/*
* iicbus_request_bus()
*
* Allocate the device to perform transfers.
*
* how : IIC_WAIT or IIC_DONTWAIT
*/
int
iicbus_request_bus(device_t bus, device_t dev, int how)
{
struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
int error = 0;
/* first, ask the underlying layers if the request is ok */
IICBUS_LOCK(sc);
do {
error = IICBUS_CALLBACK(device_get_parent(bus),
IIC_REQUEST_BUS, (caddr_t)&how);
if (error)
error = iicbus_poll(sc, how);
} while (error == EWOULDBLOCK);
while (!error) {
if (sc->owner && sc->owner != dev) {
error = iicbus_poll(sc, how);
} else {
sc->owner = dev;
IICBUS_UNLOCK(sc);
return (0);
}
/* free any allocated resource */
if (error)
IICBUS_CALLBACK(device_get_parent(bus), IIC_RELEASE_BUS,
(caddr_t)&how);
}
IICBUS_UNLOCK(sc);
return (error);
}
/*
* iicbus_release_bus()
*
* Release the device allocated with iicbus_request_dev()
*/
int
iicbus_release_bus(device_t bus, device_t dev)
{
struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
int error;
/* first, ask the underlying layers if the release is ok */
error = IICBUS_CALLBACK(device_get_parent(bus), IIC_RELEASE_BUS, NULL);
if (error)
return (error);
IICBUS_LOCK(sc);
if (sc->owner != dev) {
IICBUS_UNLOCK(sc);
return (EACCES);
}
sc->owner = NULL;
/* wakeup waiting processes */
wakeup(sc);
IICBUS_UNLOCK(sc);
return (0);
}
/*
* iicbus_release_bus()
*
* Release the device allocated with iicbus_request_dev()
*/
int
iicbus_release_bus(device_t bus, device_t dev)
{
struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
int error;
IICBUS_LOCK(sc);
if (sc->owner != dev) {
IICBUS_UNLOCK(sc);
return (EACCES);
}
/*
* Drop the lock around the call to the bus driver.
* This call should be allowed to sleep in the IIC_WAIT case.
* Drivers might also need to grab locks that would cause LOR
* if our lock is held.
*/
IICBUS_UNLOCK(sc);
/* Ask the underlying layers if the release is ok */
error = IICBUS_CALLBACK(device_get_parent(bus), IIC_RELEASE_BUS, NULL);
if (error == 0) {
IICBUS_LOCK(sc);
sc->owner = NULL;
/* wakeup a waiting thread */
wakeup_one(sc);
IICBUS_UNLOCK(sc);
}
return (error);
}
/*
* iicbus_request_bus()
*
* Allocate the device to perform transfers.
*
* how : IIC_WAIT or IIC_DONTWAIT
*/
int
iicbus_request_bus(device_t bus, device_t dev, int how)
{
struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
int error = 0;
IICBUS_LOCK(sc);
while ((error == 0) && (sc->owner != NULL))
error = iicbus_poll(sc, how);
if (error == 0) {
sc->owner = dev;
/*
* Drop the lock around the call to the bus driver.
* This call should be allowed to sleep in the IIC_WAIT case.
* Drivers might also need to grab locks that would cause LOR
* if our lock is held.
*/
IICBUS_UNLOCK(sc);
/* Ask the underlying layers if the request is ok */
error = IICBUS_CALLBACK(device_get_parent(bus),
IIC_REQUEST_BUS, (caddr_t)&how);
IICBUS_LOCK(sc);
if (error != 0) {
sc->owner = NULL;
wakeup_one(sc);
}
}
IICBUS_UNLOCK(sc);
return (error);
}