From: rafal@milecki.pl (Rafał Miłecki)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH V4 1/2] dt-bindings: thermal: add support for Broadcom's Northstar thermal
Date: Mon, 3 Apr 2017 16:57:40 +0200 [thread overview]
Message-ID: <6e040f49-deb0-a3ac-d3ee-0b0e6751a949@milecki.pl> (raw)
In-Reply-To: <CAC3K-4q4Cfo5Nzpxf3v_MHBJgPFxny5PCEEiBZM-9TBStGS-GQ@mail.gmail.com>
On 04/03/2017 04:54 PM, Jon Mason wrote:
> On Sun, Apr 2, 2017 at 11:07 PM, Jon Mason <jon.mason@broadcom.com> wrote:
>> On Sat, Apr 1, 2017 at 5:50 PM, Rafa? Mi?ecki <zajec5@gmail.com> wrote:
>>> On 04/01/2017 09:51 PM, Eduardo Valentin wrote:
>>>>
>>>> On Fri, Mar 31, 2017 at 10:11:23PM +0200, Rafa? Mi?ecki wrote:
>>>>>
>>>>> From: Rafa? Mi?ecki <rafal@milecki.pl>
>>>>>
>>>>> This commit documents binding for thermal used in Northstar family SoCs.
>>>>>
>>>>> Signed-off-by: Rafa? Mi?ecki <rafal@milecki.pl>
>>>>> ---
>>>>> 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 at 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.
next prev parent reply other threads:[~2017-04-03 14:57 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20170318155632.18099-1-zajec5@gmail.com>
2017-03-23 22:30 ` [PATCH V2 1/2] dt-bindings: thermal: add support for Broadcom's Northstar thermal Rafał Miłecki
2017-03-23 22:30 ` [PATCH V2 2/2] thermal: broadcom: add Northstar thermal driver Rafał Miłecki
2017-03-24 14:35 ` Jon Mason
2017-03-31 7:03 ` Rafał Miłecki
2017-03-31 14:23 ` Jon Mason
2017-03-31 14:49 ` Rafał Miłecki
2017-03-31 17:29 ` Jon Mason
2017-03-31 3:15 ` Eduardo Valentin
2017-03-31 7:08 ` Rafał Miłecki
2017-03-31 3:17 ` [PATCH V2 1/2] dt-bindings: thermal: add support for Broadcom's Northstar thermal Eduardo Valentin
2017-03-31 7:31 ` [PATCH V3 " Rafał Miłecki
2017-03-31 7:31 ` [PATCH V3 2/2] thermal: broadcom: add Northstar thermal driver Rafał Miłecki
2017-03-31 20:11 ` [PATCH V4 1/2] dt-bindings: thermal: add support for Broadcom's Northstar thermal Rafał Miłecki
2017-03-31 20:11 ` [PATCH V4 2/2] thermal: broadcom: add Northstar thermal driver Rafał Miłecki
2017-04-01 19:54 ` Eduardo Valentin
2017-04-01 20:20 ` Florian Fainelli
2017-04-01 21:41 ` Rafał Miłecki
2017-04-01 19:51 ` [PATCH V4 1/2] dt-bindings: thermal: add support for Broadcom's Northstar thermal Eduardo Valentin
2017-04-01 21:50 ` Rafał Miłecki
2017-04-02 4:13 ` Eduardo Valentin
2017-04-03 3:07 ` Jon Mason
2017-04-03 14:54 ` Jon Mason
2017-04-03 14:57 ` Rafał Miłecki [this message]
2017-04-03 15:48 ` [PATCH V5 " Rafał Miłecki
2017-04-03 15:48 ` [PATCH V5 2/2] thermal: broadcom: add Northstar thermal driver Rafał Miłecki
2017-04-07 4:42 ` Eduardo Valentin
2017-04-14 12:16 ` Rafał Miłecki
2017-04-14 15:16 ` Eduardo Valentin
2017-04-14 15:19 ` Rafał Miłecki
2017-04-17 20:09 ` Stefan Wahren
2017-04-10 15:00 ` [PATCH V5 1/2] dt-bindings: thermal: add support for Broadcom's Northstar thermal Rob Herring
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