int
mraa_gpio_read(mraa_gpio_context dev)
{
if (dev == NULL)
return -1;
if (dev->mmap_read != NULL)
return dev->mmap_read(dev);
if (dev->value_fp == -1) {
if (mraa_gpio_get_valfp(dev) != MRAA_SUCCESS) {
syslog(LOG_ERR, "gpio: Failed to get value file pointer");
return -1;
}
}
else {
// if value_fp is new this is pointless
lseek(dev->value_fp, 0, SEEK_SET);
}
char bu[2];
if (read(dev->value_fp, bu, 2*sizeof(char)) != 2) {
syslog(LOG_ERR, "gpio: Failed to read a sensible value from sysfs");
return -1;
}
lseek(dev->value_fp, 0, SEEK_SET);
return (int) strtol(bu, NULL, 10);
}
int
mraa_gpio_read(mraa_gpio_context dev)
{
if (dev == NULL) {
syslog(LOG_ERR, "gpio: read: context is invalid");
return -1;
}
if (IS_FUNC_DEFINED(dev, gpio_read_replace))
return dev->advance_func->gpio_read_replace(dev);
if (dev->mmap_read != NULL)
return dev->mmap_read(dev);
if (dev->value_fp == -1) {
if (mraa_gpio_get_valfp(dev) != MRAA_SUCCESS) {
return -1;
}
} else {
// if value_fp is new this is pointless
lseek(dev->value_fp, 0, SEEK_SET);
}
char bu[2];
if (read(dev->value_fp, bu, 2 * sizeof(char)) != 2) {
syslog(LOG_ERR, "gpio%i: read: Failed to read a sensible value from sysfs: %s", dev->pin, strerror(errno));
return -1;
}
lseek(dev->value_fp, 0, SEEK_SET);
return (int) strtol(bu, NULL, 10);
}