From 2f1a345905064015e7e0376665a980c1d0b7f1b0 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Mon, 26 Jan 2026 17:20:21 -1000
Subject: [PATCH] [mhz19] Refactor detection range logging to use LogString
 (#13541)

---
 esphome/components/mhz19/mhz19.cpp | 62 +++++++++++++-----------------
 esphome/components/mhz19/mhz19.h   |  8 ++--
 2 files changed, 30 insertions(+), 40 deletions(-)

diff --git a/esphome/components/mhz19/mhz19.cpp b/esphome/components/mhz19/mhz19.cpp
index 259d597b44..b6b4031e16 100644
--- a/esphome/components/mhz19/mhz19.cpp
+++ b/esphome/components/mhz19/mhz19.cpp
@@ -3,8 +3,7 @@
 
 #include <cinttypes>
 
-namespace esphome {
-namespace mhz19 {
+namespace esphome::mhz19 {
 
 static const char *const TAG = "mhz19";
 static const uint8_t MHZ19_REQUEST_LENGTH = 8;
@@ -17,6 +16,19 @@ static const uint8_t MHZ19_COMMAND_DETECTION_RANGE_0_2000PPM[] = {0xFF, 0x01, 0x
 static const uint8_t MHZ19_COMMAND_DETECTION_RANGE_0_5000PPM[] = {0xFF, 0x01, 0x99, 0x00, 0x00, 0x00, 0x13, 0x88};
 static const uint8_t MHZ19_COMMAND_DETECTION_RANGE_0_10000PPM[] = {0xFF, 0x01, 0x99, 0x00, 0x00, 0x00, 0x27, 0x10};
 
+static const LogString *detection_range_to_log_string(MHZ19DetectionRange range) {
+  switch (range) {
+    case MHZ19_DETECTION_RANGE_0_2000PPM:
+      return LOG_STR("0-2000 ppm");
+    case MHZ19_DETECTION_RANGE_0_5000PPM:
+      return LOG_STR("0-5000 ppm");
+    case MHZ19_DETECTION_RANGE_0_10000PPM:
+      return LOG_STR("0-10000 ppm");
+    default:
+      return LOG_STR("default");
+  }
+}
+
 uint8_t mhz19_checksum(const uint8_t *command) {
   uint8_t sum = 0;
   for (uint8_t i = 1; i < MHZ19_REQUEST_LENGTH; i++) {
@@ -91,24 +103,24 @@ void MHZ19Component::abc_disable() {
   this->mhz19_write_command_(MHZ19_COMMAND_ABC_DISABLE, nullptr);
 }
 
-void MHZ19Component::range_set(MHZ19DetectionRange detection_ppm) {
-  switch (detection_ppm) {
-    case MHZ19_DETECTION_RANGE_DEFAULT:
-      ESP_LOGV(TAG, "Using previously set detection range (no change)");
-      break;
+void MHZ19Component::range_set(MHZ19DetectionRange detection_range) {
+  const uint8_t *command;
+  switch (detection_range) {
     case MHZ19_DETECTION_RANGE_0_2000PPM:
-      ESP_LOGD(TAG, "Setting detection range to 0 to 2000ppm");
-      this->mhz19_write_command_(MHZ19_COMMAND_DETECTION_RANGE_0_2000PPM, nullptr);
+      command = MHZ19_COMMAND_DETECTION_RANGE_0_2000PPM;
       break;
     case MHZ19_DETECTION_RANGE_0_5000PPM:
-      ESP_LOGD(TAG, "Setting detection range to 0 to 5000ppm");
-      this->mhz19_write_command_(MHZ19_COMMAND_DETECTION_RANGE_0_5000PPM, nullptr);
+      command = MHZ19_COMMAND_DETECTION_RANGE_0_5000PPM;
       break;
     case MHZ19_DETECTION_RANGE_0_10000PPM:
-      ESP_LOGD(TAG, "Setting detection range to 0 to 10000ppm");
-      this->mhz19_write_command_(MHZ19_COMMAND_DETECTION_RANGE_0_10000PPM, nullptr);
+      command = MHZ19_COMMAND_DETECTION_RANGE_0_10000PPM;
       break;
+    default:
+      ESP_LOGV(TAG, "Using previously set detection range (no change)");
+      return;
   }
+  ESP_LOGD(TAG, "Setting detection range to %s", LOG_STR_ARG(detection_range_to_log_string(detection_range)));
+  this->mhz19_write_command_(command, nullptr);
 }
 
 bool MHZ19Component::mhz19_write_command_(const uint8_t *command, uint8_t *response) {
@@ -140,27 +152,7 @@ void MHZ19Component::dump_config() {
   }
 
   ESP_LOGCONFIG(TAG, "  Warmup time: %" PRIu32 " s", this->warmup_seconds_);
-
-  const char *range_str;
-  switch (this->detection_range_) {
-    case MHZ19_DETECTION_RANGE_DEFAULT:
-      range_str = "default";
-      break;
-    case MHZ19_DETECTION_RANGE_0_2000PPM:
-      range_str = "0 to 2000ppm";
-      break;
-    case MHZ19_DETECTION_RANGE_0_5000PPM:
-      range_str = "0 to 5000ppm";
-      break;
-    case MHZ19_DETECTION_RANGE_0_10000PPM:
-      range_str = "0 to 10000ppm";
-      break;
-    default:
-      range_str = "default";
-      break;
-  }
-  ESP_LOGCONFIG(TAG, "  Detection range: %s", range_str);
+  ESP_LOGCONFIG(TAG, "  Detection range: %s", LOG_STR_ARG(detection_range_to_log_string(this->detection_range_)));
 }
 
-}  // namespace mhz19
-}  // namespace esphome
+}  // namespace esphome::mhz19
diff --git a/esphome/components/mhz19/mhz19.h b/esphome/components/mhz19/mhz19.h
index 5898bab649..a27f1c31eb 100644
--- a/esphome/components/mhz19/mhz19.h
+++ b/esphome/components/mhz19/mhz19.h
@@ -5,8 +5,7 @@
 #include "esphome/components/sensor/sensor.h"
 #include "esphome/components/uart/uart.h"
 
-namespace esphome {
-namespace mhz19 {
+namespace esphome::mhz19 {
 
 enum MHZ19ABCLogic {
   MHZ19_ABC_NONE = 0,
@@ -32,7 +31,7 @@ class MHZ19Component : public PollingComponent, public uart::UARTDevice {
   void calibrate_zero();
   void abc_enable();
   void abc_disable();
-  void range_set(MHZ19DetectionRange detection_ppm);
+  void range_set(MHZ19DetectionRange detection_range);
 
   void set_temperature_sensor(sensor::Sensor *temperature_sensor) { temperature_sensor_ = temperature_sensor; }
   void set_co2_sensor(sensor::Sensor *co2_sensor) { co2_sensor_ = co2_sensor; }
@@ -74,5 +73,4 @@ template<typename... Ts> class MHZ19DetectionRangeSetAction : public Action<Ts..
   void play(const Ts &...x) override { this->parent_->range_set(this->detection_range_.value(x...)); }
 };
 
-}  // namespace mhz19
-}  // namespace esphome
+}  // namespace esphome::mhz19