[epaper_spi] Keep the state name table in flash

Co-authored-by: J. Nick Koston <nick@koston.org>

esphome/components/display/display.cpp

@@ -5,6 +5,7 @@
 #include "display_color_utils.h"
 #include "esphome/core/application.h"
 #include "esphome/core/hal.h"
+#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
 namespace esphome::display {
@@ -52,40 +53,65 @@ void Display::line_at_angle(int x, int y, int angle, int start_radius, int stop_
   this->line(x1, y1, x2, y2, color);
 }
 
-void Display::draw_pixels_at(int x_start, int y_start, int w, int h, const uint8_t *ptr, ColorOrder order,
-                             ColorBitness bitness, bool big_endian, int x_offset, int y_offset, int x_pad) {
-  size_t line_stride = x_offset + w + x_pad;  // length of each source line in pixels
-  uint32_t color_value;
+// flatten keeps to_color() inlined in the pixel loop; in PSRAM builds GCC at
+// -Os stops inlining it once there are two call sites, which costs a call and
+// spills per pixel. Without PSRAM there is one call site and it changes
+// nothing, and draw_pixel_at() stays a virtual call either way.
+template<ColorBitness BITNESS>
+static void __attribute__((flatten))
+draw_packed_pixels(Display *display, int x_start, int y_start, int w, int h, const uint8_t *ptr, ColorOrder order,
+                   bool big_endian, int x_offset, int y_offset, int x_pad) {
+  const size_t line_stride = x_offset + w + x_pad;  // length of each source line in pixels
+  // BITNESS is a constant here, so to_color()'s three per pixel divisions
+  // become a multiply and shift and its bitness switch folds.
+  const auto draw_source_pixel = [&](int x, int y, size_t source_idx) ESPHOME_ALWAYS_INLINE {
+    display->draw_pixel_at(
+        x + x_start, y + y_start,
+        ColorUtil::to_color(ColorUtil::read_packed<BITNESS>(ptr, source_idx, big_endian), order, BITNESS));
+  };
+  // The source and frame buffers are row-major, so walking rows keeps the read
+  // and the write sequential. When the display swaps the axes before writing,
+  // walking columns keeps the write sequential instead; with the frame buffer
+  // in PSRAM a strided write costs more than a strided read.
+#ifdef USE_PSRAM
+  if (display->pixel_axes_swapped()) {
+    size_t column_idx = y_offset * line_stride + x_offset;
+    for (int x = 0; x != w; x++, column_idx++) {
+      size_t source_idx = column_idx;
+      for (int y = 0; y != h; y++, source_idx += line_stride) {
+        draw_source_pixel(x, y, source_idx);
+      }
+    }
+    return;
+  }
+#endif
+  // Row walk: builds without PSRAM, and PSRAM builds whose axes are not swapped.
   for (int y = 0; y != h; y++) {
     size_t source_idx = (y_offset + y) * line_stride + x_offset;
-    size_t source_idx_mod;
     for (int x = 0; x != w; x++, source_idx++) {
-      switch (bitness) {
-        default:
-          color_value = ptr[source_idx];
-          break;
-        case COLOR_BITNESS_565:
-          source_idx_mod = source_idx * 2;
-          if (big_endian) {
-            color_value = (ptr[source_idx_mod] << 8) + ptr[source_idx_mod + 1];
-          } else {
-            color_value = ptr[source_idx_mod] + (ptr[source_idx_mod + 1] << 8);
-          }
-          break;
-        case COLOR_BITNESS_888:
-          source_idx_mod = source_idx * 3;
-          if (big_endian) {
-            color_value = (ptr[source_idx_mod + 0] << 16) + (ptr[source_idx_mod + 1] << 8) + ptr[source_idx_mod + 2];
-          } else {
-            color_value = ptr[source_idx_mod + 0] + (ptr[source_idx_mod + 1] << 8) + (ptr[source_idx_mod + 2] << 16);
-          }
-          break;
-      }
-      this->draw_pixel_at(x + x_start, y + y_start, ColorUtil::to_color(color_value, order, bitness));
+      draw_source_pixel(x, y, source_idx);
     }
   }
 }
 
+void Display::draw_pixels_at(int x_start, int y_start, int w, int h, const uint8_t *ptr, ColorOrder order,
+                             ColorBitness bitness, bool big_endian, int x_offset, int y_offset, int x_pad) {
+  switch (bitness) {
+    case COLOR_BITNESS_565:
+      draw_packed_pixels<COLOR_BITNESS_565>(this, x_start, y_start, w, h, ptr, order, big_endian, x_offset, y_offset,
+                                            x_pad);
+      break;
+    case COLOR_BITNESS_888:
+      draw_packed_pixels<COLOR_BITNESS_888>(this, x_start, y_start, w, h, ptr, order, big_endian, x_offset, y_offset,
+                                            x_pad);
+      break;
+    default:
+      draw_packed_pixels<COLOR_BITNESS_332>(this, x_start, y_start, w, h, ptr, order, big_endian, x_offset, y_offset,
+                                            x_pad);
+      break;
+  }
+}
+
 void HOT Display::horizontal_line(int x, int y, int width, Color color) {
   // Future: Could be made more efficient by manipulating buffer directly in certain rotations.
   for (int i = x; i < x + width; i++)

esphome/components/display/display.h

@@ -139,6 +139,11 @@ enum DisplayRotation {
   DISPLAY_ROTATION_270_DEGREES = 270,
 };
 
+/// Whether a rotation swaps the x and y axes.
+constexpr bool rotation_swaps_axes(DisplayRotation rotation) {
+  return rotation == DISPLAY_ROTATION_90_DEGREES || rotation == DISPLAY_ROTATION_270_DEGREES;
+}
+
 const int EDGES_TRIGON = 3;
 const int EDGES_TRIANGLE = 3;
 const int EDGES_TETRAGON = 4;
@@ -717,6 +722,12 @@ class Display : public PollingComponent {
 
   virtual DisplayRotation get_rotation() const { return this->rotation_; }
 
+  /// True when draw_pixel_at() swaps x and y before writing, so pixels that are
+  /// neighbours along x land a row apart in the frame buffer. Not the same as
+  /// get_width()/get_height() swapping: a display that rotates in hardware
+  /// reports swapped dimensions but writes unswapped pixels.
+  virtual bool pixel_axes_swapped() const { return rotation_swaps_axes(this->rotation_); }
+
   /** Get the type of display that the buffer corresponds to. In case of dynamically configurable displays,
    * returns the type the display is currently configured to.
    */

esphome/components/display/display_color_utils.h

@@ -2,6 +2,7 @@
 #include <array>
 #include <cstdint>
 #include "esphome/core/color.h"
+#include "esphome/core/helpers.h"
 
 namespace esphome::display {
 enum ColorOrder : uint8_t { COLOR_ORDER_RGB = 0, COLOR_ORDER_BGR = 1, COLOR_ORDER_GRB = 2 };
@@ -10,6 +11,27 @@ inline static uint8_t esp_scale(uint8_t i, uint8_t scale, uint8_t max_value = 25
 
 class ColorUtil {
  public:
+  /// Reads one packed pixel of the given bitness from a source buffer into the
+  /// value to_color() takes. BITNESS is a template argument so the byte layout
+  /// folds; pass it on to to_color() as a constant too, and its channel scaling
+  /// divides by a constant, which the compiler turns into a multiply and shift.
+  template<ColorBitness BITNESS>
+  static ESPHOME_ALWAYS_INLINE uint32_t read_packed(const uint8_t *ptr, size_t index, bool big_endian) {
+    if constexpr (BITNESS == COLOR_BITNESS_565) {
+      const size_t idx = index * 2;
+      if (big_endian)
+        return (ptr[idx] << 8) + ptr[idx + 1];
+      return ptr[idx] + (ptr[idx + 1] << 8);
+    } else if constexpr (BITNESS == COLOR_BITNESS_888) {
+      const size_t idx = index * 3;
+      if (big_endian)
+        return (ptr[idx + 0] << 16) + (ptr[idx + 1] << 8) + ptr[idx + 2];
+      return ptr[idx + 0] + (ptr[idx + 1] << 8) + (ptr[idx + 2] << 16);
+    } else {
+      return ptr[index];
+    }
+  }
+
   static Color to_color(uint32_t colorcode, ColorOrder color_order,
                         ColorBitness color_bitness = ColorBitness::COLOR_BITNESS_888, bool right_bit_aligned = true) {
     uint8_t first_color, second_color, third_color;

esphome/components/epaper_spi/epaper_spi.cpp

@@ -3,21 +3,18 @@
 #include "esphome/core/application.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
+#include "esphome/core/progmem.h"
 
 namespace esphome::epaper_spi {
 
 ESPHOME_LOG_TAG(TAG, "epaper_spi");
 static constexpr size_t EPAPER_MAX_CMD_LOG_BYTES = 128;
 
