mcp4461.cpp

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#include "mcp4461.h"
 
#include "esphome/core/hal.h"
#include "esphome/core/helpers.h"
 
namespace esphome::mcp4461 {
 
static const char *const TAG = "mcp4461";
constexpr uint8_t EEPROM_WRITE_TIMEOUT_MS = 10;
 
void Mcp4461Component::setup() {
  auto err = this->write(nullptr, 0);
  if (err != i2c::ERROR_OK) {
    this->error_code_ = MCP4461_STATUS_I2C_ERROR;
    this->mark_failed();
    return;
  }
  // save WP/WL status
  this->update_write_protection_status_();
  for (uint8_t i = 0; i < 8; i++) {
    auto init_val = this->reg_[i].initial_value;
    if (init_val.has_value()) {
      uint16_t initial_state = static_cast<uint16_t>(*init_val * 256.0f);
      if (i > 3) {
        // NV wiper: an unconditional write would cost one EEPROM erase/write cycle on EVERY
        // boot. Only write when the stored value actually differs — and always write when
        // the read itself failed (a failed read returns 0, which would silently skip the
        // write whenever initial_value is 0).
        bool read_ok = false;
        if (this->read_wiper_level_(i, &read_ok) != initial_state || !read_ok) {
          this->write_wiper_level_(i, initial_state);
        }
      } else {
        this->write_wiper_level_(i, initial_state);
      }
    }
    if (this->reg_[i].enabled) {
      this->reg_[i].state = this->read_wiper_level_(i);
    } else {
      // only volatile wipers can be set disabled on hw level
      if (i < 4) {
        this->reg_[i].state = 0;
        Mcp4461WiperIdx wiper_idx = static_cast<Mcp4461WiperIdx>(i);
        this->disable_wiper_(wiper_idx);
      }
    }
  }
  // Push the YAML terminal configuration to the TCON registers. TCON is volatile — on POR
  // the chip restores wiper levels from the NV registers but resets TCON to "all terminals
  // connected", so any terminal_a/b/w disables from the config MUST be written here.
  for (uint8_t t = 0; t < 2; t++) {
    Mcp4461TerminalIdx terminal_connector = static_cast<Mcp4461TerminalIdx>(t);
    uint8_t terminal_byte = this->calc_terminal_connector_byte_(terminal_connector);
    this->set_terminal_register_(terminal_connector, terminal_byte);
  }
}
 
void Mcp4461Component::set_nonvolatile(Mcp4461WiperIdx wiper, uint32_t write_delay_ms) {
  uint8_t wiper_idx = static_cast<uint8_t>(wiper);
  if (wiper_idx > 3) {
    return;  // NV channels E-H are the persistence target themselves
  }
  this->reg_[wiper_idx].nonvolatile = true;
  this->reg_[wiper_idx].nonvolatile_write_delay_ms = write_delay_ms;
}
 
void Mcp4461Component::set_initial_value(Mcp4461WiperIdx wiper, float initial_value) {
  uint8_t wiper_idx = static_cast<uint8_t>(wiper);
  this->reg_[wiper_idx].initial_value = initial_value;
}
 
void Mcp4461Component::initialize_terminal_disabled(Mcp4461WiperIdx wiper, char terminal) {
  uint8_t wiper_idx = static_cast<uint8_t>(wiper);
  switch (terminal) {
    case 'a':
      this->reg_[wiper_idx].terminal_a = false;
      break;
    case 'b':
      this->reg_[wiper_idx].terminal_b = false;
      break;
    case 'w':
      this->reg_[wiper_idx].terminal_w = false;
      break;
  }
}
 
void Mcp4461Component::update_write_protection_status_() {
  uint8_t status_register_value = this->get_status_register_();
  this->write_protected_ = static_cast<bool>((status_register_value >> 0) & 0x01);
  this->reg_[0].wiper_lock_active = static_cast<bool>((status_register_value >> 2) & 0x01);
  this->reg_[1].wiper_lock_active = static_cast<bool>((status_register_value >> 3) & 0x01);
  this->reg_[2].wiper_lock_active = static_cast<bool>((status_register_value >> 5) & 0x01);
  this->reg_[3].wiper_lock_active = static_cast<bool>((status_register_value >> 6) & 0x01);
}
 
