linux-kernel - Re: [PATCH 1/3] ARM: dts: imx6ul-14x14-evk: Add sensors' GPIO regulator

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Message-ID: <VI1PR04MB7023B082934A79C181DAE7DDEE5A0@VI1PR04MB7023.eurprd04.prod.outlook.com>
Date:   Wed, 11 Dec 2019 09:38:13 +0000
From:   Leonard Crestez <leonard.crestez@....com>
To:     Marco Felsch <m.felsch@...gutronix.de>,
        Anson Huang <anson.huang@....com>
CC:     "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "mark.rutland@....com" <mark.rutland@....com>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        dl-linux-imx <linux-imx@....com>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "festevam@...il.com" <festevam@...il.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 1/3] ARM: dts: imx6ul-14x14-evk: Add sensors' GPIO
 regulator

On 2019-12-11 9:27 AM, Marco Felsch wrote:
> On 19-12-11 01:06, Anson Huang wrote:
>>> Subject: Re: [PATCH 1/3] ARM: dts: imx6ul-14x14-evk: Add sensors' GPIO
>>> regulator
>>>
>>> On 24.10.2019 11:51, Anson Huang wrote:
>>>> On i.MX6UL 14x14 EVK board, sensors' power are controlled by
>>>> GPIO5_IO02, add GPIO regulator for sensors to manage their power.
>>>>
>>>> Signed-off-by: Anson Huang <Anson.Huang@....com>
>>>
>>> For me this breaks network boot on imx6ul evk, relevant log snippet is this:
>>>
>>>       fec 20b4000.ethernet eth0: Unable to connect to phy
>>>       IP-Config: Failed to open eth0
>>>
>>> Looking at schematics (SPF-28616_C2.pdf) I see that SNVS_TAMPER2 pin is
>>> connected to PERI_PWREN which controls VPERI_3V3 which is used across
>>> the board:
>>>    * Sensors (VSENSOR_3V3)
>>>    * Ethernet (VENET_3V3)
>>>    * Bluetooth
>>>    * CAN
>>>    * Arduino header
>>>    * Camera
>>>
>>> Maybe there are board revision differences? As far as I can tell this regulator
>>> is not specific to sensors so it should be always on.
>>
>> You are correct, this regulator controls many other peripherals, I should make it always ON for now
>> to make sure NOT break other peripheral, and after all other peripherals controlled
>> by this regulator have added this regulator management, then the always ON can be
>> removed.
> 
> IMHO marking the regulator as always on shouldn't be the fix. Is it to
> much work to add all required regulators? At least please add a comment
> which describes the need of the always-on property.

I don't have the hardware to test all affected peripherals on hand and 
no familiarity with stuff like CAN.

Renaming reg_sensor and adding a comment makes sense.

--
Regards,
Leonard