From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: "Lad, Prabhakar" <prabhakar.csengg@gmail.com>,
Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>,
Jens Axboe <axboe@kernel.dk>, Rob Herring <robh+dt@kernel.org>,
Ulf Hansson <ulf.hansson@linaro.org>,
Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>,
"David S. Miller" <davem@davemloft.net>,
Wim Van Sebroeck <wim@linux-watchdog.org>,
Guenter Roeck <linux@roeck-us.net>,
linux-ide@vger.kernel.org,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>,
Linux I2C <linux-i2c@vger.kernel.org>,
Linux MMC List <linux-mmc@vger.kernel.org>,
netdev <netdev@vger.kernel.org>,
Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
Linux Watchdog Mailing List <linux-watchdog@vger.kernel.org>
Subject: Re: [PATCH 03/17] ARM: dts: r8a7742: Add I2C and IIC support
Date: Mon, 25 May 2020 10:23:08 +0200 [thread overview]
Message-ID: <CAMuHMdUDs1DXfKMwDgK3e29vdzhPCPBbms2Hj8t7Pvp4j5D5Tg@mail.gmail.com> (raw)
In-Reply-To: <20200522201727.GA21376@ninjato>
Hi Wolfram,
On Fri, May 22, 2020 at 10:17 PM Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
> > > According to the Hardware User's Manual Rev. 1.00, the registers do exist
> > > on all RZ/G1, except for RZ/G1E (see below).
> > >
> > > "(automatic transmission can be used as a hardware function, but this is
> > > not meaningful for actual use cases)."
> > >
> > > (whatever that comment may mean?)
>
> Strange comment, in deed. Given the paragraph before, I would guess Gen1
> maybe had a "fitting" PMIC where SoC/PMIC handled DVFS kind of magically
> with this automatic transfer feature? And Gen2 has not.
>
> > > On R-Car E3 and RZ/G2E, which have a single IIC instance, we
> > > handled that by:
> > >
> > > The r8a77990 (R-Car E3) and r8a774c0 (RZ/G2E)
> > > controllers are not considered compatible with
> > > "renesas,rcar-gen3-iic" or "renesas,rmobile-iic"
> > > due to the absence of automatic transmission registers.
>
> From a "describe the HW" point of view, this still makes sense to me.
> Although, it is unlikely we will add support for the automatic
> transmission feature (maybe famous last words).
;-)
> > > On R-Car E2 and RZ/G1E, we forgot, and used both SoC-specific and
> > > family-specific compatible values.
>
> Okay, but we can fix DTs when they have bugs, or?
We can. But we also have to consider DT backwards compatibility: i.e.
using an old DTB with a future kernel implementing the automatic
transmission feature.
Fortunately R-Car E2 and RZ/G1E have SoC-specific compatible values,
so we can easily blacklist it in the driver based on that.
Blacklisting the last instance on the other SoCs is uglier, as it needs a
quirk that checks both the SoC-compatible value and the absence of the
generic compatible value. But it can still be done.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
i.e. will queue in renesas-devel for v5.9.
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
next prev parent reply other threads:[~2020-05-25 8:23 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-15 15:08 [PATCH 00/17] RZ/G1H describe I2C, IIC, MMC0, SATA, AVB, RWDT and APMU nodes Lad Prabhakar
2020-05-15 15:08 ` [PATCH 01/17] dt-bindings: i2c: renesas,i2c: Document r8a7742 support Lad Prabhakar
2020-05-15 17:12 ` Wolfram Sang
2020-05-18 9:56 ` Geert Uytterhoeven
2020-05-28 20:03 ` Rob Herring
2020-05-15 15:08 ` [PATCH 02/17] dt-bindings: i2c: renesas,iic: " Lad Prabhakar
