Implement battery measurement in BatteryController.

Update battery info on wake up (with button)

src/Components/Battery/BatteryController.cpp

@@ -0,0 +1,44 @@
+#include <drivers/include/nrfx_saadc.h>
+#include <hal/nrf_gpio.h>
+#include <libraries/log/nrf_log.h>
+#include "BatteryController.h"
+
+using namespace Pinetime::Controllers;
+
+void Battery::Init() {
+  nrf_gpio_cfg_input(12, (nrf_gpio_pin_pull_t)GPIO_PIN_CNF_PULL_Pullup);
+  nrf_gpio_cfg_input(19, (nrf_gpio_pin_pull_t)GPIO_PIN_CNF_PULL_Pullup);
+
+  nrfx_saadc_config_t adcConfig = NRFX_SAADC_DEFAULT_CONFIG;
+  nrfx_saadc_init(&adcConfig, SaadcEventHandler);
+  nrf_saadc_channel_config_t adcChannelConfig = {
+          .resistor_p = NRF_SAADC_RESISTOR_DISABLED,
+          .resistor_n = NRF_SAADC_RESISTOR_DISABLED,
+          .gain       = NRF_SAADC_GAIN1_5,
+          .reference  = NRF_SAADC_REFERENCE_INTERNAL,
+          .acq_time   = NRF_SAADC_ACQTIME_3US,
+          .mode       = NRF_SAADC_MODE_SINGLE_ENDED,
+          .burst      = NRF_SAADC_BURST_DISABLED,
+          .pin_p      = (nrf_saadc_input_t)(SAADC_CH_PSELP_PSELP_AnalogInput7),
+          .pin_n      = NRF_SAADC_INPUT_DISABLED
+  };
+  nrfx_saadc_channel_init(0, &adcChannelConfig);
+}
+
+void Battery::Update() {
+  isCharging = !nrf_gpio_pin_read(12);
+  isPowerPresent = !nrf_gpio_pin_read(19);
+
+  nrf_saadc_value_t value = 0;
+  nrfx_saadc_sample_convert(0, &value);
+
+  voltage = (value * 2.0f) / (1024/3.0f);
+  percentRemaining = ((voltage - 3.55)*100)*3.9;
+
+  NRF_LOG_INFO("BATTERY " NRF_LOG_FLOAT_MARKER " %% - " NRF_LOG_FLOAT_MARKER " v", NRF_LOG_FLOAT(percentRemaining), NRF_LOG_FLOAT(voltage));
+  NRF_LOG_INFO("POWER Charging : %d - Power : %d", isCharging, isPowerPresent);
+}
+
+void Battery::SaadcEventHandler(nrfx_saadc_evt_t const * event) {
+
+}

src/Components/Battery/BatteryController.h

@@ -0,0 +1,24 @@
+#pragma once
+#include <drivers/include/nrfx_saadc.h>
+
+
+namespace Pinetime {
+  namespace Controllers {
+    class Battery {
+      public:
+        void Init();
+        void Update();
+        float PercentRemaining() const { return percentRemaining; }
+        float Voltage() const { return voltage; }
+        bool IsCharging() const { return isCharging; }
+        bool IsPowerPresent() const { return isPowerPresent; }
+
+      private:
+        static void SaadcEventHandler(nrfx_saadc_evt_t const * p_event);
+        float percentRemaining = 0.0f;
+        float voltage = 0.0f;
+        bool isCharging = false;
+        bool isPowerPresent = false;
+    };
+  }
+}