-static constexpr const char *const EPAPER_STATE_STRINGS[] = {
-    "IDLE",          "UPDATE",   "RESET",          "RESET_END", "SHOULD_WAIT", "INITIALISE",
-    "TRANSFER_DATA", "POWER_ON", "REFRESH_SCREEN", "POWER_OFF", "DEEP_SLEEP",
-};
+PROGMEM_STRING_TABLE(EPaperStateStrings, "IDLE", "UPDATE", "RESET", "RESET_END", "SHOULD_WAIT", "INITIALISE",
+                     "TRANSFER_DATA", "POWER_ON", "REFRESH_SCREEN", "POWER_OFF", "DEEP_SLEEP", "Unknown");
 
-const char *EPaperBase::epaper_state_to_string_() {
-  if (auto idx = static_cast<unsigned>(this->state_); idx < std::size(EPAPER_STATE_STRINGS))
-    return EPAPER_STATE_STRINGS[idx];
-  return "Unknown";
+const LogString *EPaperBase::epaper_state_to_string_() {
+  return EPaperStateStrings::get_log_str(static_cast<uint8_t>(this->state_), EPaperStateStrings::LAST_INDEX);
 }
 
 void EPaperBase::setup() {
@@ -120,7 +117,7 @@ void EPaperBase::update_effective_transform_() {
 
 void EPaperBase::update() {
   if (this->state_ != EPaperState::IDLE) {
-    ESP_LOGE(TAG, "Display already in state %s", epaper_state_to_string_());
+    ESP_LOGE(TAG, "Display already in state %s", LOG_STR_ARG(epaper_state_to_string_()));
     return;
   }
   this->set_state_(EPaperState::UPDATE);
@@ -160,7 +157,7 @@ void EPaperBase::loop() {
       }
 #if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERBOSE
       if (now - this->waiting_for_idle_last_print_ >= 1000) {
-        ESP_LOGV(TAG, "Waiting for idle in state %s", this->epaper_state_to_string_());
+        ESP_LOGV(TAG, "Waiting for idle in state %s", LOG_STR_ARG(this->epaper_state_to_string_()));
         this->waiting_for_idle_last_print_ = millis();
       }
 #endif
@@ -173,7 +170,7 @@ void EPaperBase::loop() {
 // The busy pin never cleared: give up on this update so later ones are not refused, and make the next one full
 void EPaperBase::abandon_update_() {
   ESP_LOGE(TAG, "Display stayed busy for %u s in state %s; check the busy pin", (unsigned) this->busy_timeout_seconds_,
-           this->epaper_state_to_string_());
+           LOG_STR_ARG(this->epaper_state_to_string_()));
   this->status_set_warning(LOG_STR("Busy pin timeout"));
   if (this->state_ == EPaperState::TRANSFER_DATA)
     this->abort_transfer();
@@ -193,10 +190,10 @@ void EPaperBase::abandon_update_() {
  * Should a subclassed class need to override this, the method will need to be made virtual.
  */
 void EPaperBase::process_state_() {
-  ESP_LOGV(TAG, "Process state entered in state %s", epaper_state_to_string_());
+  ESP_LOGV(TAG, "Process state entered in state %s", LOG_STR_ARG(epaper_state_to_string_()));
   switch (this->state_) {
     default:
-      ESP_LOGE(TAG, "Display is in unhandled state %s", epaper_state_to_string_());
+      ESP_LOGE(TAG, "Display is in unhandled state %s", LOG_STR_ARG(epaper_state_to_string_()));
       this->set_state_(EPaperState::IDLE);
       break;
     case EPaperState::IDLE:
@@ -266,7 +263,7 @@ void EPaperBase::process_state_() {
 }
 
 void EPaperBase::set_state_(EPaperState state, uint16_t delay) {
-  ESP_LOGV(TAG, "Exit state %s", this->epaper_state_to_string_());
+  ESP_LOGV(TAG, "Exit state %s", LOG_STR_ARG(this->epaper_state_to_string_()));
   this->state_ = state;
   this->wait_for_idle_(state > EPaperState::SHOULD_WAIT);
   // allow subclasses to nominate delays
@@ -274,7 +271,7 @@ void EPaperBase::set_state_(EPaperState state, uint16_t delay) {
     delay = this->next_delay_;
   this->next_delay_ = 0;
   this->delay_until_ = millis() + delay;
-  ESP_LOGV(TAG, "Enter state %s, delay %u, wait_for_idle=%s", this->epaper_state_to_string_(), delay,
+  ESP_LOGV(TAG, "Enter state %s, delay %u, wait_for_idle=%s", LOG_STR_ARG(this->epaper_state_to_string_()), delay,
            TRUEFALSE(this->waiting_for_idle_));
   if (state == EPaperState::IDLE) {
     this->disable_loop();

esphome/components/epaper_spi/epaper_spi.h

@@ -106,6 +106,7 @@ class EPaperBase : public Display,
 
   int get_width() override { return this->effective_transform_ & SWAP_XY ? this->height_ : this->width_; }
   int get_height() override { return this->effective_transform_ & SWAP_XY ? this->width_ : this->height_; }
+  bool pixel_axes_swapped() const override { return this->effective_transform_ & SWAP_XY; }
   void draw_pixel_at(int x, int y, Color color) override;
   void draw_pixels_at(int x_start, int y_start, int w, int h, const uint8_t *ptr, ColorOrder order,
                       ColorBitness bitness, bool big_endian, int x_offset, int y_offset, int x_pad) override;
@@ -120,7 +121,7 @@ class EPaperBase : public Display,
   bool is_using_partial_update_() const { return this->full_update_every_ > 1; }
   void process_state_();
 
-  const char *epaper_state_to_string_();
+  const LogString *epaper_state_to_string_();
   bool is_idle_() const;
   void setup_pins_() const;
   virtual bool reset();

esphome/components/haier/hon_climate.cpp

@@ -3,6 +3,7 @@
 #include "esphome/components/climate/climate.h"
 #include "esphome/components/uart/uart.h"
 #include "esphome/core/helpers.h"
+#include "esphome/core/progmem.h"
 #include "hon_climate.h"
 #include "hon_packet.h"
 
@@ -20,6 +21,27 @@ constexpr size_t ALARM_STATUS_REQUEST_INTERVAL_MS = 600000;
 const uint8_t ONE_BUF[] = {0x00, 0x01};
 const uint8_t ZERO_BUF[] = {0x00, 0x00};
 
+// Alarm texts indexed by alarm code; the last entry is the fallback for unknown codes
+PROGMEM_STRING_TABLE(
+    HonAlarmMessages, "Outdoor module failure", "Outdoor defrost sensor failure",
+    "Outdoor compressor exhaust sensor failure", "Outdoor EEPROM abnormality", "Indoor coil sensor failure",
+    "Indoor-outdoor communication failure", "Power supply overvoltage protection",
+    "Communication failure between panel and indoor unit", "Outdoor compressor overheat protection",
+    "Outdoor environmental sensor abnormality", "Full water protection", "Indoor EEPROM failure",
+    "Outdoor out air sensor failure", "CBD and module communication failure", "Indoor DC fan failure",
+    "Outdoor DC fan failure", "Door switch failure", "Dust filter needs cleaning reminder", "Water shortage protection",
+    "Humidity sensor failure", "Indoor temperature sensor failure", "Manipulator limit failure",
+    "Indoor PM2.5 sensor failure", "Outdoor PM2.5 sensor failure", "Indoor heating overload/high load alarm",
+    "Outdoor AC current protection", "Outdoor compressor operation abnormality", "Outdoor DC current protection",
+    "Outdoor no-load failure", "CT current abnormality", "Indoor cooling freeze protection",
+    "High and low pressure protection", "Compressor out air temperature is too high",
+    "Outdoor evaporator sensor failure", "Outdoor cooling overload", "Water pump drainage failure",
+    "Three-phase power supply failure", "Four-way valve failure", "External alarm/scraper flow switch failure",
+    "Temperature cutoff protection alarm", "Different mode operation failure", "Electronic expansion valve failure",
+    "Dual heat source sensor Tw failure", "Communication failure with the wired controller",
+    "Indoor unit address duplication failure", "50Hz zero crossing failure", "Outdoor unit failure",
+    "Formaldehyde sensor failure", "VOC sensor failure", "CO2 sensor failure", "Firewall failure", "Unknown");
+
 HonClimate::HonClimate()
     : cleaning_status_(CleaningState::NO_CLEANING), got_valid_outdoor_temp_(false), active_alarms_{0x00, 0x00, 0x00,
                                                                                                    0x00, 0x00, 0x00,
@@ -687,9 +709,17 @@ void HonClimate::process_alarm_message_(const uint8_t *packet, uint8_t size, boo
             if ((packet[2 + i] & alarm_bit) != (this->active_alarms_[i] & alarm_bit)) {
               bool alarm_status = (packet[2 + i] & alarm_bit) != 0;
               int log_level = alarm_status ? ESPHOME_LOG_LEVEL_WARN : ESPHOME_LOG_LEVEL_INFO;
-              const char *alarm_message = alarm_code < esphome::haier::hon_protocol::HON_ALARM_COUNT
-                                              ? esphome::haier::hon_protocol::HON_ALARM_MESSAGES[alarm_code].c_str()
-                                              : "Unknown";
+#ifdef USE_ESP8266
+              // Static so a delayed on_alarm automation can still read it, but only until the next
+              // alarm change, including a later one in this packet; `code` stays correct
+              static char alarm_message[HonAlarmMessages::MAX_LENGTH + 1];
+              ESPHOME_strncpy_P(alarm_message,
+                                reinterpret_cast<const char *>(
+                                    HonAlarmMessages::get_progmem_str(alarm_code, HonAlarmMessages::LAST_INDEX)),
+                                sizeof(alarm_message));
+#else
+              const char *alarm_message = HonAlarmMessages::get_progmem_str(alarm_code, HonAlarmMessages::LAST_INDEX);
+#endif
               esp_log_printf_(log_level, TAG, __LINE__, "Alarm %s (%d): %s", alarm_status ? "activated" : "deactivated",
                               alarm_code, alarm_message);
               if (alarm_status) {

