linux-kernel - Re: [PATCH v1 3/3] dt-bindings: thermal: sun8i: Add binding for D1/T113s THS controller

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20230611-confront-expectant-aa5da832541c@spud>
Date:   Sun, 11 Jun 2023 11:18:34 +0100
From:   Conor Dooley <conor@...nel.org>
To:     Maxim Kiselev <bigunclemax@...il.com>
Cc:     linux-kernel@...r.kernel.org,
        Vasily Khoruzhick <anarsoul@...il.com>,
        Yangtao Li <tiny.windzz@...il.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Amit Kucheria <amitk@...nel.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Chen-Yu Tsai <wens@...e.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Samuel Holland <samuel@...lland.org>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Cristian Ciocaltea <cristian.ciocaltea@...labora.com>,
        linux-pm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev,
        linux-riscv@...ts.infradead.org
Subject: Re: [PATCH v1 3/3] dt-bindings: thermal: sun8i: Add binding for
 D1/T113s THS controller

On Sun, Jun 11, 2023 at 10:53:56AM +0300, Maxim Kiselev wrote:
> вс, 11 июн. 2023 г. в 01:14, Conor Dooley <conor@...nel.org>:
> >
> > On Sat, Jun 10, 2023 at 11:31:03PM +0300, Maxim Kiselev wrote:
> > > сб, 10 июн. 2023 г. в 21:01, Conor Dooley <conor@...nel.org>:
> > >
> > > ...
> > >
> > > > > > > +  - |
> > > > > > > +    thermal-sensor@...9400 {
> > > > > > > +          compatible = "allwinner,sun20i-d1-ths";
> > > > > > > +          reg = <0x02009400 0x400>;
> > > > > > > +          interrupts = <0 90 0>;
> > > > > > > +          clocks = <&ccu 0>;
> > > > > > > +          clock-names = "bus";
> > > > > > > +          resets = <&ccu 2>;
> > > > > > > +          nvmem-cells = <&ths_calibration>;
> > > > > > > +          nvmem-cell-names = "calibration";
> > > > > > > +          #thermal-sensor-cells = <0>;
> > > > > > >
> > > > > > >> Is this calibration required, or optional, for the d1?
> > > > > >
> > > > > > Calibration data for the D1 is optional as for the H6.
> > > > > > (But without it, the sensor data will be inaccurate).
> > > > >
> > > > > Okay. Modulo the signoff:
> > > > > Reviewed-by: Conor Dooley <conor.dooley@...rochip.com>
> > > >
> > > > Wait, that's not what I meant to say... Clearly turned my brain off for
> > > > a moment. If it is not going to function correctly without the
> > > > calibration data, why not make the calibration data required for the
> > > > d1's ths?
> > >
> > > I don't really know why, but the calibration data is optional for
> > > other controllers.
> > > So I just did it the same way.
> > > Here is explanation comment about it from the driver:
> > >         /*
> > >          * Even if the external calibration data stored in sid is
> > >          * not accessible, the THS hardware can still work, although
> > >          * the data won't be so accurate.
> > >          *
> > >          * The default value of calibration register is 0x800 for
> > >          * every sensor, and the calibration value is usually 0x7xx
> > >          * or 0x8xx, so they won't be away from the default value
> > >          * for a lot.
> > >          *
> > >          * So here we do not return error if the calibration data is
> > >          * not available, except the probe needs deferring.
> > >          */
> >
> > Wait, so if there is no calibration data then this thing will just defer
> > probing, ad infinitum? Looks like everything other than the a33 has the
> > cells in the dts, and the software seems to expect the cells.
> > What am I missing?
> 
> Not quite. If we don't have a calibration cell in the dts, then we
> just skip the calibration.
> We will only get EPROBE_DEFER if we have calibration in the dts.

Ah that makes a lot more sense, thanks.

Download attachment "signature.asc" of type "application/pgp-signature" (229 bytes)