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From: Shawn Guo <shawnguo@kernel.org>
To: Robin Gong <yibin.gong@nxp.com>
Cc: "festevam@gmail.com" <festevam@gmail.com>,
	Anson Huang <anson.huang@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>
Subject: Re: [PATCH v1] ARM: dts: imx6sl-evk: keep sw4 always on
Date: Tue, 3 Jul 2018 13:38:45 +0800	[thread overview]
Message-ID: <20180703053843.GC4348@dragon> (raw)
In-Reply-To: <1530526335.15665.13.camel@nxp.com>

On Mon, Jul 02, 2018 at 02:12:52AM +0000, Robin Gong wrote:
> But in fact, the original dts is not correct without 'regulator-always-
> on'since SW4 is the critical DDR power rail, although, it's kept on in
> the previous kernel by no switches enable/disable interfaces provided
> in pfuze driver. Adding new property which can be done totally by the
> common 'regulator-always-on' is not a good choice. Keep the dts patch
> adding 'regulator-always-on' ahead of pfuze driver pach adding
> enable/disable interface is enough for such case I think. 

We can not just break the installed DTBs like this.  If patching
regulator driver with a new property is really difficult, we could
migrate the existing users in a 'soft' way:

 - Add required regulator-always-on for regulator nodes in DTS.
 - Patch i.MX platform code to check the presence of regulator-always-on
   property for critical regulators, and give a big warning if it's
   missing.
 - Wait for a couple of release cycles for users to migrate.
 - Add regulator driver patch back and break users who keep ignoring
   the warning.

Shawn

  parent reply	other threads:[~2018-07-03  5:38 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-25 12:34 [PATCH v1] ARM: dts: imx6sl-evk: keep sw4 always on Robin Gong
2018-06-25  5:53 ` Anson Huang
2018-07-01  9:34 ` Shawn Guo
2018-07-01 23:32   ` Fabio Estevam
2018-07-02  0:53     ` Anson Huang
2018-07-02  0:54       ` Fabio Estevam
2018-07-02  0:57         ` Anson Huang
2018-07-02  1:00           ` Fabio Estevam
2018-07-02  1:03             ` Anson Huang
2018-07-02  1:05               ` Fabio Estevam
2018-07-02  1:09                 ` Anson Huang
2018-07-02  1:17                   ` Fabio Estevam
2018-07-02  1:19                     ` Anson Huang
2018-07-02  2:12                     ` Robin Gong
2018-07-02 23:14                       ` Fabio Estevam
2018-07-03  5:38                       ` Shawn Guo [this message]
2018-07-03  7:44                         ` Anson Huang
2018-07-03 11:10                           ` Fabio Estevam
2018-07-04  1:42                             ` Robin Gong
2018-07-04  6:56                               ` Lothar Waßmann

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