UART component support added for host platform (#6912)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>
Co-authored-by: Pavlo Dudnytskyi <pdudnytskyi@astrata.eu>

esphome/components/uart/__init__.py

@@ -1,5 +1,5 @@
 from typing import Optional
-
+import re
 import esphome.codegen as cg
 import esphome.config_validation as cv
 import esphome.final_validate as fv
@@ -11,6 +11,7 @@ from esphome.const import (
     CONF_NUMBER,
     CONF_RX_PIN,
     CONF_TX_PIN,
+    CONF_PORT,
     CONF_UART_ID,
     CONF_DATA,
     CONF_RX_BUFFER_SIZE,
@@ -27,6 +28,7 @@ from esphome.const import (
     CONF_DUMMY_RECEIVER,
     CONF_DUMMY_RECEIVER_ID,
     CONF_LAMBDA,
+    PLATFORM_HOST,
 )
 from esphome.core import CORE
 
@@ -45,6 +47,7 @@ RP2040UartComponent = uart_ns.class_("RP2040UartComponent", UARTComponent, cg.Co
 LibreTinyUARTComponent = uart_ns.class_(
     "LibreTinyUARTComponent", UARTComponent, cg.Component
 )
+HostUartComponent = uart_ns.class_("HostUartComponent", UARTComponent, cg.Component)
 
 NATIVE_UART_CLASSES = (
     str(IDFUARTComponent),
@@ -54,6 +57,39 @@ NATIVE_UART_CLASSES = (
     str(LibreTinyUARTComponent),
 )
 
+HOST_BAUD_RATES = [
+    50,
+    75,
+    110,
+    134,
+    150,
+    200,
+    300,
+    600,
+    1200,
+    1800,
+    2400,
+    4800,
+    9600,
+    19200,
+    38400,
+    57600,
+    115200,
+    230400,
+    460800,
+    500000,
+    576000,
+    921600,
+    1000000,
+    1152000,
+    1500000,
+    2000000,
+    2500000,
+    3000000,
+    3500000,
+    4000000,
+]
+
 UARTDevice = uart_ns.class_("UARTDevice")
 UARTWriteAction = uart_ns.class_("UARTWriteAction", automation.Action)
 UARTDebugger = uart_ns.class_("UARTDebugger", cg.Component, automation.Action)
@@ -95,6 +131,20 @@ def validate_invert_esp32(config):
     return config
 
 
+def validate_host_config(config):
+    if CORE.is_host:
+        if CONF_TX_PIN in config or CONF_RX_PIN in config:
+            raise cv.Invalid(
+                "TX and RX pins are not supported for UART on host platform."
+            )
+        if config[CONF_BAUD_RATE] not in HOST_BAUD_RATES:
+            raise cv.Invalid(
+                f"Host platform doesn't support baud rate {config[CONF_BAUD_RATE]}",
+                path=[CONF_BAUD_RATE],
+            )
+    return config
+
+
 def _uart_declare_type(value):
     if CORE.is_esp8266:
         return cv.declare_id(ESP8266UartComponent)(value)
@@ -107,6 +157,8 @@ def _uart_declare_type(value):
         return cv.declare_id(RP2040UartComponent)(value)
     if CORE.is_libretiny:
         return cv.declare_id(LibreTinyUARTComponent)(value)
+    if CORE.is_host:
+        return cv.declare_id(HostUartComponent)(value)
     raise NotImplementedError
 
 
@@ -149,6 +201,12 @@ def maybe_empty_debug(value):
     return DEBUG_SCHEMA(value)
 