2020-05-15 17:14 ` Wolfram Sang
2020-05-18 9:59 ` Geert Uytterhoeven
2020-05-28 20:03 ` Rob Herring
2020-05-15 15:08 ` [PATCH 03/17] ARM: dts: r8a7742: Add I2C and IIC support Lad Prabhakar
2020-05-15 17:10 ` Wolfram Sang
2020-05-18 8:58 ` Lad, Prabhakar
2020-05-18 9:26 ` Wolfram Sang
2020-05-18 9:43 ` Lad, Prabhakar
2020-05-18 9:53 ` Wolfram Sang
2020-05-18 10:10 ` Geert Uytterhoeven
2020-05-22 19:14 ` Lad, Prabhakar
2020-05-22 20:17 ` Wolfram Sang
2020-05-25 8:23 ` Geert Uytterhoeven [this message]
2020-05-15 15:08 ` [PATCH 04/17] dt-bindings: mmc: renesas,sdhi: Document r8a7742 support Lad Prabhakar
2020-05-15 17:17 ` Wolfram Sang
2020-05-18 11:10 ` Geert Uytterhoeven
2020-05-19 15:29 ` Ulf Hansson
2020-05-15 15:08 ` [PATCH 05/17] mmc: renesas_sdhi_sys_dmac: Add support for r8a7742 SoC Lad Prabhakar
2020-05-15 17:17 ` Wolfram Sang
2020-05-18 11:24 ` Geert Uytterhoeven
2020-05-15 15:08 ` [PATCH 06/17] ARM: dts: r8a7742: Add SDHI nodes Lad Prabhakar
2020-05-17 20:53 ` Wolfram Sang
2020-05-18 11:51 ` Geert Uytterhoeven
2020-05-15 15:08 ` [PATCH 07/17] ARM: dts: r8a7742: Add MMC0 node Lad Prabhakar
2020-05-17 20:54 ` Wolfram Sang
2020-05-18 11:52 ` Geert Uytterhoeven
2020-05-15 15:08 ` [PATCH 08/17] dt-bindings: ata: renesas,rcar-sata: Add r8a7742 support Lad Prabhakar
2020-05-17 20:55 ` Wolfram Sang
2020-05-18 11:13 ` Geert Uytterhoeven
2020-05-28 20:04 ` Rob Herring
2020-05-15 15:08 ` [PATCH 09/17] ARM: dts: r8a7742: Add sata nodes Lad Prabhakar
2020-05-17 20:57 ` Wolfram Sang
2020-05-18 11:52 ` Geert Uytterhoeven
2020-05-15 15:08 ` [PATCH 10/17] dt-bindings: net: renesas,ravb: Add support for r8a7742 SoC Lad Prabhakar
2020-05-17 20:58 ` Wolfram Sang
2020-05-18 11:14 ` Geert Uytterhoeven
2020-05-28 20:04 ` Rob Herring
2020-05-15 15:08 ` [PATCH 11/17] dt-bindings: net: renesas,ether: Document R8A7742 SoC Lad Prabhakar
2020-05-17 20:59 ` Wolfram Sang
2020-05-18 11:15 ` Geert Uytterhoeven
2020-05-28 20:04 ` Rob Herring
2020-05-15 15:08 ` [PATCH 12/17] ARM: dts: r8a7742: Add Ethernet AVB support Lad Prabhakar
2020-05-17 21:00 ` Wolfram Sang
2020-05-18 11:53 ` Geert Uytterhoeven
2020-05-15 15:08 ` [PATCH 13/17] ARM: dts: r8a7742: Add Ether support Lad Prabhakar
2020-05-17 21:01 ` Wolfram Sang
2020-05-18 11:53 ` Geert Uytterhoeven
2020-05-15 15:08 ` [PATCH 14/17] dt-bindings: power: renesas,apmu: Document r8a7742 support Lad Prabhakar
2020-05-17 21:01 ` Wolfram Sang
2020-05-18 11:16 ` Geert Uytterhoeven
2020-05-28 20:05 ` Rob Herring
2020-05-15 15:08 ` [PATCH 15/17] ARM: dts: r8a7742: Add APMU nodes Lad Prabhakar
2020-05-17 21:03 ` Wolfram Sang
2020-05-18 11:41 ` Geert Uytterhoeven
2020-05-15 15:08 ` [PATCH 16/17] dt-bindings: watchdog: renesas,wdt: Document r8a7742 support Lad Prabhakar
2020-05-17 21:03 ` Wolfram Sang
2020-05-18 11:17 ` Geert Uytterhoeven
2020-05-22 14:47 ` Guenter Roeck
2020-05-27 1:31 ` Rob Herring
2020-05-27 11:22 ` Lad, Prabhakar
2020-05-27 14:38 ` Rob Herring
2020-05-27 16:33 ` Prabhakar Mahadev Lad
2020-05-15 15:08 ` [PATCH 17/17] ARM: dts: r8a7742: Add RWDT node Lad Prabhakar
2020-05-17 21:08 ` Wolfram Sang
2020-05-18 9:16 ` Lad, Prabhakar
2020-05-18 9:28 ` Wolfram Sang
2020-05-18 11:47 ` Geert Uytterhoeven
2020-05-18 12:27 ` Lad, Prabhakar
2020-05-18 13:17 ` Sergei Shtylyov
2020-05-18 13:23 ` Lad, Prabhakar
2020-05-18 15:45 ` Geert Uytterhoeven
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