Tidak bisa get data - trying to get property of non-object

Ketika saya mau edit data dari halaman list, data yang mau saya edit tidak muncul malah muncul eror Trying to get property of non-object. saya sudah get data nya padahal. berikut saya lampirkan code dari model view dan kontrollernya- mohon bantuannya terima kasih...

// code controller
//edit outlet
	public function edit($id_toko)
	{
		$toko_kami 		= 	$this->toko_kami_model->listing();
		$data_toko_kami =	count($toko_kami);
		$pengguna 		= 	$this->pengguna_model->listing();
		$data_pengguna	= 	count($pengguna);

		//validaasi input
		$valid = $this->form_validation;

		$valid->set_rules('nama_toko','Nama Outlet','required',
			array(	'required'	=>	'%s Harus Diisi'));

		if($valid->run()=== FALSE){
			//end validaasi
		$data = array(	'title'				=>	'Edit Outlet',
						'id_toko'			=>	'id_toko',
						'toko_kami'			=>	$toko_kami,
						'data_toko_kami'	=>	$data_toko_kami,
						'data_pengguna'		=> 	$data_pengguna,
						'isi'				=>	'admin/toko_kami/edit'
					);
		$this->load->view('admin/layout/wrapper', $data, FALSE);
		//start masuk ddatabase
		}else{
			$i = $this->input;
			$data = array(	'id_toko'			=>	$id_toko,
							'lokasi_toko'	=>	$i->post('lokasi_toko'),
							'nama_toko'		=>	$i->post('nama_toko'),
							'alamat_toko'	=>	$i->post('alamat_toko'),
							'urutan_toko'	=>	$i->post('urutan_toko')
						);
			$this->toko_kami_model->edit($data);
			$this->session->set_flashdata('sukses', 'Data Outlet Berhasil Diedit');
			redirect(base_url('backend/toko_kami'),'refresh');

		}
		//end masuk database
	}

//code model
// listing data cabang toko
		public function listing()
		{
			$this->db->select('*');
			$this->db->from('tbl_toko_kami');
			$this->db->order_by('id_toko', 'desc');
			$query = $this->db->get();
			return $query->result();
		}

	// detail data outlet
		public function detail($id_toko)
		{
			$this->db->select('*');
			$this->db->from('tbl_toko_kami');
			//where
			$this->db->where('id_toko', $id_toko);
			$this->db->order_by('id_toko', 'desc');
			$query = $this->db->get();
			return $query->row();
		}

//code view list
<p>
  <a href="<?php echo base_url('backend/toko_kami/tambah')?>" class="btn btn-success btn-lg">
    <i class="fa fa-plus"></i> Tambah Data</a>
</p>
  <table id="example1" class="table table-bordered table-striped">
    <thead>
      <tr>
        <th>NO</th>
        <th>KOTA</th>
        <th>NAMA OUTLET</th>
        <th>ALAMAT</th>
        <th>URUTAN</th>
        <th>ACTION</th>
      </tr>
      </thead>
       <tbody>
          <?php $i = 1; foreach($toko_kami as $toko_kami) { ?>
              <tr>
                <td><?php echo $i ?></td>
                <td><?php echo $toko_kami->lokasi_toko ?></td>
                <td><?php echo $toko_kami->nama_toko ?></td>
                <td width="300px" align="justify"><?php echo $toko_kami->alamat_toko ?></td>
                <td><?php echo $toko_kami->urutan_toko ?></td>
                <td>


                  <a href="<?php echo base_url('backend/toko_kami/edit/'.$toko_kami->id_toko) ?>" class="btn btn-warning btn-xs"><i class="fa fa-edit"></i> Edit</a>

                  <a href="<?php echo base_url('backend/toko_kami/delete/'.$toko_kami->id_toko) ?>" class="btn btn-danger btn-xs" onclick="return confirm('Yakin Menghapus Data ini?')"><i class="fa fa-trash-o"></i> hapus</a>

                </td>
              </tr>
            </tbody>
          <?php $i++; } ?>
      </table>
        <!-- /.box-body -->

// code views edit halaman
<?php
// Error input trigger alert
echo validation_errors('<div class="alert alert-warning">','</div>');

// form open
echo form_open(base_url('admin/suplier/edit/'.$toko_kami->$id_toko));
?>

<div class="col-md-5">
  <div class="form-group">
    <label>Nama Outlet</label>
    <input type="text" name="nama_toko"  class="form-control" placeholder="Masukan Nama Toko" value="<?php echo $toko_kami->nama_toko ?>" required>
  </div>
</div>
<div class="col-md-5">
    <div class="form-group">
      <label>Lokasi Kota Outlet</label>
      <input type="text" name="lokasi_toko"  class="form-control" placeholder="Lokasi Kota Toko" value="<?php echo $toko_kami->lokasi_toko ?>" required>
    </div>
</div>
<div class="col-md-2">
    <div class="form-group">
      <label>Urutan</label>
      <input type="text" name="urutan_toko"  class="form-control" placeholder="Urutan" value="<?php echo $toko_kami->urutan_toko ?>" required>
    </div>
</div>

<div class="col-md-12">
  <div class="form-group">
    <label>Alamat Lengkap</label>
    <textarea type="input" name="alamat_toko"  class="form-control" rows="5" value="" required><?php echo $toko_kami->alamat_toko ?></textarea>
  </div>
</div>

    <di class="form-group">
    <button type="submit" class="btn btn-success btn-lg">
      <i class="fa fa-save"> Edit Data</i>
    </button>

    <button type="reset" class="btn btn-default btn-lg">
      <i class="fa fa-times"> Reset</i>
    </button>
  </di>
</div>

<?php
// form close
echo form_close();
?>