hook_permission and control access [how to redirect to the login page if user not logged in] - drupal-7

Question

How does one limit "what" can access a page. I have little understanding on how to use hook_permission() to set user permission based on a role to control access to hook_menu() items. However, what if I have a hook_menu() item that is to be used solely by the system itself? For example, say I have a registration page in a custom module: module/register - Anyone can access that page. Then, say I have an another page which is only for admin. So, I register another item in hook_menu(), call it module/register/reg_user_details - I do not want anyone to be able to browse to module/register/reg_user_details
Instead I want page to be visible only when user is logged in, I have already created a hook_permission
/**
* Implements hook_menu()
*
*/
function video_subtitles_menu() {
$items = array();
$items['video_subtitles/upload'] = array( //this creates a URL that will call this form at "video_subtitles_test/upload"
'title' => 'Upload Subtitle', //page title
'description' => 'Uploading subtitle for videos',
'page callback' => 'drupal_get_form', //this is the function that will be called when the page is accessed. for a form, drupal_get_form need to be used
'page arguments' => array('video_upload_subtitles_form'), //Name of the Uplaod Form
'access callback' => 'user_access',
'access arguments' => array('administer video_subtitles module'),
);
$items['player/video_subtitle_status'] = array(
'page callback' => 'video_subtitle_status',
'access callback' => 'user_access',
'access arguments' => array('administer video_subtitles status'),
);
return $items;
}
/**
* Implements hook_permission.
*/
function video_subtitles_permission() {
return array(
'administer video_subtitles module' => array(
'title' => t('Administer video_subtitles module'),
'description' => t('Access the video_subtitles upload module Page'),
),
'administer video_subtitles status' => array(
'title' => t('Administer video_subtitles module status'),
'description' => t('Access the video_subtitles module status Page'),
));
}
So User is not able to access my page unless user is logged in, but
what I need user should be redirected to the login page when he is not logged in as admin , if he successfully login it should be redirected to my page.
visit url d-7/example/my-module
if already logged in show the page
if not logged in redirect to the login page
if user logged in successfully redirect to d-7/example/my-module page
What is best way to achieve this
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