wip

common/gpio.cc

@@ -0,0 +1,84 @@
+#include "common/gpio.h"
+
+#include <string>
+
+#ifdef __APPLE__
+int gpio_init(int pin_nr, bool output) {
+  return 0;
+}
+
+int gpio_set(int pin_nr, bool high) {
+  return 0;
+}
+
+int gpiochip_get_ro_value_fd(const char* consumer_label, int gpiochiop_id, int pin_nr) {
+  return 0;
+}
+
+#else
+
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <cstring>
+#include <linux/gpio.h>
+#include <sys/ioctl.h>
+
+#include "common/util.h"
+#include "common/swaglog.h"
+
+int gpio_init(int pin_nr, bool output) {
+  char pin_dir_path[50];
+  int pin_dir_path_len = snprintf(pin_dir_path, sizeof(pin_dir_path),
+                           "/sys/class/gpio/gpio%d/direction", pin_nr);
+  if (pin_dir_path_len <= 0) {
+    return -1;
+  }
+  const char *value = output ? "out" : "in";
+  return util::write_file(pin_dir_path, (void*)value, strlen(value));
+}
+
+int gpio_set(int pin_nr, bool high) {
+  char pin_val_path[50];
+  int pin_val_path_len = snprintf(pin_val_path, sizeof(pin_val_path),
+                           "/sys/class/gpio/gpio%d/value", pin_nr);
+  if (pin_val_path_len <= 0) {
+    return -1;
+  }
+  return util::write_file(pin_val_path, (void*)(high ? "1" : "0"), 1);
+}
+
+int gpiochip_get_ro_value_fd(const char* consumer_label, int gpiochiop_id, int pin_nr) {
+
+  // Assumed that all interrupt pins are unexported and rights are given to
+  // read from gpiochip0.
+  std::string gpiochip_path = "/dev/gpiochip" + std::to_string(gpiochiop_id);
+  int fd = open(gpiochip_path.c_str(), O_RDONLY);
+  if (fd < 0) {
+    LOGE("Error opening gpiochip0 fd");
+    return -1;
+  }
+
+  // Setup event
+  struct gpioevent_request rq;
+  rq.lineoffset = pin_nr;
+  rq.handleflags = GPIOHANDLE_REQUEST_INPUT;
+
+  /* Requesting both edges as the data ready pulse from the lsm6ds sensor is
+     very short(75us) and is mostly detected as falling edge instead of rising.
+     So if it is detected as rising the following falling edge is skipped. */
+  rq.eventflags = GPIOEVENT_REQUEST_BOTH_EDGES;
+
+  strncpy(rq.consumer_label, consumer_label, std::size(rq.consumer_label) - 1);
+  int ret = util::safe_ioctl(fd, GPIO_GET_LINEEVENT_IOCTL, &rq);
+  if (ret == -1) {
+    LOGE("Unable to get line event from ioctl : %s", strerror(errno));
+    close(fd);
+    return -1;
+  }
+
+  close(fd);
+  return rq.fd;
+}
+
+#endif