esphome/components/haier/hon_packet.h

@@ -197,60 +197,4 @@ enum class SubcommandsControl : uint16_t {
                                   // content: all values like in status packet)
 };
 
-const std::string HON_ALARM_MESSAGES[] = {
-    "Outdoor module failure",
-    "Outdoor defrost sensor failure",
-    "Outdoor compressor exhaust sensor failure",
-    "Outdoor EEPROM abnormality",
-    "Indoor coil sensor failure",
-    "Indoor-outdoor communication failure",
-    "Power supply overvoltage protection",
-    "Communication failure between panel and indoor unit",
-    "Outdoor compressor overheat protection",
-    "Outdoor environmental sensor abnormality",
-    "Full water protection",
-    "Indoor EEPROM failure",
-    "Outdoor out air sensor failure",
-    "CBD and module communication failure",
-    "Indoor DC fan failure",
-    "Outdoor DC fan failure",
-    "Door switch failure",
-    "Dust filter needs cleaning reminder",
-    "Water shortage protection",
-    "Humidity sensor failure",
-    "Indoor temperature sensor failure",
-    "Manipulator limit failure",
-    "Indoor PM2.5 sensor failure",
-    "Outdoor PM2.5 sensor failure",
-    "Indoor heating overload/high load alarm",
-    "Outdoor AC current protection",
-    "Outdoor compressor operation abnormality",
-    "Outdoor DC current protection",
-    "Outdoor no-load failure",
-    "CT current abnormality",
-    "Indoor cooling freeze protection",
-    "High and low pressure protection",
-    "Compressor out air temperature is too high",
-    "Outdoor evaporator sensor failure",
-    "Outdoor cooling overload",
-    "Water pump drainage failure",
-    "Three-phase power supply failure",
-    "Four-way valve failure",
-    "External alarm/scraper flow switch failure",
-    "Temperature cutoff protection alarm",
-    "Different mode operation failure",
-    "Electronic expansion valve failure",
-    "Dual heat source sensor Tw failure",
-    "Communication failure with the wired controller",
-    "Indoor unit address duplication failure",
-    "50Hz zero crossing failure",
-    "Outdoor unit failure",
-    "Formaldehyde sensor failure",
-    "VOC sensor failure",
-    "CO2 sensor failure",
-    "Firewall failure",
-};
-
-constexpr size_t HON_ALARM_COUNT = sizeof(HON_ALARM_MESSAGES) / sizeof(HON_ALARM_MESSAGES[0]);
-
 }  // namespace esphome::haier::hon_protocol

esphome/components/it8951/it8951.h

@@ -204,6 +204,7 @@ class IT8951Display : public Display,
                       ColorBitness bitness, bool big_endian, int x_offset, int y_offset, int x_pad) override;
   int get_width() override { return (this->effective_transform_ & TRANSFORM_SWAP_XY) ? this->height_ : this->width_; }
   int get_height() override { return (this->effective_transform_ & TRANSFORM_SWAP_XY) ? this->width_ : this->height_; }
+  bool pixel_axes_swapped() const override { return this->effective_transform_ & TRANSFORM_SWAP_XY; }
 
  protected:
   int get_height_internal() override { return this->height_; }

esphome/components/mipi_spi/mipi_spi.h

@@ -130,19 +130,8 @@ class MipiSpi : public display::Display,
   }
   display::DisplayType get_display_type() override { return display::DisplayType::DISPLAY_TYPE_COLOR; }
 
-  int get_width() override {
-    if (this->rotation_ == display::DISPLAY_ROTATION_90_DEGREES ||
-        this->rotation_ == display::DISPLAY_ROTATION_270_DEGREES)
-      return HEIGHT;
-    return WIDTH;
-  }
-
-  int get_height() override {
-    if (this->rotation_ == display::DISPLAY_ROTATION_90_DEGREES ||
-        this->rotation_ == display::DISPLAY_ROTATION_270_DEGREES)
-      return WIDTH;
-    return HEIGHT;
-  }
+  int get_width() override { return display::rotation_swaps_axes(this->rotation_) ? HEIGHT : WIDTH; }
+  int get_height() override { return display::rotation_swaps_axes(this->rotation_) ? WIDTH : HEIGHT; }
 
   void set_init_sequence(const uint8_t *sequence, size_t len) {
     this->init_sequence_ = sequence;
@@ -621,6 +610,9 @@ class MipiSpiBuffer
 #endif
   }
 
+  // With hardware rotation the buffer is written in drawn coordinates.
+  bool pixel_axes_swapped() const override { return !HAS_HARDWARE_ROTATION && display::Display::pixel_axes_swapped(); }
+
   // Draw a pixel at the given coordinates.
   void draw_pixel_at(int x, int y, Color color) override {
     if (this->is_point_clipped(x, y))

esphome/components/tmp102/text_sensor.py

@@ -0,0 +1,31 @@
+"""TMP102 threshold status entity."""
+
+import esphome.codegen as cg
+from esphome.components import text_sensor
+import esphome.config_validation as cv
+from esphome.const import ENTITY_CATEGORY_DIAGNOSTIC
+from esphome.types import ConfigType
+
+from . import CONF_TMP102_ID, TMP102Component, validate_unique_child
+
+CONFIG_SCHEMA = text_sensor.text_sensor_schema(
+    entity_category=ENTITY_CATEGORY_DIAGNOSTIC
+).extend(
+    {
+        cv.GenerateID(CONF_TMP102_ID): cv.use_id(TMP102Component),
+    }
+)
+
+
+def _final_validate(config: ConfigType) -> ConfigType:
+    return validate_unique_child(config, "text_sensor")
+
+
+FINAL_VALIDATE_SCHEMA = _final_validate
+
+
+async def to_code(config: ConfigType) -> None:
+    cg.add_define("USE_TMP102_TEXT_SENSOR")
+    parent = await cg.get_variable(config[CONF_TMP102_ID])
+    var = await text_sensor.new_text_sensor(config)
+    cg.add(parent.set_threshold_status_text_sensor(var))

esphome/components/tmp102/tmp102.cpp

@@ -1,8 +1,14 @@
 #include "tmp102.h"
 #include "esphome/core/log.h"
 #include "esphome/core/hal.h"
+#ifdef USE_TMP102_TEXT_SENSOR
+#include "esphome/core/progmem.h"
+#endif
 