void Mcp4461Component::dump_config() {
  ESP_LOGCONFIG(TAG, "mcp4461:");
  LOG_I2C_DEVICE(this);
  if (this->is_failed()) {
    ESP_LOGE(TAG, "%s", LOG_STR_ARG(this->get_message_string(this->error_code_)));
  }
  // log wiper status
  for (uint8_t i = 0; i < 8; ++i) {
    // terminals only valid for volatile wipers 0-3 - enable/disable is terminal hw
    // so also invalid for nonvolatile. For these, only print current level.
    // reworked to be a one-line intentionally, as output would not be in order
    if (i < 4) {
      ESP_LOGCONFIG(TAG,
                    "  ├── Volatile wiper [%u] level: %u, Status: %s, HW: %s, "
                    "A: %s, B: %s, W: %s, NV: %s",
                    i, this->reg_[i].state, ONOFF(this->reg_[i].enabled), ONOFF(this->reg_[i].terminal_hw),
                    ONOFF(this->reg_[i].terminal_a), ONOFF(this->reg_[i].terminal_b), ONOFF(this->reg_[i].terminal_w),
                    ONOFF(this->reg_[i].nonvolatile));
    } else {
      ESP_LOGCONFIG(TAG, "  ├── Nonvolatile wiper [%u] level: %u", i, this->reg_[i].state);
    }
  }
}
 
void Mcp4461Component::loop() {
  if (this->status_has_warning()) {
    this->get_status_register_();
  }
  for (uint8_t i = 0; i < 8; i++) {
    if (this->reg_[i].update_level) {
      // set wiper i state if changed — a failed read (returns 0) must not suppress the
      // write when the target state is 0, same hardening as the NV read-compare paths
      bool read_ok = false;
      if (this->reg_[i].state != this->read_wiper_level_(i, &read_ok) || !read_ok) {
        this->write_wiper_level_(i, this->reg_[i].state);
      }
    }
    this->reg_[i].update_level = false;
    // can be true only for wipers 0-3
    // setting changes for terminals of nonvolatile wipers
    // is prohibited in public methods
    if (this->reg_[i].update_terminal) {
      // set terminal register changes
      Mcp4461TerminalIdx terminal_connector =
          i < 2 ? Mcp4461TerminalIdx::MCP4461_TERMINAL_0 : Mcp4461TerminalIdx::MCP4461_TERMINAL_1;
      uint8_t new_terminal_value = this->calc_terminal_connector_byte_(terminal_connector);
      ESP_LOGV(TAG, "updating terminal %u to new value %u", static_cast<uint8_t>(terminal_connector),
               new_terminal_value);
      this->set_terminal_register_(terminal_connector, new_terminal_value);
    }
    this->reg_[i].update_terminal = false;
  }
  this->process_nonvolatile_dirty_();
}
 
void Mcp4461Component::process_nonvolatile_dirty_() {
  const uint32_t now = millis();
  for (uint8_t i = 0; i < 4; i++) {
    if (!this->reg_[i].nonvolatile || !this->reg_[i].nonvolatile_dirty) {
      continue;
    }
    if ((now - this->reg_[i].last_level_change_ms) < this->reg_[i].nonvolatile_write_delay_ms) {
      continue;  // still settling — debounce window not over yet
    }
    // Never block the loop on a still-running EEPROM cycle (t_WC up to 10 ms); datasheet:
    // during an EEPROM write only volatile commands are accepted. Retry on the next loop.
    if (this->is_writing_()) {
      continue;
    }
    // Clear the dirty flag on success — and equally when WP or WiperLock block the write
    // permanently, instead of retrying forever.
    if (this->store_level_nonvolatile_(static_cast<Mcp4461WiperIdx>(i)) || this->write_protected_ ||
        this->reg_[i].wiper_lock_active) {
      this->reg_[i].nonvolatile_dirty = false;
    } else {
      // Transient failure (e.g. I2C error): without this, the retry fires on every single
      // loop() iteration, spamming a warning each time. Re-arming the timestamp reuses the
      // stability delay as a natural retry backoff.
      this->reg_[i].last_level_change_ms = now;
    }
  }
}
 
