From babaa1db3f7e6d09448d4745772493d7aab7169e Mon Sep 17 00:00:00 2001
From: Jesse Hills <3060199+jesserockz@users.noreply.github.com>
Date: Wed, 23 Jul 2025 23:31:13 +1200
Subject: [PATCH] [i2c] Use ``i2c_master_probe`` to scan i2c bus (#9831)

---
 esphome/components/i2c/i2c_bus.h           |  2 +-
 esphome/components/i2c/i2c_bus_arduino.cpp |  2 +-
 esphome/components/i2c/i2c_bus_esp_idf.cpp | 17 ++++++++++++++---
 esphome/components/i2c/i2c_bus_esp_idf.h   |  3 ++-
 4 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/esphome/components/i2c/i2c_bus.h b/esphome/components/i2c/i2c_bus.h
index 5c1e15d814..da94aa940d 100644
--- a/esphome/components/i2c/i2c_bus.h
+++ b/esphome/components/i2c/i2c_bus.h
@@ -94,7 +94,7 @@ class I2CBus {
  protected:
   /// @brief Scans the I2C bus for devices. Devices presence is kept in an array of std::pair
   /// that contains the address and the corresponding bool presence flag.
-  void i2c_scan_() {
+  virtual void i2c_scan() {
     for (uint8_t address = 8; address < 120; address++) {
       auto err = writev(address, nullptr, 0);
       if (err == ERROR_OK) {
diff --git a/esphome/components/i2c/i2c_bus_arduino.cpp b/esphome/components/i2c/i2c_bus_arduino.cpp
index a85df0a4cd..1e84f122de 100644
--- a/esphome/components/i2c/i2c_bus_arduino.cpp
+++ b/esphome/components/i2c/i2c_bus_arduino.cpp
@@ -42,7 +42,7 @@ void ArduinoI2CBus::setup() {
   this->initialized_ = true;
   if (this->scan_) {
     ESP_LOGV(TAG, "Scanning bus for active devices");
-    this->i2c_scan_();
+    this->i2c_scan();
   }
 }
 
diff --git a/esphome/components/i2c/i2c_bus_esp_idf.cpp b/esphome/components/i2c/i2c_bus_esp_idf.cpp
index c57d537bdb..141e6a670d 100644
--- a/esphome/components/i2c/i2c_bus_esp_idf.cpp
+++ b/esphome/components/i2c/i2c_bus_esp_idf.cpp
@@ -1,13 +1,13 @@
 #ifdef USE_ESP_IDF
 
 #include "i2c_bus_esp_idf.h"
+#include <driver/gpio.h>
 #include <cinttypes>
 #include <cstring>
 #include "esphome/core/application.h"
 #include "esphome/core/hal.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
-#include <driver/gpio.h>
 
 #if ESP_IDF_VERSION < ESP_IDF_VERSION_VAL(5, 3, 0)
 #define SOC_HP_I2C_NUM SOC_I2C_NUM
@@ -78,7 +78,7 @@ void IDFI2CBus::setup() {
 
   if (this->scan_) {
     ESP_LOGV(TAG, "Scanning for devices");
-    this->i2c_scan_();
+    this->i2c_scan();
   }
 #else
 #if SOC_HP_I2C_NUM > 1
@@ -125,7 +125,7 @@ void IDFI2CBus::setup() {
   initialized_ = true;
   if (this->scan_) {
     ESP_LOGV(TAG, "Scanning bus for active devices");
-    this->i2c_scan_();
+    this->i2c_scan();
   }
 #endif
 }
@@ -167,6 +167,17 @@ void IDFI2CBus::dump_config() {
   }
 }
 
+#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 4, 2)
+void IDFI2CBus::i2c_scan() {
+  for (uint8_t address = 8; address < 120; address++) {
+    auto err = i2c_master_probe(this->bus_, address, 20);
+    if (err == ESP_OK) {
+      this->scan_results_.emplace_back(address, true);
+    }
+  }
+}
+#endif
+
 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
diff --git a/esphome/components/i2c/i2c_bus_esp_idf.h b/esphome/components/i2c/i2c_bus_esp_idf.h
index 8d325de6bc..4e8f86fd0c 100644
--- a/esphome/components/i2c/i2c_bus_esp_idf.h
+++ b/esphome/components/i2c/i2c_bus_esp_idf.h
@@ -2,9 +2,9 @@
 
 #ifdef USE_ESP_IDF
 
+#include "esp_idf_version.h"
 #include "esphome/core/component.h"
 #include "i2c_bus.h"
-#include "esp_idf_version.h"
 #if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 4, 2)
 #include <driver/i2c_master.h>
 #else
@@ -46,6 +46,7 @@ class IDFI2CBus : public InternalI2CBus, public Component {
 #if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 4, 2)
   i2c_master_dev_handle_t dev_;
   i2c_master_bus_handle_t bus_;
+  void i2c_scan() override;
 #endif
   i2c_port_t port_;
   uint8_t sda_pin_;