 #include <cmath>
+#ifdef USE_TMP102_TEXT_SENSOR
+#include <cstdio>
+#endif
 
 namespace esphome::tmp102 {
 
@@ -12,6 +18,30 @@ static constexpr uint32_t READ_TEMP_TIMEOUT_ID = 0;
 
 static constexpr uint8_t TMP102_REGISTER_TEMPERATURE = 0x00;
 static constexpr float TMP102_CONVERSION_FACTOR = 0.0625f;
+
+enum TMP102ThresholdStatus : uint8_t {
+  TMP102_THRESHOLD_STATUS_NOT_CONFIGURED,
+  TMP102_THRESHOLD_STATUS_SETUP_FAILED,
+  TMP102_THRESHOLD_STATUS_OK,
+  TMP102_THRESHOLD_STATUS_RESTORE_RESET,
+  TMP102_THRESHOLD_STATUS_RESTORE_RESET_SAVE_FAILED,
+  TMP102_THRESHOLD_STATUS_PREFERENCE_SAVE_FAILED,
+  TMP102_THRESHOLD_STATUS_RECOVERY_FAILED,
+  TMP102_THRESHOLD_STATUS_RECOVERED,
+  TMP102_THRESHOLD_STATUS_WRITE_HIGH_FAILED,
+  TMP102_THRESHOLD_STATUS_WRITE_LOW_FAILED,
+  TMP102_THRESHOLD_STATUS_SENSOR_SETUP_FAILED,
+  TMP102_THRESHOLD_STATUS_COUNT,
+};
+
+#ifdef USE_TMP102_TEXT_SENSOR
+PROGMEM_STRING_TABLE(ThresholdStatusStrings, "Not configured", "Setup failed", "OK", "Restored thresholds reset",
+                     "Restore reset; save failed", "Preference save failed", "Configuration recovery failed",
+                     "Configuration restored", "Write failed: high threshold", "Write failed: low threshold",
+                     "Rejected: sensor setup failed");
+static_assert(ThresholdStatusStrings::COUNT == TMP102_THRESHOLD_STATUS_COUNT);
+#endif
+
 #if defined(USE_TMP102_CONFIGURE) || defined(USE_TMP102_BINARY_SENSOR)
 static constexpr uint8_t TMP102_REGISTER_CONFIGURATION = 0x01;
 static constexpr uint16_t TMP102_ALERT_BIT = 0x0020;
@@ -42,15 +72,30 @@ static uint16_t encode_temperature(float temperature, bool extended) {
   return static_cast<uint16_t>(static_cast<uint32_t>(static_cast<uint16_t>(steps)) << (extended ? 3 : 4));
 }
 #endif
+#endif
 
+#if defined(USE_TMP102_CONFIGURE) || defined(USE_TMP102_TEXT_SENSOR)
 void TMP102Component::setup() {
-  if (!this->configure_)
+#ifdef USE_TMP102_CONFIGURE
+  if (this->configure_) {
+    this->setup_configured_();
     return;
+  }
+#endif
+  this->publish_threshold_status_(TMP102_THRESHOLD_STATUS_NOT_CONFIGURED);
+}
+#endif
+
+#ifdef USE_TMP102_CONFIGURE
+void TMP102Component::setup_configured_() {
+  bool corrected = false;
 #ifdef USE_TMP102_NUMBER
   float restored[2]{};
-  this->prepare_number_limits_(restored);
+  bool restore_corrected[2]{};
+  corrected = this->prepare_number_limits_(restored, restore_corrected);
 #endif
   if (!this->write_configuration_()) {
+    this->publish_threshold_status_(TMP102_THRESHOLD_STATUS_SETUP_FAILED);
     this->mark_failed();
     return;
   }
@@ -61,14 +106,17 @@ void TMP102Component::setup() {
     if (control == nullptr)
       continue;
     const float value = this->get_limit_temperature_(static_cast<TMP102LimitType>(limit));
-    if (value != restored[limit])
+    if (restore_corrected[limit] || value != restored[limit])
       saved &= control->save_value_(value);
     control->publish_state(value);
   }
   if (!saved) {
     ESP_LOGW(TAG, "Failed to save threshold preferences");
+    this->publish_threshold_status_(TMP102_THRESHOLD_STATUS_RESTORE_RESET_SAVE_FAILED);
+    return;
   }
 #endif
+  this->publish_threshold_status_(corrected ? TMP102_THRESHOLD_STATUS_RESTORE_RESET : TMP102_THRESHOLD_STATUS_OK);
 }
 #endif
 
@@ -83,6 +131,9 @@ void TMP102Component::dump_config() {
 #ifdef USE_TMP102_BINARY_SENSOR
   LOG_BINARY_SENSOR("  ", "Alert", this->alert_binary_sensor_);
 #endif
+#ifdef USE_TMP102_TEXT_SENSOR
+  LOG_TEXT_SENSOR("  ", "Threshold Status", this->threshold_status_text_sensor_);
+#endif
 #ifdef USE_TMP102_CONFIGURE
   if (!this->configure_)
     return;
@@ -203,6 +254,9 @@ bool TMP102Component::check_configuration_() {
   this->set_warning_and_invalidate_alert_();
   if (!this->write_configuration_()) {
     ESP_LOGW(TAG, "Failed to restore configuration and thresholds");
+    this->publish_threshold_status_(TMP102_THRESHOLD_STATUS_RECOVERY_FAILED);
+  } else {
+    this->publish_threshold_status_(TMP102_THRESHOLD_STATUS_RECOVERED);
   }
   return false;
 }
@@ -228,22 +282,25 @@ void TMP102Component::set_limit_control(TMP102LimitNumber *number) {
   this->limit_controls_[number->limit_type_] = number;
 }
 
-void TMP102Component::prepare_number_limits_(float *restored) {
+bool TMP102Component::prepare_number_limits_(float *restored, bool *restore_corrected) {
   const bool extended = this->config_ & TMP102_EXTENDED_MODE_BIT;
   uint16_t raw[2] = {this->low_limit_, this->high_limit_};
+  bool corrected = false;
   for (uint8_t limit = 0; limit < 2; ++limit) {
     TMP102LimitNumber *control = this->limit_controls_[limit];
     if (control == nullptr)
       continue;
-    restored[limit] = control->load_value_(decode_temperature(raw[limit], extended));
+    restored[limit] = control->load_value_(decode_temperature(raw[limit], extended), restore_corrected[limit]);
+    corrected |= restore_corrected[limit];
     raw[limit] = encode_temperature(restored[limit], extended);
   }
   if (static_cast<int16_t>(raw[TMP102_LIMIT_LOW]) > static_cast<int16_t>(raw[TMP102_LIMIT_HIGH])) {
     ESP_LOGW(TAG, "Restored thresholds are inverted; using configured values");
-    return;
+    return true;
   }
   this->low_limit_ = raw[TMP102_LIMIT_LOW];
   this->high_limit_ = raw[TMP102_LIMIT_HIGH];
+  return corrected;
 }
 
 float TMP102Component::get_limit_temperature_(TMP102LimitType limit) const {
@@ -261,10 +318,13 @@ bool TMP102Component::set_limit_temperature_(TMP102LimitType limit, float temper
     ESP_LOGW(TAG, "Rejected %s threshold %.4f°C: crosses %s threshold %.4f°C",
              high ? LOG_STR_LITERAL("high") : LOG_STR_LITERAL("low"), decode_temperature(raw, extended),
              high ? LOG_STR_LITERAL("low") : LOG_STR_LITERAL("high"), decode_temperature(other, extended));
+    this->publish_threshold_rejection_(high, decode_temperature(raw, extended), decode_temperature(other, extended));
     return false;
   }
   if (!this->write_register_(static_cast<uint8_t>(TMP102_REGISTER_LOW_LIMIT + limit), raw)) {
     this->status_set_warning();
+    this->publish_threshold_status_(high ? TMP102_THRESHOLD_STATUS_WRITE_HIGH_FAILED
+                                         : TMP102_THRESHOLD_STATUS_WRITE_LOW_FAILED);
     return false;
   }
   (high ? this->high_limit_ : this->low_limit_) = raw;
@@ -273,6 +333,32 @@ bool TMP102Component::set_limit_temperature_(TMP102LimitType limit, float temper
 #endif
 #endif
 
+#ifdef USE_TMP102_TEXT_SENSOR
+void TMP102Component::publish_threshold_status_(uint8_t status) {
+  if (this->threshold_status_text_sensor_ == nullptr)
+    return;
+  char text[40];
+  ESPHOME_strncpy_P(
+      text,
+      reinterpret_cast<ESPHOME_PGM_P>(ThresholdStatusStrings::get_progmem_str(status, TMP102_THRESHOLD_STATUS_OK)),
+      sizeof(text));
+  text[sizeof(text) - 1] = '\0';
+  this->threshold_status_text_sensor_->publish_state(text);
+}
+
+void TMP102Component::publish_threshold_rejection_(bool high, float value, float other) {
+  if (this->threshold_status_text_sensor_ == nullptr)
+    return;
+  char text[96];
+  if (high) {
+    ESPHOME_snprintf_P(text, sizeof(text), ESPHOME_PSTR("Rejected: high %.4f°C crosses low %.4f°C"), value, other);
+  } else {
+    ESPHOME_snprintf_P(text, sizeof(text), ESPHOME_PSTR("Rejected: low %.4f°C crosses high %.4f°C"), value, other);
+  }
+  this->threshold_status_text_sensor_->publish_state(text);
+}
+#endif
+
 #ifdef USE_TMP102_BINARY_SENSOR
 void TMP102Component::invalidate_alert_() {
   if (this->alert_binary_sensor_ != nullptr)
@@ -294,7 +380,7 @@ bool TMP102Component::read_alert_state_() {
 #endif
 
