Re: [PATCH 1/2] thermal: db8500: Finalize device tree conversion

[Linus Walleij <linus.walleij@linaro.org>]

On Thu, Aug 22, 2019 at 8:16 AM Daniel Lezcano
<daniel.lezcano@linaro.org> wrote:

> I've been through the DT and I don't understand why there is:
>
>         [ ... ]
>         trip0-temp = <70000>;
>         trip0-type = "active";
>         trip0-cdev-num = <1>;
>         trip0-cdev-name0 = "thermal-cpufreq-0";
>         [ ... ]
>
> Those bindings already exists for the thermal no?
>
> Why not create a thermal-zone node and then add the values above?

I guess you refer to arch/arm/boot/dts/ste-snowball.dts
where this is in the thermal@801573c0 node.
(I moved it to the main SoC file for the next kernel.)

I think the reason is that this was merged in:
commit dc1956b5f84de7d453ec4d9fe68385fffd689686
"Thermal: Add ST-Ericsson DB8500 thermal properties and platform data."
Date:   Thu Nov 15 18:56:43 2012 +0800

Thermal zones were not added until:
commit 4e5e4705bf69ea450f58fc709ac5888f321a9299
"thermal: introduce device tree parser"
Date:   Wed Jul 3 15:35:39 2013 -0400

Which is half a year after this device tree was written.

Apparently Hongbo stopped working on this driver before
that and didn't convert the driver or consumers over to the
new thermal zone APIs with trip points and cooling maps
defined in the device tree (which by the way is an awesome
feature).

> Another point is there are too many trip points, two should be enough,
> one for throttling and one for critical, the governor will handle that
> properly by stepping the opps.
>
> And one last point is the trip point should be passive, not active.

OK I get it, can we merge these two patches that just move
the code to the thermal driver and then I can make
a new patch or some new patches on top to migrate to
Eduardo's new framework for device tree defined thermal
zones?

Yours,
Linus Walleij