2c-algo-bit.o: SCL stuck high!\n");
|
|||
|
|
goto bailout;
|
|||
|
|
}
|
|||
|
|
if ( 0 == sda ) {
|
|||
|
|
printk(KERN_WARNING "i2c-algo-bit.o: SDA unexpected low "
|
|||
|
|
"while pulling SCL low!\n");
|
|||
|
|
goto bailout;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
sclhi(adap);
|
|||
|
|
sda=getsda(adap);
|
|||
|
|
scl=(adap->getscl==NULL?1:getscl(adap));
|
|||
|
|
printk(KERN_DEBUG "i2c-algo-bit.o: (4) scl=%d, sda=%d\n",scl,sda);
|
|||
|
|
if ( 0 == scl ) {
|
|||
|
|
printk(KERN_WARNING "i2c-algo-bit.o: SCL stuck low!\n");
|
|||
|
|
goto bailout;
|
|||
|
|
}
|
|||
|
|
if ( 0 == sda ) {
|
|||
|
|
printk(KERN_WARNING "i2c-algo-bit.o: SDA unexpected low "
|
|||
|
|
"while pulling SCL high!\n");
|
|||
|
|
goto bailout;
|
|||
|
|
}
|
|||
|
|
printk(KERN_INFO "i2c-algo-bit.o: %s passed test.\n",name);
|
|||
|
|
return 0;
|
|||
|
|
bailout:
|
|||
|
|
sdahi(adap);
|
|||
|
|
sclhi(adap);
|
|||
|
|
return -ENODEV;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/* ----- Utility functions
|
|||
|
|
*/
|
|||
|
|
|
|||
|
|
/* try_address tries to contact a chip for a number of
|
|||
|
|
* times before it gives up.
|
|||
|
|
* return values:
|
|||
|
|
* 1 chip answered
|
|||
|
|
* 0 chip did not answer
|
|||
|
|
* -x transmission error
|
|||
|
|
*/
|
|||
|
|
static inline int try_address(struct i2c_adapter *i2c_adap,
|
|||
|
|
unsigned char addr, int retries)
|
|||
|
|
{
|
|||
|
|
struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
|
|||
|
|
int i,ret = -1;
|
|||
|
|
for (i=0;i<=retries;i++) {
|
|||
|
|
ret = i2c_outb(i2c_adap,addr);
|
|||
|
|
if (ret==1)
|
|||
|
|
break; /* success! */
|
|||
|
|
i2c_stop(adap);
|
|||
|
|
udelay(5/*adap->udelay*/);
|
|||
|
|
if (i==retries) /* no success */
|
|||
|
|
break;
|
|||
|
|
i2c_start(adap);
|
|||
|
|
udelay(adap->udelay);
|
|||
|
|
}
|
|||
|
|
DEB2(if (i)
|
|||
|
|
printk(KERN_DEBUG "i2c-algo-bit.o: Used %d tries to %s client at 0x%02x : %s\n",
|
|||
|
|
i+1, addr & 1 ? "read" : "write", addr>>1,
|
|||
|
|
ret==1 ? "success" : ret==0 ? "no ack" : "failed, timeout?" )
|
|||
|
|
);
|
|||
|
|
return ret;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
static int sendbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
|
|||
|
|
{
|
|||
|
|
struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
|
|||
|
|
char c;
|
|||
|
|
const char *temp = msg->buf;
|
|||
|
|
int count = msg->len;
|
|||
|
|
unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK;
|
|||
|
|
int retval;
|
|||
|
|
int wrcount=0;
|
|||
|
|
|
|||
|
|
while (count > 0) {
|
|||
|
|
c = *temp;
|
|||
|
|
DEB2(dev_dbg(&i2c_adap->dev, "sendbytes: writing %2.2X\n", c&0xff));
|
|||
|
|
retval = i2c_outb(i2c_adap,c);
|
|||
|
|
if ((retval>0) || (nak_ok && (retval==0))) { /* ok or ignored NAK */
|
|||
|
|
count--;
|
|||
|
|
temp++;
|
|||
|
|
wrcount++;
|
|||
|
|
} else { /* arbitration or no acknowledge */
|
|||
|
|
dev_err(&i2c_adap->dev, "sendbytes: error - bailout.\n");
|
|||
|
|
i2c_stop(adap);
|
|||
|
|
return (retval<0)? retval : -EFAULT;
|
|||
|
|
/* got a better one ?? */
|
|||
|
|
}
|
|||
|
|
#if 0
|
|||
|
|
/* from asm/delay.h */
|
|||
|
|
__delay(adap->mdelay * (loops_per_sec / 1000) );
|
|||
|
|
#endif
|
|||
|
|
}
|
|||
|
|
return wrcount;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
static inline int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
|
|||
|
|
{
|
|||
|
|
int inval;
|
|||
|
|
int rdcount=0; /* counts bytes read */
|
|||
|
|
struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
|
|||
