-/* ------------------------------------------------------------------------- */
-/* i2c-algo-bit.c i2c driver algorithms for bit-shift adapters */
-/* ------------------------------------------------------------------------- */
-/* Copyright (C) 1995-2000 Simon G. Vogl
+/* -------------------------------------------------------------------------
+ * 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
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. */
-/* ------------------------------------------------------------------------- */
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * ------------------------------------------------------------------------- */
/* With some changes from Frodo Looijaard <frodol@dds.nl>, Kyösti Mälkki
<kmalkki@cc.hut.fi> and Jean Delvare <khali@linux-fr.org> */
/* --- 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)
+#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);
+ setsda(adap, 0);
udelay((adap->udelay + 1) / 2);
}
static inline void sdahi(struct i2c_algo_bit_data *adap)
{
- setsda(adap,1);
+ setsda(adap, 1);
udelay((adap->udelay + 1) / 2);
}
static inline void scllo(struct i2c_algo_bit_data *adap)
{
- setscl(adap,0);
+ setscl(adap, 0);
udelay(adap->udelay / 2);
}
{
unsigned long start;
- setscl(adap,1);
+ setscl(adap, 1);
/* Not all adapters have scl sense line... */
if (!adap->getscl)
goto done;
- 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)) {
+ start = jiffies;
+ while (!getscl(adap)) {
+ /* This 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 ("clock stretching") while they
+ * are processing data internally.
+ */
+ if (time_after_eq(jiffies, start + adap->timeout))
return -ETIMEDOUT;
- }
cond_resched();
}
#ifdef DEBUG
done:
udelay(adap->udelay);
return 0;
-}
+}
/* --- other auxiliary functions -------------------------------------- */
-static void i2c_start(struct i2c_algo_bit_data *adap)
+static void i2c_start(struct i2c_algo_bit_data *adap)
{
/* assert: scl, sda are high */
setsda(adap, 0);
scllo(adap);
}
-static void i2c_repstart(struct i2c_algo_bit_data *adap)
+static void i2c_repstart(struct i2c_algo_bit_data *adap)
{
/* assert: scl is low */
sdahi(adap);
}
-static void i2c_stop(struct i2c_algo_bit_data *adap)
+static void i2c_stop(struct i2c_algo_bit_data *adap)
{
/* assert: scl is low */
sdalo(adap);
- sclhi(adap);
+ sclhi(adap);
setsda(adap, 1);
udelay(adap->udelay);
}
-/* send a byte without start cond., look for arbitration,
+/* send a byte without start cond., look for arbitration,
check ackn. from slave */
/* returns:
* 1 if the device acknowledged
struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
/* assert: scl is low */
- for ( i=7 ; i>=0 ; i-- ) {
+ for (i = 7; i >= 0; i--) {
sb = (c >> i) & 1;
- setsda(adap,sb);
+ setsda(adap, sb);
udelay((adap->udelay + 1) / 2);
- if (sclhi(adap)<0) { /* timed out */
+ if (sclhi(adap) < 0) { /* timed out */
bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, "
"timeout at bit #%d\n", (int)c, i);
return -ETIMEDOUT;
- };
- /* do arbitration here:
- * if ( sb && ! getsda(adap) ) -> ouch! Get out of here.
+ }
+ /* FIXME do arbitration here:
+ * if (sb && !getsda(adap)) -> ouch! Get out of here.
+ *
+ * Report a unique code, so higher level code can retry
+ * the whole (combined) message and *NOT* issue STOP.
*/
scllo(adap);
}
sdahi(adap);
- if (sclhi(adap)<0){ /* timeout */
+ if (sclhi(adap) < 0) { /* timeout */
bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, "
"timeout at ack\n", (int)c);
return -ETIMEDOUT;
- };
- /* read ack: SDA should be pulled down by slave */
+ }
+
+ /* read ack: SDA should be pulled down by slave, or it may
+ * NAK (usually to report problems with the data we wrote).
