Realtek RTL8326S is an RTL8326 with disabled gigabit ports. Only 24 100Mbit ports are available.

Here is manufacturer’s product description:

http://www.realtek.com.tw/products/productsView.aspx?Langid=1&PFid=19&Level=5&Conn=4&ProdID=30

Here is datasheet for this chip, including detailed RRCP protocol description and internal register mapping:

RTL8326_8326S_DataSheet_3.1.pdf