Re: [PATCH 5/6] tty: serial: Add linflexuart driver for S32V234

From: Will Deacon <will@kernel.org>
To: Stefan-gabriel Mirea <stefan-gabriel.mirea@nxp.com>
Cc: "corbet@lwn.net" <corbet@lwn.net>,
	"robh+dt@kernel.org" <robh+dt@kernel.org>,
	"mark.rutland@arm.com" <mark.rutland@arm.com>,
	"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
	"shawnguo@kernel.org" <shawnguo@kernel.org>,
	Leo Li <leoyang.li@nxp.com>, "jslaby@suse.com" <jslaby@suse.com>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	Cosmin Stefan Stoica <cosmin.stoica@nxp.com>,
	Larisa Ileana Grigore <larisa.grigore@nxp.com>
Subject: Re: [PATCH 5/6] tty: serial: Add linflexuart driver for S32V234
Date: Fri, 9 Aug 2019 10:53:38 +0100	[thread overview]
Message-ID: <20190809095338.d73fomq424gayf2b@willie-the-truck> (raw)
In-Reply-To: <VI1PR0402MB2863B3E3E2F93CBA8ADB96E5DFD60@VI1PR0402MB2863.eurprd04.prod.outlook.com>

On Fri, Aug 09, 2019 at 09:45:40AM +0000, Stefan-gabriel Mirea wrote:
> On 8/8/2019 8:17 PM, Will Deacon wrote:
> > On Thu, Aug 08, 2019 at 12:47:00PM +0000, Stefan-gabriel Mirea wrote:
> >> On 8/8/2019 11:08 AM, Will Deacon wrote:
> >>> On Fri, Aug 02, 2019 at 07:47:23PM +0000, Stefan-gabriel Mirea wrote:
> >>>> +             linflex,<addr>
> >>>> +                     Use early console provided by Freescale LinFlex UART
> >>>> +                     serial driver for NXP S32V234 SoCs. A valid base
> >>>> +                     address must be provided, and the serial port must
> >>>> +                     already be setup and configured.
> >>>
> >>> Why isn't earlycon= sufficient for this?
> >>
> >> "earlycon=" is not actually supported. I will fix this in the next
> >> version by adding a /chosen/stdout-path to the dts. The compatible
> >> string provided to OF_EARLYCON_DECLARE will also be changed from
> >> "fsl,s32v234-linflexuart" to "fsl,s32-linflexuart" to match the one in
> >> the device tree nodes. I missed this after importing a rename from our
> >> codebase.
> >>
> >> Should I remove this addition from kernel-parameters.txt after that?
> > 
> > Yes, if you can use earlycon instead, then you can drop your custom option
> > entirely and therefore there's no need to document it either.
> 
> Can you please clarify what you mean by "drop your custom option"? The
> "linflex" option documented in the paragraph is the name of the
> earlycon_id declared via "OF_EARLYCON_DECLARE(linflex, ...)". We have
> not done anything particular to accept it in the parameter value.

My apologies, I completely misread your patch and thought your were adding
a *new* kernel parameter. Having looked at the context, I now see you're
adding a new earlycon option, which is what I was suggesting :)

By all means, please update the stdout-path, because then you can just pass
"earlycon" and things will work as expected.

Will