Thread (29 messages) 29 messages, 5 authors, 2014-10-03

[PATCH v3 03/13] PM / Domains: Add DT bindings for PM QoS device latencies

From: Ulf Hansson <hidden>
Date: 2014-09-26 08:28:52
Also in: linux-devicetree, linux-pm, linux-sh, lkml

On 25 September 2014 18:28, Geert Uytterhoeven [off-list ref] wrote:
PM QoS device start/stop and save/restore state latencies are more or
less properties of the hardware.
In legacy code, they're specified from platform code.
On DT platforms, their values should come from DT.
I am not so sure about this.

First, I think there a too much software affecting these latencies to
call them hardware properties.

Second, I am not sure that the future version of genpd will have all
these four latencies, but maybe only two. Let's see. I would thus
suggest to put this patch on hold for a while.

Kind regards
Uffe
quoted hunk ↗ jump to hunk
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
Should these properties be called "linux,*-latency"?

v3:
  - No changes
v2:
  - New

 Documentation/devicetree/bindings/power/power_domain.txt | 10 ++++++++++
 1 file changed, 10 insertions(+)
diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
index 7bc421d84367d636..024815bc257723b1 100644
--- a/Documentation/devicetree/bindings/power/power_domain.txt
+++ b/Documentation/devicetree/bindings/power/power_domain.txt
@@ -42,12 +42,22 @@ Required properties:
  - power-domains : A phandle and PM domain specifier as defined by bindings of
                    the power controller specified by phandle.

+Optional properties:
+ - stop-latency: Stop latency of the device, in ns,
+ - start-latency: Start latency of the device, in ns,
+ - save-state-latency: Save-state latency of the device, in ns,
+ - restore-state-latency: Restore-state latency of the device, in ns.
+
 Example:

        leaky-device at 12350000 {
                compatible = "foo,i-leak-current";
                reg = <0x12350000 0x1000>;
                power-domains = <&power 0>;
+               stop-latency = <250000>;
+               start-latency = <250000>;
+               save-state-latency = <250000>;
+               restore-state-latency = <250000>;
        };

 The node above defines a typical PM domain consumer device, which is located
--
1.9.1
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