From f35bb64c2b8dbb72fd15f1880e4d01d263660910 Mon Sep 17 00:00:00 2001
From: jacqueline <me@jacqueline.id.au>
Date: Tue, 6 Dec 2022 13:17:56 +1100
Subject: basic i2s output element

---
 src/drivers/dac.cpp | 80 +++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 72 insertions(+), 8 deletions(-)

(limited to 'src/drivers/dac.cpp')

diff --git a/src/drivers/dac.cpp b/src/drivers/dac.cpp
index f01d701f..23c67e88 100644
--- a/src/drivers/dac.cpp
+++ b/src/drivers/dac.cpp
@@ -4,11 +4,13 @@
 
 #include "assert.h"
 #include "driver/i2c.h"
+#include "driver/i2s.h"
 #include "esp_err.h"
 #include "esp_log.h"
 #include "hal/i2c_types.h"
 
 #include "gpio_expander.hpp"
+#include "hal/i2s_types.h"
 #include "i2c.hpp"
 
 namespace drivers {
@@ -16,11 +18,55 @@ namespace drivers {
 static const char* kTag = "AUDIODAC";
 static const uint8_t kPcm5122Address = 0x4C;
 static const uint8_t kPcm5122Timeout = 100 / portTICK_RATE_MS;
+static const i2s_port_t kI2SPort = I2S_NUM_0;
+
+static const AudioDac::SampleRate kDefaultSampleRate =
+    AudioDac::SAMPLE_RATE_44_1;
+static const AudioDac::BitsPerSample kDefaultBps = AudioDac::BPS_16;
 
 auto AudioDac::create(GpioExpander* expander)
     -> cpp::result<std::unique_ptr<AudioDac>, Error> {
+  // First, instantiate the instance so it can do all of its power on
+  // configuration.
   std::unique_ptr<AudioDac> dac = std::make_unique<AudioDac>(expander);
 
+  // Whilst we wait for the initial boot, we can work on installing the I2S
+  // driver.
+  i2s_config_t 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,
+      // TODO(jacqueline): tune dma buffer size. this seems very smol.
+      .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,
+  };
+
+  if (esp_err_t err =
+          i2s_driver_install(kI2SPort, &i2s_config, 0, NULL) != ESP_OK) {
+    ESP_LOGE(kTag, "failed to configure i2s pins %x", err);
+    return cpp::fail(Error::FAILED_TO_INSTALL_I2S);
+  }
+
+  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::FAILED_TO_INSTALL_I2S);
+  }
+
+  // Now let's double check that the DAC itself came up whilst we we working.
   bool is_booted = dac->WaitForPowerState(
       [](bool booted, PowerState state) { return booted; });
   if (!is_booted) {
@@ -28,8 +74,9 @@ auto AudioDac::create(GpioExpander* expander)
     return cpp::fail(Error::FAILED_TO_BOOT);
   }
 
+  // Write the initial configuration.
   dac->WriteRegister(Register::DE_EMPHASIS, 1 << 4);
-  dac->WriteVolume(100);
+  dac->WriteVolume(255);
 
   bool is_configured =
       dac->WaitForPowerState([](bool booted, PowerState state) {
@@ -43,14 +90,16 @@ auto AudioDac::create(GpioExpander* expander)
   return dac;
 }
 
-AudioDac::AudioDac(GpioExpander* gpio) {
-  this->gpio_ = gpio;
-};
+AudioDac::AudioDac(GpioExpander* gpio) : gpio_(gpio) {
+  gpio_->set_pin(GpioExpander::AUDIO_POWER_ENABLE, true);
+  gpio_->Write();
+}
 
-AudioDac::~AudioDac(){
-    // TODO: reset stuff like de-emphasis? Reboot the whole dac? Need to think
-    // about this.
-};
+AudioDac::~AudioDac() {
+  i2s_driver_uninstall(kI2SPort);
+  gpio_->set_pin(GpioExpander::AUDIO_POWER_ENABLE, false);
+  gpio_->Write();
+}
 
 void AudioDac::WriteVolume(uint8_t volume) {
   WriteRegister(Register::DIGITAL_VOLUME_L, volume);
@@ -93,6 +142,21 @@ bool AudioDac::WaitForPowerState(
   return has_matched;
 }
 
+auto AudioDac::Reconfigure(BitsPerSample bps, SampleRate rate) -> bool {
+  // TODO(jacqueline): investigate how reliable the auto-clocking of the dac
+  // is. We might need to explicit reconfigure the dac here as well if it's not
+  // good enough.
+  i2s_set_clk(kI2SPort, rate, bps, I2S_CHANNEL_STEREO);
+  return true;
+}
+
+auto AudioDac::WriteData(const cpp::span<std::byte>& data, TickType_t max_wait)
+    -> std::size_t {
+  std::size_t res = 0;
+  i2s_write(kI2SPort, data.data(), data.size(), &res, max_wait);
+  return res;
+}
+
 void AudioDac::WriteRegister(Register reg, uint8_t val) {
   I2CTransaction transaction;
   transaction.start()
-- 
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