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Subject: Re: [PATCH 3/3] arm64: dts: rk3399: Add init voltage for vdd_log
To:     Kever Yang <kever.yang@rock-chips.com>,
        Markus Reichl <m.reichl@fivetechno.de>, heiko@sntech.de
Cc:     Mark Rutland <mark.rutland@arm.com>,
        =?UTF-8?Q?Andrius_=c5=a0tikonas?= <andrius@stikonas.eu>,
        linux-kernel@vger.kernel.org, Alexis Ballier <aballier@gentoo.org>,
        linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
        Katsuhiro Suzuki <katsuhiro@katsuster.net>,
        Hugh Cole-Baker <sigmaris@gmail.com>,
        Elaine Zhang <zhangqing@rock-chips.com>,
        Andy Yan <andyshrk@gmail.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Vicente Bergas <vicencb@gmail.com>,
        Oskari Lemmela <oskari@lemmela.net>,
        linux-rockchip@lists.infradead.org,
        Rob Herring <robh+dt@kernel.org>,
        Pragnesh Patel <Pragnesh_Patel@mentor.com>,
        Peter Robinson <pbrobinson@gmail.com>,
        Nick Xie <nick@khadas.com>,
        Ezequiel Garcia <ezequiel@collabora.com>,
        Vivek Unune <npcomplete13@gmail.com>,
        Akash Gajjar <akash@openedev.com>
References: <20191111005158.25070-1-kever.yang@rock-chips.com>
 <20191111005158.25070-3-kever.yang@rock-chips.com>
 <ef8830f3-10d1-7b71-0e18-232f2eaeef2d@web.de>
 <1eaef5d5-c923-da56-b9c4-48d517b3c969@rock-chips.com>
 <acbab893-9e9a-cfe1-67bf-a9e2b2e50114@fivetechno.de>
 <17e14b30-02ee-2379-8891-088677924479@rock-chips.com>
From:   Soeren Moch <smoch@web.de>
Message-ID: <fd9ee2bc-9dfb-1aa2-f00f-add9b3069876@web.de>
Date:   Tue, 12 Nov 2019 11:19:19 +0100
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On 12.11.19 11:02, Kever Yang wrote:
> Markus,
>
>
> On 2019/11/12 =E4=B8=8B=E5=8D=884:16, Markus Reichl wrote:
>> Hi Kever,
>>
>> have a rk3399-roc-pc running mainline U-Boot and kernel and vdd_log is
>> showing 1118 mV.
>
> The rk3399-roc-pc have the same vdd_log circuit in schematic, so it
> should like the patch 1/3 of
>
> this patch set.
>
> I don't understand who is setting this value, maybe the default value
> without pwm regulator enabled?
>
>> Is this a danger for the board?
>> How to fix it?
>
> The best way is to set correct min/max microvolt of the
> regulator(measure with PWM output low and high),
I didn't look into the schematic of this board, but if it is similar to
RockPro64, setting the pwm regulator to the max voltage of 1.7V will
probably kill the rk3399 immediately. So I recommend not to do this...

Regards,
Soeren
>
> (note that if=C2=A0 no driver touch the regulator, the PWM is default
> input, not output;)
> to
> and set a init-microvolt for U-Boot driver, and I think no kernel
> driver touch this regulator now.
>
>
> Thanks,
>
> - Kever
>
>> Btw. vin-supply for this pwm-regulator is ignored and I could not
>> find it
>> in bindings doc.
>>
>> Gru=C3=9F,
>
>