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Subject: Re: [PATCH 3/3] arm64: dts: rk3399: Add init voltage for vdd_log
To:     Markus Reichl <m.reichl@fivetechno.de>, Soeren Moch <smoch@web.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>
From:   Kever Yang <kever.yang@rock-chips.com>
Message-ID: <17e14b30-02ee-2379-8891-088677924479@rock-chips.com>
Date:   Tue, 12 Nov 2019 18:02:37 +0800
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Markus,


On 2019/11/12 下午4:16, 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),

(note that if  no driver touch the regulator, the PWM is default input, 
not output;)

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.
>
> Gruß,