 
+def validate_port(value):
+    if not re.match(r"^/(?:[^/]+/)[^/]+$", value):
+        raise cv.Invalid("Port must be a valid device path")
+    return value
+
+
 DEBUG_SCHEMA = cv.Schema(
     {
         cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(UARTDebugger),
@@ -181,6 +239,7 @@ CONFIG_SCHEMA = cv.All(
             cv.Required(CONF_BAUD_RATE): cv.int_range(min=1),
             cv.Optional(CONF_TX_PIN): pins.internal_gpio_output_pin_schema,
             cv.Optional(CONF_RX_PIN): validate_rx_pin,
+            cv.Optional(CONF_PORT): cv.All(validate_port, cv.only_on(PLATFORM_HOST)),
             cv.Optional(CONF_RX_BUFFER_SIZE, default=256): cv.validate_bytes,
             cv.Optional(CONF_STOP_BITS, default=1): cv.one_of(1, 2, int=True),
             cv.Optional(CONF_DATA_BITS, default=8): cv.int_range(min=5, max=8),
@@ -193,8 +252,9 @@ CONFIG_SCHEMA = cv.All(
             cv.Optional(CONF_DEBUG): maybe_empty_debug,
         }
     ).extend(cv.COMPONENT_SCHEMA),
-    cv.has_at_least_one_key(CONF_TX_PIN, CONF_RX_PIN),
+    cv.has_at_least_one_key(CONF_TX_PIN, CONF_RX_PIN, CONF_PORT),
     validate_invert_esp32,
+    validate_host_config,
 )
 
 
@@ -236,6 +296,8 @@ async def to_code(config):
     if CONF_RX_PIN in config:
         rx_pin = await cg.gpio_pin_expression(config[CONF_RX_PIN])
         cg.add(var.set_rx_pin(rx_pin))
+    if CONF_PORT in config:
+        cg.add(var.set_name(config[CONF_PORT]))
     cg.add(var.set_rx_buffer_size(config[CONF_RX_BUFFER_SIZE]))
     cg.add(var.set_stop_bits(config[CONF_STOP_BITS]))
     cg.add(var.set_data_bits(config[CONF_DATA_BITS]))

