Lantiq SoC Serial To Parallel (STP) GPIO controller The Serial To Parallel (STP) is found on MIPS based Lantiq socs. It is a peripheral controller used to drive external shift register cascades. At most 3 groups of 8 bits can be driven. The hardware is able to allow the DSL modem to drive the 2 LSBs of the cascade automatically. Required properties: - compatible : Should be "lantiq,gpio-stp-xway" - reg : Address and length of the register set for the device - #gpio-cells : Should be two. The first cell is the pin number and the second cell is used to specify optional parameters (currently unused). - gpio-controller : Marks the device node as a gpio controller. Optional properties: - lantiq,shadow : The default value that we shall assume as already set on the shift register cascade. - lantiq,groups : Set the 3 bit mask to select which of the 3 groups are enabled in the shift register cascade. - lantiq,dsl : The dsl core can control the 2 LSBs of the gpio cascade. This 2 bit property can enable this feature. - lantiq,phy1 : The gphy1 core can control 3 bits of the gpio cascade. - lantiq,phy2 : The gphy2 core can control 3 bits of the gpio cascade. - lantiq,rising : use rising instead of falling edge for the shift register Example: gpio1: stp@e100bb0 { compatible = "lantiq,gpio-stp-xway"; reg = <0xE100BB0 0x40>; #gpio-cells = <2>; gpio-controller; lantiq,shadow = <0xffff>; lantiq,groups = <0x7>; lantiq,dsl = <0x3>; lantiq,phy1 = <0x7>; lantiq,phy2 = <0x7>; /* lantiq,rising; */ };