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gpio: make isr_exit function use pthread_cancel and treat error cases more cleanly

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Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
This commit is contained in:
Brendan Le Foll
2014-05-15 14:42:18 +01:00
parent 8460b1f743
commit 6dc1500f5a
1 changed files with 35 additions and 16 deletions
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51
src/gpio/gpio.c
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@@ -73,6 +73,7 @@ maa_gpio_init_raw(int pin)
maa_gpio_context* dev = (maa_gpio_context*) malloc(sizeof(maa_gpio_context));
memset(dev, 0, sizeof(maa_gpio_context));
dev->value_fp = -1;
dev->isr_value_fp = -1;
dev->pin = pin;
if ((export_f = fopen(SYSFS_CLASS_GPIO "/export", "w")) == NULL) {
@@ -103,7 +104,8 @@ maa_gpio_wait_interrupt(int fd)
return MAA_ERROR_INVALID_RESOURCE;
}
// Wait for it forever
// Wait for it forever or until pthread_cancel
// poll is a cancelable point like sleep()
int x = poll (&pfd, 1, -1);
// do a final read to clear interupt
@@ -126,6 +128,7 @@ maa_gpio_interrupt_handler(void* arg)
for (;;) {
ret = maa_gpio_wait_interrupt(dev->isr_value_fp);
if (ret == MAA_SUCCESS) {
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
#ifdef SWIGPYTHON
// In order to call a python object (all python functions are objects) we
// need to aquire the GIL (Global Interpreter Lock). This may not always be
@@ -139,9 +142,12 @@ maa_gpio_interrupt_handler(void* arg)
#else
dev->isr();
#endif
pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
} else {
// we must have got an error code so die nicely
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
close(dev->isr_value_fp);
dev->isr_value_fp = -1;
return NULL;
}
}
@@ -192,6 +198,11 @@ maa_gpio_edge_mode(maa_gpio_context *dev, gpio_edge_t mode)
maa_result_t
maa_gpio_isr(maa_gpio_context *dev, gpio_edge_t mode, void (*fptr)(void))
{
// we only allow one isr per maa_gpio_context
if (dev->thread_id != 0) {
return MAA_ERROR_NO_RESOURCES;
}
maa_gpio_edge_mode(dev, mode);
dev->isr = fptr;
pthread_create (&dev->thread_id, NULL, maa_gpio_interrupt_handler, (void *) dev);
@@ -204,26 +215,34 @@ maa_gpio_isr_exit(maa_gpio_context *dev)
{
maa_result_t ret = MAA_SUCCESS;
// wasting our time, there is no isr to exit from
if (dev->thread_id == 0 && dev->isr_value_fp == -1) {
return ret;
}
// stop isr being useful
ret = maa_gpio_edge_mode(dev, MAA_GPIO_EDGE_NONE);
if ((dev->thread_id != 0) &&
(pthread_cancel(dev->thread_id) != 0)) {
ret = MAA_ERROR_INVALID_HANDLE;
}
// close the filehandle in case it's still open
if (dev->isr_value_fp != -1) {
if (close(dev->isr_value_fp) != 0) {
ret = MAA_ERROR_INVALID_PARAMETER;
}
}
#ifdef SWIGPYTHON
// Dereference our Python call back function
Py_DECREF(dev->isr);
#endif
if (dev->thread_id == 0) {
return ret;
}
if (pthread_kill(dev->thread_id, SIGTERM) != 0) {
ret = MAA_ERROR_INVALID_HANDLE;
}
if (close(dev->isr_value_fp) != 0) {
ret = MAA_ERROR_INVALID_PARAMETER;
}
// this is only required if we had an isr setup
if (ret == MAA_SUCCESS) {
ret = maa_gpio_edge_mode(dev, MAA_GPIO_EDGE_NONE);
}
// assume our thread will exit either way we just lost it's handle
dev->thread_id = 0;
dev->isr_value_fp = -1;
return ret;
}