gpio-eic-sprd.txt (3410B)
1Spreadtrum EIC controller bindings 2 3The EIC is the abbreviation of external interrupt controller, which can 4be used only in input mode. The Spreadtrum platform has 2 EIC controllers, 5one is in digital chip, and another one is in PMIC. The digital chip EIC 6controller contains 4 sub-modules: EIC-debounce, EIC-latch, EIC-async and 7EIC-sync. But the PMIC EIC controller contains only one EIC-debounce sub- 8module. 9 10The EIC-debounce sub-module provides up to 8 source input signal 11connections. A debounce mechanism is used to capture the input signals' 12stable status (millisecond resolution) and a single-trigger mechanism 13is introduced into this sub-module to enhance the input event detection 14reliability. In addition, this sub-module's clock can be shut off 15automatically to reduce power dissipation. Moreover the debounce range 16is from 1ms to 4s with a step size of 1ms. The input signal will be 17ignored if it is asserted for less than 1 ms. 18 19The EIC-latch sub-module is used to latch some special power down signals 20and generate interrupts, since the EIC-latch does not depend on the APB 21clock to capture signals. 22 23The EIC-async sub-module uses a 32kHz clock to capture the short signals 24(microsecond resolution) to generate interrupts by level or edge trigger. 25 26The EIC-sync is similar with GPIO's input function, which is a synchronized 27signal input register. It can generate interrupts by level or edge trigger 28when detecting input signals. 29 30Required properties: 31- compatible: Should be one of the following: 32 "sprd,sc9860-eic-debounce", 33 "sprd,sc9860-eic-latch", 34 "sprd,sc9860-eic-async", 35 "sprd,sc9860-eic-sync", 36 "sprd,sc2731-eic". 37- reg: Define the base and range of the I/O address space containing 38 the GPIO controller registers. 39- gpio-controller: Marks the device node as a GPIO controller. 40- #gpio-cells: Should be <2>. The first cell is the gpio number and 41 the second cell is used to specify optional parameters. 42- interrupt-controller: Marks the device node as an interrupt controller. 43- #interrupt-cells: Should be <2>. Specifies the number of cells needed 44 to encode interrupt source. 45- interrupts: Should be the port interrupt shared by all the gpios. 46 47Example: 48 eic_debounce: gpio@40210000 { 49 compatible = "sprd,sc9860-eic-debounce"; 50 reg = <0 0x40210000 0 0x80>; 51 gpio-controller; 52 #gpio-cells = <2>; 53 interrupt-controller; 54 #interrupt-cells = <2>; 55 interrupts = <GIC_SPI 52 IRQ_TYPE_LEVEL_HIGH>; 56 }; 57 58 eic_latch: gpio@40210080 { 59 compatible = "sprd,sc9860-eic-latch"; 60 reg = <0 0x40210080 0 0x20>; 61 gpio-controller; 62 #gpio-cells = <2>; 63 interrupt-controller; 64 #interrupt-cells = <2>; 65 interrupts = <GIC_SPI 52 IRQ_TYPE_LEVEL_HIGH>; 66 }; 67 68 eic_async: gpio@402100a0 { 69 compatible = "sprd,sc9860-eic-async"; 70 reg = <0 0x402100a0 0 0x20>; 71 gpio-controller; 72 #gpio-cells = <2>; 73 interrupt-controller; 74 #interrupt-cells = <2>; 75 interrupts = <GIC_SPI 52 IRQ_TYPE_LEVEL_HIGH>; 76 }; 77 78 eic_sync: gpio@402100c0 { 79 compatible = "sprd,sc9860-eic-sync"; 80 reg = <0 0x402100c0 0 0x20>; 81 gpio-controller; 82 #gpio-cells = <2>; 83 interrupt-controller; 84 #interrupt-cells = <2>; 85 interrupts = <GIC_SPI 52 IRQ_TYPE_LEVEL_HIGH>; 86 }; 87 88 pmic_eic: gpio@300 { 89 compatible = "sprd,sc2731-eic"; 90 reg = <0x300>; 91 interrupt-parent = <&sc2731_pmic>; 92 interrupts = <5 IRQ_TYPE_LEVEL_HIGH>; 93 gpio-controller; 94 #gpio-cells = <2>; 95 interrupt-controller; 96 #interrupt-cells = <2>; 97 };