linux-kernel - Re: [PATCH 0/2] soc: imx: gpc: Power off PU domain in suspend/resume on 6qp

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Date:   Mon, 2 Jul 2018 13:49:47 +0000
From:   Leonard Crestez <leonard.crestez@....com>
To:     "l.stach@...gutronix.de" <l.stach@...gutronix.de>
CC:     dl-linux-imx <linux-imx@....com>,
        "A.s. Dong" <aisheng.dong@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        Fabio Estevam <fabio.estevam@....com>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "andrew.smirnov@...il.com" <andrew.smirnov@...il.com>,
        Anson Huang <anson.huang@....com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        Robin Gong <yibin.gong@....com>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>
Subject: Re: [PATCH 0/2] soc: imx: gpc: Power off PU domain in suspend/resume
 on 6qp

On Mon, 2018-07-02 at 14:15 +0200, Lucas Stach wrote:
> Am Montag, den 02.07.2018, 14:52 +0300 schrieb Leonard Crestez:

> > With current code (even without my patches) attempting to dynamically
> > remove/probe the GPC fils since since the per-pgc platform_device
> > instances are not removed. I'm trying something like this:
> > 
> > echo 130000.gpu > /sys/bus/platform/drivers/etnaviv-gpu/unbind
> > echo 134000.gpu > /sys/bus/platform/drivers/etnaviv-gpu/unbind
> > echo 20dc000.gpc  > /sys/bus/platform/drivers/imx-gpc/unbind
> > echo 20dc000.gpc  > /sys/bus/platform/drivers/imx-gpc/bind
> > 
> > But is there any usecase for dynamically removing the GPC? Instead of
> > trying to fix it I'd rather delete imx_gpc_driver.remove, just like
> > for gpcv2. Would anyone object to a patch doing this?
> 
> Yes, as this is taking things in wrong direction. With device-links we
> are able to unbind consumer devices when a provider is removed. As the
> GPC is a consumer of a regulator, not having the ability to unbind it
> would break that use case.

The GPC is a "consumer" of the LDO regulators which are built into the
SOC. Why would you want to unbind any of this stuff?

I don't understand the usecase, maybe you can elaborate?