Reading ADC value in nrf52805

Question

I want to read ADC values from AIN2 (P0.04), and AIN3 (P0.05) channels of nrf52805. I am using S112, and I have the following code found in the internet.

float readADC(uint8_t channel)
{
   volatile int16_t result = 0;
volatile float precise_result = 0;

// Start HFCLK from crystal oscillator, this will give the SAADC higher accuracy
NRF_CLOCK->TASKS_HFCLKSTART = 1;
while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0);
NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;

// Configure SAADC singled-ended channel, Internal reference (0.6V) and 1/6 gain.
NRF_SAADC->CH[channel].CONFIG = (SAADC_CH_CONFIG_GAIN_Gain1_6    << SAADC_CH_CONFIG_GAIN_Pos) |
                            (SAADC_CH_CONFIG_MODE_SE         << SAADC_CH_CONFIG_MODE_Pos) |
                            (SAADC_CH_CONFIG_REFSEL_Internal << SAADC_CH_CONFIG_REFSEL_Pos) |
                            (SAADC_CH_CONFIG_RESN_Bypass     << SAADC_CH_CONFIG_RESN_Pos) |
                            (SAADC_CH_CONFIG_RESP_Bypass     << SAADC_CH_CONFIG_RESP_Pos) |
                            (SAADC_CH_CONFIG_TACQ_3us        << SAADC_CH_CONFIG_TACQ_Pos);

// Configure the SAADC channel with VDD as positive input, no negative input(single ended).
NRF_SAADC->CH[channel].PSELP = SAADC_CH_PSELP_PSELP_VDD << SAADC_CH_PSELP_PSELP_Pos;
NRF_SAADC->CH[channel].PSELN = SAADC_CH_PSELN_PSELN_NC << SAADC_CH_PSELN_PSELN_Pos;

// Configure the SAADC resolution.
NRF_SAADC->RESOLUTION = SAADC_RESOLUTION_VAL_14bit << SAADC_RESOLUTION_VAL_Pos;

// Configure result to be put in RAM at the location of "result" variable.
NRF_SAADC->RESULT.MAXCNT = 1;
NRF_SAADC->RESULT.PTR = (uint32_t)&result;

// No automatic sampling, will trigger with TASKS_SAMPLE.
NRF_SAADC->SAMPLERATE = SAADC_SAMPLERATE_MODE_Task << SAADC_SAMPLERATE_MODE_Pos;

// Enable SAADC (would capture analog pins if they were used in CH[0].PSELP)
NRF_SAADC->ENABLE = SAADC_ENABLE_ENABLE_Enabled << SAADC_ENABLE_ENABLE_Pos;

// Calibrate the SAADC (only needs to be done once in a while)
NRF_SAADC->TASKS_CALIBRATEOFFSET = 1;
while (NRF_SAADC->EVENTS_CALIBRATEDONE == 0);
NRF_SAADC->EVENTS_CALIBRATEDONE = 0;
while (NRF_SAADC->STATUS == (SAADC_STATUS_STATUS_Busy <<SAADC_STATUS_STATUS_Pos));

// Start the SAADC and wait for the started event.
NRF_SAADC->TASKS_START = 1;
while (NRF_SAADC->EVENTS_STARTED == 0);
NRF_SAADC->EVENTS_STARTED = 0;

// Do a SAADC sample, will put the result in the configured RAM buffer.
NRF_SAADC->TASKS_SAMPLE = 1;
while (NRF_SAADC->EVENTS_END == 0);
NRF_SAADC->EVENTS_END = 0;

// Convert the result to voltage
// Result = [V(p) - V(n)] * GAIN/REFERENCE * 2^(RESOLUTION)
// Result = (VDD - 0) * ((1/6) / 0.6) * 2^14
// VDD = Result / 4551.1
precise_result = (float)result / 4551.1f;

// Stop the SAADC, since it's not used anymore.
NRF_SAADC->TASKS_STOP = 1;
while (NRF_SAADC->EVENTS_STOPPED == 0);
NRF_SAADC->EVENTS_STOPPED = 0;

   return precise_result;
}
/**
* @brief Function for application main entry.
*/

int main(void)
{

   ret_code_t err_code;

      timers_init();
     power_management_init();

      float value1 = readADC(2);
      float value2 = readADC(3);

    // Enter main loop.
    for (;; )
    {
        idle_state_handle();
    }
}

The voltage input on both channels is 1.2V.

value1 reads -0.012 (which fluctuates around 0) and value2 shows 2.4V.

I am not sure why value2 = Actual voltage * 2 but I can live with it as it is consistent.

Why am I not getting ADC value from AIN2?

I tested this with multiple nrf52805 chips but the same result.