From 5f7444d7956a6cc517ada1b8b96c4f9cdd408fd5 Mon Sep 17 00:00:00 2001
From: jacqueline <me@jacqueline.id.au>
Date: Mon, 21 Nov 2022 08:00:52 +1100
Subject: WIP

---
 src/audio/i2s_audio_output.cpp | 114 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 src/audio/i2s_audio_output.cpp

(limited to 'src/audio/i2s_audio_output.cpp')

diff --git a/src/audio/i2s_audio_output.cpp b/src/audio/i2s_audio_output.cpp
new file mode 100644
index 00000000..77d01b6a
--- /dev/null
+++ b/src/audio/i2s_audio_output.cpp
@@ -0,0 +1,114 @@
+#include "i2s_audio_output.hpp"
+
+#include <algorithm>
+
+#include "audio_element.h"
+#include "driver/i2s.h"
+#include "esp_err.h"
+#include "freertos/portmacro.h"
+#include "i2s_stream.h"
+
+static const i2s_port_t kI2SPort = I2S_NUM_0;
+static const char* kTag = "I2SOUT";
+
+namespace drivers {
+
+auto I2SAudioOutput::create(GpioExpander* expander)
+    -> cpp::result<std::unique_ptr<I2SAudioOutput>, Error> {
+  // First, we need to perform initial configuration of the DAC chip.
+  auto dac_result = drivers::AudioDac::create(expander);
+  if (dac_result.has_error()) {
+    ESP_LOGE(kTag, "failed to init dac: %d", dac_result.error());
+    return cpp::fail(DAC_CONFIG);
+  }
+  std::unique_ptr<AudioDac> dac = std::move(dac_result.value());
+
+  // Soft mute immediately, in order to minimise any clicks and pops caused by
+  // the initial output element and pipeline configuration.
+  dac->WriteVolume(255);
+
+  i2s_stream_cfg_t i2s_stream_config = i2s_stream_cfg_t{
+      .type = AUDIO_STREAM_WRITER,
+      .i2s_config =
+          {
+              // static_cast bc esp-adf uses enums incorrectly
+              .mode = static_cast<i2s_mode_t>(I2S_MODE_MASTER | I2S_MODE_TX),
+              .sample_rate = 44100,
+              .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,
+              .channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT,
+              .communication_format = I2S_COMM_FORMAT_STAND_I2S,
+              .intr_alloc_flags = ESP_INTR_FLAG_LOWMED,
+              .dma_buf_count = 8,
+              .dma_buf_len = 64,
+              .use_apll = false,
+              .tx_desc_auto_clear = false,
+              .fixed_mclk = 0,
+              .mclk_multiple = I2S_MCLK_MULTIPLE_DEFAULT,
+              .bits_per_chan = I2S_BITS_PER_CHAN_DEFAULT,
+          },
+      .i2s_port = kI2SPort,
+      .use_alc = false,
+      .volume = 0,  // Does nothing; use AudioDac to change this.
+      .out_rb_size = I2S_STREAM_RINGBUFFER_SIZE,
+      .task_stack = I2S_STREAM_TASK_STACK,
+      .task_core = I2S_STREAM_TASK_CORE,
+      .task_prio = I2S_STREAM_TASK_PRIO,
+      .stack_in_ext = false,
+      .multi_out_num = 0,
+      .uninstall_drv = true,
+      .need_expand = false,
+      .expand_src_bits = I2S_BITS_PER_SAMPLE_16BIT,
+  };
+  audio_element_handle_t i2s_stream_writer =
+      i2s_stream_init(&i2s_stream_config);
+  if (i2s_stream_writer == NULL) {
+    return cpp::fail(Error::STREAM_INIT);
+  }
+
+  // NOTE: i2s_stream_init does some additional setup that hardcodes MCK as
+  // GPIO0. This happens to work fine for us, but be careful if changing.
+  i2s_pin_config_t pin_config = {.mck_io_num = GPIO_NUM_0,
+                                 .bck_io_num = GPIO_NUM_26,
+                                 .ws_io_num = GPIO_NUM_27,
+                                 .data_out_num = GPIO_NUM_5,
+                                 .data_in_num = I2S_PIN_NO_CHANGE};
+  if (esp_err_t err = i2s_set_pin(kI2SPort, &pin_config) != ESP_OK) {
+    ESP_LOGE(kTag, "failed to configure i2s pins %x", err);
+    return cpp::fail(Error::I2S_CONFIG);
+  }
+
+  return std::make_unique<I2SAudioOutput>(dac, i2s_stream_writer);
+}
+
+I2SAudioOutput::I2SAudioOutput(std::unique_ptr<AudioDac>& dac,
+                               audio_element_handle_t element)
+    : IAudioOutput(element), dac_(std::move(dac)) {
+  volume_ = 255;
+}
+I2SAudioOutput::~I2SAudioOutput() {
+  // TODO: power down the DAC.
+}
+
+auto I2SAudioOutput::SetVolume(uint8_t volume) -> void {
+  volume_ = volume;
+  if (!is_soft_muted_) {
+    dac_->WriteVolume(volume);
+  }
+}
+
+auto I2SAudioOutput::SetSoftMute(bool enabled) -> void {
+  if (enabled) {
+    is_soft_muted_ = true;
+    dac_->WriteVolume(255);
+  } else {
+    is_soft_muted_ = false;
+    dac_->WriteVolume(volume_);
+  }
+}
+
+auto I2SAudioOutput::Configure(audio_element_info_t& info) -> void {
+  audio_element_setinfo(element_, &info);
+  i2s_stream_set_clk(element_, info.sample_rates, info.bits, info.channels);
+}
+
+}  // namespace drivers
-- 
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