xref: /OK3568_Linux_fs/kernel/Documentation/devicetree/bindings/gpio/gpio-eic-sprd.txt (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593SmuzhiyunSpreadtrum EIC controller bindings
2*4882a593Smuzhiyun
3*4882a593SmuzhiyunThe EIC is the abbreviation of external interrupt controller, which can
4*4882a593Smuzhiyunbe used only in input mode. The Spreadtrum platform has 2 EIC controllers,
5*4882a593Smuzhiyunone is in digital chip, and another one is in PMIC. The digital chip EIC
6*4882a593Smuzhiyuncontroller contains 4 sub-modules: EIC-debounce, EIC-latch, EIC-async and
7*4882a593SmuzhiyunEIC-sync. But the PMIC EIC controller contains only one EIC-debounce sub-
8*4882a593Smuzhiyunmodule.
9*4882a593Smuzhiyun
10*4882a593SmuzhiyunThe EIC-debounce sub-module provides up to 8 source input signal
11*4882a593Smuzhiyunconnections. A debounce mechanism is used to capture the input signals'
12*4882a593Smuzhiyunstable status (millisecond resolution) and a single-trigger mechanism
13*4882a593Smuzhiyunis introduced into this sub-module to enhance the input event detection
14*4882a593Smuzhiyunreliability. In addition, this sub-module's clock can be shut off
15*4882a593Smuzhiyunautomatically to reduce power dissipation. Moreover the debounce range
16*4882a593Smuzhiyunis from 1ms to 4s with a step size of 1ms. The input signal will be
17*4882a593Smuzhiyunignored if it is asserted for less than 1 ms.
18*4882a593Smuzhiyun
19*4882a593SmuzhiyunThe EIC-latch sub-module is used to latch some special power down signals
20*4882a593Smuzhiyunand generate interrupts, since the EIC-latch does not depend on the APB
21*4882a593Smuzhiyunclock to capture signals.
22*4882a593Smuzhiyun
23*4882a593SmuzhiyunThe EIC-async sub-module uses a 32kHz clock to capture the short signals
24*4882a593Smuzhiyun(microsecond resolution) to generate interrupts by level or edge trigger.
25*4882a593Smuzhiyun
26*4882a593SmuzhiyunThe EIC-sync is similar with GPIO's input function, which is a synchronized
27*4882a593Smuzhiyunsignal input register. It can generate interrupts by level or edge trigger
28*4882a593Smuzhiyunwhen detecting input signals.
29*4882a593Smuzhiyun
30*4882a593SmuzhiyunRequired properties:
31*4882a593Smuzhiyun- compatible: Should be one of the following:
32*4882a593Smuzhiyun  "sprd,sc9860-eic-debounce",
33*4882a593Smuzhiyun  "sprd,sc9860-eic-latch",
34*4882a593Smuzhiyun  "sprd,sc9860-eic-async",
35*4882a593Smuzhiyun  "sprd,sc9860-eic-sync",
36*4882a593Smuzhiyun  "sprd,sc2731-eic".
37*4882a593Smuzhiyun- reg: Define the base and range of the I/O address space containing
38*4882a593Smuzhiyun  the GPIO controller registers.
39*4882a593Smuzhiyun- gpio-controller: Marks the device node as a GPIO controller.
40*4882a593Smuzhiyun- #gpio-cells: Should be <2>. The first cell is the gpio number and
41*4882a593Smuzhiyun  the second cell is used to specify optional parameters.
42*4882a593Smuzhiyun- interrupt-controller: Marks the device node as an interrupt controller.
43*4882a593Smuzhiyun- #interrupt-cells: Should be <2>. Specifies the number of cells needed
44*4882a593Smuzhiyun  to encode interrupt source.
45*4882a593Smuzhiyun- interrupts: Should be the port interrupt shared by all the gpios.
46*4882a593Smuzhiyun
47*4882a593SmuzhiyunExample:
48*4882a593Smuzhiyun	eic_debounce: gpio@40210000 {
49*4882a593Smuzhiyun		compatible = "sprd,sc9860-eic-debounce";
50*4882a593Smuzhiyun		reg = <0 0x40210000 0 0x80>;
51*4882a593Smuzhiyun		gpio-controller;
52*4882a593Smuzhiyun		#gpio-cells = <2>;
53*4882a593Smuzhiyun		interrupt-controller;
54*4882a593Smuzhiyun		#interrupt-cells = <2>;
55*4882a593Smuzhiyun		interrupts = <GIC_SPI 52 IRQ_TYPE_LEVEL_HIGH>;
56*4882a593Smuzhiyun	};
57*4882a593Smuzhiyun
58*4882a593Smuzhiyun	eic_latch: gpio@40210080 {
59*4882a593Smuzhiyun		compatible = "sprd,sc9860-eic-latch";
60*4882a593Smuzhiyun		reg = <0 0x40210080 0 0x20>;
61*4882a593Smuzhiyun		gpio-controller;
62*4882a593Smuzhiyun		#gpio-cells = <2>;
63*4882a593Smuzhiyun		interrupt-controller;
64*4882a593Smuzhiyun		#interrupt-cells = <2>;
65*4882a593Smuzhiyun		interrupts = <GIC_SPI 52 IRQ_TYPE_LEVEL_HIGH>;
66*4882a593Smuzhiyun	};
67*4882a593Smuzhiyun
68*4882a593Smuzhiyun	eic_async: gpio@402100a0 {
69*4882a593Smuzhiyun		compatible = "sprd,sc9860-eic-async";
70*4882a593Smuzhiyun		reg = <0 0x402100a0 0 0x20>;
71*4882a593Smuzhiyun		gpio-controller;
72*4882a593Smuzhiyun		#gpio-cells = <2>;
73*4882a593Smuzhiyun		interrupt-controller;
74*4882a593Smuzhiyun		#interrupt-cells = <2>;
75*4882a593Smuzhiyun		interrupts = <GIC_SPI 52 IRQ_TYPE_LEVEL_HIGH>;
76*4882a593Smuzhiyun	};
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun	eic_sync: gpio@402100c0 {
79*4882a593Smuzhiyun		compatible = "sprd,sc9860-eic-sync";
80*4882a593Smuzhiyun		reg = <0 0x402100c0 0 0x20>;
81*4882a593Smuzhiyun		gpio-controller;
82*4882a593Smuzhiyun		#gpio-cells = <2>;
83*4882a593Smuzhiyun		interrupt-controller;
84*4882a593Smuzhiyun		#interrupt-cells = <2>;
85*4882a593Smuzhiyun		interrupts = <GIC_SPI 52 IRQ_TYPE_LEVEL_HIGH>;
86*4882a593Smuzhiyun	};
87*4882a593Smuzhiyun
88*4882a593Smuzhiyun	pmic_eic: gpio@300 {
89*4882a593Smuzhiyun		compatible = "sprd,sc2731-eic";
90*4882a593Smuzhiyun		reg = <0x300>;
91*4882a593Smuzhiyun		interrupt-parent = <&sc2731_pmic>;
92*4882a593Smuzhiyun		interrupts = <5 IRQ_TYPE_LEVEL_HIGH>;
93*4882a593Smuzhiyun		gpio-controller;
94*4882a593Smuzhiyun		#gpio-cells = <2>;
95*4882a593Smuzhiyun		interrupt-controller;
96*4882a593Smuzhiyun		#interrupt-cells = <2>;
97*4882a593Smuzhiyun	};
98