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From: "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
To: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
	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: Fri, 22 May 2020 20:14:45 +0100
Message-ID: <CA+V-a8tVx6D8Vh=rYD2=Z-14GAW0puo009FtjYM++sw8PAtJug@mail.gmail.com> (raw)
In-Reply-To: <CAMuHMdVWe1EEAtP64VW+0zXNingM1LiENv_Rfz5qTQ+C0dtGSw@mail.gmail.com>

Hi Wolfram,

On Mon, May 18, 2020 at 11:10 AM Geert Uytterhoeven
<geert@linux-m68k.org> wrote:
>
> Hi Wolfram,
>
> On Mon, May 18, 2020 at 11:26 AM Wolfram Sang
> <wsa+renesas@sang-engineering.com> wrote:
> > > > However, both versions (with and without automatic transmission) are
> > > > described with the same "renesas,iic-r8a7742" compatible. Is it possible
> > > > to detect the reduced variant at runtime somehow?
> > > >
> > > I couldn't find anything the manual that would be useful to detect at runtime.
>
> Hence if we really need that (see below), we need a quirk based on compatible
> value + base address.
>
> > > > My concern is that the peculiarity of this SoC might be forgotten if we
> > > > describe it like this and ever add "automatic transmissions" somewhen.
> > > >
> > > Agreed.
> >
> > Well, I guess reading from a register which is supposed to not be there
> > on the modified IP core is too hackish.
>
> 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?)
>
> > Leaves us with a seperate compatible entry for it?
>
> 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.
>
> On R-Car E2 and RZ/G1E, we forgot, and used both SoC-specific and
> family-specific compatible values.
>
What are your thoughts on the above.

Cheers,
--Prabhakar

> 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: 70+ 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
2020-05-15 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
2020-05-15 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 [this message]
2020-05-22 20:17             ` Wolfram Sang
2020-05-25  8:23               ` Geert Uytterhoeven
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
2020-05-15 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
2020-05-15 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
2020-05-15 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
2020-05-15 15:08 ` [PATCH 15/17] ARM: dts: r8a7742: Add APMU nodes Lad Prabhakar
2020-05-17 21:03   ` Wolfram Sang
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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