Move i2c scan to setup (#2869)

Co-authored-by: Oxan van Leeuwen <oxan@oxanvanleeuwen.nl>

esphome/components/i2c/i2c_bus.h

@@ -1,6 +1,8 @@
 #pragma once
 #include <cstdint>
 #include <cstddef>
+#include <utility>
+#include <vector>
 
 namespace esphome {
 namespace i2c {
@@ -40,6 +42,20 @@ class I2CBus {
     return writev(address, &buf, 1);
   }
   virtual ErrorCode writev(uint8_t address, WriteBuffer *buffers, size_t cnt) = 0;
+
+ protected:
+  void i2c_scan_() {
+    for (uint8_t address = 8; address < 120; address++) {
+      auto err = writev(address, nullptr, 0);
+      if (err == ERROR_OK) {
+        scan_results_.emplace_back(address, true);
+      } else if (err == ERROR_UNKNOWN) {
+        scan_results_.emplace_back(address, false);
+      }
+    }
+  }
+  std::vector<std::pair<uint8_t, bool>> scan_results_;
+  bool scan_{false};
 };
 
 }  // namespace i2c

esphome/components/i2c/i2c_bus_arduino.cpp

@@ -2,6 +2,7 @@
 
 #include "i2c_bus_arduino.h"
 #include "esphome/core/log.h"
+#include "esphome/core/helpers.h"
 #include <Arduino.h>
 #include <cstring>
 
@@ -27,6 +28,10 @@ void ArduinoI2CBus::setup() {
   wire_->begin(sda_pin_, scl_pin_);
   wire_->setClock(frequency_);
   initialized_ = true;
+  if (this->scan_) {
+    ESP_LOGV(TAG, "Scanning i2c bus for active devices...");
+    this->i2c_scan_();
+  }
 }
 void ArduinoI2CBus::dump_config() {
   ESP_LOGCONFIG(TAG, "I2C Bus:");
@@ -45,22 +50,20 @@ void ArduinoI2CBus::dump_config() {
       break;
   }
   if (this->scan_) {
-    ESP_LOGI(TAG, "Scanning i2c bus for active devices...");
+    ESP_LOGI(TAG, "Results from i2c bus scan:");
-    uint8_t found = 0;
+    if (scan_results_.empty()) {
-    for (uint8_t address = 8; address < 120; address++) {
-      auto err = writev(address, nullptr, 0);
-      if (err == ERROR_OK) {
-        ESP_LOGI(TAG, "Found i2c device at address 0x%02X", address);
-        found++;
-      } else if (err == ERROR_UNKNOWN) {
-        ESP_LOGI(TAG, "Unknown error at address 0x%02X", address);
-      }
-    }
-    if (found == 0) {
       ESP_LOGI(TAG, "Found no i2c devices!");
+    } else {
+      for (const auto &s : scan_results_) {
+        if (s.second)
+          ESP_LOGI(TAG, "Found i2c device at address 0x%02X", s.first);
+        else
+          ESP_LOGE(TAG, "Unknown error at address 0x%02X", s.first);
       }
     }
   }
+}
+
 ErrorCode ArduinoI2CBus::readv(uint8_t address, ReadBuffer *buffers, size_t cnt) {
   // logging is only enabled with vv level, if warnings are shown the caller
   // should log them

esphome/components/i2c/i2c_bus_arduino.h

@@ -34,7 +34,6 @@ class ArduinoI2CBus : public I2CBus, public Component {
 
  protected:
   TwoWire *wire_;
-  bool scan_;
   uint8_t sda_pin_;
   uint8_t scl_pin_;
   uint32_t frequency_;

esphome/components/i2c/i2c_bus_esp_idf.cpp

@@ -3,6 +3,7 @@
 #include "i2c_bus_esp_idf.h"
 #include "esphome/core/hal.h"
 #include "esphome/core/log.h"
+#include "esphome/core/helpers.h"
 #include <cstring>
 
 namespace esphome {
@@ -37,6 +38,10 @@ void IDFI2CBus::setup() {
     return;
   }
   initialized_ = true;
+  if (this->scan_) {
+    ESP_LOGV(TAG, "Scanning i2c bus for active devices...");
+    this->i2c_scan_();
+  }
 }
 void IDFI2CBus::dump_config() {
   ESP_LOGCONFIG(TAG, "I2C Bus:");
@@ -55,23 +60,20 @@ void IDFI2CBus::dump_config() {
       break;
   }
   if (this->scan_) {
-    ESP_LOGI(TAG, "Scanning i2c bus for active devices...");
+    ESP_LOGI(TAG, "Results from i2c bus scan:");
-    uint8_t found = 0;
+    if (scan_results_.empty()) {
-    for (uint8_t address = 8; address < 120; address++) {
-      auto err = writev(address, nullptr, 0);
-
-      if (err == ERROR_OK) {
-        ESP_LOGI(TAG, "Found i2c device at address 0x%02X", address);
-        found++;
-      } else if (err == ERROR_UNKNOWN) {
-        ESP_LOGI(TAG, "Unknown error at address 0x%02X", address);
-      }
-    }
-    if (found == 0) {
       ESP_LOGI(TAG, "Found no i2c devices!");
+    } else {
+      for (const auto &s : scan_results_) {
+        if (s.second)
+          ESP_LOGI(TAG, "Found i2c device at address 0x%02X", s.first);
+        else
+          ESP_LOGE(TAG, "Unknown error at address 0x%02X", s.first);
       }
     }
   }
+}
+
 ErrorCode IDFI2CBus::readv(uint8_t address, ReadBuffer *buffers, size_t cnt) {
   // logging is only enabled with vv level, if warnings are shown the caller
   // should log them

esphome/components/i2c/i2c_bus_esp_idf.h

@@ -36,7 +36,6 @@ class IDFI2CBus : public I2CBus, public Component {
 
  protected:
   i2c_port_t port_;
-  bool scan_;
   uint8_t sda_pin_;
   bool sda_pullup_enabled_;
   uint8_t scl_pin_;