bool Mcp4461Component::store_level_nonvolatile_(Mcp4461WiperIdx wiper) {
  if (this->is_failed()) {
    ESP_LOGE(TAG, "%s", LOG_STR_ARG(this->get_message_string(this->error_code_)));
    return false;
  }
  uint8_t wiper_idx = static_cast<uint8_t>(wiper);
  if (wiper_idx > 3) {
    // E-H ARE the nonvolatile registers — keep this consistent with the other guards
    // instead of failing silently (reachable via the store_nonvolatile action).
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_PROHIBITED_FOR_NONVOLATILE)));
    return false;
  }
  if (this->reg_[wiper_idx].wiper_lock_active) {
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_WIPER_LOCKED)));
    return false;
  }
  const uint16_t level = this->reg_[wiper_idx].state;
  // Skip the EEPROM cycle entirely when the NV register already holds the value. A failed
  // read must NOT count as a match (it returns 0): fall through to the write instead — if
  // the bus is really down, the write fails too and the dirty flag stays set for a retry.
  bool read_ok = false;
  if (this->read_wiper_level_(wiper_idx + 4, &read_ok) == level && read_ok) {
    return true;
  }
  ESP_LOGV(TAG, "Persisting wiper %u level %u to nonvolatile register", wiper_idx, level);
  if (!this->mcp4461_write_(this->get_wiper_address_(wiper_idx + 4), level, true)) {
    ESP_LOGW(TAG, "Error persisting wiper %u level %u", wiper_idx, level);
    return false;
  }
  return true;
}
 
uint8_t Mcp4461Component::get_status_register_() {
  if (this->is_failed()) {
    ESP_LOGE(TAG, "%s", LOG_STR_ARG(this->get_message_string(this->error_code_)));
    return 0;
  }
  uint8_t addr = static_cast<uint8_t>(Mcp4461Addresses::MCP4461_STATUS);
  uint8_t reg = addr | static_cast<uint8_t>(Mcp4461Commands::READ);
  uint16_t buf;
  if (!this->read_16_(reg, &buf)) {
    this->error_code_ = MCP4461_STATUS_REGISTER_ERROR;
    this->mark_failed();
    return 0;
  }
  uint8_t msb = buf >> 8;
  uint8_t lsb = static_cast<uint8_t>(buf & 0x00ff);
  if (msb != 1 || ((lsb >> 7) & 0x01) != 1 || ((lsb >> 1) & 0x01) != 1) {
    // D8, D7 and R1 bits are hardlocked to 1 -> a status msb bit 0 (bit 9 of status register) of 0 or lsb bit 1/7 = 0
    // indicate device/communication issues, therefore mark component failed
    this->error_code_ = MCP4461_STATUS_REGISTER_INVALID;
    this->mark_failed();
    return 0;
  }
  this->status_clear_warning();
  return lsb;
}
 
void Mcp4461Component::read_status_register_to_log() {
  uint8_t status_register_value = this->get_status_register_();
  ESP_LOGI(TAG, "D7:  %u, WL3: %u, WL2: %u, EEWA: %u, WL1: %u, WL0: %u, R1: %u, WP: %u",
           ((status_register_value >> 7) & 0x01), ((status_register_value >> 6) & 0x01),
           ((status_register_value >> 5) & 0x01), ((status_register_value >> 4) & 0x01),
           ((status_register_value >> 3) & 0x01), ((status_register_value >> 2) & 0x01),
           ((status_register_value >> 1) & 0x01), ((status_register_value >> 0) & 0x01));
}
bool Mcp4461Component::read_16_(uint8_t address, uint16_t *buf) {
  // read 16 bits and convert from big endian to host,
  // Do this as two separate operations to ensure a stop condition between the write and read
  i2c::ErrorCode err = this->write(&address, 1);
  if (err != i2c::ERROR_OK) {
    return false;
  }
  err = this->read(reinterpret_cast<uint8_t *>(buf), 2);
  if (err != i2c::ERROR_OK) {
    return false;
  }
  *buf = convert_big_endian(*buf);
  return true;
}
 
uint8_t Mcp4461Component::get_wiper_address_(uint8_t wiper) {
  uint8_t addr;
  bool nonvolatile = false;
  if (wiper > 3) {
    nonvolatile = true;
    wiper = wiper - 4;
  }
  switch (wiper) {
    case 0:
      addr = static_cast<uint8_t>(Mcp4461Addresses::MCP4461_VW0);
      break;
    case 1:
      addr = static_cast<uint8_t>(Mcp4461Addresses::MCP4461_VW1);
      break;
    case 2:
      addr = static_cast<uint8_t>(Mcp4461Addresses::MCP4461_VW2);
      break;
    case 3:
      addr = static_cast<uint8_t>(Mcp4461Addresses::MCP4461_VW3);
      break;
    default:
      ESP_LOGW(TAG, "unknown wiper specified");
      return 0;
  }
  if (nonvolatile) {
    addr = addr + 0x20;
  }
  return addr;
}
 
