1 files changed, 109 insertions, 0 deletions
diff --git a/src/drivers/samd.cpp b/src/drivers/samd.cpp
new file mode 100644
index 00000000..3b275c47
--- /dev/null
+++ b/src/drivers/samd.cpp
@@ -0,0 +1,109 @@
+#include "samd.hpp"
+#include <stdint.h>
+#include <optional>
+
+#include "esp_err.h"
+#include "esp_log.h"
+#include "hal/i2c_types.h"
+#include "i2c.hpp"
+
+enum Registers {
+  kRegisterVersion = 0,
+  kRegisterCharge = 1,
+  kRegisterUsbMsc = 2,
+  kRegisterFlashing = 3,
+};
+
+static const uint8_t kAddress = 0x45;
+static const char kTag[] = "SAMD";
+
+namespace drivers {
+
+Samd::Samd() {
+  // Being able to interface with the SAMD properly is critical. To ensure we
+  // will be able to, we begin by checking the I2C protocol version is
+  // compatible, and throw if it's not.
+  uint8_t raw_res = 0;
+  I2CTransaction transaction;
+  transaction.start()
+      .write_addr(kAddress, I2C_MASTER_WRITE)
+      .write_ack(kRegisterVersion)
+      .write_addr(kAddress, I2C_MASTER_READ)
+      .read(&raw_res, I2C_MASTER_NACK)
+      .stop();
+  ESP_LOGI(kTag, "checking samd firmware rev");
+  ESP_ERROR_CHECK(transaction.Execute());
+  ESP_LOGI(kTag, "samd firmware: %u", raw_res);
+}
+Samd::~Samd() {}
+
+auto Samd::ReadChargeStatus() -> std::optional<ChargeStatus> {
+  uint8_t raw_res;
+  I2CTransaction transaction;
+  transaction.start()
+      .write_addr(kAddress, I2C_MASTER_WRITE)
+      .write_ack(kRegisterCharge)
+      .write_addr(kAddress, I2C_MASTER_READ)
+      .read(&raw_res, I2C_MASTER_NACK)
+      .stop();
+  ESP_LOGI(kTag, "checking charge status");
+  ESP_ERROR_CHECK(transaction.Execute());
+  ESP_LOGI(kTag, "raw charge status: %x", raw_res);
+
+  uint8_t usb_state = raw_res & 0b11;
+  uint8_t charge_state = (raw_res >> 2) & 0b111;
+  switch (charge_state) {
+    case 0:
+      return ChargeStatus::kNoBattery;
+    case 1:
+      return usb_state == 1 ? ChargeStatus::kChargingRegular
+                            : ChargeStatus::kChargingFast;
+    case 2:
+      return ChargeStatus::kFullCharge;
+    case 4:
+      return ChargeStatus::kBatteryCritical;
+    case 5:
+      return ChargeStatus::kDischarging;
+    case 3:
+      // Fall-through.
+    default:
+      return {};
+  }
+}
+
+auto Samd::WriteAllowUsbMsc(bool is_allowed) -> void {
+  I2CTransaction transaction;
+  transaction.start()
+      .write_addr(kAddress, I2C_MASTER_WRITE)
+      .write_ack(kRegisterUsbMsc, is_allowed)
+      .stop();
+  ESP_ERROR_CHECK(transaction.Execute());
+}
+
+auto Samd::ReadUsbMscStatus() -> UsbMscStatus {
+  return UsbMscStatus::kDetached;
+}
+
+auto Samd::ReadFlashingEnabled() -> bool {
+  uint8_t raw_res;
+  I2CTransaction transaction;
+  transaction.start()
+      .write_addr(kAddress, I2C_MASTER_WRITE)
+      .write_ack(kRegisterVersion)
+      .write_addr(kAddress, I2C_MASTER_READ)
+      .read(&raw_res, I2C_MASTER_NACK)
+      .stop();
+  ESP_ERROR_CHECK(transaction.Execute());
+  return raw_res;
+}
+
+auto Samd::WriteFlashingEnabled(bool is_enabled) -> void {
+  I2CTransaction transaction;
+  transaction.start()
+      .write_addr(kAddress, I2C_MASTER_WRITE)
+      .write_ack(kRegisterFlashing, is_enabled)
+      .stop();
+  ESP_ERROR_CHECK(transaction.Execute());
+}
+
+}  // namespace drivers