1 files changed, 106 insertions, 0 deletions
diff --git a/src/drivers/dac.cpp b/src/drivers/dac.cpp
new file mode 100644
index 00000000..d74e9523
--- /dev/null
+++ b/src/drivers/dac.cpp
@@ -0,0 +1,106 @@
+#include "dac.hpp"
+
+#include "gpio-expander.hpp"
+#include "i2c.hpp"
+
+#include <cstdint>
+
+#include "assert.h"
+#include "driver/i2c.h"
+#include "esp_err.h"
+#include "esp_log.h"
+#include "hal/i2c_types.h"
+
+namespace gay_ipod {
+
+static const char* kTag = "AUDIODAC";
+static const uint8_t kPcm5122Address = 0x4C;
+static const uint8_t kPcm5122Timeout = 100 / portTICK_RATE_MS;
+
+auto AudioDac::create(GpioExpander* expander)
+    -> cpp::result<std::unique_ptr<AudioDac>, Error> {
+  std::unique_ptr<AudioDac> dac = std::make_unique<AudioDac>(expander);
+
+  bool is_booted = dac->WaitForPowerState(
+      [](bool booted, PowerState state) { return booted; });
+  if (!is_booted) {
+    ESP_LOGE(kTag, "Timed out waiting for boot");
+    return cpp::fail(Error::FAILED_TO_BOOT);
+  }
+
+  dac->WriteRegister(Register::DE_EMPHASIS, 1 << 4);
+  dac->WriteVolume(100);
+
+  bool is_configured =
+      dac->WaitForPowerState([](bool booted, PowerState state) {
+        return state == WAIT_FOR_CP || state == RAMP_UP || state == RUN ||
+               state == STANDBY;
+      });
+  if (!is_configured) {
+    return cpp::fail(Error::FAILED_TO_CONFIGURE);
+  }
+
+  return dac;
+}
+
+AudioDac::AudioDac(GpioExpander* gpio) {
+  this->gpio_ = gpio;
+};
+
+AudioDac::~AudioDac(){
+    // TODO: reset stuff like de-emphasis? Reboot the whole dac? Need to think
+    // about this.
+};
+
+void AudioDac::WriteVolume(uint8_t volume) {
+  WriteRegister(Register::DIGITAL_VOLUME_L, volume);
+  WriteRegister(Register::DIGITAL_VOLUME_R, volume);
+}
+
+std::pair<bool, AudioDac::PowerState> AudioDac::ReadPowerState() {
+  uint8_t result = 0;
+
+  I2CTransaction transaction;
+  transaction.start()
+      .write_addr(kPcm5122Address, I2C_MASTER_WRITE)
+      .write_ack(DSP_BOOT_POWER_STATE)
+      .start()
+      .write_addr(kPcm5122Address, I2C_MASTER_READ)
+      .read(&result, I2C_MASTER_NACK)
+      .stop();
+
+  ESP_ERROR_CHECK(transaction.Execute());
+
+  bool is_booted = result >> 7;
+  PowerState detail = (PowerState)(result & 0b1111);
+  return std::pair(is_booted, detail);
+}
+
+bool AudioDac::WaitForPowerState(
+    std::function<bool(bool, AudioDac::PowerState)> predicate) {
+  bool has_matched = false;
+  for (int i = 0; i < 10; i++) {
+    std::pair<bool, PowerState> result = ReadPowerState();
+    has_matched = predicate(result.first, result.second);
+    if (has_matched) {
+      break;
+    } else {
+      ESP_LOGI(kTag, "Waiting for power state (was %d %x)", result.first,
+               (uint8_t)result.second);
+      vTaskDelay(pdMS_TO_TICKS(1));
+    }
+  }
+  return has_matched;
+}
+
+void AudioDac::WriteRegister(Register reg, uint8_t val) {
+  I2CTransaction transaction;
+  transaction.start()
+      .write_addr(kPcm5122Address, I2C_MASTER_WRITE)
+      .write_ack(reg, val)
+      .stop();
+  // TODO: Retry once?
+  ESP_ERROR_CHECK(transaction.Execute());
+}
+
+}  // namespace gay_ipod