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| -rw-r--r-- | Documentation/devicetree/bindings/gpio/gpio-eic-sprd.txt | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/gpio/gpio-eic-sprd.txt b/Documentation/devicetree/bindings/gpio/gpio-eic-sprd.txt new file mode 100644 index 000000000..93d98d09d --- /dev/null +++ b/Documentation/devicetree/bindings/gpio/gpio-eic-sprd.txt @@ -0,0 +1,97 @@ +Spreadtrum EIC controller bindings + +The EIC is the abbreviation of external interrupt controller, which can +be used only in input mode. The Spreadtrum platform has 2 EIC controllers, +one is in digital chip, and another one is in PMIC. The digital chip EIC +controller contains 4 sub-modules: EIC-debounce, EIC-latch, EIC-async and +EIC-sync. But the PMIC EIC controller contains only one EIC-debounce sub- +module. + +The EIC-debounce sub-module provides up to 8 source input signal +connections. A debounce mechanism is used to capture the input signals' +stable status (millisecond resolution) and a single-trigger mechanism +is introduced into this sub-module to enhance the input event detection +reliability. In addition, this sub-module's clock can be shut off +automatically to reduce power dissipation. Moreover the debounce range +is from 1ms to 4s with a step size of 1ms. The input signal will be +ignored if it is asserted for less than 1 ms. + +The EIC-latch sub-module is used to latch some special power down signals +and generate interrupts, since the EIC-latch does not depend on the APB +clock to capture signals. + +The EIC-async sub-module uses a 32kHz clock to capture the short signals +(microsecond resolution) to generate interrupts by level or edge trigger. + +The EIC-sync is similar with GPIO's input function, which is a synchronized +signal input register. It can generate interrupts by level or edge trigger +when detecting input signals. + +Required properties: +- compatible: Should be one of the following: + "sprd,sc9860-eic-debounce", + "sprd,sc9860-eic-latch", + "sprd,sc9860-eic-async", + "sprd,sc9860-eic-sync", + "sprd,sc27xx-eic". +- reg: Define the base and range of the I/O address space containing + the GPIO controller registers. +- gpio-controller: Marks the device node as a GPIO controller. +- #gpio-cells: Should be <2>. The first cell is the gpio number and + the second cell is used to specify optional parameters. +- interrupt-controller: Marks the device node as an interrupt controller. +- #interrupt-cells: Should be <2>. Specifies the number of cells needed + to encode interrupt source. +- interrupts: Should be the port interrupt shared by all the gpios. + +Example: + eic_debounce: gpio@40210000 { + compatible = "sprd,sc9860-eic-debounce"; + reg = <0 0x40210000 0 0x80>; + gpio-controller; + #gpio-cells = <2>; + interrupt-controller; + #interrupt-cells = <2>; + interrupts = <GIC_SPI 52 IRQ_TYPE_LEVEL_HIGH>; + }; + + eic_latch: gpio@40210080 { + compatible = "sprd,sc9860-eic-latch"; + reg = <0 0x40210080 0 0x20>; + gpio-controller; + #gpio-cells = <2>; + interrupt-controller; + #interrupt-cells = <2>; + interrupts = <GIC_SPI 52 IRQ_TYPE_LEVEL_HIGH>; + }; + + eic_async: gpio@402100a0 { + compatible = "sprd,sc9860-eic-async"; + reg = <0 0x402100a0 0 0x20>; + gpio-controller; + #gpio-cells = <2>; + interrupt-controller; + #interrupt-cells = <2>; + interrupts = <GIC_SPI 52 IRQ_TYPE_LEVEL_HIGH>; + }; + + eic_sync: gpio@402100c0 { + compatible = "sprd,sc9860-eic-sync"; + reg = <0 0x402100c0 0 0x20>; + gpio-controller; + #gpio-cells = <2>; + interrupt-controller; + #interrupt-cells = <2>; + interrupts = <GIC_SPI 52 IRQ_TYPE_LEVEL_HIGH>; + }; + + pmic_eic: gpio@300 { + compatible = "sprd,sc27xx-eic"; + reg = <0x300>; + interrupt-parent = <&sc2731_pmic>; + interrupts = <5 IRQ_TYPE_LEVEL_HIGH>; + gpio-controller; + #gpio-cells = <2>; + interrupt-controller; + #interrupt-cells = <2>; + }; |