From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 18F5EC433E0 for ; Fri, 22 May 2020 19:15:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DA572206D5 for ; Fri, 22 May 2020 19:15:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="DODxib5K" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730912AbgEVTPO (ORCPT ); Fri, 22 May 2020 15:15:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41974 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730840AbgEVTPO (ORCPT ); Fri, 22 May 2020 15:15:14 -0400 Received: from mail-oi1-x242.google.com (mail-oi1-x242.google.com [IPv6:2607:f8b0:4864:20::242]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E3549C061A0E; Fri, 22 May 2020 12:15:13 -0700 (PDT) Received: by mail-oi1-x242.google.com with SMTP id s198so10225376oie.6; Fri, 22 May 2020 12:15:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=hVx1XifLiqzcR3aQze/vFy6FED+f9dHS5bmNRNU3BI4=; b=DODxib5KAH/Nd+AyiGl825EhHvcG4yhTievh7rjSrX3My7cKppuNLNm8NxaL3YwXot T/MOQsMI0rDLqClT+6RoK8ZpEIAqzowtQSPxfuBHtkixZbrXKvtz4bAB0LsmB9CPJdPe PSiPJbv/0CXYjS9HuKP29lklEtuQSIP4enu9s40ncQUNJfhEmPoAldw0XuGYYUwtT0kJ C/ZevB8jaweU1tyRwD52p556RsTJHJP3t/vtIFDyF0MmO7YyQpIWkgOMUhuD/giJJzQq YQCn73IsOX8xTjpodE9srWBXvJxmALphyESoL6hMrk4kNeewgof8srdZWBrrmb909EBK t3kw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=hVx1XifLiqzcR3aQze/vFy6FED+f9dHS5bmNRNU3BI4=; b=G9cBUvcr5d1+oDOJATPZKdvUuDvhC7O4KPhir6kDW8+u4SLl+DU1dK/NET1pu8CHKg o+aHfSkgGnjx+qA5KHyjdwHMVsVlCBTyGDod20h920qK3tTkw+HxBX4+4XfO3raVbGtO XJGa+r0rzlCsk/RmBsmQbgmVIowfKHYgR8x34ixM+tvnX8yTOyFyd96Cqpmz6of17bns 9m88lftVAmXxJbjCIM3PosRy0Qcjd74ZRfvIsl0EDyP1vWsjZjt7SLoSGLSri3AInvqq Ort+DQ0zMUiR30te0DNsZXjrbTChF4jVgHMUn6LR0HoK8989qE5YOqvLlrurZ4/QgYiy Ne5A== X-Gm-Message-State: AOAM533dsFlP3GJ2vprbxyGkLC+JRM0SAUmv1KyZRJDzfdVwIDgpVzIj KhL3z1nOWUX+ZHHo3f1e7c/hMR0XOny7+YM3RUY= X-Google-Smtp-Source: ABdhPJw6Z5oNxrJWWe2Z/VJ2dyoZ1svG+k7EHt8Gg0jkoo++Q6jrBStOvw/KaCbC6YON1Bc8ZAZfRDt4pi6Pp4vKXfo= X-Received: by 2002:aca:f550:: with SMTP id t77mr3774172oih.8.1590174913262; Fri, 22 May 2020 12:15:13 -0700 (PDT) MIME-Version: 1.0 References: <1589555337-5498-1-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.com> <1589555337-5498-4-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.com> <20200515171031.GB19423@ninjato> <20200518092601.GA3268@ninjato> In-Reply-To: From: "Lad, Prabhakar" Date: Fri, 22 May 2020 20:14:45 +0100 Message-ID: Subject: Re: [PATCH 03/17] ARM: dts: r8a7742: Add I2C and IIC support To: Wolfram Sang Cc: Geert Uytterhoeven , Lad Prabhakar , Jens Axboe , Rob Herring , Ulf Hansson , Sergei Shtylyov , "David S. Miller" , Wim Van Sebroeck , Guenter Roeck , linux-ide@vger.kernel.org, "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , LKML , Linux I2C , Linux MMC List , netdev , Linux-Renesas , Linux Watchdog Mailing List Content-Type: text/plain; charset="UTF-8" Sender: linux-ide-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ide@vger.kernel.org Hi Wolfram, On Mon, May 18, 2020 at 11:10 AM Geert Uytterhoeven wrote: > > Hi Wolfram, > > On Mon, May 18, 2020 at 11:26 AM Wolfram Sang > 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