uint16_t Mcp4461Component::get_wiper_level_(Mcp4461WiperIdx wiper) {
  if (this->is_failed()) {
    ESP_LOGE(TAG, "%s", LOG_STR_ARG(this->get_message_string(this->error_code_)));
    return 0;
  }
  uint8_t wiper_idx = static_cast<uint8_t>(wiper);
  if (!(this->reg_[wiper_idx].enabled)) {
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_WIPER_DISABLED)));
    return 0;
  }
  if (!(this->reg_[wiper_idx].enabled)) {
    ESP_LOGW(TAG, "reading from disabled volatile wiper %u, returning 0", wiper_idx);
    return 0;
  }
  return this->read_wiper_level_(wiper_idx);
}
 
uint16_t Mcp4461Component::read_wiper_level_(uint8_t wiper_idx, bool *ok) {
  if (ok != nullptr) {
    *ok = false;
  }
  uint8_t addr = this->get_wiper_address_(wiper_idx);
  uint8_t reg = addr | static_cast<uint8_t>(Mcp4461Commands::READ);
  if (wiper_idx > 3) {
    if (!this->is_eeprom_ready_for_writing_(true)) {
      return 0;
    }
  }
  uint16_t buf = 0;
  if (!(this->read_16_(reg, &buf))) {
    this->error_code_ = MCP4461_STATUS_I2C_ERROR;
    this->status_set_warning();
    ESP_LOGW(TAG, "Error fetching %swiper %u value", (wiper_idx > 3) ? LOG_STR_LITERAL("nonvolatile ") : "", wiper_idx);
    return 0;
  }
  if (ok != nullptr) {
    *ok = true;
  }
  return buf;
}
 
bool Mcp4461Component::update_wiper_level_(Mcp4461WiperIdx wiper) {
  if (this->is_failed()) {
    ESP_LOGE(TAG, "%s", LOG_STR_ARG(this->get_message_string(this->error_code_)));
    return false;
  }
  uint8_t wiper_idx = static_cast<uint8_t>(wiper);
  if (!(this->reg_[wiper_idx].enabled)) {
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_WIPER_DISABLED)));
    return false;
  }
  uint16_t data = this->get_wiper_level_(wiper);
  ESP_LOGV(TAG, "Got value %u from wiper %u", data, wiper_idx);
  this->reg_[wiper_idx].state = data;
  return true;
}
 
bool Mcp4461Component::set_wiper_level_(Mcp4461WiperIdx wiper, uint16_t value) {
  if (this->is_failed()) {
    ESP_LOGE(TAG, "%s", LOG_STR_ARG(this->get_message_string(this->error_code_)));
    return false;
  }
  uint8_t wiper_idx = static_cast<uint8_t>(wiper);
  if (value > 0x100) {
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_VALUE_INVALID)));
    return false;
  }
  if (!(this->reg_[wiper_idx].enabled)) {
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_WIPER_DISABLED)));
    return false;
  }
  if (this->reg_[wiper_idx].wiper_lock_active) {
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_WIPER_LOCKED)));
    return false;
  }
  ESP_LOGV(TAG, "Setting MCP4461 wiper %u to %u", wiper_idx, value);
  this->reg_[wiper_idx].state = value;
  this->reg_[wiper_idx].update_level = true;
  if (this->reg_[wiper_idx].nonvolatile) {
    this->reg_[wiper_idx].nonvolatile_dirty = true;
    this->reg_[wiper_idx].last_level_change_ms = millis();
  }
  return true;
}
 
void Mcp4461Component::write_wiper_level_(uint8_t wiper, uint16_t value) {
  bool nonvolatile = wiper > 3;
  if (!(this->mcp4461_write_(this->get_wiper_address_(wiper), value, nonvolatile))) {
    this->error_code_ = MCP4461_STATUS_I2C_ERROR;
    this->status_set_warning();
    ESP_LOGW(TAG, "Error writing %swiper %u level %u", (wiper > 3) ? LOG_STR_LITERAL("nonvolatile ") : "", wiper,
             value);
  }
}
 
