From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: MIME-Version: 1.0 References: <1537530911-443-1-git-send-email-fabrizio.castro@bp.renesas.com> <1537530911-443-2-git-send-email-fabrizio.castro@bp.renesas.com> <20180925074751.m2lwlinpebcun4a7@verge.net.au> <20180925082216.GA2270@kunai> In-Reply-To: From: Geert Uytterhoeven Date: Tue, 25 Sep 2018 15:03:46 +0200 Message-ID: Subject: Re: [PATCH 1/4] dt-bindings: mmc: renesas_sdhi: Add r8a77470 support Content-Type: text/plain; charset="UTF-8" To: Fabrizio Castro Cc: Wolfram Sang , Simon Horman , Ulf Hansson , Rob Herring , Mark Rutland , Laurent Pinchart , Geert Uytterhoeven , Linus Walleij , Wolfram Sang , Magnus Damm , Linux MMC List , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Linux-Renesas , "open list:GPIO SUBSYSTEM" , Chris Paterson , Biju Das List-ID: Hi Fabrizio, On Tue, Sep 25, 2018 at 2:45 PM Fabrizio Castro wrote: > > Subject: Re: [PATCH 1/4] dt-bindings: mmc: renesas_sdhi: Add r8a77470 support > > On Tue, Sep 25, 2018 at 10:22 AM Wolfram Sang wrote: > > > > > Perhaps stating the obvious: this feels a lot like the problem we thought > > > > > we had with different Gen-3 SoCs/ES versions. And in that case we decided > > > > > against using compat strings to differentiate. The main difference here > > > > > seems to be that we need to differentiate between different ports on the > > > > > same SoC. > > > > > > Yes, I agree. Our so far agreed solution didn't take into account that > > > there are different SDHI versions on the same SoC. Adding a compatible > > > might be the easiest solution, but then we have a mix of compatibles, > > > soc_device_match, and even version register (deeper in the driver). My > > > gut feeling is we should take the time to rethink all this? > > > > > > > So either > > > > a) SDHI0/2 vs. SDHI1 are different, deserving different compatible values, or > > > > b) SDHI0/1/2 are identical, but SDHI1 is wired different, deserving the same > > > > compatible value, but one or more additional properties describing the > > > > different wiring. > > > > > > Actually, SDHI2 seems different, too. It doesn't support SDR104. I don't > > > have the SDHI specific docs, but from the main docs, all SDHI instances > > > are different. > > > > I forgot about the version register. > > > > Fabrizio: can you please check what the 3 instances report in their version > > registers? Thanks! > > SDHI0: 0xcc0d > SDHI1: 0xcc10 > SDHI2: 0xcc0d Thank you. So SDHI1 differs from SDH0/2. SDHI2 probably doesn't support SDR104 because its parent clock is a div6 clock, while the others have SDCKCR parents. Plus we don't describe the relation to the SDH clock yet. 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