|
|
char *temp = msg->buf;
|
|||
|
|
int count = msg->len;
|
|||
|
|
|
|||
|
|
while (count > 0) {
|
|||
|
|
inval = i2c_inb(i2c_adap);
|
|||
|
|
/*printk("%#02x ",inval); if ( ! (count % 16) ) printk("\n"); */
|
|||
|
|
if (inval>=0) {
|
|||
|
|
*temp = inval;
|
|||
|
|
rdcount++;
|
|||
|
|
} else { /* read timed out */
|
|||
|
|
printk(KERN_ERR "i2c-algo-bit.o: readbytes: i2c_inb timed out.\n");
|
|||
|
|
break;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
temp++;
|
|||
|
|
count--;
|
|||
|
|
|
|||
|
|
if (msg->flags & I2C_M_NO_RD_ACK)
|
|||
|
|
continue;
|
|||
|
|
|
|||
|
|
if ( count > 0 ) { /* send ack */
|
|||
|
|
sdalo(adap);
|
|||
|
|
DEBPROTO(printk(" Am "));
|
|||
|
|
} else {
|
|||
|
|
sdahi(adap); /* neg. ack on last byte */
|
|||
|
|
DEBPROTO(printk(" NAm "));
|
|||
|
|
}
|
|||
|
|
if (sclhi(adap)<0) { /* timeout */
|
|||
|
|
sdahi(adap);
|
|||
|
|
printk(KERN_ERR "i2c-algo-bit.o: readbytes: Timeout at ack\n");
|
|||
|
|
return -ETIMEDOUT;
|
|||
|
|
};
|
|||
|
|
scllo(adap);
|
|||
|
|
sdahi(adap);
|
|||
|
|
}
|
|||
|
|
return rdcount;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
/* doAddress initiates the transfer by generating the start condition (in
|
|||
|
|
* try_address) and transmits the address in the necessary format to handle
|
|||
|
|
* reads, writes as well as 10bit-addresses.
|
|||
|
|
* returns:
|
|||
|
|
* 0 everything went okay, the chip ack'ed, or IGNORE_NAK flag was set
|
|||
|
|
* -x an error occurred (like: -EREMOTEIO if the device did not answer, or
|
|||
|
|
* -ETIMEDOUT, for example if the lines are stuck...)
|
|||
|
|
*/
|
|||
|
|
static inline int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
|
|||
|
|
{
|
|||
|
|
unsigned short flags = msg->flags;
|
|||
|
|
unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK;
|
|||
|
|
struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
|
|||
|
|
|
|||
|
|
unsigned char addr;
|
|||
|
|
int ret, retries;
|
|||
|
|
|
|||
|
|
retries = nak_ok ? 0 : i2c_adap->retries;
|
|||
|
|
|
|||
|
|
if ( (flags & I2C_M_TEN) ) {
|
|||
|
|
/* a ten bit address */
|
|||
|
|
addr = 0xf0 | (( msg->addr >> 7) & 0x03);
|
|||
|
|
DEB2(printk(KERN_DEBUG "addr0: %d\n",addr));
|
|||
|
|
/* try extended address code...*/
|
|||
|
|
ret = try_address(i2c_adap, addr, retries);
|
|||
|
|
if ((ret != 1) && !nak_ok) {
|
|||
|
|
printk(KERN_ERR "died at extended address code.\n");
|
|||
|
|
return -EREMOTEIO;
|
|||
|
|
}
|
|||
|
|
/* the remaining 8 bit address */
|
|||
|
|
ret = i2c_outb(i2c_adap,msg->addr & 0x7f);
|
|||
|
|
if ((ret != 1) && !nak_ok) {
|
|||
|
|
/* the chip did not ack / xmission error occurred */
|
|||
|
|
printk(KERN_ERR "died at 2nd address code.\n");
|
|||
|
|
return -EREMOTEIO;
|
|||
|
|
}
|
|||
|
|
if ( flags & I2C_M_RD ) {
|
|||
|
|
i2c_repstart(adap);
|
|||
|
|
/* okay, now switch into reading mode */
|
|||
|
|
addr |= 0x01;
|
|||
|
|
ret = try_address(i2c_adap, addr, retries);
|
|||
|
|
if ((ret!=1) && !nak_ok) {
|
|||
|
|
printk(KERN_ERR "died at extended address code.\n");
|
|||
|
|
return -EREMOTEIO;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
} else { /* normal 7bit address */
|
|||
|
|
addr = ( msg->addr << 1 );
|
|||
|
|
if (flags & I2C_M_RD )
|
|||
|
|
addr |= 1;
|
|||
|
|
if (flags & I2C_M_REV_DIR_ADDR )
|
|||
|
|
addr ^= 1;
|
|||
|
|
ret = try_address(i2c_adap, addr, retries);
|
|||
|
|
if ((ret!=1) && !nak_ok)
|
|||
|
|
return -EREMOTEIO;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
return 0;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