void Mcp4461Component::enable_wiper_(Mcp4461WiperIdx wiper) {
  if (this->is_failed()) {
    ESP_LOGE(TAG, "%s", LOG_STR_ARG(this->get_message_string(this->error_code_)));
    return;
  }
  uint8_t wiper_idx = static_cast<uint8_t>(wiper);
  if ((this->reg_[wiper_idx].enabled)) {
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_WIPER_ENABLED)));
    return;
  }
  if (this->reg_[wiper_idx].wiper_lock_active) {
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_WIPER_LOCKED)));
    return;
  }
  ESP_LOGV(TAG, "Enabling wiper %u", wiper_idx);
  this->reg_[wiper_idx].enabled = true;
  if (wiper_idx < 4) {
    this->reg_[wiper_idx].terminal_hw = true;
    this->reg_[wiper_idx].update_terminal = true;
  }
}
 
void Mcp4461Component::disable_wiper_(Mcp4461WiperIdx wiper) {
  if (this->is_failed()) {
    ESP_LOGE(TAG, "%s", LOG_STR_ARG(this->get_message_string(this->error_code_)));
    return;
  }
  uint8_t wiper_idx = static_cast<uint8_t>(wiper);
  if (!(this->reg_[wiper_idx].enabled)) {
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_WIPER_DISABLED)));
    return;
  }
  if (this->reg_[wiper_idx].wiper_lock_active) {
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_WIPER_LOCKED)));
    return;
  }
  ESP_LOGV(TAG, "Disabling wiper %u", wiper_idx);
  this->reg_[wiper_idx].enabled = false;
  if (wiper_idx < 4) {
    this->reg_[wiper_idx].terminal_hw = false;
    this->reg_[wiper_idx].update_terminal = true;
  }
}
 
bool Mcp4461Component::increase_wiper_(Mcp4461WiperIdx wiper) {
  if (this->is_failed()) {
    ESP_LOGE(TAG, "%s", LOG_STR_ARG(this->get_message_string(this->error_code_)));
    return false;
  }
  uint8_t wiper_idx = static_cast<uint8_t>(wiper);
  if (!(this->reg_[wiper_idx].enabled)) {
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_WIPER_DISABLED)));
    return false;
  }
  if (this->reg_[wiper_idx].wiper_lock_active) {
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_WIPER_LOCKED)));
    return false;
  }
  if (wiper_idx > 3) {
    // Datasheet: increment commands are only valid for the volatile wiper registers —
    // the chip NACKs them on nonvolatile addresses.
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_PROHIBITED_FOR_NONVOLATILE)));
    return false;
  }
  if (this->reg_[wiper_idx].state == 256) {
    ESP_LOGV(TAG, "Maximum wiper level reached, further increase of wiper %u prohibited", wiper_idx);
    return false;
  }
  ESP_LOGV(TAG, "Increasing wiper %u", wiper_idx);
  uint8_t addr = this->get_wiper_address_(wiper_idx);
  uint8_t reg = addr | static_cast<uint8_t>(Mcp4461Commands::INCREMENT);
  auto err = this->write(&reg, 1);
  if (err != i2c::ERROR_OK) {
    this->error_code_ = MCP4461_STATUS_I2C_ERROR;
    this->status_set_warning();
    return false;
  }
  this->reg_[wiper_idx].state++;
  if (this->reg_[wiper_idx].nonvolatile) {
    this->reg_[wiper_idx].nonvolatile_dirty = true;
    this->reg_[wiper_idx].last_level_change_ms = millis();
  }
  return true;
}
 
