tangara-fw/src/drivers/touchwheel.cpp

#include "touchwheel.hpp"
#include <stdint.h>

#include <cstdint>

#include "assert.h"
#include "driver/gpio.h"
#include "driver/i2c.h"
#include "esp_err.h"
#include "esp_log.h"
#include "freertos/projdefs.h"
#include "hal/gpio_types.h"
#include "hal/i2c_types.h"

#include "i2c.hpp"

namespace drivers {

static const char* kTag = "TOUCHWHEEL";
static const uint8_t kTouchWheelAddress = 0x1C;
static const gpio_num_t kIntPin = GPIO_NUM_25;

TouchWheel::TouchWheel() {
  gpio_config_t int_config{
      .pin_bit_mask = 1ULL << kIntPin,
      .mode = GPIO_MODE_INPUT,
      .pull_up_en = GPIO_PULLUP_ENABLE,
      .pull_down_en = GPIO_PULLDOWN_DISABLE,
      .intr_type = GPIO_INTR_DISABLE,
  };
  gpio_config(&int_config);

  WriteRegister(Register::RESET, 1);
  // TODO(daniel): do we need this? how long does reset take?
  vTaskDelay(pdMS_TO_TICKS(1));
  WriteRegister(Register::SLIDER_OPTIONS, 0b11000000);
  WriteRegister(Register::CALIBRATE, 1);
  // Confusingly-named; this sets to max-power max-response-time.
  WriteRegister(Register::LOW_POWER, 1);
  // TODO(jacqueline): Temp to debug touchwheel responsiveness.
  WriteRegister(Register::CHARGE_TIME, 8);
}

TouchWheel::~TouchWheel() {}

void TouchWheel::WriteRegister(uint8_t reg, uint8_t val) {
  // uint8_t maskedReg = reg | kWriteMask;
  uint8_t maskedReg = reg;
  I2CTransaction transaction;
  transaction.start()
      .write_addr(kTouchWheelAddress, I2C_MASTER_WRITE)
      .write_ack(maskedReg, val)
      .stop();
  transaction.Execute();
  // TODO(jacqueline): check for errors again when i find where all the ffc
  // cables went q.q
  // ESP_ERROR_CHECK(transaction.Execute());
}

uint8_t TouchWheel::ReadRegister(uint8_t reg) {
  uint8_t res;
  I2CTransaction transaction;
  transaction.start()
      .write_addr(kTouchWheelAddress, I2C_MASTER_WRITE)
      .write_ack(reg)
      .start()
      .write_addr(kTouchWheelAddress, I2C_MASTER_READ)
      .read(&res, I2C_MASTER_NACK)
      .stop();
  ESP_ERROR_CHECK(transaction.Execute());
  return res;
}

void TouchWheel::Update() {
  // Read data from device into member struct
  bool has_data = !gpio_get_level(GPIO_NUM_25);
  if (!has_data) {
    return;
  }
  uint8_t status = ReadRegister(Register::DETECTION_STATUS);
  if (status & 0b10000000) {
    // Still calibrating.
    return;
  }
  if (status & 0b01000000) {
    // Probably okay, but we should keep an eye on this for development.
    ESP_LOGW(kTag, "touchwheel acquisition >16ms");
  }
  if (status & 0b10) {
    // Slider detect.
    data_.wheel_position = ReadRegister(Register::SLIDER_POSITION);
  }
  if (status & 0b1) {
    // Key detect.
    // TODO(daniel): implement me
    // Ensure we read all status registers -- even if we're not using them -- to
    // ensure that INT can float high again.
    ReadRegister(Register::KEY_STATUS_A);
    ReadRegister(Register::KEY_STATUS_B);
  }
}

TouchWheelData TouchWheel::GetTouchWheelData() const {
  return data_;
}

}  // namespace drivers