linux-kernel - Re: [PATCH] ARM: dts: sun8i-a83t: Add thermal trip points/cooling maps

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Message-ID: <20200223101050.lqe5uegpmoyqvna6@core.my.home>
Date:   Sun, 23 Feb 2020 11:10:50 +0100
From:   Ondřej Jirman <megous@...ous.com>
To:     Chen-Yu Tsai <wens@...e.org>
Cc:     linux-sunxi <linux-sunxi@...glegroups.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Maxime Ripard <mripard@...nel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        "moderated list:ARM/Allwinner sunXi SoC support" 
        <linux-arm-kernel@...ts.infradead.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ARM: dts: sun8i-a83t: Add thermal trip points/cooling
 maps

Hello,

On Sun, Feb 23, 2020 at 11:29:07AM +0800, Chen-Yu Tsai wrote:
> Hi,
> 
> On Sun, Feb 23, 2020 at 5:40 AM Ondrej Jirman <megous@...ous.com> wrote:
> >
> > This enables passive cooling by down-regulating CPU voltage
> > and frequency.
> 
> Please state for the record how the trip points were derived. Were they from
> the BSP? Or the user manual?

The values are taken from the BSP for A83T:

https://megous.com/git/linux/tree/drivers/thermal/sunxi-temperature.c?h=a83t-3.4-bsp-tbs-a711#n747

The datasheet only mentions recommended Ta (ambient operating temperature) range
-20 to +70°C. So die voltages will be larger than that. I guess that roughly
matches the BSP values.

regards,
	o.

> ChenYu