bool Mcp4461Component::decrease_wiper_(Mcp4461WiperIdx wiper) {
  if (this->is_failed()) {
    ESP_LOGE(TAG, "%s", LOG_STR_ARG(this->get_message_string(this->error_code_)));
    return false;
  }
  uint8_t wiper_idx = static_cast<uint8_t>(wiper);
  if (!(this->reg_[wiper_idx].enabled)) {
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_WIPER_DISABLED)));
    return false;
  }
  if (this->reg_[wiper_idx].wiper_lock_active) {
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_WIPER_LOCKED)));
    return false;
  }
  if (wiper_idx > 3) {
    // Datasheet: decrement commands are only valid for the volatile wiper registers —
    // the chip NACKs them on nonvolatile addresses.
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_PROHIBITED_FOR_NONVOLATILE)));
    return false;
  }
  if (this->reg_[wiper_idx].state == 0) {
    ESP_LOGV(TAG, "Minimum wiper level reached, further decrease of wiper %u prohibited", wiper_idx);
    return false;
  }
  ESP_LOGV(TAG, "Decreasing wiper %u", wiper_idx);
  uint8_t addr = this->get_wiper_address_(wiper_idx);
  uint8_t reg = addr | static_cast<uint8_t>(Mcp4461Commands::DECREMENT);
  auto err = this->write(&reg, 1);
  if (err != i2c::ERROR_OK) {
    this->error_code_ = MCP4461_STATUS_I2C_ERROR;
    this->status_set_warning();
    return false;
  }
  this->reg_[wiper_idx].state--;
  if (this->reg_[wiper_idx].nonvolatile) {
    this->reg_[wiper_idx].nonvolatile_dirty = true;
    this->reg_[wiper_idx].last_level_change_ms = millis();
  }
  return true;
}
 
uint8_t Mcp4461Component::calc_terminal_connector_byte_(Mcp4461TerminalIdx terminal_connector) {
  // TCON0 covers wipers 0/1 (A/B), TCON1 covers wipers 2/3 (C/D). The enum only holds
  // 0 and 1, so the old `<= 1 ? 0 : 2` collapsed to always-0 and built TCON1 from
  // channels A/B's flags — mirror the (correct) read path in update_terminal_register_().
  uint8_t i = static_cast<uint8_t>(terminal_connector) == 0 ? 0 : 2;
  uint8_t new_value_byte = 0;
  new_value_byte += static_cast<uint8_t>(this->reg_[i].terminal_b);
  new_value_byte += static_cast<uint8_t>(this->reg_[i].terminal_w) << 1;
  new_value_byte += static_cast<uint8_t>(this->reg_[i].terminal_a) << 2;
  new_value_byte += static_cast<uint8_t>(this->reg_[i].terminal_hw) << 3;
  new_value_byte += static_cast<uint8_t>(this->reg_[(i + 1)].terminal_b) << 4;
  new_value_byte += static_cast<uint8_t>(this->reg_[(i + 1)].terminal_w) << 5;
  new_value_byte += static_cast<uint8_t>(this->reg_[(i + 1)].terminal_a) << 6;
  new_value_byte += static_cast<uint8_t>(this->reg_[(i + 1)].terminal_hw) << 7;
  return new_value_byte;
}
 
uint8_t Mcp4461Component::get_terminal_register_(Mcp4461TerminalIdx terminal_connector) {
  if (this->is_failed()) {
    ESP_LOGE(TAG, "%s", LOG_STR_ARG(this->get_message_string(this->error_code_)));
    return 0;
  }
  uint8_t reg = static_cast<uint8_t>(terminal_connector) == 0 ? static_cast<uint8_t>(Mcp4461Addresses::MCP4461_TCON0)
                                                              : static_cast<uint8_t>(Mcp4461Addresses::MCP4461_TCON1);
  reg |= static_cast<uint8_t>(Mcp4461Commands::READ);
  uint16_t buf;
  if (this->read_16_(reg, &buf)) {
    return static_cast<uint8_t>(buf & 0x00ff);
  } else {
    this->error_code_ = MCP4461_STATUS_I2C_ERROR;
    this->status_set_warning();
    ESP_LOGW(TAG, "Error fetching terminal register value");
    return 0;
  }
}
 
void Mcp4461Component::update_terminal_register_(Mcp4461TerminalIdx terminal_connector) {
  if (this->is_failed()) {
    ESP_LOGE(TAG, "%s", LOG_STR_ARG(this->get_message_string(this->error_code_)));
    return;
  }
  if ((static_cast<uint8_t>(terminal_connector) != 0 && static_cast<uint8_t>(terminal_connector) != 1)) {
    return;
  }
  uint8_t terminal_data = this->get_terminal_register_(terminal_connector);
  if (terminal_data == 0) {
    return;
  }
  ESP_LOGV(TAG, "Got terminal register %u data 0x%02X", static_cast<uint8_t>(terminal_connector), terminal_data);
  uint8_t wiper_index = 0;
  if (static_cast<uint8_t>(terminal_connector) == 1) {
    wiper_index = 2;
  }
  this->reg_[wiper_index].terminal_b = ((terminal_data >> 0) & 0x01);
  this->reg_[wiper_index].terminal_w = ((terminal_data >> 1) & 0x01);
  this->reg_[wiper_index].terminal_a = ((terminal_data >> 2) & 0x01);
  this->reg_[wiper_index].terminal_hw = ((terminal_data >> 3) & 0x01);
  this->reg_[(wiper_index + 1)].terminal_b = ((terminal_data >> 4) & 0x01);
  this->reg_[(wiper_index + 1)].terminal_w = ((terminal_data >> 5) & 0x01);
  this->reg_[(wiper_index + 1)].terminal_a = ((terminal_data >> 6) & 0x01);
  this->reg_[(wiper_index + 1)].terminal_hw = ((terminal_data >> 7) & 0x01);
}
 
