Re: Sense of soc bus? (was: [PATCH] base: soc: Export soc_device_to_device() helper)

From: "Andreas Färber" <afaerber@suse.de>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "Neil Armstrong" <narmstrong@baylibre.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Geert Uytterhoeven" <geert+renesas@glider.be>,
	linux-realtek-soc@lists.infradead.org,
	"Tony Lindgren" <tony@atomide.com>,
	"Linus Walleij" <linus.walleij@linaro.org>,
	"Bjorn Andersson" <bjorn.andersson@linaro.org>,
	"Thierry Reding" <thierry.reding@gmail.com>,
	"Lee Jones" <lee.jones@linaro.org>,
	"Rob Herring" <robh@kernel.org>,
	"Kevin Hilman" <khilman@baylibre.com>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	"Michal Simek" <michal.simek@xilinx.com>,
	"Jonathan Hunter" <jonathanh@nvidia.com>,
	"NXP Linux Team" <linux-imx@nxp.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	boot-architecture@lists.linaro.org,
	"Sascha Hauer" <s.hauer@pengutronix.de>,
	"Fabio Estevam" <festevam@gmail.com>,
	"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
	linux-amlogic@lists.infradead.org, linux-omap@vger.kernel.org,
	"Alexander Sverdlin" <alexander.sverdlin@gmail.com>,
	"Linux ARM" <linux-arm-kernel@lists.infradead.org>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
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	"Pengutronix Kernel Team" <kernel@pengutronix.de>,
	"Shawn Guo" <shawnguo@kernel.org>
Subject: Re: Sense of soc bus? (was: [PATCH] base: soc: Export soc_device_to_device() helper)
Date: Fri, 15 Nov 2019 13:00:59 +0100	[thread overview]
Message-ID: <a0a6d71f-4fb7-51ce-fe33-74f9e588b791@suse.de> (raw)
In-Reply-To: <CAMuHMdWOWWQoJh5=07VMRhtrFR_Gc_qNhjTV4tCsvwvMn0kYfA@mail.gmail.com>

Hi Geert,

Am 15.11.19 um 09:58 schrieb Geert Uytterhoeven:
> On Fri, Nov 15, 2019 at 9:52 AM Neil Armstrong <narmstrong@baylibre.com> wrote:
>> On 12/11/2019 11:47, Andreas Färber wrote:
>>> For example, RTD1295 will support LSADC only from revision B00
>>> on (and it's not the first time I'm seeing such things in the industry).
>>> So if a user complains, it will be helpful to see that information.
>>>
>>> Referencing your Amlogic review, with all due respect for its authors,
>>> the common framework here just lets that information evaporate into the
>>> deeps of sysfs.
>>
>> Hopefully we never had the case where needed to use the soc info in drivers,
>> but now we have one and having such infrastructure already in-place will help.
>>
>> Renesas platforms makes a extensive usage of the soc info infrastructure to
>> figure out plenty of HW parameters at runtime and lower their DT changes.
> 
> We do our best to use it solely for detecting quirks in early SoC revisions.

Got a pointer? I fail to immediately understand how sysfs would help
drivers (as opposed to userspace) detect quirks: Parsing strings back
doesn't sound efficient, and I don't see you exporting any custom APIs
in drivers/soc/renesas/renesas-soc.c?

Regards,
Andreas

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