After submitting form, if form_validation false, then redirect user to view and show form's filled input values using redirect()

In CodeIgniter, after submitting form, when we get POST data in controller function of form action, I am checking for form_validation. But if form_validation checking returns false, I want to redirect the user to view and show him the form's filled values. I have tried with redirect(), but I can't get the form's posted data to view after redirect.

My View File Code =>

<div class="form-group">
<label class="control-label" for="firstname">First Name<span class="required">*</span></label>
<div class="controls">
<?php echo form_input(array('type'=>'text','class'=>'form-control','name'=>'firstname','id'=>'firstname','placeholder'=>'First Name','required'=>'required')); ?>
</div>
</div>
<div class="form-group">
<label class="control-label" for="lastname">Last Name<span class="required">*</span></label>
<div class="controls">
<?php echo form_input(array('type'=>'text','class'=>'form-control','name'=>'lastname','id'=>'lastname','placeholder'=>'Last Name','required'=>'required')); ?>
</div>
</div>
<div class="form-group">
<label class="control-label" for="address">Address<span class="required">*</span></label>
<div class="controls">
<?php echo form_textarea(array('class'=>'form-control','name'=>'address','id'=>'address','placeholder'=>'Address','required'=>'required')); ?>
</div>
</div>

My Controller File Code =>

//Getting value
$firstname = trim($this->input->post('firstname'));
$lastname = trim($this->input->post('lastname'));
$address = trim($this->input->post('address'));
// SET VALIDATION RULES
$this->form_validation->set_rules('firstname', 'First Name', 'trim|required');
$this->form_validation->set_rules('lastname', 'Last Name', 'trim|required');
$this->form_validation->set_rules('address', 'Address', 'trim|required');
if( $this->form_validation->run() )
{
    //insert into database function
}
else
{
    //Here, If validation I want to pass my form's filled data to view file i.e. refill form after redirect.
    //I have tried using below, but I can't get filled form in view file after redirect.
    $this->data['fname'] = $firstname;
    $this->data['lname'] = $lastname;
    $this->data['address'] = $address;
    $this->session->set_flashdata('error',validation_errors());
    redirect('employee/add', 'refresh');
}

So please let me know how to get all form data refilled after redirect. Thanks.