static int bit_xfer(struct i2c_adapter *i2c_adap,
|
|||
|
|
struct i2c_msg msgs[], int num)
|
|||
|
|
{
|
|||
|
|
struct i2c_msg *pmsg;
|
|||
|
|
struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
|
|||
|
|
|
|||
|
|
int i,ret;
|
|||
|
|
unsigned short nak_ok;
|
|||
|
|
|
|||
|
|
i2c_start(adap);
|
|||
|
|
for (i=0;i<num;i++) {
|
|||
|
|
pmsg = &msgs[i];
|
|||
|
|
nak_ok = pmsg->flags & I2C_M_IGNORE_NAK;
|
|||
|
|
if (!(pmsg->flags & I2C_M_NOSTART)) {
|
|||
|
|
if (i) {
|
|||
|
|
i2c_repstart(adap);
|
|||
|
|
}
|
|||
|
|
ret = bit_doAddress(i2c_adap, pmsg);
|
|||
|
|
if ((ret != 0) && !nak_ok) {
|
|||
|
|
DEB2(printk(KERN_DEBUG "i2c-algo-bit.o: NAK from device addr %2.2x msg #%d\n"
|
|||
|
|
,msgs[i].addr,i));
|
|||
|
|
return (ret<0) ? ret : -EREMOTEIO;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
if (pmsg->flags & I2C_M_RD ) {
|
|||
|
|
/* read bytes into buffer*/
|
|||
|
|
ret = readbytes(i2c_adap, pmsg);
|
|||
|
|
DEB2(printk(KERN_DEBUG "i2c-algo-bit.o: read %d bytes.\n",ret));
|
|||
|
|
if (ret < pmsg->len ) {
|
|||
|
|
return (ret<0)? ret : -EREMOTEIO;
|
|||
|
|
}
|
|||
|
|
} else {
|
|||
|
|
/* write bytes from buffer */
|
|||
|
|
ret = sendbytes(i2c_adap, pmsg);
|
|||
|
|
DEB2(printk(KERN_DEBUG "i2c-algo-bit.o: wrote %d bytes.\n",ret));
|
|||
|
|
if (ret < pmsg->len ) {
|
|||
|
|
return (ret<0) ? ret : -EREMOTEIO;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
i2c_stop(adap);
|
|||
|
|
return num;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
static u32 bit_func(struct i2c_adapter *adap)
|
|||
|
|
{
|
|||
|
|
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
|
|||
|
|
I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
|
|||
|
|
/* -----exported algorithm data: ------------------------------------- */
|
|||
|
|
|
|||
|
|
static struct i2c_algorithm i2c_bit_algo = {
|
|||
|
|
.master_xfer = bit_xfer,
|
|||
|
|
.functionality = bit_func,
|
|||
|
|
};
|
|||
|
|
|
|||
|
|
/*
|
|||
|
|
* registering functions to load algorithms at runtime
|
|||
|
|
*/
|
|||
|
|
int i2c_bit_add_bus(struct i2c_adapter *adap)
|
|||
|
|
{
|
|||
|
|
struct i2c_algo_bit_data *bit_adap = adap->algo_data;
|
|||
|
|
|
|||
|
|
if (bit_test) {
|
|||
|
|
int ret = test_bus(bit_adap, adap->name);
|
|||
|
|
if (ret<0)
|
|||
|
|
return -ENODEV;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
DEB2(dev_dbg(&adap->dev, "hw routines registered.\n"));
|
|||
|
|
|
|||
|
|
/* register new adapter to i2c module... */
|
|||
|
|
adap->algo = &i2c_bit_algo;
|
|||
|
|
|
|||
|
|
adap->timeout = 100; /* default values, should */
|
|||
|
|
adap->retries = 3; /* be replaced by defines */
|
|||
|
|
|
|||
|
|
i2c_add_adapter(adap);
|
|||
|
|
return 0;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
|
|||
|
|
int i2c_bit_del_bus(struct i2c_adapter *adap)
|
|||
|
|
{
|
|||
|
|
return i2c_del_adapter(adap);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
EXPORT_SYMBOL(i2c_bit_add_bus);
|
|||
|
|
EXPORT_SYMBOL(i2c_bit_del_bus);
|
|||
|
|
|
|||
|
|
MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
|
|||
|
|
MODULE_DESCRIPTION("I2C-Bus bit-banging algorithm");
|
|||
|
|
MODULE_LICENSE("GPL");
|
|||
|
|
|
|||
|
|
module_param(bit_test, bool, 0);
|
|||
|
|
module_param(i2c_debug, int, S_IRUGO | S_IWUSR);
|
|||
|
|
|
|||
|
|
MODULE_PARM_DESC(bit_test, "Test the lines of the bus to see if it is stuck");
|
|||
|
|
MODULE_PARM_DESC(i2c_debug,
|
|||
|
|
"debug level - 0 off; 1 normal; 2,3 more verbose; 9 bit-protocol");
|