 #ifdef USE_TMP102_NUMBER
-float TMP102LimitNumber::load_value_(float fallback) {
+float TMP102LimitNumber::load_value_(float fallback, bool &corrected) {
   float value = fallback;
   if (this->restore_value_) {
     this->pref_ = this->make_entity_preference<float>();
@@ -303,6 +389,7 @@ float TMP102LimitNumber::load_value_(float fallback) {
   if (!std::isfinite(value) || value < this->traits.get_min_value() || value > this->traits.get_max_value()) {
     ESP_LOGW(TAG, "Invalid restored threshold; using configured value");
     value = fallback;
+    corrected = true;
   }
   return value;
 }
@@ -313,6 +400,7 @@ void TMP102LimitNumber::control(float value) {
   // A chip that failed setup holds nothing the entity could show
   if (this->parent_->is_failed()) {
     ESP_LOGW(TAG, "Rejected threshold change: sensor setup failed");
+    this->parent_->publish_threshold_status_(TMP102_THRESHOLD_STATUS_SENSOR_SETUP_FAILED);
     return;
   }
   const bool accepted = this->parent_->set_limit_temperature_(this->limit_type_, value);
@@ -320,6 +408,9 @@ void TMP102LimitNumber::control(float value) {
   this->publish_state(value);
   if (accepted && !this->save_value_(value)) {
     ESP_LOGW(TAG, "Failed to save threshold preference");
+    this->parent_->publish_threshold_status_(TMP102_THRESHOLD_STATUS_PREFERENCE_SAVE_FAILED);
+  } else if (accepted) {
+    this->parent_->publish_threshold_status_(TMP102_THRESHOLD_STATUS_OK);
   }
 }
 #endif

esphome/components/tmp102/tmp102.h

@@ -12,11 +12,20 @@
 #include "esphome/core/preferences.h"
 #endif
 #include "esphome/components/sensor/sensor.h"
+#ifdef USE_TMP102_TEXT_SENSOR
+#include "esphome/components/text_sensor/text_sensor.h"
+#endif
 
 #include <cstdint>
 
 namespace esphome::tmp102 {
 
+#ifdef USE_HOST
+namespace testing {
+class TMP102Test;
+}
+#endif
+
 #ifdef USE_TMP102_NUMBER
 enum TMP102LimitType : uint8_t {
   TMP102_LIMIT_LOW = 0,
@@ -31,8 +40,13 @@ class TMP102Component final : public PollingComponent, public i2c::I2CDevice, pu
 #ifdef USE_TMP102_BINARY_SENSOR
   SUB_BINARY_SENSOR(alert)
 #endif
-#ifdef USE_TMP102_CONFIGURE
+#ifdef USE_TMP102_TEXT_SENSOR
+  SUB_TEXT_SENSOR(threshold_status)
+#endif
+#if defined(USE_TMP102_CONFIGURE) || defined(USE_TMP102_TEXT_SENSOR)
   void setup() override;
+#endif
+#ifdef USE_TMP102_CONFIGURE
   void set_configuration(uint16_t config, uint16_t high_limit, uint16_t low_limit) {
     this->config_ = config;
     this->high_limit_ = high_limit;
@@ -47,6 +61,13 @@ class TMP102Component final : public PollingComponent, public i2c::I2CDevice, pu
   void update() override;
 
  protected:
+#ifdef USE_TMP102_TEXT_SENSOR
+  void publish_threshold_status_(uint8_t status);
+  void publish_threshold_rejection_(bool high, float value, float other);
+#else
+  void publish_threshold_status_(uint8_t) {}
+  void publish_threshold_rejection_(bool, float, float) {}
+#endif
   void set_warning_and_invalidate_alert_() {
     this->status_set_warning();
 #ifdef USE_TMP102_BINARY_SENSOR
@@ -58,6 +79,7 @@ class TMP102Component final : public PollingComponent, public i2c::I2CDevice, pu
   void invalidate_alert_();
 #endif
 #ifdef USE_TMP102_CONFIGURE
+  void setup_configured_();
   bool write_register_(uint8_t reg, uint16_t value);
   bool write_configuration_();
   bool check_configuration_();
@@ -67,11 +89,10 @@ class TMP102Component final : public PollingComponent, public i2c::I2CDevice, pu
   friend class TMP102LimitNumber;
   bool set_limit_temperature_(TMP102LimitType limit, float temperature);
   float get_limit_temperature_(TMP102LimitType limit) const;
-  void prepare_number_limits_(float *restored);
+  bool prepare_number_limits_(float *restored, bool *restore_corrected);
 
   TMP102LimitNumber *limit_controls_[2]{};
 #endif
-
   uint16_t config_{0};
   uint16_t high_limit_{0};
   uint16_t low_limit_{0};
@@ -87,7 +108,10 @@ class TMP102LimitNumber final : public number::Number, public Parented<TMP102Com
 
  protected:
   friend class TMP102Component;
-  float load_value_(float fallback);
+#ifdef USE_HOST
+  friend class testing::TMP102Test;
+#endif
+  float load_value_(float fallback, bool &corrected);
   bool save_value_(float value);
   void control(float value) override;
 

esphome/core/defines.h

@@ -272,6 +272,7 @@
 #define USE_TMP102_BINARY_SENSOR
 #define USE_TMP102_CONFIGURE
 #define USE_TMP102_NUMBER
+#define USE_TMP102_TEXT_SENSOR
 #define USE_TOUCHSCREEN
 #define USE_UART_DEBUGGER
 #define USE_UART_WAKE_LOOP_ON_RX

esphome/core/progmem.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <algorithm>
 #include <array>
 #include <cstddef>
 #include <cstdint>
@@ -68,6 +69,7 @@ template<size_t N> struct FixedString {
 };
 
 /// Compile-time string table that packs strings into a single blob with offset lookup.
+/// Blobs over 255 bytes have no offsets and are scanned, so keep those for rarely read strings.
 /// Use PROGMEM_STRING_TABLE macro to instantiate with proper flash placement on ESP8266.
 ///
 /// Example:
@@ -78,6 +80,11 @@ template<size_t N> struct FixedString {
 template<FixedString... Strs> struct ProgmemStringTable {
   static constexpr size_t COUNT = sizeof...(Strs);
   static constexpr size_t BLOB_SIZE = (0 + ... + (Strs.size() + 1));
+  /// Length of the longest string, for sizing a RAM copy on ESP8266
+  static constexpr size_t MAX_LENGTH = std::max({Strs.size()...});
+  /// One-byte offsets address up to 255 bytes; a larger blob has no offset table and is scanned instead,
+  /// which costs less flash than wider offsets for the rarely read tables that get this big.
+  static constexpr bool INDEXED = BLOB_SIZE <= UINT8_MAX;
 
   /// Generate packed string blob at compile time
   static constexpr auto make_blob() {
@@ -91,18 +98,28 @@ template<FixedString... Strs> struct ProgmemStringTable {
     return result;
   }
 
-  /// Generate offset table at compile time (uint8_t limits blob to 255 bytes)
+  /// Generate offset table at compile time
   static constexpr auto make_offsets() {
     static_assert(COUNT > 0, "PROGMEM_STRING_TABLE must contain at least one string");
     static_assert(COUNT <= 255, "PROGMEM_STRING_TABLE supports at most 255 strings with uint8_t indices");
-    static_assert(BLOB_SIZE <= 255, "PROGMEM_STRING_TABLE blob exceeds 255 bytes; use fewer/shorter strings");
-    std::array<uint8_t, COUNT> result{};
-    size_t pos = 0, idx = 0;
-    ((result[idx++] = static_cast<uint8_t>(pos), pos += Strs.size() + 1), ...);
-    return result;
+    if constexpr (INDEXED) {
+      std::array<uint8_t, COUNT> result{};
+      size_t pos = 0, idx = 0;
+      ((result[idx++] = static_cast<uint8_t>(pos), pos += Strs.size() + 1), ...);
+      return result;
+    } else {
+      return std::array<uint8_t, 0>{};
+    }
   }
 };
 
+/// Skip idx strings in a packed NUL-separated blob that may live in flash.
+inline const char *progmem_skip_strings(const char *blob, uint8_t idx) {
+  while (idx-- > 0)
+    blob += ESPHOME_strlen_P(blob) + 1;
+  return blob;
+}
+
 // Forward declaration for LogString (defined in log.h)
 struct LogString;
 
