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/*
* Copyright 2023 jacqueline <me@jacqueline.id.au>
*
* SPDX-License-Identifier: GPL-3.0-only
*/
#pragma once
#include <stdint.h>
#include <functional>
#include <memory>
#include <optional>
#include <utility>
#include "driver/i2s_std.h"
#include "driver/i2s_types.h"
#include "esp_err.h"
#include "freertos/FreeRTOS.h"
#include "freertos/portmacro.h"
#include "freertos/stream_buffer.h"
#include "result.hpp"
#include "span.hpp"
#include "gpios.hpp"
#include "sys/_stdint.h"
namespace drivers {
// DMA max buffer size for I2S is 4092. We normalise to 2-channel, 16 bit
// audio, which gives us a max of 4092 / 2 / 2 (16 bits) frames. This in turn
// means that at 48kHz, we have about 21ms of budget to fill each buffer.
// We base this off of the maximum DMA size in order to minimise the amount of
// work the CPU has to do to service the DMA callbacks.
constexpr size_t kI2SBufferLengthFrames = 1023;
/**
* Interface for a DAC that receives PCM samples over I2S.
*/
class I2SDac {
public:
static auto create(IGpios& expander) -> std::optional<I2SDac*>;
I2SDac(IGpios& gpio, i2s_chan_handle_t i2s_handle);
~I2SDac();
auto Start() -> void;
auto Stop() -> void;
auto SetPaused(bool) -> void;
enum Channels {
CHANNELS_MONO,
CHANNELS_STEREO,
};
enum BitsPerSample {
BPS_16 = I2S_DATA_BIT_WIDTH_16BIT,
BPS_24 = I2S_DATA_BIT_WIDTH_24BIT,
BPS_32 = I2S_DATA_BIT_WIDTH_32BIT,
};
enum SampleRate {
SAMPLE_RATE_8 = 8000,
SAMPLE_RATE_32 = 32000,
SAMPLE_RATE_44_1 = 44100,
SAMPLE_RATE_48 = 48000,
SAMPLE_RATE_88_2 = 88200,
SAMPLE_RATE_96 = 96000,
};
auto Reconfigure(Channels ch, BitsPerSample bps, SampleRate rate) -> void;
auto WriteData(const cpp::span<const std::byte>& data) -> void;
auto SetSource(StreamBufferHandle_t buffer) -> void;
// Not copyable or movable.
I2SDac(const I2SDac&) = delete;
I2SDac& operator=(const I2SDac&) = delete;
private:
auto set_channel(bool) -> void;
IGpios& gpio_;
i2s_chan_handle_t i2s_handle_;
bool i2s_active_;
StreamBufferHandle_t buffer_;
std::mutex configure_mutex_;
i2s_std_clk_config_t clock_config_;
i2s_std_slot_config_t slot_config_;
};
} // namespace drivers
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