esphome/components/uart/uart_component_host.cpp

@@ -0,0 +1,295 @@
+#ifdef USE_HOST
+#include "uart_component_host.h"
+#include "esphome/core/application.h"
+#include "esphome/core/defines.h"
+#include "esphome/core/helpers.h"
+#include "esphome/core/log.h"
+
+#ifndef __linux__
+#error This HostUartComponent implementation is only for Linux
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <termios.h>
+#include <sys/ioctl.h>
+
+#ifdef USE_LOGGER
+#include "esphome/components/logger/logger.h"
+#endif
+
+namespace {
+
+speed_t get_baud(int baud) {
+  switch (baud) {
+    case 50:
+      return B50;
+    case 75:
+      return B75;
+    case 110:
+      return B110;
+    case 134:
+      return B134;
+    case 150:
+      return B150;
+    case 200:
+      return B200;
+    case 300:
+      return B300;
+    case 600:
+      return B600;
+    case 1200:
+      return B1200;
+    case 1800:
+      return B1800;
+    case 2400:
+      return B2400;
+    case 4800:
+      return B4800;
+    case 9600:
+      return B9600;
+    case 19200:
+      return B19200;
+    case 38400:
+      return B38400;
+    case 57600:
+      return B57600;
+    case 115200:
+      return B115200;
+    case 230400:
+      return B230400;
+    case 460800:
+      return B460800;
+    case 500000:
+      return B500000;
+    case 576000:
+      return B576000;
+    case 921600:
+      return B921600;
+    case 1000000:
+      return B1000000;
+    case 1152000:
+      return B1152000;
+    case 1500000:
+      return B1500000;
+    case 2000000:
+      return B2000000;
+    case 2500000:
+      return B2500000;
+    case 3000000:
+      return B3000000;
+    case 3500000:
+      return B3500000;
+    case 4000000:
+      return B4000000;
+    default:
+      return B0;
+  }
+}
+
+}  // namespace
+
+namespace esphome {
+namespace uart {
+
+static const char *const TAG = "uart.host";
+
+HostUartComponent::~HostUartComponent() {
+  if (this->file_descriptor_ != -1) {
+    close(this->file_descriptor_);
+    this->file_descriptor_ = -1;
+  }
+}
+
+void HostUartComponent::setup() {
+  ESP_LOGCONFIG(TAG, "Opening UART port...");
+  speed_t baud = get_baud(this->baud_rate_);
+  if (baud == B0) {
+    ESP_LOGE(TAG, "Unsupported baud rate: %d", this->baud_rate_);
+    this->mark_failed();
+    return;
+  }
+  this->file_descriptor_ = ::open(this->port_name_.c_str(), O_RDWR | O_NOCTTY | O_NDELAY);
+  if (this->file_descriptor_ == -1) {
+    this->update_error_(strerror(errno));
+    this->mark_failed();
+    return;
+  }
+  fcntl(this->file_descriptor_, F_SETFL, 0);
+  struct termios options;
+  tcgetattr(this->file_descriptor_, &options);
+  options.c_cflag &= ~CRTSCTS;
+  options.c_cflag |= CREAD | CLOCAL;
+  options.c_lflag &= ~ICANON;
+  options.c_lflag &= ~ECHO;
+  options.c_lflag &= ~ECHOE;
+  options.c_lflag &= ~ECHONL;
+  options.c_lflag &= ~ISIG;
+  options.c_iflag &= ~(IXON | IXOFF | IXANY);
+  options.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL);
+  options.c_oflag &= ~OPOST;
+  options.c_oflag &= ~ONLCR;
+  // Set data bits
+  options.c_cflag &= ~CSIZE;  // Mask the character size bits
+  switch (this->data_bits_) {
+    case 5:
+      options.c_cflag |= CS5;
+      break;
+    case 6:
+      options.c_cflag |= CS6;
+      break;
+    case 7:
+      options.c_cflag |= CS7;
+      break;
+    case 8:
+    default:
+      options.c_cflag |= CS8;
+      break;
+  }
+  // Set parity
+  switch (this->parity_) {
+    case UART_CONFIG_PARITY_NONE:
+      options.c_cflag &= ~PARENB;
+      break;
+    case UART_CONFIG_PARITY_EVEN:
+      options.c_cflag |= PARENB;
+      options.c_cflag &= ~PARODD;
+      break;
+    case UART_CONFIG_PARITY_ODD:
+      options.c_cflag |= PARENB;
+      options.c_cflag |= PARODD;
+      break;
+  };
+  // Set stop bits
+  if (this->stop_bits_ == 2) {
+    options.c_cflag |= CSTOPB;
+  } else {
+    options.c_cflag &= ~CSTOPB;
+  }
+  cfsetispeed(&options, baud);
+  cfsetospeed(&options, baud);
+  tcsetattr(this->file_descriptor_, TCSANOW, &options);
+}
+
+void HostUartComponent::dump_config() {
+  ESP_LOGCONFIG(TAG, "UART:");
+  ESP_LOGCONFIG(TAG, "  Port: %s", this->port_name_.c_str());
+  if (this->file_descriptor_ == -1) {
+    ESP_LOGCONFIG(TAG, "  Port status: Not opened");
+    if (!this->first_error_.empty()) {
+      ESP_LOGCONFIG(TAG, "  Error: %s", this->first_error_.c_str());
+    }
+    return;
+  }
+  ESP_LOGCONFIG(TAG, "  Port status: opened");
+  ESP_LOGCONFIG(TAG, "  Baud Rate: %d", this->baud_rate_);
+  ESP_LOGCONFIG(TAG, "  Data Bits: %d", this->data_bits_);
+  ESP_LOGCONFIG(TAG, "  Parity: %s",
+                this->parity_ == UART_CONFIG_PARITY_NONE   ? "None"
+                : this->parity_ == UART_CONFIG_PARITY_EVEN ? "Even"
+                                                           : "Odd");
+  ESP_LOGCONFIG(TAG, "  Stop Bits: %d", this->stop_bits_);
+  this->check_logger_conflict();
+}
+
+void HostUartComponent::write_array(const uint8_t *data, size_t len) {
+  if (this->file_descriptor_ == -1) {
+    return;
+  }
+  size_t written = ::write(this->file_descriptor_, data, len);
+  if (written != len) {
+    this->update_error_(strerror(errno));
+    return;
+  }
+#ifdef USE_UART_DEBUGGER
+  for (size_t i = 0; i < len; i++) {
+    this->debug_callback_.call(UART_DIRECTION_TX, data[i]);
+  }
+#endif
+  return;
+}
+
+bool HostUartComponent::peek_byte(uint8_t *data) {
+  if (this->file_descriptor_ == -1) {
+    return false;
+  }
+  if (!this->has_peek_) {
+    if (!this->check_read_timeout_()) {
+      return false;
+    }
+    if (::read(this->file_descriptor_, &this->peek_byte_, 1) != 1) {
+      this->update_error_(strerror(errno));
+      return false;
+    }
+    this->has_peek_ = true;
+  }
+  *data = this->peek_byte_;
+  return true;
+}
+
+bool HostUartComponent::read_array(uint8_t *data, size_t len) {
+  if ((this->file_descriptor_ == -1) || (len == 0)) {
+    return false;
+  }
+  if (!this->check_read_timeout_(len))
+    return false;
+  uint8_t *data_ptr = data;
+  size_t length_to_read = len;
+  if (this->has_peek_) {
+    length_to_read--;
+    *data_ptr = this->peek_byte_;
+    data_ptr++;
+    this->has_peek_ = false;
+  }
+  if (length_to_read > 0) {
+    int sz = ::read(this->file_descriptor_, data_ptr, length_to_read);
+    if (sz == -1) {
+      this->update_error_(strerror(errno));
+      return false;
+    }
+  }
+#ifdef USE_UART_DEBUGGER
+  for (size_t i = 0; i < len; i++) {
+    this->debug_callback_.call(UART_DIRECTION_RX, data[i]);
+  }
+#endif
+  return true;
+}
+
+int HostUartComponent::available() {
+  if (this->file_descriptor_ == -1) {
+    return 0;
+  }
+  int available;
+  int res = ioctl(this->file_descriptor_, FIONREAD, &available);
+  if (res == -1) {
+    this->update_error_(strerror(errno));
+    return 0;
+  }
+  if (this->has_peek_)
+    available++;
+  return available;
+};
+
+void HostUartComponent::flush() {
+  if (this->file_descriptor_ == -1) {
+    return;
+  }
+  tcflush(this->file_descriptor_, TCIOFLUSH);
+  ESP_LOGV(TAG, "    Flushing...");
+}
+
+void HostUartComponent::update_error_(const std::string &error) {
+  if (this->first_error_.empty()) {
+    this->first_error_ = error;
+  }
+  ESP_LOGE(TAG, "Port error: %s", error.c_str());
+}
+
+}  // namespace uart
+}  // namespace esphome
+
+#endif  // USE_HOST

