Thread (54 messages) 54 messages, 7 authors, 2016-05-11

Re: [PATCH 1/4] clocksource: Add brcm,bcm6345-timer device tree binding

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From: Jonas Gorski <hidden>
Date: 2015-11-23 15:33:34
Also in: linux-mips, linux-watchdog, lkml

On Sat, Nov 21, 2015 at 8:02 PM, Simon Arlott [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Add device tree binding for the BCM6345 timer. This is required for the
BCM6345 watchdog which needs to respond to one of the timer interrupts.

Signed-off-by: Simon Arlott <redacted>
---
 .../bindings/timer/brcm,bcm6345-timer.txt          | 57 ++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/timer/brcm,bcm6345-timer.txt
diff --git a/Documentation/devicetree/bindings/timer/brcm,bcm6345-timer.txt b/Documentation/devicetree/bindings/timer/brcm,bcm6345-timer.txt
new file mode 100644
index 0000000..2593907
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/brcm,bcm6345-timer.txt
@@ -0,0 +1,57 @@
+Broadcom BCM6345 Timer
+
+This block is a timer that is connected to one interrupt on the main interrupt
+controller and functions as a programmable interrupt controller for timer events.
+
+- 3 to 4 independent timers with their own maskable level interrupt bit (but not
+  per CPU because there is only one parent interrupt and the timers share it)
+
This is true for the 6345 one but not the 6318/63148/63381 one, which
has one interrupt per timer (+ one extra watchdog interrupt on
6318/63148), and the parent interrupt controller supports affinity. So
you could e.g. route the timer 0 irq to cpu 0 and timer1 irq on cpu 1.
quoted hunk ↗ jump to hunk
+- 1 watchdog timer with an unmaskable level interrupt
+
+- Contains one enable/status word pair
+
+- No atomic set/clear operations
+
+The lack of per CPU ability of timers makes them unusable as a set of
+clockevent devices, otherwise they could be attached to the remaining
+interrupts.
+
+The BCM6318 also has a separate interrupt for every timer except the watchdog.
+
+Required properties:
+
+- compatible: should be "brcm,bcm<soc>-timer", "brcm,bcm6345-timer"
Since bcm6318 uses a slightly different register layout than the
earlier SoCs, I'd argue that using bcm6345-timer as a compatible for
bcm6318 is wrong.


Jonas
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