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Date: Mon, 19 Jan 2026 15:46:06 +0000
From: Leo Yan <leo.yan@arm.com>
To: James Clark <james.clark@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	linux-stm32@st-md-mailman.stormreply.com,
	linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org,
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	Alexandre Torgue <alexandre.torgue@foss.st.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH] stm class: Fix Kconfig symbols
Message-ID: <20260119154606.GE2732125@e132581.arm.com>
References: <20251217-fix_stm_kconfig-v1-1-531fb3674549@arm.com>
 <8d48dd55-d78d-4cbf-88b0-5427a731ba7d@linaro.org>
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In-Reply-To: <8d48dd55-d78d-4cbf-88b0-5427a731ba7d@linaro.org>

On Mon, Jan 19, 2026 at 12:35:23PM +0000, James Clark wrote:

[...]

> > @@ -28,7 +28,7 @@ config STM_PROTO_BASIC
> >   config STM_PROTO_SYS_T
> >   	tristate "MIPI SyS-T STM framing protocol driver"
> > -	default CONFIG_STM
> > +	default STM
> 
> The help below here says "If you don't know what this is, say N." which
> makes me wonder if this should be on by default or not?

STM_PROTO_BASIC is a must have config when enabling STM.  While
STM_PROTO_SYS_T is not mandatory, but it is useful to build it so that
users can select the protocol dynamically at runtime.

> Also everything is in an "if STM" block, so "default STM" is a bit
> redundant. It's not that obvious what the intention was.

They are two different things.

"if STM" expresses a dependency (the module depends on STM), while
"default STM" means the module will be selected by default if STM is
enabled.

Thanks,
Leo

P.s. I also tried using the "select" and "imply" syntax to enable the
protocol configurations.  Based on testing, I did not observe any
difference compared to using the "default" syntax.