From mboxrd@z Thu Jan 1 00:00:00 1970 From: Geert Uytterhoeven Subject: Re: [PATCH] pinctrl: sh-pfc: r8a7796: Add group for AVB MDIO and MII pins Date: Thu, 11 May 2017 10:49:38 +0200 Message-ID: References: <1492681746-20005-1-git-send-email-geert+renesas@glider.be> <2338736.vqmUpXt7la@avalon> <5295991.u29V8BK3nd@avalon> <20170502143350.GM1532@bigcity.dyn.berto.se> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20170502143350.GM1532@bigcity.dyn.berto.se> Sender: linux-renesas-soc-owner@vger.kernel.org To: =?UTF-8?Q?Niklas_S=C3=B6derlund?= Cc: Laurent Pinchart , Geert Uytterhoeven , Linus Walleij , Linux-Renesas , "linux-gpio@vger.kernel.org" List-Id: linux-gpio@vger.kernel.org On Tue, May 2, 2017 at 4:33 PM, Niklas S=C3=B6derlund wrote: > On 2017-04-20 13:47:19 +0200, Geert Uytterhoeven wrote: >> On Thu, Apr 20, 2017 at 1:44 PM, Laurent Pinchart >> wrote: >> > On Thursday 20 Apr 2017 13:37:27 Geert Uytterhoeven wrote: >> >> On Thu, Apr 20, 2017 at 12:18 PM, Laurent Pinchart wrote: >> >> > On Thursday 20 Apr 2017 12:11:41 Geert Uytterhoeven wrote: >> >> >> On Thu, Apr 20, 2017 at 12:02 PM, Laurent Pinchart wrote: >> >> >>> On Thursday 20 Apr 2017 11:49:06 Geert Uytterhoeven wrote: >> >> >>>> Group the AVB pins into similar groups as found in other >> >> >>>> sh-pfc >> >> >>>> drivers. The pins can not be muxed between functions other than = AVB, >> >> >>>> but their drive strengths can be controlled. >> >> >>>> >> >> >>>> The group avb_mdc containing ADV_MDC and ADV_MDIO is called avb_= mdio >> >> >>>> on other SoCs. In pfc-r8a7796 the avb_mdc group already existed = and is >> >> >>>> in use in DT. Therefore add the ADV_MDIO pin to the existing gro= up >> >> >>>> instead of renaming it. >> >> >>> >> >> >>> This clearly shows that we need a few kernel releases to test >> >> >>> PFC-related code and DT before we can commit to an ABI. How do yo= u >> >> >>> think we should handle this ? >> >> >> >> >> >> That's a difficult question >> >> >> >> >> >> For now I'd like to treat R-Car M3-W the same as H3. >> >> > >> >> > I still believe we should introduce some kind of unstable period fo= r DT >> >> > bindings, during which they will be merged in mainline but still su= bject >> >> > to modification. It could just be a few kernel releases. >> >> >> >> Like, from v4.4 (when avb_mdc was added for H3) until v4.12 (earliest >> >> we can correct this)? >> > >> > Sorry, I misread you, I thought that H3 named the group mdio (you migh= t want >> > to clarify this in the commit message). I was referring to when M3 PFC= support >> >> Sorry, this was a bit unclear (I reused the description from the H3 patc= h). >> This was actually referring to R-Car Gen2. Will fix. >> >> > was introduced, which was v4.10, so that's just two releases. We obvio= usly >> > can't rename mdc to mdio on H3 if we want to keep backward compatibili= ty. >> >> And because of pin-compatibility and board sharing of H3 and M3-W, I >> want both to use identical group naming. > > I also think it's a benefit if the group names are identical on H3 and > M3-W. And I think it is unfortunate that the name do not match Gen2 > naming. > > When adding the pins to r8a7795 I thought of instead adding AVB_MDIO to > the group avb_mdc add a new group with the Gen2 naming (avb_mdio) and > add both AVB_MDC and AVB_MDIO to this group but still also keep the > group avb_mdc. If I had done that it would be compatible with Gen2 > naming and backward compatible with old H3 DT. Maybe I was wrong of not > doing it like this and perhaps that solution should be revisited? That > is keep avb_mdc as is on H3 for backward compatibility but add avb_mdio t= o > both H3 and M3-W and update H3 DT to use avb_mdio. We can do that later... For now I like to move forward with M3-W like H3. > In any case I reviewed the pins as it is identical to how it's done on > H3. So if you choose to move forward with this approach feel free to > add: > > Reviewed-by: Niklas S=C3=B6derlund Thanks, applied to sh-pfc-for-v4.13 with reference to R-Car Gen2 SoC and Reviewed-by. 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. Bu= t when I'm talking to journalists I just say "programmer" or something like t= hat. -- Linus Torvalds