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Date:   Fri, 17 Sep 2021 10:21:25 +0200
From:   Michael Walle <michael@walle.cc>
To:     Heiko Thiery <heiko.thiery@gmail.com>,
        Frieder Schrempf <frieder.schrempf@kontron.de>
CC:     devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Joakim Zhang <qiangqing.zhang@nxp.com>,
        Shengjiu Wang <shengjiu.wang@nxp.com>,
        Rob Herring <robh+dt@kernel.org>,
        Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        =?ISO-8859-1?Q?Guido_G=FCnther?= <agx@sigxcpu.org>,
        "Angus Ainslie (Purism)" <angus@akkea.ca>
Subject: =?US-ASCII?Q?Re=3A_=5BPATCH=5D_arm64=3A_dts=3A_imx8mm-kontron-n8?= =?US-ASCII?Q?01x-som=3A_do_not_allow_to_switch_off_buck2?=
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Am 17=2E September 2021 09:28:51 MESZ schrieb Heiko Thiery <heiko=2Ethiery@=
gmail=2Ecom>:
>Hi Frieder,
>
>Am Mi=2E, 15=2E Sept=2E 2021 um 14:09 Uhr schrieb Frieder Schrempf
><frieder=2Eschrempf@kontron=2Ede>:
>>
>> On 15=2E09=2E21 14:05, Michael Walle wrote:
>> > Am 2021-09-15 14:03, schrieb Heiko Thiery:
>> >> The buck2 output of the PMIC is the VDD core voltage of the cpu=2E
>> >> Switching off this will poweroff the CPU=2E Add the 'regulator-alway=
s-on'
>> >> property to avoid this=2E
>> >
>> > Mh, have this ever worked? Is there a commit which introduced a regre=
ssion?
>>
>> Yes, this did work before, even without 'regulator-always-on'=2E I
>> currently don't understand why this is needed=2E The regulator is
>> referenced in the CPU nodes as 'cpu-supply'=2E This should be enough to
>> not disable it as long as the CPU is up=2E
>
>I rechecked that with 5=2E11, 5=2E10 and 5=2E9 and I see on all of them t=
he
>same issue:
>
>[ 31=2E716031] vdd-5v: disabling
>[ 31=2E719032] rst-usb-eth2: disabling
>[ 31=2E722553] buck2: disabling
>
>While on that I tried to compare with other boards and see that they
>also have the cpu-voltage marked as "regulator-always-on"=2E The only
>exception in dts/freescale is in imx8mq-librem5-devkit=2Edts [1] that
>has not set this property=2E
>
>I agree with you and don't understand why this is happening=2E Has
>anyone else an explanation?

Do you have the CPU frequency scaling driver enabled?=20

-michael