[PATCH] dt-bindings: document how to setup rockchip timers as clocksource

The patch describes how to setup rockchip timers in device tree
so they can be used as clocksource.

I'm going to implement this feature.

Signed-off-by: Alexander Kochetkov <redacted>
---
 .../bindings/timer/rockchip,rk-timer.txt           |   35 +++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/timer/rockchip,rk-timer.txt b/Documentation/devicetree/bindings/timer/rockchip,rk-timer.txt
index 7bc9691..15f8fed 100644
--- a/Documentation/devicetree/bindings/timer/rockchip,rk-timer.txt
+++ b/Documentation/devicetree/bindings/timer/rockchip,rk-timer.txt

@@ -16,7 +16,18 @@ Required properties:
 - clock-names : must include the following entries:
   "timer", "pclk"
 
-Example:
+Note:
+If device tree contain only one timer, than the timer will be intialized
+as clockevent provider. If device tree contain two timers, than first timer
+will be initialized as clockevent provider and second one as clocksource.
+
+If you want to bind specific timer as clockevent (i.e. one from alive subsystem)
+and specific timer as clocksource, you can number the timers in "aliases" node.
+
+If device tree contain only one timer and the timer is named as timer1 in
+"aliases" node, then the timer will be initialized as clocksource.
+
+Example (clockevent only):
 	timer: timer@ff810000 {
 		compatible = "rockchip,rk3288-timer";
 		reg = <0xff810000 0x20>;

@@ -24,3 +35,25 @@ Example:
 		clocks = <&xin24m>, <&cru PCLK_TIMER>;
 		clock-names = "timer", "pclk";
 	};
+
+Example (clockevent and clocksource with explicit numbering):
+	aliases {
+		timer0 = &timer6;
+		timer1 = &timer5;
+	};
+
+	timer5: timer@20038080 {
+		compatible = "rockchip,rk3188-timer", "rockchip,rk3288-timer";
+		reg = <0x20038080 0x20>;
+		interrupts = <GIC_SPI 60 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&cru SCLK_TIMER5>, <&cru PCLK_TIMER0>;
+		clock-names = "timer", "pclk";
+	};
+
+	timer6: timer@200380A0 {
+		compatible = ""rockchip,rk3188-timer", rockchip,rk3288-timer";
+		reg = <0x200380A0 0x20>;
+		interrupts = <GIC_SPI 64 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&cru SCLK_TIMER6>, <&cru PCLK_TIMER0>;
+		clock-names = "timer", "pclk";
+	};

-- 
1.7.9.5

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On Fri, Nov 25, 2016 at 01:12:16AM +0300, Alexander Kochetkov wrote:

1st and 2nd are ambiguous. Plus this is an OS implementation detail that 
doesn't belong in the binding.

+If you want to bind specific timer as clockevent (i.e. one from alive subsystem)
+and specific timer as clocksource, you can number the timers in "aliases" node.

No. 

Use and/or describe what are the features of a timer to make the 
decision. There has to be some reason you care which one. One has an 
interrupt and the other doesn't. One is always on. Etc.

Rob
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1 дек. 2016 г., в 0:30, Rob Herring [off-list ref] написал(а):

1st and 2nd are ambiguous. Plus this is an OS implementation detail that 
doesn't belong in the binding.

quoted

+If you want to bind specific timer as clockevent (i.e. one from alive subsystem)
+and specific timer as clocksource, you can number the timers in "aliases" node.

No. 

Use and/or describe what are the features of a timer to make the 
decision. There has to be some reason you care which one. One has an 
interrupt and the other doesn't. One is always on. Etc.

Thank you, Rob.

Eventually I abandoned this decision.
I left only one patch, which you confirmed recently.

And sorry for making noise with duplicate patches.

Alexander.