bool Mcp4461Component::set_terminal_register_(Mcp4461TerminalIdx terminal_connector, uint8_t data) {
  if (this->is_failed()) {
    ESP_LOGE(TAG, "%s", LOG_STR_ARG(this->get_message_string(this->error_code_)));
    return false;
  }
  uint8_t addr;
  if (static_cast<uint8_t>(terminal_connector) == 0) {
    addr = static_cast<uint8_t>(Mcp4461Addresses::MCP4461_TCON0);
  } else if (static_cast<uint8_t>(terminal_connector) == 1) {
    addr = static_cast<uint8_t>(Mcp4461Addresses::MCP4461_TCON1);
  } else {
    ESP_LOGW(TAG, "Invalid terminal connector id %u specified", static_cast<uint8_t>(terminal_connector));
    return false;
  }
  if (!(this->mcp4461_write_(addr, data))) {
    this->error_code_ = MCP4461_STATUS_I2C_ERROR;
    this->status_set_warning();
    return false;
  }
  return true;
}
 
void Mcp4461Component::enable_terminal_(Mcp4461WiperIdx wiper, char terminal) {
  if (this->is_failed()) {
    ESP_LOGE(TAG, "%s", LOG_STR_ARG(this->get_message_string(this->error_code_)));
    return;
  }
  uint8_t wiper_idx = static_cast<uint8_t>(wiper);
  if (wiper_idx > 3) {
    // Terminal control only exists for the volatile wipers; loop() would otherwise emit
    // an unrelated TCON write and silently drop the request.
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_PROHIBITED_FOR_NONVOLATILE)));
    return;
  }
  ESP_LOGV(TAG, "Enabling terminal %c of wiper %u", terminal, wiper_idx);
  switch (terminal) {
    case 'h':
      this->reg_[wiper_idx].terminal_hw = true;
      break;
    case 'a':
      this->reg_[wiper_idx].terminal_a = true;
      break;
    case 'b':
      this->reg_[wiper_idx].terminal_b = true;
      break;
    case 'w':
      this->reg_[wiper_idx].terminal_w = true;
      break;
    default:
      ESP_LOGW(TAG, "Unknown terminal %c specified", terminal);
      return;
  }
  this->reg_[wiper_idx].update_terminal = true;
}
 
void Mcp4461Component::disable_terminal_(Mcp4461WiperIdx wiper, char terminal) {
  if (this->is_failed()) {
    ESP_LOGE(TAG, "%s", LOG_STR_ARG(this->get_message_string(this->error_code_)));
    return;
  }
  uint8_t wiper_idx = static_cast<uint8_t>(wiper);
  if (wiper_idx > 3) {
    ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_PROHIBITED_FOR_NONVOLATILE)));
    return;
  }
  ESP_LOGV(TAG, "Disabling terminal %c of wiper %u", terminal, wiper_idx);
  switch (terminal) {
    case 'h':
      this->reg_[wiper_idx].terminal_hw = false;
      break;
    case 'a':
      this->reg_[wiper_idx].terminal_a = false;
      break;
    case 'b':
      this->reg_[wiper_idx].terminal_b = false;
      break;
    case 'w':
      this->reg_[wiper_idx].terminal_w = false;
      break;
    default:
      ESP_LOGW(TAG, "Unknown terminal %c specified", terminal);
      return;
  }
  this->reg_[wiper_idx].update_terminal = true;
}
 