@@ -115,6 +132,7 @@ struct LogString;
     static constexpr size_t COUNT = Table::COUNT; \
     static constexpr uint8_t LAST_INDEX = COUNT - 1; \
     static constexpr size_t BLOB_SIZE = Table::BLOB_SIZE; \
+    static constexpr size_t MAX_LENGTH = Table::MAX_LENGTH; \
     static constexpr auto BLOB ESPHOME_PROGMEM_STRING_TABLE_STORAGE = Table::make_blob(); \
     static constexpr auto OFFSETS ESPHOME_PROGMEM_STRING_TABLE_STORAGE = Table::make_offsets(); \
     static const char *get_(uint8_t idx, uint8_t fallback) { \
@@ -122,7 +140,10 @@ struct LogString;
         idx = fallback; \
       /* std::launder is used here to prevent the inter-procedural analysis that */ \
       /* causes the false positive that the string is not null terminated */ \
-      return std::launder(&BLOB[::esphome::progmem_read_byte(&OFFSETS[idx])]); \
+      if constexpr (Table::INDEXED) \
+        return std::launder(&BLOB[::esphome::progmem_read_byte(&OFFSETS[idx])]); \
+      else \
+        return std::launder(::esphome::progmem_skip_strings(BLOB.data(), idx)); \
     } \
     static ::ProgmemStr get_progmem_str(uint8_t idx, uint8_t fallback) { \
       return reinterpret_cast<::ProgmemStr>(get_(idx, fallback)); \

tests/component_tests/tmp102/config/duplicate_status.yaml

@@ -0,0 +1,23 @@
+---
+esphome:
+  name: tmp102-test
+
+esp32:
+  board: esp32dev
+
+i2c:
+  sda: GPIO21
+  scl: GPIO22
+
+sensor:
+  - platform: tmp102
+    id: parent_sensor
+    name: Temperature
+
+text_sensor:
+  - platform: tmp102
+    tmp102_id: parent_sensor
+    name: First Status
+  - platform: tmp102
+    tmp102_id: parent_sensor
+    name: Second Status

tests/component_tests/tmp102/config/status.yaml

@@ -0,0 +1,20 @@
+---
+esphome:
+  name: tmp102-test
+
+esp32:
+  board: esp32dev
+
+i2c:
+  sda: GPIO21
+  scl: GPIO22
+
+sensor:
+  - platform: tmp102
+    id: parent_sensor
+    name: Temperature
+
+text_sensor:
+  - platform: tmp102
+    tmp102_id: parent_sensor
+    name: Threshold Status

tests/component_tests/tmp102/test_config.py

@@ -58,6 +58,30 @@ def test_duplicate_alert_entities_are_rejected(
     )
 
 
+def test_status_entity_is_read_only(
+    generate_main: Callable[[Path], str],
+    component_config_path: Callable[[str], Path],
+) -> None:
+    source = generate_main(component_config_path("status.yaml"))
+    assert "set_threshold_status_text_sensor" in source
+    assert "set_configuration" not in source
+    defines = " ".join(define.name for define in CORE.defines)
+    assert "USE_TMP102_TEXT_SENSOR" in defines
+    assert "USE_TMP102_CONFIGURE" not in defines
+
+
+def test_duplicate_status_entities_are_rejected(
+    component_config_path: Callable[[str], Path],
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    CORE.config_path = component_config_path("duplicate_status.yaml")
+    assert read_config({}) is None
+    assert (
+        "Only one TMP102 text_sensor may reference each temperature sensor"
+        in capsys.readouterr().out
+    )
+
+
 def test_threshold_numbers_enable_configuration_once(
     generate_main: Callable[[Path], str],
     component_config_path: Callable[[str], Path],

tests/components/core/test_progmem_string_table.cpp

@@ -0,0 +1,65 @@
+#include <gtest/gtest.h>
+
+#include <cstring>
+
+#include "esphome/core/log.h"
+#include "esphome/core/progmem.h"
+
+namespace esphome::core::testing {
+
+PROGMEM_STRING_TABLE(SmallStrings, "OFF", "HEAT", "COOL", "UNKNOWN");
+
+// Eight strings of 40 characters: a 328-byte blob, past what one-byte offsets can address, so it is scanned.
+PROGMEM_STRING_TABLE(LargeStrings, "0123456789012345678901234567890123456789",
+                     "1123456789012345678901234567890123456789", "2123456789012345678901234567890123456789",
+                     "3123456789012345678901234567890123456789", "4123456789012345678901234567890123456789",
+                     "5123456789012345678901234567890123456789", "6123456789012345678901234567890123456789",
+                     "7123456789012345678901234567890123456789");
+
+// Five 50-character strings pack into exactly 255 bytes; one more byte switches to scanning.
+PROGMEM_STRING_TABLE(Exactly255, "01234567890123456789012345678901234567890123456789",
+                     "01234567890123456789012345678901234567890123456789",
+                     "01234567890123456789012345678901234567890123456789",
+                     "01234567890123456789012345678901234567890123456789",
+                     "01234567890123456789012345678901234567890123456789");
+PROGMEM_STRING_TABLE(Exactly256, "01234567890123456789012345678901234567890123456789",
+                     "01234567890123456789012345678901234567890123456789",
+                     "01234567890123456789012345678901234567890123456789",
+                     "01234567890123456789012345678901234567890123456789",
+                     "01234567890123456789012345678901234567890123456789x");
+
+TEST(ProgmemStringTable, ScansInsteadOfIndexingAfter255Bytes) {
+  static_assert(Exactly255::BLOB_SIZE == 255);
+  static_assert(Exactly255::Table::INDEXED);
+  static_assert(Exactly256::BLOB_SIZE == 256);
+  static_assert(!Exactly256::Table::INDEXED);
+  static_assert(Exactly256::OFFSETS.empty());
+  EXPECT_EQ(Exactly255::OFFSETS[4], 204);
+  EXPECT_STREQ(reinterpret_cast<const char *>(Exactly256::get_progmem_str(4, 0)),
+               "01234567890123456789012345678901234567890123456789x");
+}
+
+TEST(ProgmemStringTable, SmallTableKeepsOneByteOffsets) {
+  static_assert(SmallStrings::BLOB_SIZE <= 255);
+  static_assert(SmallStrings::Table::INDEXED);
+  static_assert(SmallStrings::MAX_LENGTH == 7);
+  EXPECT_STREQ(reinterpret_cast<const char *>(SmallStrings::get_log_str(0, SmallStrings::LAST_INDEX)), "OFF");
+  EXPECT_STREQ(reinterpret_cast<const char *>(SmallStrings::get_log_str(2, SmallStrings::LAST_INDEX)), "COOL");
+  EXPECT_STREQ(reinterpret_cast<const char *>(SmallStrings::get_log_str(200, SmallStrings::LAST_INDEX)), "UNKNOWN");
+}
+
+TEST(ProgmemStringTable, LargeTableIsScanned) {
+  static_assert(LargeStrings::BLOB_SIZE > 255);
+  static_assert(!LargeStrings::Table::INDEXED);
+  static_assert(LargeStrings::MAX_LENGTH == 40);
+  EXPECT_STREQ(reinterpret_cast<const char *>(LargeStrings::get_progmem_str(0, LargeStrings::LAST_INDEX)),
+               "0123456789012345678901234567890123456789");
+  EXPECT_STREQ(reinterpret_cast<const char *>(LargeStrings::get_progmem_str(7, LargeStrings::LAST_INDEX)),
+               "7123456789012345678901234567890123456789");
+  EXPECT_STREQ(reinterpret_cast<const char *>(LargeStrings::get_progmem_str(8, LargeStrings::LAST_INDEX)),
+               "7123456789012345678901234567890123456789");
+  EXPECT_STREQ(reinterpret_cast<const char *>(LargeStrings::get_progmem_str(3, LargeStrings::LAST_INDEX)),
+               "3123456789012345678901234567890123456789");
+}
+
+}  // namespace esphome::core::testing

tests/components/display/__init__.py

@@ -0,0 +1,20 @@
+from pathlib import Path
+
+import esphome.codegen as cg
+from esphome.const import CONF_ESPHOME, CONF_INCLUDES
+from esphome.core import CORE
+from esphome.types import ConfigType
+from tests.testing_helpers import ComponentManifestOverride
+
+TESTS_DIR = Path(__file__).parent
+
+
+def override_manifest(manifest: ComponentManifestOverride) -> None:
+    # The column walk in Display::draw_pixels_at() is only built with PSRAM; define it
+    # when display's own tests are built so both walk orders run, and leave other
+    # components' test binaries on the plain build.
+    async def to_code_testing(config: ConfigType) -> None:
+        if any(Path(p) == TESTS_DIR for p in CORE.config[CONF_ESPHOME][CONF_INCLUDES]):
+            cg.add_define("USE_PSRAM")
+
+    manifest.to_code = to_code_testing

