linux-kernel - Re: [PATCH 3/3] arm64: dts: rk3399: Add init voltage for vdd_log

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Date:   Tue, 12 Nov 2019 12:06:36 +0100
From:   Markus Reichl <m.reichl@...etechno.de>
To:     Soeren Moch <smoch@....de>, Kever Yang <kever.yang@...k-chips.com>,
        heiko@...ech.de
Cc:     Mark Rutland <mark.rutland@....com>,
        Andrius Štikonas <andrius@...konas.eu>,
        Vivek Unune <npcomplete13@...il.com>,
        Alexis Ballier <aballier@...too.org>,
        devicetree@...r.kernel.org,
        Katsuhiro Suzuki <katsuhiro@...suster.net>,
        Robin Murphy <robin.murphy@....com>,
        Elaine Zhang <zhangqing@...k-chips.com>,
        linux-kernel@...r.kernel.org, Vicente Bergas <vicencb@...il.com>,
        Ezequiel Garcia <ezequiel@...labora.com>,
        linux-rockchip@...ts.infradead.org,
        Rob Herring <robh+dt@...nel.org>,
        Pragnesh Patel <Pragnesh_Patel@...tor.com>,
        Oskari Lemmela <oskari@...mela.net>,
        Akash Gajjar <akash@...nedev.com>, Nick Xie <nick@...das.com>,
        Peter Robinson <pbrobinson@...il.com>,
        Hugh Cole-Baker <sigmaris@...il.com>,
        linux-arm-kernel@...ts.infradead.org, Andy Yan <andyshrk@...il.com>
Subject: Re: [PATCH 3/3] arm64: dts: rk3399: Add init voltage for vdd_log

Dear Sore, Kever,

Am 12.11.19 um 11:19 schrieb Soeren Moch:
> 
> 
> On 12.11.19 11:02, Kever Yang wrote:
>> 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),
> 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...
> 
It has to be set to 450mV - 1400mV to give 953mV.
I will come out with a patch that fixes this.

> Regards,
> Soeren
>>
>> (note that if  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.
>>>
>>> Gruß,
>>
>>
> 
> 
> _______________________________________________
> Linux-rockchip mailing list
> Linux-rockchip@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-rockchip
> 

Gruß,
-- 
Markus Reichl

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