uint16_t Mcp4461Component::get_eeprom_value(Mcp4461EepromLocation location) {
  if (this->is_failed()) {
    ESP_LOGE(TAG, "%s", LOG_STR_ARG(this->get_message_string(this->error_code_)));
    return 0;
  }
  uint8_t reg = 0;
  reg |= static_cast<uint8_t>(Mcp4461EepromLocation::MCP4461_EEPROM_1) + (static_cast<uint8_t>(location) * 0x10);
  reg |= static_cast<uint8_t>(Mcp4461Commands::READ);
  uint16_t buf;
  if (!this->is_eeprom_ready_for_writing_(true)) {
    return 0;
  }
  if (!this->read_16_(reg, &buf)) {
    this->error_code_ = MCP4461_STATUS_I2C_ERROR;
    this->status_set_warning();
    ESP_LOGW(TAG, "Error fetching EEPROM location value");
    return 0;
  }
  return buf;
}
 
bool Mcp4461Component::set_eeprom_value(Mcp4461EepromLocation location, uint16_t value) {
  if (this->is_failed()) {
    ESP_LOGE(TAG, "%s", LOG_STR_ARG(this->get_message_string(this->error_code_)));
    return false;
  }
  uint8_t addr = 0;
  if (value > 511) {
    return false;
  }
  if (value > 256) {
    addr = 1;
  }
  addr |= static_cast<uint8_t>(Mcp4461EepromLocation::MCP4461_EEPROM_1) + (static_cast<uint8_t>(location) * 0x10);
  if (!(this->mcp4461_write_(addr, value, true))) {
    this->error_code_ = MCP4461_STATUS_I2C_ERROR;
    this->status_set_warning();
    ESP_LOGW(TAG, "Error writing EEPROM value");
    return false;
  }
  return true;
}
 
bool Mcp4461Component::is_writing_() {
  /* Read the EEPROM write-active status from the status register */
  bool writing = static_cast<bool>((this->get_status_register_() >> 4) & 0x01);
 
  /* If EEPROM is no longer writing, reset the timeout flag */
  if (!writing) {
    /* This is protected boolean flag in Mcp4461Component class */
    this->last_eeprom_write_timed_out_ = false;
  }
 
  return writing;
}
 
bool Mcp4461Component::is_eeprom_ready_for_writing_(bool wait_if_not_ready) {
  /* Check initial write status */
  bool ready_for_write = !this->is_writing_();
 
  /* Return early if no waiting is required or EEPROM is already ready */
  if (ready_for_write || !wait_if_not_ready || this->last_eeprom_write_timed_out_) {
    return ready_for_write;
  }
 
  /* Timestamp before starting the loop */
  const uint32_t start_millis = millis();
 
  ESP_LOGV(TAG, "Waiting until EEPROM is ready for write, start_millis = %" PRIu32, start_millis);
 
  /* Loop until EEPROM is ready or timeout is reached */
  while (!ready_for_write && ((millis() - start_millis) < EEPROM_WRITE_TIMEOUT_MS)) {
    ready_for_write = !this->is_writing_();
 
    /* If ready, exit early */
    if (ready_for_write) {
      ESP_LOGV(TAG, "EEPROM is ready for new write, elapsed_millis = %" PRIu32, millis() - start_millis);
      return true;
    }
 
    /* Not ready yet, yield before checking again */
    yield();
  }
 
  /* If still not ready after timeout, log error and mark the timeout */
  ESP_LOGE(TAG, "EEPROM write timeout exceeded (%u ms)", EEPROM_WRITE_TIMEOUT_MS);
  this->last_eeprom_write_timed_out_ = true;
 
  return false;
}
 
bool Mcp4461Component::mcp4461_write_(uint8_t addr, uint16_t data, bool nonvolatile) {
  uint8_t reg = data > 0xff ? 1 : 0;
  uint8_t value_byte = static_cast<uint8_t>(data & 0x00ff);
  ESP_LOGV(TAG, "Writing value %u to address %u", data, addr);
  reg |= addr;
  reg |= static_cast<uint8_t>(Mcp4461Commands::WRITE);
  if (nonvolatile) {
    if (this->write_protected_) {
      ESP_LOGW(TAG, "%s", LOG_STR_ARG(this->get_message_string(MCP4461_WRITE_PROTECTED)));
      return false;
    }
    if (!this->is_eeprom_ready_for_writing_(true)) {
      return false;
    }
  }
  return this->write_byte(reg, value_byte);
}
}  // namespace esphome::mcp4461