Add fuel gauge driver

Author: sebromero

src/MAX1726Driver.h

@@ -0,0 +1,49 @@
+#include "WireUtils.h"
+// TODO extract into a separate header file and check how PF1550Driver is implemented
+#include "BatteryConstants.h"
+
+enum class FuelGaugeOperationMode
+{
+    hibernate,
+    shutdown,
+    active
+};
+
+// TODO Extract into a separate header file or use this file in Battery.h
+constexpr uint8_t I2C_ADDRESS = 0x36; // I2C address of the fuel gauge
+
+class MAX1726Driver {
+private:
+    TwoWire *wire;
+public:
+    bool setOperationMode(FuelGaugeOperationMode mode);
+    MAX1726Driver(TwoWire *wire);
+    ~MAX1726Driver();
+};
+
+MAX1726Driver::MAX1726Driver(TwoWire *wire) {
+    this->wire = wire;
+}
+
+MAX1726Driver::~MAX1726Driver(){}
+
+bool MAX1726Driver::setOperationMode(FuelGaugeOperationMode mode) {
+    if(mode == FuelGaugeOperationMode::active){
+        // See section "Soft-Wakeup" in user manual https://www.analog.com/media/en/technical-documentation/user-guides/max1726x-modelgauge-m5-ez-user-guide.pdf
+        writeRegister16Bits(this->wire, I2C_ADDRESS, HIB_CFG_REG, 0x0);      // Exit Hibernate Mode
+        writeRegister16Bits(this->wire, I2C_ADDRESS, SOFT_WAKEUP_REG, 0x90); // Wakes up the fuel gauge from hibernate mode to reduce the response time of the IC to configuration changes  
+        writeRegister16Bits(this->wire, I2C_ADDRESS, SOFT_WAKEUP_REG, 0x0);  // This command must be manually cleared (0x0000) afterward to keep proper fuel gauge timing
+    } else if(mode == FuelGaugeOperationMode::hibernate){
+        // Enters hibernate mode somewhere between 2.812s and 5.625s if the threshold conditions are met
+        replaceRegisterBit(this->wire, I2C_ADDRESS, HIB_CFG_REG, 1, EN_HIBERNATION_BIT); // Enter Hibernate Mode
+    } else if(mode == FuelGaugeOperationMode::shutdown){
+        // Enter active mode
+        // TODO use function instead        
+        replaceRegisterBit(this->wire, I2C_ADDRESS, HIB_CFG_REG, 0, EN_HIBERNATION_BIT); // Exit Hibernate Mode
+        // TODO check if we can enter shutdown quicker by setting CTR manually in ShdnTimer
+        // The default shutdown timeout is 45s
+        replaceRegisterBit(this->wire, I2C_ADDRESS, CONFIG_REG, 1, SHDN_BIT); // Command shutdown mode
+    }
+    
+    return false;
+}