allwpilib/hal/src/main/native/systemcore/PWM.cpp

// Copyright (c) FIRST and other WPILib contributors.
// Open Source Software; you can modify and/or share it under the terms of
// the WPILib BSD license file in the root directory of this project.

#include "wpi/hal/PWM.h"

#include <cmath>
#include <cstdio>
#include <thread>

#include <fmt/format.h>

#include "HALInitializer.hpp"
#include "PortsInternal.hpp"
#include "SmartIo.hpp"
#include "wpi/hal/ErrorHandling.hpp"
#include "wpi/hal/Errors.h"
#include "wpi/hal/handles/HandlesInternal.hpp"
#include "wpi/hal/monotonic_clock.hpp"

using namespace wpi::hal;

namespace wpi::hal::init {
void InitializePWM() {}
}  // namespace wpi::hal::init

extern "C" {

HAL_DigitalHandle HAL_InitializePWMPort(int32_t channel,
                                        const char* allocationLocation,
                                        int32_t* status) {
  wpi::hal::init::CheckInit();

  if (channel < 0 || channel >= kNumSmartIo) {
    *status = MakeErrorIndexOutOfRange(HAL_RESOURCE_OUT_OF_RANGE,
                                       "Invalid Index for PWM", 0, kNumSmartIo,
                                       channel);
    return HAL_INVALID_HANDLE;
  }

  auto resource = smartIoHandles->Allocate(channel, HAL_HandleEnum::PWM, "PWM");

  if (!resource) {
    *status = resource.error();
    return HAL_INVALID_HANDLE;  // failed to allocate. Pass error back.
  }

  auto [handle, port] = *resource;
  port->channel = channel;

  *status = port->InitializeMode(SmartIoMode::PwmOutput);
  if (*status != 0) {
    smartIoHandles->Free(handle, HAL_HandleEnum::PWM);
    return HAL_INVALID_HANDLE;
  }

  // Disable the PWM output.
  HAL_SetPWMPulseTimeMicroseconds(handle, 0, status);
  if (*status != 0) {
    smartIoHandles->Free(handle, HAL_HandleEnum::PWM);
    return HAL_INVALID_HANDLE;
  }

  port->previousAllocation = allocationLocation ? allocationLocation : "";

  return handle;
}

void HAL_FreePWMPort(HAL_DigitalHandle pwmPortHandle) {
  auto port = smartIoHandles->Get(pwmPortHandle, HAL_HandleEnum::PWM);
  if (port == nullptr) {
    return;
  }

  smartIoHandles->Free(pwmPortHandle, HAL_HandleEnum::PWM);

  // Wait for no other object to hold this handle.
  auto start = wpi::hal::monotonic_clock::now();
  while (port.use_count() != 1) {
    auto current = wpi::hal::monotonic_clock::now();
    if (start + std::chrono::seconds(1) < current) {
      std::puts("PWM handle free timeout");
      std::fflush(stdout);
      break;
    }
    std::this_thread::yield();
  }
}

void HAL_SetPWMSimDevice(HAL_DigitalHandle handle, HAL_SimDeviceHandle device) {
}

HAL_Bool HAL_CheckPWMChannel(int32_t channel) {
  return channel < kNumSmartIo && channel >= 0;
}

void HAL_SetPWMPulseTimeMicroseconds(HAL_DigitalHandle pwmPortHandle,
                                     int32_t microsecondPulseTime,
                                     int32_t* status) {
  auto port = smartIoHandles->Get(pwmPortHandle, HAL_HandleEnum::PWM);
  if (port == nullptr) {
    *status = HAL_HANDLE_ERROR;
    return;
  }

  if (microsecondPulseTime < 0 ||
      (microsecondPulseTime != 0xFFFF && microsecondPulseTime >= 4096)) {
    *status = MakeError(
        HAL_PARAMETER_OUT_OF_RANGE,
        fmt::format("Pulse time {} out of range. Expect [0-4096) or 0xFFFF",
                    microsecondPulseTime));
    return;
  }

  *status = port->SetPwmMicroseconds(microsecondPulseTime);
}

int32_t HAL_GetPWMPulseTimeMicroseconds(HAL_DigitalHandle pwmPortHandle,
                                        int32_t* status) {
  auto port = smartIoHandles->Get(pwmPortHandle, HAL_HandleEnum::PWM);
  if (port == nullptr) {
    *status = HAL_HANDLE_ERROR;
    return 0;
  }

  uint16_t microseconds = 0;
  *status = port->GetPwmMicroseconds(&microseconds);
  return microseconds;
}

void HAL_SetPWMOutputPeriod(HAL_DigitalHandle pwmPortHandle, int32_t period,
                            int32_t* status) {
  auto port = smartIoHandles->Get(pwmPortHandle, HAL_HandleEnum::PWM);
  if (port == nullptr) {
    *status = HAL_HANDLE_ERROR;
    return;
  }

  switch (period) {
    case 0:
      *status = port->SetPwmOutputPeriod(wpi::hal::PwmOutputPeriod::k5ms);
      break;
    case 1:
    case 2:
      *status = port->SetPwmOutputPeriod(wpi::hal::PwmOutputPeriod::k10ms);
      break;
    case 3:
      *status = port->SetPwmOutputPeriod(wpi::hal::PwmOutputPeriod::k20ms);
      break;
    default:
      *status = HAL_PARAMETER_OUT_OF_RANGE;
      return;
  }
}

}  // extern "C"