esphome/components/uart/uart_component_host.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#ifdef USE_HOST
+
+#include "esphome/core/component.h"
+#include "esphome/core/log.h"
+#include "uart_component.h"
+
+namespace esphome {
+namespace uart {
+
+class HostUartComponent : public UARTComponent, public Component {
+ public:
+  virtual ~HostUartComponent();
+  void setup() override;
+  void dump_config() override;
+  float get_setup_priority() const override { return setup_priority::BUS; }
+  void write_array(const uint8_t *data, size_t len) override;
+  bool peek_byte(uint8_t *data) override;
+  bool read_array(uint8_t *data, size_t len) override;
+  int available() override;
+  void flush() override;
+  void set_name(std::string port_name) { port_name_ = port_name; };
+
+ protected:
+  void update_error_(const std::string &error);
+  void check_logger_conflict() override {}
+  std::string port_name_;
+  std::string first_error_{""};
+  int file_descriptor_ = -1;
+  bool has_peek_{false};
+  uint8_t peek_byte_;
+};
+
+}  // namespace uart
+}  // namespace esphome
+
+#endif  // USE_HOST

tests/components/uart/test.host.yaml

@@ -0,0 +1,13 @@
+esphome:
+  on_boot:
+    then:
+      - uart.write: 'Hello World'
+      - uart.write: [0x00, 0x20, 0x42]
+
+uart:
+  - id: uart_uart
+    port: "/dev/ttyS0"
+    baud_rate: 9600
+    data_bits: 8
+    parity: EVEN
+    stop_bits: 2