From 6e6d9a2ff045f09d5a03e876becea5e6a1dabe90 Mon Sep 17 00:00:00 2001 From: Sascha Hauer Date: Tue, 8 Dec 2015 07:35:17 +0100 Subject: dts: update to v4.4-rc1 Signed-off-by: Sascha Hauer --- dts/Bindings/interrupt-controller/open-pic.txt | 98 ++++++++++++++++++++++++++ 1 file changed, 98 insertions(+) create mode 100644 dts/Bindings/interrupt-controller/open-pic.txt (limited to 'dts/Bindings/interrupt-controller/open-pic.txt') diff --git a/dts/Bindings/interrupt-controller/open-pic.txt b/dts/Bindings/interrupt-controller/open-pic.txt new file mode 100644 index 0000000000..909a902dff --- /dev/null +++ b/dts/Bindings/interrupt-controller/open-pic.txt @@ -0,0 +1,98 @@ +* Open PIC Binding + +This binding specifies what properties must be available in the device tree +representation of an Open PIC compliant interrupt controller. This binding is +based on the binding defined for Open PIC in [1] and is a superset of that +binding. + +Required properties: + + NOTE: Many of these descriptions were paraphrased here from [1] to aid + readability. + + - compatible: Specifies the compatibility list for the PIC. The type + shall be and the value shall include "open-pic". + + - reg: Specifies the base physical address(s) and size(s) of this + PIC's addressable register space. The type shall be . + + - interrupt-controller: The presence of this property identifies the node + as an Open PIC. No property value shall be defined. + + - #interrupt-cells: Specifies the number of cells needed to encode an + interrupt source. The type shall be a and the value shall be 2. + + - #address-cells: Specifies the number of cells needed to encode an + address. The type shall be and the value shall be 0. As such, + 'interrupt-map' nodes do not have to specify a parent unit address. + +Optional properties: + + - pic-no-reset: The presence of this property indicates that the PIC + shall not be reset during runtime initialization. No property value shall + be defined. The presence of this property also mandates that any + initialization related to interrupt sources shall be limited to sources + explicitly referenced in the device tree. + +* Interrupt Specifier Definition + + Interrupt specifiers consists of 2 cells encoded as + follows: + + - <1st-cell>: The interrupt-number that identifies the interrupt source. + + - <2nd-cell>: The level-sense information, encoded as follows: + 0 = low-to-high edge triggered + 1 = active low level-sensitive + 2 = active high level-sensitive + 3 = high-to-low edge triggered + +* Examples + +Example 1: + + /* + * An Open PIC interrupt controller + */ + mpic: pic@40000 { + // This is an interrupt controller node. + interrupt-controller; + + // No address cells so that 'interrupt-map' nodes which reference + // this Open PIC node do not need a parent address specifier. + #address-cells = <0>; + + // Two cells to encode interrupt sources. + #interrupt-cells = <2>; + + // Offset address of 0x40000 and size of 0x40000. + reg = <0x40000 0x40000>; + + // Compatible with Open PIC. + compatible = "open-pic"; + + // The PIC shall not be reset. + pic-no-reset; + }; + +Example 2: + + /* + * An interrupt generating device that is wired to an Open PIC. + */ + serial0: serial@4500 { + // Interrupt source '42' that is active high level-sensitive. + // Note that there are only two cells as specified in the interrupt + // parent's '#interrupt-cells' property. + interrupts = <42 2>; + + // The interrupt controller that this device is wired to. + interrupt-parent = <&mpic>; + }; + +* References + +[1] Power.org (TM) Standard for Embedded Power Architecture (TM) Platform + Requirements (ePAPR), Version 1.0, July 2008. + (http://www.power.org/resources/downloads/Power_ePAPR_APPROVED_v1.0.pdf) + -- cgit v1.2.3