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From:   Fabio Estevam <festevam@gmail.com>
Date:   Tue, 3 Jul 2018 08:10:32 -0300
Message-ID: <CAOMZO5BY99f5jjU+73=8WjqwBKr_q2S1mvx90URZUBkgOVn9YA@mail.gmail.com>
Subject: Re: [PATCH v1] ARM: dts: imx6sl-evk: keep sw4 always on
To:     Anson Huang <anson.huang@nxp.com>
Cc:     Shawn Guo <shawnguo@kernel.org>, Robin Gong <yibin.gong@nxp.com>,
        "mark.rutland@arm.com" <mark.rutland@arm.com>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "robh+dt@kernel.org" <robh+dt@kernel.org>,
        dl-linux-imx <linux-imx@nxp.com>,
        "kernel@pengutronix.de" <kernel@pengutronix.de>,
        Fabio Estevam <fabio.estevam@nxp.com>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>
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Hi Anson,

On Tue, Jul 3, 2018 at 4:44 AM, Anson Huang <anson.huang@nxp.com> wrote:

> It is NOT easy to identify which switch is critical or NOT, and different platforms
> have different board design, it will introduce many platform specified code, so I think
> just revert the pfuze100 switch enable/disable patch should be OK for now.

I have sent the pfuze100 regulator patch revert and it is linux-next
now. Should probably reach 4.18-rc4.

> After a couple of release cycles, add the pfuze100 switch enable/disable patch
> back to support this feature, I believe users should switch to new dtb with "regulator-always-on"
> existing already.

That will still break old dtb compatibility.

You cannot force users to use "regulator-always-on" and the old dtbs
need to always work.

So whatever new feature you need to introduce it needs to be done in
such a way that the existing dtb's will continue working.