add GPS time component

Author: Samuel Sieb

components/gpstime/README.md

@@ -0,0 +1,11 @@
+# GPS component that only gets the time
+
+A configured uart is required.
+
+Example:
+```yaml
+time:
+  - platform: gpstime
+    uart_id: my_uart   # optional
+```
+

components/gpstime/__init__.py

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+#include "gpstime.h"
+#include "esphome/core/log.h"
+
+namespace esphome {
+namespace gpstime {
+
+static const char *TAG = "GPS.time";
+
+void GPSTime::loop() {
+  while (this->available()) {
+    uint8_t c;
+    this->read_byte(&c);
+    if (this->have_time_)
+      continue;
+    if (c == '$') {
+      this->receiving_ = true;
+      this->ending_ = false;
+      this->rx_buffer_.clear();
+      continue;
+    }
+    if (!this->receiving_)
+      continue;
+    if (c == '\r') {
+      if (this->ending_) {
+        ESP_LOGW(TAG, "unexpected return");
+        this->receiving_ = false;
+      } else {
+        this->ending_ = true;
+      }
+      continue;
+    }
+    if (c == '\n') {
+      this->receiving_ = false;
+      if (!this->ending_) {
+        ESP_LOGW(TAG, "unexpected newline");
+        continue;
+      }
+      this->handle_message_();
+      continue;
+    }
+    if (this->ending_) {
+      ESP_LOGW(TAG, "unexpected character");
+      this->receiving_ = false;
+      continue;
+    }
+    if (this->rx_buffer_.size() < 90)
+      this->rx_buffer_.push_back(c);
+  }
+}
+
+void GPSTime::handle_message_() {
+  std::vector<std::string> terms;
+  std::string data(this->rx_buffer_.begin(), this->rx_buffer_.end());
+  ESP_LOGD(TAG, "received: %s", data.c_str());
+  int start = 0;
+  int end;
+  int csum_pos = data.find('*');
+  if (csum_pos != std::string::npos) {
+    if (data.size() - csum_pos != 3) {
+      ESP_LOGE(TAG, "invalid checksum data");
+      return;
+    }
+    uint8_t csum = 0;
+    parse_hex(data.c_str() + csum_pos + 1, &csum, 1);
+    data.resize(csum_pos);
+    uint8_t ccsum = 0;
+    for (auto c : data)
+      ccsum ^= c;
+    if (csum != ccsum) {
+      ESP_LOGE(TAG, "checksum failed: %02x != %02x", csum, ccsum);
+      return;
+    }
+  }
+  do {
+    end = data.find(',', start);
+    int len = end != std::string::npos ? end - start : end;
+    terms.push_back(data.substr(start, len));
+    start = end + 1;
+  } while (end != std::string::npos);
+  ESP_LOGD(TAG, "message: %s", terms[0].c_str());
+  if (terms[0] != "GPRMC")
+    return;
+  ESP_LOGD(TAG, "time: '%s', date: '%s'", terms[1].c_str(), terms[9].c_str());
+  if ((terms[1].size() < 6) || (terms[9].size() < 6))
+    return;
+  uint32_t timeinfo = int(parse_number<float>(terms[1]).value());
+  uint32_t dateinfo = int(parse_number<uint32_t>(terms[9]).value());
+  ESP_LOGD(TAG, "processing %d %d", timeinfo, dateinfo);
+  ESPTime now{};
+  now.year = dateinfo % 100 + 2000;
+  now.month = dateinfo / 100 % 100;
+  now.day_of_month = dateinfo / 10000;
+  // Set these to valid value for  recalc_timestamp_utc - it's not used for calculation
+  now.day_of_week = 1;
+  now.day_of_year = 1;
+
+  now.hour = timeinfo / 10000;
+  now.minute = timeinfo / 100 % 100;
+  now.second = timeinfo % 100;
+  now.recalc_timestamp_utc(false);
+  this->synchronize_epoch_(now.timestamp);
+  this->have_time_ = true;
+}
+
+void GPSTime::update() { this->have_time_ = false; }
+
+void GPSTime::dump_config() { ESP_LOGCONFIG("", "GPS time", this); }
+
+}  // namespace gpstime
+}  // namespace esphome

components/gpstime/gpstime.cpp

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+#pragma once
+
+#include "esphome/components/time/real_time_clock.h"
+#include "esphome/components/uart/uart.h"
+
+namespace esphome {
+namespace gpstime {
+
+class GPSTime : public time::RealTimeClock, public uart::UARTDevice {
+ public:
+  float get_setup_priority() const override { return setup_priority::LATE; }
+  void loop() override;
+  void update() override;
+  void dump_config() override;
+
+ protected:
+  bool receiving_{false};
+  bool ending_{false};
+  void handle_message_();
+  std::vector<uint8_t> rx_buffer_;
+  bool have_time_{false};
+};
+
+}  // namespace gpstime
+}  // namespace esphome

components/gpstime/gpstime.h

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+from esphome.components import time as time_
+import esphome.config_validation as cv
+import esphome.codegen as cg
+from esphome.components import uart
+from esphome.const import CONF_ID
+
+CODEOWNERS = ["@ssieb"]
+
+DEPENDENCIES = ['uart']
+
+gpstime_ns = cg.esphome_ns.namespace('gpstime')
+
+GPSTime = gpstime_ns.class_('GPSTime', time_.RealTimeClock, uart.UARTDevice)
+
+CONFIG_SCHEMA = (
+    time_.TIME_SCHEMA.extend(
+        {
+            cv.GenerateID(): cv.declare_id(GPSTime),
+        }
+    )
+    .extend(uart.UART_DEVICE_SCHEMA)
+    .extend(cv.polling_component_schema("15min"))
+)
+
+async def to_code(config):
+    var = cg.new_Pvariable(config[CONF_ID])
+    await cg.register_component(var, config)
+    await time_.register_time(var, config)
+    await uart.register_uart_device(var, config)
+