+ */
ack = !getsda(adap); /* ack: sda is pulled low -> success */
bit_dbg(2, &i2c_adap->dev, "i2c_outb: 0x%02x %s\n", (int)c,
ack ? "A" : "NA");
}
-static int i2c_inb(struct i2c_adapter *i2c_adap)
+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;
+ 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 */
+ for (i = 0; i < 8; i++) {
+ if (sclhi(adap) < 0) { /* timeout */
bit_dbg(1, &i2c_adap->dev, "i2c_inb: timeout at bit "
"#%d\n", 7 - i);
return -ETIMEDOUT;
- };
+ }
indata *= 2;
- if ( getsda(adap) )
+ if (getsda(adap))
indata |= 0x01;
setscl(adap, 0);
udelay(i == 7 ? adap->udelay / 2 : adap->udelay);
* 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;
+static int test_bus(struct i2c_algo_bit_data *adap, char *name)
+{
+ int scl, sda;
- if (adap->getscl==NULL)
+ if (adap->getscl == NULL)
pr_info("%s: Testing SDA only, SCL is not readable\n", name);
- sda=getsda(adap);
- scl=(adap->getscl==NULL?1:getscl(adap));
- if (!scl || !sda ) {
+ sda = getsda(adap);
+ scl = (adap->getscl == NULL) ? 1 : getscl(adap);
+ if (!scl || !sda) {
printk(KERN_WARNING "%s: bus seems to be busy\n", name);
goto bailout;
}
sdalo(adap);
- sda=getsda(adap);
- scl=(adap->getscl==NULL?1:getscl(adap));
- if ( 0 != sda ) {
+ sda = getsda(adap);
+ scl = (adap->getscl == NULL) ? 1 : getscl(adap);
+ if (sda) {
printk(KERN_WARNING "%s: SDA stuck high!\n", name);
goto bailout;
}
- if ( 0 == scl ) {
+ if (!scl) {
printk(KERN_WARNING "%s: SCL unexpected low "
"while pulling SDA low!\n", name);
goto bailout;
- }
+ }
sdahi(adap);
- sda=getsda(adap);
- scl=(adap->getscl==NULL?1:getscl(adap));
- if ( 0 == sda ) {
+ sda = getsda(adap);
+ scl = (adap->getscl == NULL) ? 1 : getscl(adap);
+ if (!sda) {
printk(KERN_WARNING "%s: SDA stuck low!\n", name);
goto bailout;
}
- if ( 0 == scl ) {
+ if (!scl) {
printk(KERN_WARNING "%s: SCL unexpected low "
"while pulling SDA high!\n", name);
goto bailout;
}
scllo(adap);
- sda=getsda(adap);
- scl=(adap->getscl==NULL?0:getscl(adap));
- if ( 0 != scl ) {
+ sda = getsda(adap);
+ scl = (adap->getscl == NULL) ? 0 : getscl(adap);
+ if (scl) {
printk(KERN_WARNING "%s: SCL stuck high!\n", name);
goto bailout;
}
- if ( 0 == sda ) {
+ if (!sda) {
printk(KERN_WARNING "%s: SDA unexpected low "
"while pulling SCL low!\n", name);
goto bailout;
}
-
+
sclhi(adap);
- sda=getsda(adap);
- scl=(adap->getscl==NULL?1:getscl(adap));
- if ( 0 == scl ) {
+ sda = getsda(adap);
+ scl = (adap->getscl == NULL) ? 1 : getscl(adap);
+ if (!scl) {
printk(KERN_WARNING "%s: SCL stuck low!\n", name);
goto bailout;
}
- if ( 0 == sda ) {
+ if (!sda) {
printk(KERN_WARNING "%s: SDA unexpected low "
"while pulling SCL high!\n", name);
goto bailout;
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);
+ int i, ret = -1;
+
+ for (i = 0; i <= retries; i++) {
+ ret = i2c_outb(i2c_adap, addr);
if (ret == 1 || i == retries)
break;
bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n");
{
const unsigned char *temp = msg->buf;
int count = msg->len;
- unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK;
+ unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK;
int retval;
- int wrcount=0;
+ int wrcount = 0;
while (count > 0) {
retval = i2c_outb(i2c_adap, *temp);
- if ((retval>0) || (nak_ok && (retval==0))) { /* ok or ignored NAK */
- count--;
+
+ /* OK/ACK; or ignored NAK */
+ if ((retval > 0) || (nak_ok && (retval == 0))) {
+ count--;
temp++;
wrcount++;
} else { /* arbitration or no acknowledge */
static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
{
int inval;
- int rdcount=0; /* counts bytes read */
+ int rdcount = 0; /* counts bytes read */
unsigned char *temp = msg->buf;
int count = msg->len;
const unsigned flags = msg->flags;
while (count > 0) {
inval = i2c_inb(i2c_adap);
- if (inval>=0) {
+ if (inval >= 0) {
*temp = inval;
rdcount++;
} else { /* read timed out */
* 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...)
