Set Gravity Forms price field value based on custom field

gf.php

<?php

// Set product price if dyncialy populate vlaue is set to 'workshop_price'
add_filter( 'gform_field_value_workshop_price', 'cf_custom_product_price', 10, 2 );
function cf_custom_product_price( $value, $field ) {

    global $post;

    // Get the workshop price
    $quantity = get_post_meta( $post->ID, 'workshop_price', true );

    // Default value
    $quantity_value = '';

    // Check if set
    if ( ! empty( $quantity ) && $field->type === 'product' ) {
        $quantity_value = esc_attr( $quantity );
    }

    return $quantity_value;
}