Magento 2 - How to get attribute options value of eav entity?

you can add to the constructor of your class an instance of \Magento\Eav\Model\Config like this:

protected $eavConfig;
public function __construct(
    ...
    \Magento\Eav\Model\Config $eavConfig,
    ...
){
    ...
    $this->eavConfig = $eavConfig;
    ...
}

then you can use that in your class

$attribute = $this->eavConfig->getAttribute('catalog_product', 'attribute_code_here');
$options = $attribute->getSource()->getAllOptions();

Use the following code to get all attribute options.

function getExistingOptions( $object_Manager ) {

$eavConfig = $object_Manager->get('\Magento\Eav\Model\Config');
$attribute = $eavConfig->getAttribute('catalog_product', 'color');
$options = $attribute->getSource()->getAllOptions();

$optionsExists = array();

foreach($options as $option) {
    $optionsExists[] = $option['label'];
}

return $optionsExists;

 }

Please Can you click here for more detailed explanation. http://www.pearlbells.co.uk/code-snippets/get-magento-attribute-options-programmatically/

You can do it simply call below code inside your Block file.

<?php
namespace Vendor\Package\Block;

class Blockname extends \Magento\Framework\View\Element\Template
{
    protected $_productAttributeRepository;

    public function __construct(        
        \Magento\Framework\View\Element\Template\Context $context,   
        \Magento\Catalog\Model\Product\Attribute\Repository $productAttributeRepository,
        array $data = [] 
    ){        
        parent::__construct($context,$data);
        $this->_productAttributeRepository = $productAttributeRepository;
    } 

    public function getAllBrand(){
        $manufacturerOptions = $this->_productAttributeRepository->get('manufacturer')->getOptions();       
        $values = array();
        foreach ($manufacturerOptions as $manufacturerOption) { 
           //$manufacturerOption->getValue();  // Value
            $values[] = $manufacturerOption->getLabel();  // Label
        }
        return $values;
    }  
}

Call inside your phtml file,

<div class="manufacturer-name">
      <?php $getOptionValue = $this->getAllBrand();?>
      <?php foreach($getOptionValue as $value){ ?>
           <span><?php echo $value;?></span>
      <?php } ?>
</div>

Thanks.