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From: Geert Uytterhoeven <geert@linux-m68k.org>
To: "Andreas Färber" <afaerber@suse.de>
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>,
	"open list:ARM/Amlogic Meson..."
	<linux-amlogic@lists.infradead.org>,
	"open list:TI ETHERNET SWITCH DRIVER (CPSW)"
	<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>,
	"Hartley Sweeten" <hsweeten@visionengravers.com>,
	"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 13:34:55 +0100
Message-ID: <CAMuHMdU7EYHWRAR+s3ee4Wy6+6_MZON5xARszO7TDXZGyw8d5w@mail.gmail.com> (raw)
In-Reply-To: <a0a6d71f-4fb7-51ce-fe33-74f9e588b791@suse.de>

Hi Andreas,

On Fri, Nov 15, 2019 at 1:01 PM Andreas Färber <afaerber@suse.de> wrote:
> 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?

We use soc_device_match(), inside kernel drivers.
Exposure through sysfs is a side-effect of using soc_device_register(),
and welcomed, as it allows the user to find out quickly which SoC and
revision is being used.

FTR, lshw (Ubuntu 18.04 has v2.18, which does seem to be the latest
upstream version) does not parse /sys/devices/soc0/.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

  reply index

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-03  1:36 [RFC 00/11] ARM: Realtek RTD1195/RTD1295 SoC info Andreas Färber
2019-11-03  1:36 ` [RFC 01/11] dt-bindings: soc: Add Realtek RTD1195 chip info binding Andreas Färber
2019-11-06  4:41   ` Rob Herring
2019-11-03  1:36 ` [RFC 02/11] soc: Add Realtek chip info driver for RTD1195 and RTD1295 Andreas Färber
2019-11-03  1:45   ` Andreas Färber
2019-11-11  4:56   ` [PATCH] base: soc: Export soc_device_to_device() helper Andreas Färber
2019-11-11  5:27     ` Greg Kroah-Hartman
2019-11-11  5:42       ` Andreas Färber
2019-11-11  6:40         ` Greg Kroah-Hartman
2019-11-11 20:10           ` Andreas Färber
2019-11-12  0:29             ` Andreas Färber
2019-11-12  5:23             ` Greg Kroah-Hartman
2019-11-12  7:29               ` Uwe Kleine-König
2019-11-12 10:47                 ` Sense of soc bus? (was: [PATCH] base: soc: Export soc_device_to_device() helper) Andreas Färber
2019-11-14 22:09                   ` Rob Herring
2019-11-15 11:15                     ` Andreas Färber
2019-11-15 11:49                     ` Andreas Färber
2019-11-15  8:52                   ` Neil Armstrong
2019-11-15  8:58                     ` Geert Uytterhoeven
2019-11-15 12:00                       ` Andreas Färber
2019-11-15 12:34                         ` Geert Uytterhoeven [this message]
2019-11-18 15:55                           ` Tony Lindgren
2019-11-12 10:48                 ` [PATCH] base: soc: Export soc_device_to_device() helper Lee Jones
2019-11-03  1:36 ` [RFC 03/11] arm64: dts: realtek: rtd129x: Add chip info node Andreas Färber
2019-11-03  1:36 ` [RFC 04/11] ARM: dts: rtd1195: " Andreas Färber
2019-11-03  1:36 ` [RFC 05/11] dt-bindings: soc: realtek: rtd1195-chip: Extend reg property Andreas Färber
2019-11-06  4:46   ` Rob Herring
2019-11-06  8:42     ` Andreas Färber
2019-11-03  1:36 ` [RFC 06/11] soc: realtek: chip: Detect RTD1296 Andreas Färber
2019-11-03  1:36 ` [RFC 07/11] arm64: dts: realtek: rtd129x: Extend chip-info reg with CHIP_INFO1 Andreas Färber
2019-11-03  1:36 ` [RFC 08/11] soc: realtek: chip: Detect RTD1293 Andreas Färber
2019-11-03  1:36 ` [RFC 09/11] dt-bindings: soc: realtek: rtd1195-chip: Extend reg node again Andreas Färber
2019-11-03  1:36 ` [RFC 10/11] soc: realtek: chip: Detect RTD1294 Andreas Färber
2019-11-03  1:36 ` [RFC 11/11] arm64: dts: realtek: rtd129x: Extend chip-info reg with efuse Andreas Färber
2019-11-07  7:16 ` [RFC 00/11] ARM: Realtek RTD1195/RTD1295 SoC info Andreas Färber

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