+ * -ETIMEDOUT, for example if the lines are stuck...)
*/
static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
{
int ret, retries;
retries = nak_ok ? 0 : i2c_adap->retries;
-
- if ( (flags & I2C_M_TEN) ) {
+
+ if (flags & I2C_M_TEN) {
/* a ten bit address */
- addr = 0xf0 | (( msg->addr >> 7) & 0x03);
+ addr = 0xf0 | ((msg->addr >> 7) & 0x03);
bit_dbg(2, &i2c_adap->dev, "addr0: %d\n", addr);
/* try extended address code...*/
ret = try_address(i2c_adap, addr, retries);
return -EREMOTEIO;
}
/* the remaining 8 bit address */
- ret = i2c_outb(i2c_adap,msg->addr & 0x7f);
+ ret = i2c_outb(i2c_adap, msg->addr & 0x7f);
if ((ret != 1) && !nak_ok) {
/* the chip did not ack / xmission error occurred */
dev_err(&i2c_adap->dev, "died at 2nd address code\n");
return -EREMOTEIO;
}
- if ( flags & I2C_M_RD ) {
+ if (flags & I2C_M_RD) {
bit_dbg(3, &i2c_adap->dev, "emitting repeated "
"start condition\n");
i2c_repstart(adap);
/* okay, now switch into reading mode */
addr |= 0x01;
ret = try_address(i2c_adap, addr, retries);
- if ((ret!=1) && !nak_ok) {
+ if ((ret != 1) && !nak_ok) {
dev_err(&i2c_adap->dev,
"died at repeated address code\n");
return -EREMOTEIO;
}
}
} else { /* normal 7bit address */
- addr = ( msg->addr << 1 );
- if (flags & I2C_M_RD )
+ addr = msg->addr << 1;
+ if (flags & I2C_M_RD)
addr |= 1;
- if (flags & I2C_M_REV_DIR_ADDR )
+ if (flags & I2C_M_REV_DIR_ADDR)
addr ^= 1;
ret = try_address(i2c_adap, addr, retries);
- if ((ret!=1) && !nak_ok)
+ if ((ret != 1) && !nak_ok)
return -EREMOTEIO;
}
{
struct i2c_msg *pmsg;
struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
-
- int i,ret;
+ int i, ret;
unsigned short nak_ok;
bit_dbg(3, &i2c_adap->dev, "emitting start condition\n");
i2c_start(adap);
- for (i=0;i<num;i++) {
+ for (i = 0; i < num; i++) {
pmsg = &msgs[i];
- nak_ok = pmsg->flags & I2C_M_IGNORE_NAK;
+ nak_ok = pmsg->flags & I2C_M_IGNORE_NAK;
if (!(pmsg->flags & I2C_M_NOSTART)) {
if (i) {
bit_dbg(3, &i2c_adap->dev, "emitting "
goto bailout;
}
}
- if (pmsg->flags & I2C_M_RD ) {
+ if (pmsg->flags & I2C_M_RD) {
/* read bytes into buffer*/
ret = readbytes(i2c_adap, pmsg);
if (ret >= 1)
static u32 bit_func(struct i2c_adapter *adap)
{
- return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
I2C_FUNC_SMBUS_READ_BLOCK_DATA |
I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
.functionality = bit_func,
};
-/*
- * registering functions to load algorithms at runtime
+/*
+ * registering functions to load algorithms at runtime
*/
static int i2c_bit_prepare_bus(struct i2c_adapter *adap)
{
if (bit_test) {
int ret = test_bus(bit_adap, adap->name);
- if (ret<0)
+ if (ret < 0)
return -ENODEV;
}
projects / linux-2.6 / commitdiff