tests/components/display/test_draw_pixels_at.cpp

@@ -0,0 +1,109 @@
+#include <gtest/gtest.h>
+
+#include <algorithm>
+#include <initializer_list>
+#include <tuple>
+#include <vector>
+
+#include "esphome/components/display/display.h"
+
+namespace esphome::display::testing {
+
+// Records every pixel write; pixel_axes_swapped() picks the walk order.
+class RecordingDisplay : public Display {
+ public:
+  void set_axes_swapped(bool swapped) { this->axes_swapped_ = swapped; }
+  bool pixel_axes_swapped() const override { return this->axes_swapped_; }
+  void draw_pixel_at(int x, int y, Color color) override { this->pixels_.emplace_back(x, y, color.raw_32); }
+  void update() override {}
+  DisplayType get_display_type() override { return DisplayType::DISPLAY_TYPE_COLOR; }
+  int get_width_internal() override { return 64; }
+  int get_height_internal() override { return 64; }
+
+  std::vector<std::tuple<int, int, uint32_t>> sorted_pixels() const {
+    auto sorted = this->pixels_;
+    std::sort(sorted.begin(), sorted.end());
+    return sorted;
+  }
+  size_t count() const { return this->pixels_.size(); }
+  const std::vector<std::tuple<int, int, uint32_t>> &pixels() const { return this->pixels_; }
+
+ protected:
+  bool axes_swapped_{false};
+  std::vector<std::tuple<int, int, uint32_t>> pixels_;
+};
+
+// A 7x5 region with a 2 pixel left offset, a 3 line top offset and 4 pixels of
+// right padding, so the source index arithmetic of both walks is exercised.
+static constexpr int W = 7, H = 5, X_OFFSET = 2, Y_OFFSET = 3, X_PAD = 4;
+static constexpr int LINE_STRIDE = X_OFFSET + W + X_PAD;
+static constexpr int LINES = Y_OFFSET + H;
+
+static std::vector<uint8_t> make_source(int bytes_per_pixel) {
+  std::vector<uint8_t> source(LINE_STRIDE * LINES * bytes_per_pixel);
+  uint8_t value = 1;
+  for (auto &byte : source)
+    byte = value++;
+  return source;
+}
+
+static void expect_walks_match(ColorBitness bitness, int bytes_per_pixel, bool big_endian) {
+  const auto source = make_source(bytes_per_pixel);
+  RecordingDisplay rows;
+  RecordingDisplay columns;
+  columns.set_axes_swapped(true);
+  rows.draw_pixels_at(10, 20, W, H, source.data(), COLOR_ORDER_RGB, bitness, big_endian, X_OFFSET, Y_OFFSET, X_PAD);
+  columns.draw_pixels_at(10, 20, W, H, source.data(), COLOR_ORDER_RGB, bitness, big_endian, X_OFFSET, Y_OFFSET, X_PAD);
+  EXPECT_EQ(rows.count(), static_cast<size_t>(W * H));
+  EXPECT_EQ(columns.count(), static_cast<size_t>(W * H));
+  EXPECT_EQ(rows.sorted_pixels(), columns.sorted_pixels());
+}
+
+TEST(DrawPixelsAt, ColumnWalkMatchesRowWalk332) { expect_walks_match(COLOR_BITNESS_332, 1, true); }
+TEST(DrawPixelsAt, ColumnWalkMatchesRowWalk565BigEndian) { expect_walks_match(COLOR_BITNESS_565, 2, true); }
+TEST(DrawPixelsAt, ColumnWalkMatchesRowWalk565LittleEndian) { expect_walks_match(COLOR_BITNESS_565, 2, false); }
+TEST(DrawPixelsAt, ColumnWalkMatchesRowWalk888BigEndian) { expect_walks_match(COLOR_BITNESS_888, 3, true); }
+TEST(DrawPixelsAt, ColumnWalkMatchesRowWalk888LittleEndian) { expect_walks_match(COLOR_BITNESS_888, 3, false); }
+
+// One known pixel per bitness and byte order, so a decode that swapped bytes or channels
+// could not pass the walk comparison above by being wrong the same way twice.
+static void expect_golden(ColorBitness bitness, std::initializer_list<uint8_t> bytes, bool big_endian, Color expected) {
+  const std::vector<uint8_t> source(bytes);
+  RecordingDisplay display;
+  display.draw_pixels_at(3, 4, 1, 1, source.data(), COLOR_ORDER_RGB, bitness, big_endian, 0, 0, 0);
+  ASSERT_EQ(display.count(), 1u);
+  EXPECT_EQ(display.pixels()[0], std::make_tuple(3, 4, expected.raw_32));
+}
+
+TEST(DrawPixelsAt, Golden565BigEndian) {
+  expect_golden(COLOR_BITNESS_565, {0xE0, 0x07}, true, Color(230, 0, 57));  // 0xE007: r 28, g 0, b 7
+}
+TEST(DrawPixelsAt, Golden565LittleEndian) {
+  expect_golden(COLOR_BITNESS_565, {0xE0, 0x07}, false, Color(0, 255, 0));  // 0x07E0: pure green
+}
+TEST(DrawPixelsAt, Golden888BigEndian) {
+  expect_golden(COLOR_BITNESS_888, {0x10, 0x20, 0x30}, true, Color(0x10, 0x20, 0x30));
+}
+TEST(DrawPixelsAt, Golden888LittleEndian) {
+  expect_golden(COLOR_BITNESS_888, {0x10, 0x20, 0x30}, false, Color(0x30, 0x20, 0x10));
+}
+TEST(DrawPixelsAt, Golden332) {
+  expect_golden(COLOR_BITNESS_332, {0xE3}, true, Color(255, 0, 255));  // r 7 of 7, g 0, b 3 of 3
+}
+
+// The column walk really is a different order, otherwise the tests above prove nothing.
+TEST(DrawPixelsAt, ColumnWalkChangesOrder) {
+  const auto source = make_source(1);
+  RecordingDisplay rows;
+  RecordingDisplay columns;
+  columns.set_axes_swapped(true);
+  rows.draw_pixels_at(0, 0, W, H, source.data(), COLOR_ORDER_RGB, COLOR_BITNESS_332, true, X_OFFSET, Y_OFFSET, X_PAD);
+  columns.draw_pixels_at(0, 0, W, H, source.data(), COLOR_ORDER_RGB, COLOR_BITNESS_332, true, X_OFFSET, Y_OFFSET,
+                         X_PAD);
+  ASSERT_GT(rows.count(), 1u);
+  ASSERT_GT(columns.count(), 1u);
+  EXPECT_EQ(std::get<0>(rows.pixels()[1]), 1);     // the row walk steps x first
+  EXPECT_EQ(std::get<1>(columns.pixels()[1]), 1);  // the column walk steps y first
+}
+
+}  // namespace esphome::display::testing

tests/components/tmp102/__init__.py

@@ -6,11 +6,12 @@ from tests.testing_helpers import ComponentManifestOverride
 
 def override_manifest(manifest: ComponentManifestOverride) -> None:
     async def to_code_testing(config: ConfigType) -> None:
-        for platform in ("sensor", "binary_sensor", "number"):
+        for platform in ("sensor", "binary_sensor", "number", "text_sensor"):
             CORE.testing_ensure_platform_registered(platform)
         cg.add_define("USE_TMP102_CONFIGURE")
         cg.add_define("USE_TMP102_BINARY_SENSOR")
         cg.add_define("USE_TMP102_NUMBER")
+        cg.add_define("USE_TMP102_TEXT_SENSOR")
 
     manifest.to_code = to_code_testing
     manifest.dependencies = manifest.dependencies + [
@@ -18,4 +19,5 @@ def override_manifest(manifest: ComponentManifestOverride) -> None:
         "sensor",
         "binary_sensor",
         "number",
+        "text_sensor",
     ]

tests/components/tmp102/common.yaml

@@ -30,3 +30,8 @@ binary_sensor:
   - platform: tmp102
     tmp102_id: tmp102_extended_temperature
     name: TMP102 Alert
+
+text_sensor:
+  - platform: tmp102
+    tmp102_id: tmp102_extended_temperature
+    name: TMP102 Threshold Status

tests/components/tmp102/test-text-sensor-only.esp32-idf.yaml

@@ -0,0 +1,12 @@
+packages:
+  i2c: !include ../../test_build_components/common/i2c/esp32-idf.yaml
+
+sensor:
+  - platform: tmp102
+    id: tmp102_text_sensor_parent
+    name: TMP102 Temperature
+
+text_sensor:
+  - platform: tmp102
+    tmp102_id: tmp102_text_sensor_parent
+    name: TMP102 Threshold Status

tests/components/tmp102/test_tmp102.cpp

@@ -4,6 +4,7 @@
 
 #include <array>
 #include <cmath>
+#include <functional>
 #include <utility>
 #include "esphome/components/host/preferences.h"
 #include "esphome/components/tmp102/tmp102.h"
@@ -29,6 +30,7 @@ class RegisterBus final : public i2c::I2CBus {
   unsigned transactions{0};
   unsigned writes{0};
   uint8_t pointer{0};
+  std::function<void()> on_write;
 
   i2c::ErrorCode write_readv(uint8_t address, const uint8_t *data, size_t size, uint8_t *out,
                              size_t out_size) override {
@@ -42,6 +44,10 @@ class RegisterBus final : public i2c::I2CBus {
           return i2c::ERROR_NOT_ACKNOWLEDGED;
         ++this->writes;
         this->registers[this->pointer] = (uint16_t(data[1]) << 8) | data[2];
+        if (this->on_write) {
+          auto callback = std::move(this->on_write);
+          callback();
+        }
       }
     }
     if (out_size != 0) {
@@ -59,6 +65,7 @@ class TMP102Test : public ::testing::Test {
   RegisterBus bus_;
   TMP102Component chip_;
   binary_sensor::BinarySensor alert_;
+  text_sensor::TextSensor status_;
   TMP102LimitNumber high_{TMP102_LIMIT_HIGH};
   TMP102LimitNumber low_{TMP102_LIMIT_LOW};
   unsigned publications_{0};
@@ -122,6 +129,8 @@ class TMP102Test : public ::testing::Test {
   static void save(TMP102LimitNumber &number, float value) {
     ASSERT_TRUE(number.make_entity_preference<float>().save(&value));
   }
+
+  static void fail_saves(TMP102LimitNumber &number) { number.pref_ = {}; }
 };
 
