R4 pre-emptive bringup

Includes stripping out the IC-specific I2S stuff, and doing more manual
volume control using pots

1 files changed, 49 insertions, 0 deletions

diff --git a/src/drivers/include/digital_pot.hpp b/src/drivers/include/digital_pot.hpp
new file mode 100644
index 00000000..e2ca00b1
--- /dev/null
+++ b/src/drivers/include/digital_pot.hpp
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2023 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <functional>
+
+#include "esp_err.h"
+#include "result.hpp"
+
+#include "gpio_expander.hpp"
+
+namespace drivers {
+
+/*
+ * Driver for a two-channel digital potentiometer, with steps measured in
+ * decibels.
+ */
+class DigitalPot {
+ public:
+  explicit DigitalPot(GpioExpander* gpios);
+  ~DigitalPot() {}
+
+  // Not copyable or movable.
+  DigitalPot(const DigitalPot&) = delete;
+  DigitalPot& operator=(const DigitalPot&) = delete;
+
+  enum class Channel {
+    kLeft,
+    kRight,
+  };
+
+  auto SetRelative(int_fast8_t change) -> void;
+  auto SetRelative(Channel ch, int_fast8_t change) -> void;
+
+  auto SetZeroCrossDetect(bool enabled) -> void;
+
+  auto GetMaxAttenuation() -> int_fast8_t;
+  auto GetMinAttenuation() -> int_fast8_t;
+
+ private:
+  GpioExpander* gpios_;
+};
+
+}  // namespace drivers