sensord: use interrupts to improve LSM6DS3 timing accuracy (#24525)

* change LSM6DS3TR(-c) gyroscope  and accelerometer to interrupt

* add pthread for linking

* add interrupt collector thread to fetch in parallel to non interrupt based sensors

* change get_event interface to return true on successful read

* fetch sensor interrupts via gpiochip

* avoid sending empty messages (interrupt only, non interupt magn can leave a gap in the orphan block)

* add verifier script to sensor interrupts (sensor_data_to_hist.py)

* add/update sensord testsweet (test_sensord.py)

* add poll timed out check

* unexport interrupt gpio pins

* gpiochip on both edges, but skip falling edge if rising edge is detected, this is handled in the sensor as the status flag is checked if new data is availble

* add test to sensord to verify 100Hz interrupt frequency

* add sensor shutdown/low power mode functionality on sensord exit

* relax test, will be readded in the splitup PR

Co-authored-by: Kurt Nistelberger <kurt.nistelberger@gmail.com>

common/gpio.cc

@@ -4,11 +4,11 @@
 #include <unistd.h>
 
 #include <cstring>
+#include <linux/gpio.h>
+#include <sys/ioctl.h>
 
 #include "common/util.h"
-
-// We assume that all pins have already been exported on boot,
-// and that we have permission to write to them.
+#include "common/swaglog.h"
 
 int gpio_init(int pin_nr, bool output) {
   char pin_dir_path[50];
@@ -30,3 +30,36 @@ int gpio_set(int pin_nr, bool high) {
   }
   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 = 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;
+}

common/gpio.h

@@ -8,6 +8,11 @@
   #define GPIO_UBLOX_PWR_EN     34
   #define GPIO_STM_RST_N        124
   #define GPIO_STM_BOOT0        134
+  #define GPIO_BMX_ACCEL_INT    21
+  #define GPIO_BMX_GYRO_INT     23
+  #define GPIO_BMX_MAGN_INT     87
+  #define GPIO_LSM_INT          84
+  #define GPIOCHIP_INT          0
 #else
   #define GPIO_HUB_RST_N        0
   #define GPIO_UBLOX_RST_N      0
@@ -15,7 +20,14 @@
   #define GPIO_UBLOX_PWR_EN     0
   #define GPIO_STM_RST_N        0
   #define GPIO_STM_BOOT0        0
+  #define GPIO_BMX_ACCEL_INT    0
+  #define GPIO_BMX_GYRO_INT     0
+  #define GPIO_BMX_MAGN_INT     0
+  #define GPIO_LSM_INT          0
+  #define GPIOCHIP_INT          0
 #endif
 
 int gpio_init(int pin_nr, bool output);
 int gpio_set(int pin_nr, bool high);
+
+int gpiochip_get_ro_value_fd(const char* consumer_label, int gpiochiop_id, int pin_nr);