 TEST_F(TMP102Test, LegacySetupAndContinuousReadDoNotWriteRegisters) {
@@ -136,6 +145,24 @@ TEST_F(TMP102Test, LegacySetupAndContinuousReadDoNotWriteRegisters) {
   EXPECT_EQ(this->bus_.registers, original);
 }
 
+TEST_F(TMP102Test, ReadOnlyStatusDoesNotConfigureOrWriteRegisters) {
+  this->chip_.set_threshold_status_text_sensor(&this->status_);
+  const auto original = this->bus_.registers;
+  this->chip_.setup();
+  EXPECT_EQ(this->bus_.transactions, 0);
+  EXPECT_EQ(this->bus_.registers, original);
+  ASSERT_TRUE(this->status_.has_state());
+  EXPECT_EQ(this->status_.state, "Not configured");
+}
+
+TEST_F(TMP102Test, ConfiguredSetupPublishesStatus) {
+  this->chip_.set_threshold_status_text_sensor(&this->status_);
+  this->configure();
+  this->chip_.setup();
+  ASSERT_TRUE(this->status_.has_state());
+  EXPECT_EQ(this->status_.state, "OK");
+}
+
 TEST_F(TMP102Test, SampleFormatOverridesConfiguredModeInBothDirections) {
   for (bool configured_extended : {false, true}) {
     this->configure(configured_extended ? 0x0010 : 0, configured_extended ? 0x2800 : 0x5000,
@@ -408,6 +435,7 @@ TEST_F(TMP102Test, FailureOfAnySetupWriteMarksComponentFailed) {
 }
 
 TEST_F(TMP102Test, InvalidRestoredPairIsRepairedAfterSuccessfulSetup) {
+  this->chip_.set_threshold_status_text_sensor(&this->status_);
   this->numbers_();
   save(this->high_, 20);
   save(this->low_, 35);
@@ -416,30 +444,53 @@ TEST_F(TMP102Test, InvalidRestoredPairIsRepairedAfterSuccessfulSetup) {
   EXPECT_FLOAT_EQ(this->low_.state, 25);
   EXPECT_FLOAT_EQ(saved(this->high_), 30);
   EXPECT_FLOAT_EQ(saved(this->low_), 25);
+  EXPECT_EQ(this->status_.state, "Restored thresholds reset");
+}
+
+TEST_F(TMP102Test, InvalidRestoredPairAndSaveFailurePublishCombinedStatus) {
+  this->chip_.set_threshold_status_text_sensor(&this->status_);
+  this->numbers_();
+  save(this->high_, 20);
+  save(this->low_, 35);
+  this->bus_.on_write = [this]() {
+    fail_saves(this->high_);
+    fail_saves(this->low_);
+  };
+  this->chip_.setup();
+  EXPECT_FLOAT_EQ(this->high_.state, 30);
+  EXPECT_FLOAT_EQ(this->low_.state, 25);
+  EXPECT_EQ(this->status_.state, "Restore reset; save failed");
 }
 
 TEST_F(TMP102Test, InvalidRestoredValuesAreRepaired) {
+  this->chip_.set_threshold_status_text_sensor(&this->status_);
   this->numbers_();
   save(this->high_, NAN);
   save(this->low_, INFINITY);
   this->chip_.setup();
   EXPECT_FLOAT_EQ(this->high_.state, 30);
   EXPECT_FLOAT_EQ(this->low_.state, 25);
+  EXPECT_FLOAT_EQ(saved(this->high_), 30);
+  EXPECT_FLOAT_EQ(saved(this->low_), 25);
+  EXPECT_EQ(this->status_.state, "Restored thresholds reset");
 }
 
 TEST_F(TMP102Test, FailedSetupDoesNotOverwritePreferences) {
+  this->chip_.set_threshold_status_text_sensor(&this->status_);
   this->numbers_();
   save(this->high_, 90);
   save(this->low_, 85);
   this->bus_.fail_write = 3;
   this->chip_.setup();
   EXPECT_TRUE(this->chip_.is_failed());
+  EXPECT_EQ(this->status_.state, "Setup failed");
   EXPECT_FALSE(this->high_.has_state());
   EXPECT_FLOAT_EQ(saved(this->high_), 90);
   EXPECT_FLOAT_EQ(saved(this->low_), 85);
 }
 
 TEST_F(TMP102Test, FailedSetupRejectsThresholdChanges) {
+  this->chip_.set_threshold_status_text_sensor(&this->status_);
   this->numbers_();
   save(this->high_, 90);
   this->bus_.fail_write = 3;
@@ -450,6 +501,7 @@ TEST_F(TMP102Test, FailedSetupRejectsThresholdChanges) {
   EXPECT_FALSE(this->high_.has_state());
   EXPECT_EQ(this->bus_.writes, writes);
   EXPECT_FLOAT_EQ(saved(this->high_), 90);
+  EXPECT_EQ(this->status_.state, "Rejected: sensor setup failed");
 }
 
 TEST_F(TMP102Test, SetupOnlySavesChangedThresholds) {
@@ -464,6 +516,7 @@ TEST_F(TMP102Test, SetupOnlySavesChangedThresholds) {
 }
 
 TEST_F(TMP102Test, FailedNumberWriteKeepsAcceptedState) {
+  this->chip_.set_threshold_status_text_sensor(&this->status_);
   this->numbers_();
   save(this->high_, 90);
   save(this->low_, 85);
@@ -475,6 +528,47 @@ TEST_F(TMP102Test, FailedNumberWriteKeepsAcceptedState) {
   EXPECT_FLOAT_EQ(this->high_.state, 90);
   EXPECT_EQ(publications, 1);
   EXPECT_FLOAT_EQ(saved(this->high_), 90);
+  EXPECT_EQ(this->status_.state, "Write failed: high threshold");
+
+  this->bus_.fail_write = 2;
+  this->low_.make_call().set_value(80).perform();
+  EXPECT_FLOAT_EQ(this->low_.state, 85);
+  EXPECT_FLOAT_EQ(saved(this->low_), 85);
+  EXPECT_EQ(this->status_.state, "Write failed: low threshold");
+}
+
+TEST_F(TMP102Test, PreferenceSaveFailurePublishesStatus) {
+  this->chip_.set_threshold_status_text_sensor(&this->status_);
+  this->numbers_();
+  this->chip_.setup();
+  fail_saves(this->high_);
+  this->high_.make_call().set_value(35).perform();
+  EXPECT_FLOAT_EQ(this->high_.state, 35);
+  EXPECT_EQ(this->status_.state, "Preference save failed");
+}
+
+TEST_F(TMP102Test, RejectedNumberWritePublishesStatus) {
+  this->chip_.set_threshold_status_text_sensor(&this->status_);
+  this->numbers_();
+  this->chip_.setup();
+  this->high_.make_call().set_value(20).perform();
+  EXPECT_EQ(this->status_.state, "Rejected: high 20.0000°C crosses low 25.0000°C");
+  this->high_.make_call().set_value(35).perform();
+  EXPECT_EQ(this->status_.state, "OK");
+}
+
+TEST_F(TMP102Test, ConfigurationRecoveryPublishesStatus) {
+  this->chip_.set_threshold_status_text_sensor(&this->status_);
+  this->configure();
+  this->chip_.setup();
+  this->bus_.registers[1] = 0;
+  this->chip_.update();
+  EXPECT_EQ(this->status_.state, "Configuration restored");
+
+  this->bus_.registers[1] = 0;
+  this->bus_.fail_write = 1;
+  this->chip_.update();
+  EXPECT_EQ(this->status_.state, "Configuration recovery failed");
 }
 
 TEST_F(TMP102Test, RestoreDisabledNeverChangesSavedValue) {