Hello Simon, Thank you for your feedback! > Subject: Re: [PATCH 1/6] dt-bindings: mmc: renesas_sdhi: Add r8a77470 support > > On Wed, Oct 03, 2018 at 12:05:39PM +0100, Fabrizio Castro wrote: > > The RZ/G1C (a.k.a. R8A77470) comes with three SDHI interfaces, > > SDHI0 and SDHI2 are compatible with R-Car Gen2 SDHIs, and > > SDHI1 is compatible with R-Car Gen3 SDHIs, as it comes with an > > internal DMAC, therefore SDHI1 is fully compatible with driver > > renesas_sdhi_internal_dmac driver. As a result, the compatible > > strings for the R8A77470 SDHI interfaces are a little bit special. > > Document SDHI support for the RZ/G1C SoC. > > > > Signed-off-by: Fabrizio Castro <fabrizio.castro@xxxxxxxxxxxxxx> > > Reviewed-by: Biju Das <biju.das@xxxxxxxxxxxxxx> > > > > --- > > v1->v2: > > * Added "renesas,sdhi-mmc-r8a77470" > > * Using generic/fallback compatibilty only for SDHI[02] > > * Reworked changelog > > --- > > Documentation/devicetree/bindings/mmc/tmio_mmc.txt | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > diff --git a/Documentation/devicetree/bindings/mmc/tmio_mmc.txt b/Documentation/devicetree/bindings/mmc/tmio_mmc.txt > > index d39d5e4..247abee 100644 > > --- a/Documentation/devicetree/bindings/mmc/tmio_mmc.txt > > +++ b/Documentation/devicetree/bindings/mmc/tmio_mmc.txt > > @@ -19,6 +19,8 @@ Required properties: > > "renesas,sdhi-r8a7744" - SDHI IP on R8A7744 SoC > > "renesas,sdhi-r8a7745" - SDHI IP on R8A7745 SoC > > "renesas,sdhi-r8a774a1" - SDHI IP on R8A774A1 SoC > > +"renesas,sdhi-r8a77470" - SDHI IP on R8A77470 SoC (SDHI[02]) > > +"renesas,sdhi-mmc-r8a77470" - SDHI IP on R8A77470 SoC (SDHI1) > > I understand that SDHI[02] is different to SDHI1 on this SoC. > But I'm not clear on why SDHI1 is more "mmc" than SDHI[02]. Only SDHI1 can be used as MMC interface, from Section 40.1.1 of the SD Card manual: " This LSI has three SD card interfaces (SDHI0 to SDHI2), one of which can also be used as MMC interfaces (SDHI1)." > > > "renesas,sdhi-r8a7778" - SDHI IP on R8A7778 SoC > > "renesas,sdhi-r8a7779" - SDHI IP on R8A7779 SoC > > "renesas,sdhi-r8a7790" - SDHI IP on R8A7790 SoC > > @@ -35,8 +37,8 @@ Required properties: > > "renesas,sdhi-r8a77995" - SDHI IP on R8A77995 SoC > > "renesas,sdhi-shmobile" - a generic sh-mobile SDHI controller > > "renesas,rcar-gen1-sdhi" - a generic R-Car Gen1 SDHI controller > > -"renesas,rcar-gen2-sdhi" - a generic R-Car Gen2 or RZ/G1 > > - SDHI controller > > +"renesas,rcar-gen2-sdhi" - a generic R-Car Gen2 and RZ/G1 (but > > + not RZ/G1C SDHI1) SDHI controller > > "renesas,rcar-gen3-sdhi" - a generic R-Car Gen3 or RZ/G2 > > SDHI controller > > renesas,rcar-gen3-sdhi can be used with RZ/G1C SDHI1, right? It can be used, but when we previously discussed about this I have received bad feedbacks from both yourself and Geert: Geert: "I'm a bit reluctant to add "renesas,rcar-gen3-sdhi", though" You: "I am also reluctant to add "renesas,rcar-gen3-sdhi", because as we are seeing things are not so simple wrt to compatible." We need to make a final decision here, but automatically detecting the IP doesn't seem to be great, so the final solution has to rely on compatible strings. > The naming is starting to break down at this point :( Personally, I am not too bothered about using "renesas,rcar-gen3-sdhi" for this specific IP, as this chip "borrows" Gen3 implementation, but of course it exposes some cross compatibility with other families of products which could result in some confusion to the final user. Anyway, as long as we document things properly there should be no confusion. Thanks, Fab > > > > > -- > > 2.7.4 > > Renesas Electronics Europe Ltd, Dukes Meadow, Millboard Road, Bourne End, Buckinghamshire, SL8 5FH, UK. Registered in England & Wales under Registered No. 04586709.
