Add serial text sensor

example.yaml

@@ -31,3 +31,8 @@ sensor:
       name: "Projector signal status"
     illuminance:
       name: "Projector luminance level"
+
+text_sensor:
+  - platform: tw7100
+    serial:
+      name: "Serial number"

text_sensor.py

@@ -0,0 +1,29 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome.components import text_sensor
+from esphome.const import (
+    ENTITY_CATEGORY_DIAGNOSTIC,
+    CONF_ID,
+)
+
+from . import tw7100
+
+DEPENDENCIES = ["tw7100"]
+CONF_SERIAL = "serial"
+
+CONFIG_SCHEMA = cv.Schema(
+    {
+        cv.GenerateID(): cv.use_id(tw7100),
+        cv.Optional(CONF_SERIAL): text_sensor.text_sensor_schema(
+            entity_category=ENTITY_CATEGORY_DIAGNOSTIC
+        ),
+    }
+)
+
+
+async def to_code(config):
+    parent = await cg.get_variable(config[CONF_ID])
+
+    if CONF_SERIAL in config:
+        sens = await text_sensor.new_text_sensor(config[CONF_SERIAL])
+        cg.add(parent.set_serial(sens))

tw7100.cpp

@@ -101,9 +101,9 @@ void tw7100Component::update() {
       cmd_queue.push_back(cmd);
     }
     if ((powered_->state)) {
-      //if (this->serial_->state.length() < 1) {
+      if (this->serial_->state.length() < 1) {
-      //  cmd_queue.push_back("SNO?");
+        cmd_queue.push_back("SNO?");
-      //}
+      }
       for (auto &cmd : pwr_on_query_cmds) {
         cmd_queue.push_back(cmd);
       }
@@ -178,9 +178,11 @@ void tw7100Component::update_sensor(std::pair<std::string, std::string> data) {
     int value = std::stoi(value_string);
     luminance_level_->publish_state(value);
   } else if (cmd == "SOURCELIST") {
-    for(char& c : value_string) {
+    //for(char& c : value_string) {
-      ESP_LOGV(TAG, "%c (%02x)", c, c);
+    //  ESP_LOGV(TAG, "%c (%02x)", c, c);
-    }
+    //}
+  } else if (cmd == "SNO") {
+    serial_->publish_state(value_string);
   } else {
     ESP_LOGW(TAG, "Command %s unknown, skipping updating sensor with value", cmd.c_str());
   }