1Lantiq SoC Serial To Parallel (STP) GPIO controller 2 3The Serial To Parallel (STP) is found on MIPS based Lantiq socs. It is a 4peripheral controller used to drive external shift register cascades. At most 53 groups of 8 bits can be driven. The hardware is able to allow the DSL modem 6to drive the 2 LSBs of the cascade automatically. 7 8 9Required properties: 10- compatible : Should be "lantiq,gpio-stp-xway" 11- reg : Address and length of the register set for the device 12- #gpio-cells : Should be two. The first cell is the pin number and 13 the second cell is used to specify optional parameters (currently 14 unused). 15- gpio-controller : Marks the device node as a gpio controller. 16 17Optional properties: 18- lantiq,shadow : The default value that we shall assume as already set on the 19 shift register cascade. 20- lantiq,groups : Set the 3 bit mask to select which of the 3 groups are enabled 21 in the shift register cascade. 22- lantiq,dsl : The dsl core can control the 2 LSBs of the gpio cascade. This 2 bit 23 property can enable this feature. 24- lantiq,phy1 : The gphy1 core can control 3 bits of the gpio cascade. 25- lantiq,phy2 : The gphy2 core can control 3 bits of the gpio cascade. 26- lantiq,rising : use rising instead of falling edge for the shift register 27 28Example: 29 30gpio1: stp@e100bb0 { 31 compatible = "lantiq,gpio-stp-xway"; 32 reg = <0xE100BB0 0x40>; 33 #gpio-cells = <2>; 34 gpio-controller; 35 36 lantiq,shadow = <0xffff>; 37 lantiq,groups = <0x7>; 38 lantiq,dsl = <0x3>; 39 lantiq,phy1 = <0x7>; 40 lantiq,phy2 = <0x7>; 41 /* lantiq,rising; */ 42}; 43