This patch adds the Device Tree binding document for the Broadcom
BCM7120-style Set-top-box Level 2 interrupt controller hardware.
We provide some ascii art explaining the different roles and reasons why
some properties are introduced to represent that interrupt controller.
Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
---
Changes in v2:
- add an ascii diagram explaining how the HW works to clarify the binding
- add some small bullet points explaining the HW roles and features
- remove 'interrupt-names' since we are not using it and cannot document all
possible names as of today
- clarify the values for the 'interrupts' property
- clarify the terminology used to avoid using software concepts
.../interrupt-controller/brcm,bcm7120-l2-intc.txt | 86 ++++++++++++++++++++++
1 file changed, 86 insertions(+)
create mode 100644 Documentation/devicetree/bindings/interrupt-controller/brcm,bcm7120-l2-intc.txt
diff --git a/Documentation/devicetree/bindings/interrupt-controller/brcm,bcm7120-l2-intc.txt b/Documentation/devicetree/bindings/interrupt-controller/brcm,bcm7120-l2-intc.txt
new file mode 100644
index 000000000000..67651886a317
--- /dev/null
+++ b/Documentation/devicetree/bindings/interrupt-controller/brcm,bcm7120-l2-intc.txt
@@ -0,0 +1,86 @@
+Broadcom BCM7120-style Level 2 interrupt controller
+
+This interrupt controller hardware is a second level interrupt controller that
+is hooked to a parent interrupt controller: e.g: ARM GIC for ARM-based
+platforms. It can be found on BCM7xxx products starting with BCM7120.
+
+Such an interrupt controller has the following hardware design:
+
+- outputs multiple interrupts signals towards its interrupt controller parent
+
+- controls how some of the interrupts will be flowing, whether they will
+ directly output an interrupt signal towards the interrupt controller parent,
+ or if they will output an interrupt signal at this 2nd level interrupt
+ controller, in particular for UARTs
+
+- not all 32-bits within the interrupt controller actually map to an interrupt
+
+The typical hardware layout for this controller is represented below:
+
+2nd level interrupt line Outputs for the parent controller (e.g: ARM GIC)
+
+0 -----[ MUX ] ------------|==========> GIC interrupt 75
+ \-----------\
+ |
+1 -----[ MUX ] --------)---|==========> GIC interrupt 76
+ \------------|
+ |
+2 -----[ MUX ] --------)---|==========> GIC interrupt 77
+ \------------|
+ |
+3 ---------------------|
+4 ---------------------|
+5 ---------------------|
+7 ---------------------|---|===========> GIC interrupt 66
+9 ---------------------|
+10 --------------------|
+11 --------------------/
+
+6 ------------------------\
+ |===========> GIC interrupt 64
+8 ------------------------/
+
+12 ........................ X
+13 ........................ X (not connected)
+..
+31 ........................ X
+
+Required properties:
+
+- compatible: should be "brcm,bcm7120-l2-intc"
+- reg: specifies the base physical address and size of the registers
+- interrupt-controller: identifies the node as an interrupt controller
+- #interrupt-cells: specifies the number of cells needed to encode an interrupt
+ source, should be 1.
+- interrupt-parent: specifies the phandle to the parent interrupt controller
+ this one is cascaded from
+- interrupts: specifies the interrupt line(s) in the interrupt-parent controller
+ node, valid values depend on the type of parent interrupt controller
+- brcm,int-map-mask: 32-bits bit mask describing how many and which interrupts
+ are wired to this 2nd level interrupt controller, and how they match their
+ respective interrupt parents. Should match exactly the number of interrupts
+ specified in the 'interrupts' property.
+
+Optional properties:
+
+- brcm,irq-can-wake: if present, this means the L2 controller can be used as a
+ wakeup source for system suspend/resume.
+
+- brcm,int-fwd-mask: if present, a 32-bits bit mask to configure for the
+ interrupts which have a mux gate, typically UARTs. Setting these bits will
+ make their respective interrupts outputs bypass this 2nd level interrupt
+ controller completely, it completely transparent for the interrupt controller
+ parent
+
+Example:
+
+irq0_intc: interrupt-controller@f0406800 {
+ compatible = "brcm,bcm7120-l2-intc";
+ interrupt-parent = <&intc>;
+ #interrupt-cells = <1>;
+ reg = <0xf0406800 0x8>;
+ interrupt-controller;
+ interrupts = <0x0 0x42 0x0>, <0x0 0x40 0x0>;
+ brcm,int-map-mask = <0xeb8>, <0x140>;
+ brcm,int-fwd-mask = <0x7>;
+};
--
1.9.1
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