You have two option 
1) take a selection field on the model and get data using model method call like

@api.model
def _get_csv_data(self):
    # here read the csv file and get data
    # return values as list of tuple like [('key1', 'value1')('key2', 'value2')]      
 
my_selection = fields.Selection(selection='_get_csv_data', string='Select data')​

2) take a many2one field model and on model initialization write data to a related table

@api.model_cr
def init(self):
    #here read the csv file and get data
    # write data to a related table using a cursor 
    # like self.env.cr.execute("INSERT INTO csv_data('name', ...)" values ('first' ...)

my_many2one_id - field.Many2one('csv.data') 
​
Note: In both cases, you have to restart the server to get new data if CSV file changes dynamically after the server start. odoo load data only on start of the server