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Date:   Wed, 18 Nov 2020 15:10:42 +0100
From:   Krzysztof Kozlowski <krzk@kernel.org>
To:     Alice Guo <alice.guo@nxp.com>
Cc:     "robh+dt@kernel.org" <robh+dt@kernel.org>,
        "shawnguo@kernel.org" <shawnguo@kernel.org>,
        "s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
        dl-linux-imx <linux-imx@nxp.com>, Peng Fan <peng.fan@nxp.com>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>
Subject: Re: [EXT] Re: [PATCH v3 4/4] soc: imx8m: change to use platform
 driver
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On Wed, Nov 18, 2020 at 02:07:41PM +0000, Alice Guo wrote:
> 
> 
> > -----Original Message-----
> > From: Krzysztof Kozlowski <krzk@kernel.org>
> > Sent: 2020年11月18日 18:42
> > To: Alice Guo <alice.guo@nxp.com>
> > Cc: robh+dt@kernel.org; shawnguo@kernel.org; s.hauer@pengutronix.de;
> > dl-linux-imx <linux-imx@nxp.com>; Peng Fan <peng.fan@nxp.com>;
> > devicetree@vger.kernel.org; linux-kernel@vger.kernel.org;
> > linux-arm-kernel@lists.infradead.org
> > Subject: Re: [EXT] Re: [PATCH v3 4/4] soc: imx8m: change to use platform
> > driver
> > 
> > Caution: EXT Email
> > 
> > On Wed, Nov 18, 2020 at 10:28:47AM +0000, Alice Guo wrote:
> >  >
> > > > If it is properly explained and there is no other way then yes, you
> > > > could. Here, for old DTBs, I would prefer to use
> > > > of_platform_device_create() and bind to "soc" node (child of root).
> > > > This way you would always have device and exactly one entry point
> > > > for the probe.
> > > >
> > >
> > > static struct platform_driver imx8_soc_init_driver = {
> > >       .probe = imx8_soc_init_probe,
> > >       .driver = {
> > >               .name = "soc@0",
> > >       },
> > > };
> > > Can I use "soc@0" to match this driver? It will not use
> > > of_platform_device_create(). It will use of_find_property() to
> > > determine whether and nvmem-cells can be used. If there is no nvmem-cells,
> > it will use the old way, which supports old DTBS. There is no need to add new
> > compatible.
> > 
> > No, the soc@0 is not a proper name for the driver.
> 
> I have no good idea, please give suggestion. Should I still add new compatible?
> Should I still keep device_initcall? If use of_platform_device_create(), which
> node should I use?

I mentioned my idea in the email before - of_platform_device_create() to
bind to the soc node. This will have to be in the initcall, you don't
have a choice to avoid it, since there was no compatible before.

Best regards,
Krzysztof