DHT22 is not working how I want it to

Need to keep debugging it... think of a different way to approach it maybe

components/dht22/CMakeLists.txt

@@ -1,3 +1,3 @@
 idf_component_register(SRCS "dht22.c"
   INCLUDE_DIRS "."
-  REQUIRES driver)
+  REQUIRES driver esp_timer)

components/dht22/dht22.c

@@ -1,6 +1,11 @@
 #include "dht22.h"
 #include "esp_log.h"
+#include "hal/gpio_types.h"
 #include "sdkconfig.h"
+#include "driver/gpio.h"
+#include <rom/ets_sys.h>
+#include "esp_timer.h"
+#include "freertos/portmacro.h"
 
 #define DATA_GPIO CONFIG_DHT22_DATA_GPIO
 
@@ -24,8 +29,65 @@ void dht22_handle_error(dht22_error e) {
 
 dht22_error dht22_read() {
   uint8_t data[5] = {0};
+  uint32_t tick_total = 0;
 
-  // TODO: Actually figure out how to read the data from the chip.
+  /*
+   * From datasheet:
+   *  - Host pulls low "beyond at least 1ms"
+   *  - Host pulls up 20us to 40us
+   */
+  gpio_set_direction(CONFIG_DHT22_DATA_GPIO, GPIO_MODE_OUTPUT);
+
+  gpio_set_level(CONFIG_DHT22_DATA_GPIO, 0);
+  ets_delay_us(5000);
+
+  gpio_set_level(CONFIG_DHT22_DATA_GPIO, 1);
+  ets_delay_us(25);
+
+  /*
+   * From datasheet:
+   *  - DHT pulls low 80us
+   *  - DHT pulls high 80us
+   */
+  gpio_set_direction(CONFIG_DHT22_DATA_GPIO, GPIO_MODE_INPUT);
+
+  // Maybe wait here until it goes high?
+  while (gpio_get_level(CONFIG_DHT22_DATA_GPIO) == 1) {
+    // wait for a while - should only be 20 uS
+  }
+
+
+  uint64_t start_time = esp_timer_get_time();
+
+  while (gpio_get_level(CONFIG_DHT22_DATA_GPIO) == 0) {
+    tick_total += 1;
+    if (tick_total == UINT32_MAX - 1) {
+      return DHT22_TIMING_ERROR;
+    }
+  }
+  uint64_t next_time = esp_timer_get_time();
+  uint32_t elapsed_time = next_time - start_time;
+  if (elapsed_time < 75 || elapsed_time > 85) {
+    return DHT22_TIMING_ERROR;
+  }
+
+  tick_total = 0;
+  start_time = esp_timer_get_time();
+  while (gpio_get_level(CONFIG_DHT22_DATA_GPIO) == 0) {
+    tick_total += 1;
+    if (tick_total == UINT32_MAX - 1) {
+      return DHT22_TIMING_ERROR;
+    }
+  }
+  next_time = esp_timer_get_time();
+  elapsed_time = next_time - start_time;
+
+  portENABLE_INTERRUPTS();
+  ESP_LOGW(TAG, "etime: %lu", elapsed_time);
+
+  if (elapsed_time < 70 || elapsed_time > 90) {
+    return DHT22_TIMING_ERROR;
+  }
 
   // TODO test that data[x] << 8 will be promoted to 16bits otherwise I'm
   // shifting them to just zeros

main/main.c

@@ -70,6 +70,7 @@ void read_from_dht22() {
     portDISABLE_INTERRUPTS();
     int ret = dht22_read();
     portENABLE_INTERRUPTS();
+    ESP_LOGE(TAG, "dht_ret: %i", ret);
     if (ret != DHT22_OK) {
       dht22_handle_error(ret);
     } else {
@@ -79,8 +80,8 @@ void read_from_dht22() {
       if (has_ntp_time_obtained_once()) {
         // I _think_ I only want to be doing that rolling average and saving
         // if/when we've got an actual time to do that with. I think that'd
-        // avoid some weird bugs (time changing from 1970 -> current time within
-        // a 10 min period)
+        // avoid some weird bugs (e.g. time changing from 1970 -> current time within
+        // a 10 min period or just saving data saying it's from the 70s)
 
         if (num_samples_last_ten_mins == 0) {
           ten_minute_rolling_average.rh = latest_datapoint.rh;
@@ -100,7 +101,7 @@ void read_from_dht22() {
         // samples per 10 minutes than can be stored in a uint32 - I'll
         // calculate what that is and perhaps raise a compile error if too high.
         if (num_samples_last_ten_mins >=
-            (CONFIG_DHT22_PERIOD_POLL * 1000 * 60 * 10)) {
+            ((uint32_t) CONFIG_DHT22_PERIOD_POLL * 1000 * 60 * 10)) {
           num_samples_last_ten_mins = 0;
 
           time_t epoch;
@@ -158,5 +159,5 @@ void app_main(void) {
 
 #endif /* CONFIG_PMS5003_ENABLED */
 
-  start_wifi();
+  //start_wifi();
 }