void i2c_stop(struct i2c_bus *bus)
{
I2C_SET(bus,0,0);
I2C_SET(bus,1,0);
I2C_SET(bus,1,1);
I2C_DEBUG(printk(">\n"));
}
static int
iicbb_start(device_t dev, u_char slave, int timeout)
{
int error;
I2C_DEBUG(printf("<"));
I2C_SET(dev,1,1);
I2C_SET(dev,1,0);
I2C_SET(dev,0,0);
/* send address */
iicbb_sendbyte(dev, slave, timeout);
/* check for ack */
if (iicbb_ack(dev, timeout)) {
error = IIC_ENOACK;
goto error;
}
return(0);
error:
iicbb_stop(dev);
return (error);
}
static void
iicbb_zero(device_t dev, int timeout)
{
I2C_SET(dev,0,0);
I2C_SET(dev,1,0);
I2C_SET(dev,0,0);
return;
}
static void
iicbb_one(device_t dev, int timeout)
{
I2C_SET(dev,0,1);
I2C_SET(dev,1,1);
I2C_SET(dev,0,1);
return;
}
void i2c_start(struct i2c_bus *bus)
{
I2C_SET(bus,0,1);
I2C_SET(bus,1,1);
I2C_SET(bus,1,0);
I2C_SET(bus,0,0);
I2C_DEBUG(printk("%s: < ",bus->name));
}
static int
iicbb_stop(device_t dev)
{
I2C_SET(dev,0,0);
I2C_SET(dev,1,0);
I2C_SET(dev,1,1);
I2C_DEBUG(printf(">"));
return (0);
}
static void
iicbb_zero(device_t dev, int timeout)
{
struct iicbb_softc *sc = device_get_softc(dev);
I2C_SET(sc,dev,0,0);
I2C_SET(sc,dev,1,0);
I2C_SET(sc,dev,0,0);
return;
}
int i2c_ack(struct i2c_bus *bus)
{
int ack;
I2C_SET(bus,0,1);
I2C_SET(bus,1,1);
ack = I2C_GET(bus);
I2C_SET(bus,0,1);
return ack;
}
static int
iicbb_stop(device_t dev)
{
struct iicbb_softc *sc = device_get_softc(dev);
I2C_SET(sc,dev,0,0);
I2C_SET(sc,dev,1,0);
I2C_SET(sc,dev,1,1);
I2C_DEBUG(printf(">"));
I2C_DEBUG(printf("\n"));
return (0);
}
unsigned char i2c_readbyte(struct i2c_bus *bus,int last)
{
int i;
unsigned char data=0;
I2C_SET(bus,0,1);
for (i=7; i>=0; i--)
{
I2C_SET(bus,1,1);
if (I2C_GET(bus))
data |= (1<<i);
I2C_SET(bus,0,1);
}
last ? i2c_one(bus) : i2c_zero(bus);
I2C_DEBUG(printk("=%02x%c ",(int)data,last?'-':'+'));
return data;
}
/*
* Waiting for ACKNOWLEDGE.
*
* When a chip is being addressed or has received data it will issue an
* ACKNOWLEDGE pulse. Therefore the MASTER must release the DATA line
* (set it to high level) and then release the CLOCK line.
* Now it must wait for the SLAVE to pull the DATA line low.
* Actually on the bus this looks like a START condition so nothing happens
* because of the fact that the IC's that have not been addressed are doing
* nothing.
*
* When the SLAVE has pulled this line low the MASTER will take the CLOCK
* line low and then the SLAVE will release the SDA (data) line.
*/
static int
iicbb_ack(device_t dev, int timeout)
{
int noack;
int k = 0;
I2C_SET(dev,0,1);
I2C_SET(dev,1,1);
do {
noack = I2C_GETSDA(dev);
if (!noack)
break;
DELAY(10);
k += 10;
} while (k < timeout);
I2C_SET(dev,0,1);
I2C_DEBUG(printf("%c ",noack?'-':'+'));
return (noack);
}
static u_char
iicbb_readbyte(device_t dev, int last, int timeout)
{
int i;
unsigned char data=0;
I2C_SET(dev,0,1);
for (i=7; i>=0; i--)
{
I2C_SET(dev,1,1);
if (I2C_GETSDA(dev))
data |= (1<<i);
I2C_SET(dev,0,1);
}
if (last) {
iicbb_one(dev, timeout);
} else {
iicbb_zero(dev, timeout);
}
I2C_DEBUG(printf("r%02x%c ",(int)data,last?'-':'+'));
return data;
}
/*
* Waiting for ACKNOWLEDGE.
*
* When a chip is being addressed or has received data it will issue an
* ACKNOWLEDGE pulse. Therefore the MASTER must release the DATA line
* (set it to high level) and then release the CLOCK line.
* Now it must wait for the SLAVE to pull the DATA line low.
* Actually on the bus this looks like a START condition so nothing happens
* because of the fact that the IC's that have not been addressed are doing
* nothing.
*
* When the SLAVE has pulled this line low the MASTER will take the CLOCK
* line low and then the SLAVE will release the SDA (data) line.
*/
static int
iicbb_ack(device_t dev, int timeout)
{
struct iicbb_softc *sc = device_get_softc(dev);
int noack;
int k = 0;
I2C_SET(sc,dev,0,1);
I2C_SET(sc,dev,1,1);
do {
noack = I2C_GETSDA(dev);
if (!noack)
break;
DELAY(1);
k++;
} while (k < timeout);
I2C_SET(sc,dev,0,1);
I2C_DEBUG(printf("%c ",noack?'-':'+'));
return (noack);
}
int i2c_sendbyte(struct i2c_bus *bus,unsigned char data,int wait_for_ack)
{
int i, ack;
I2C_SET(bus,0,0);
for (i=7; i>=0; i--)
(data&(1<<i)) ? i2c_one(bus) : i2c_zero(bus);
if (wait_for_ack)
udelay(wait_for_ack);
ack=i2c_ack(bus);
I2C_DEBUG(printk("%02x%c ",(int)data,ack?'-':'+'));
return ack;
}
void i2c_zero(struct i2c_bus *bus)
{
I2C_SET(bus,0,0);
I2C_SET(bus,1,0);
I2C_SET(bus,0,0);
}
void i2c_one(struct i2c_bus *bus)
{
I2C_SET(bus,0,1);
I2C_SET(bus,1,1);
I2C_SET(bus,0,1);
}