On 04/03/2017 04:54 PM, Jon Mason wrote:
On Sun, Apr 2, 2017 at 11:07 PM, Jon Mason <jon.mason@xxxxxxxxxxxx> wrote:
On Sat, Apr 1, 2017 at 5:50 PM, Rafał Miłecki <zajec5@xxxxxxxxx> wrote:
On 04/01/2017 09:51 PM, Eduardo Valentin wrote:
On Fri, Mar 31, 2017 at 10:11:23PM +0200, Rafał Miłecki wrote:
From: Rafał Miłecki <rafal@xxxxxxxxxx>
This commit documents binding for thermal used in Northstar family SoCs.
Signed-off-by: Rafał Miłecki <rafal@xxxxxxxxxx>
---
V3: Add thermal-zones to the example
Rob: Because of this update, I didn't include Acked-by I got for V2
---
.../devicetree/bindings/thermal/brcm,ns-thermal | 26
++++++++++++++++++++++
1 file changed, 26 insertions(+)
create mode 100644
Documentation/devicetree/bindings/thermal/brcm,ns-thermal
diff --git a/Documentation/devicetree/bindings/thermal/brcm,ns-thermal
b/Documentation/devicetree/bindings/thermal/brcm,ns-thermal
new file mode 100644
index 000000000000..c561c7349f17
--- /dev/null
+++ b/Documentation/devicetree/bindings/thermal/brcm,ns-thermal
@@ -0,0 +1,26 @@
+* Broadcom Northstar Thermal
+
+This binding describes thermal sensor that is part of Northstar's DMU
(Device
+Management Unit).
+
+Required properties:
+- compatible : Must be "brcm,ns-thermal"
+- reg : iomem address range of PVTMON registers
+- #thermal-sensor-cells : Should be <0>
+
+Example:
+
+thermal: thermal@1800c2c0 {
+ compatible = "brcm,ns-thermal";
+ reg = <0x1800c2c0 0x10>;
+ #thermal-sensor-cells = <0>;
+};
+
+thermal-zones {
+ cpu_thermal: cpu-thermal {
+ polling-delay-passive = <0>;
+ polling-delay = <1000>;
+ coefficients = <(-556) 418000>;
+ thermal-sensors = <&thermal>;
You need to define trips and cooling devices here. Otherwise, makes
little sense to have this device in thermal subsystem. Here is an
example of minimal set:
https://git.kernel.org/pub/scm/linux/kernel/git/evalenti/linux-soc-thermal.git/commit/?h=linus&id=1e2ac9821de6a85d3e8358f238436708d1d46869
The above has no passive action. It is just gonna shutdown the system if
temperature crosses a threshold.
But, a typical cooling device would be CPU frequency throttling. Do you
have
that up and running in your routers?
I don't have CPU freq throttling, so shutdown will be the only solution for
critical temp right now.
I know I should have at least a trip for critical temperature, but the
problem
is I don't know what value to use. There isn't any info about this in public
datasheets. Broadcom's SDK doesn't mention it. Vendors share only the max
environment temp, not the max CPU temp.
So for now I only meant to provide user space access to reading current CPU
temperature. I could do some stress tests and ask other users to do it as
well.
Or maybe I could just put in Documentation some round value that makes more
or
less sense and then work on a proper content of real DTS files?
Unless we can get some hint from Broadcom people. Jon? Florian? Anyone?
I'll poke around and see if I can find a datasheet for NS/NSP. Worst
case, I can ask one of the HW engineers for NSP, and we can use the
same value for NS.
In the NS documentation, under "Absolute Maximum Ratings":
The "Maximum Junction Temperature" is 125 C
The "Commercial Ambient Temperature (Operating)" range is 0 to 75 C
The "Industrial Ambient Temperature (Operating)" range is -40 to 85 C
The "Storage Temperature" range is -40 to 125 C
In the NSP documentation, under "Absolute Maximum Ratings":
The "Maximum Junction Temperature" is 110 C
The "Commercial Ambient Temperature (Operating)" range is 0 to 75 C
The "Industrial Ambient Temperature (Operating)" range is -40 to 85 C
The "Storage Temperature" range is -40 to 125 C
I believe the first one is the number you are looking for.
Thanks a lot for this valuable info! I'll send next version today.
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