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
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linux-mips, linux-watchdog, lkml
On Sat, Nov 21, 2015 at 8:02 PM, Simon Arlott [off-list ref] wrote:
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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.txtdiff --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.
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+- 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