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authorJosé Pekkarinen <jose.pekkarinen@nokia.com>2016-04-11 10:41:07 +0300
committerJosé Pekkarinen <jose.pekkarinen@nokia.com>2016-04-13 08:17:18 +0300
commite09b41010ba33a20a87472ee821fa407a5b8da36 (patch)
treed10dc367189862e7ca5c592f033dc3726e1df4e3 /kernel/Documentation/devicetree/bindings/interrupt-controller/st,spear3xx-shirq.txt
parentf93b97fd65072de626c074dbe099a1fff05ce060 (diff)
These changes are the raw update to linux-4.4.6-rt14. Kernel sources
are taken from kernel.org, and rt patch from the rt wiki download page. During the rebasing, the following patch collided: Force tick interrupt and get rid of softirq magic(I70131fb85). Collisions have been removed because its logic was found on the source already. Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769 Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>
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+* SPEAr Shared IRQ layer (shirq)
+
+SPEAr3xx architecture includes shared/multiplexed irqs for certain set
+of devices. The multiplexor provides a single interrupt to parent
+interrupt controller (VIC) on behalf of a group of devices.
+
+There can be multiple groups available on SPEAr3xx variants but not
+exceeding 4. The number of devices in a group can differ, further they
+may share same set of status/mask registers spanning across different
+bit masks. Also in some cases the group may not have enable or other
+registers. This makes software little complex.
+
+A single node in the device tree is used to describe the shared
+interrupt multiplexor (one node for all groups). A group in the
+interrupt controller shares config/control registers with other groups.
+For example, a 32-bit interrupt enable/disable config register can
+accommodate up to 4 interrupt groups.
+
+Required properties:
+ - compatible: should be, either of
+ - "st,spear300-shirq"
+ - "st,spear310-shirq"
+ - "st,spear320-shirq"
+ - interrupt-controller: Identifies the node as an interrupt controller.
+ - #interrupt-cells: should be <1> which basically contains the offset
+ (starting from 0) of interrupts for all the groups.
+ - reg: Base address and size of shirq registers.
+ - interrupts: The list of interrupts generated by the groups which are
+ then connected to a parent interrupt controller. Each group is
+ associated with one of the interrupts, hence number of interrupts (to
+ parent) is equal to number of groups. The format of the interrupt
+ specifier depends in the interrupt parent controller.
+
+ Optional properties:
+ - interrupt-parent: pHandle of the parent interrupt controller, if not
+ inherited from the parent node.
+
+Example:
+
+The following is an example from the SPEAr320 SoC dtsi file.
+
+shirq: interrupt-controller@0xb3000000 {
+ compatible = "st,spear320-shirq";
+ reg = <0xb3000000 0x1000>;
+ interrupts = <28 29 30 1>;
+ #interrupt-cells = <1>;
+ interrupt-controller;
+};