On Mon, 1 Aug 2016 16:30:19 +0100 Mark Rutland <mark.rutland@xxxxxxx> wrote: > On Mon, Aug 01, 2016 at 03:10:29PM +0200, Jean-Francois Moine wrote: > > Some MMC devices as mmc2 in the A83T or mmc1 and mmc2 in the H3 have > > a 'New Timings' mode. > > Set this capacity in the DT and use it when possible. > > What exactly is this "New Timings" mode? > > Why do we wnat to set it? Improved performance, power? > > Is it *necessary* to use it? This mode is described at least in the Allwinner's documentation of the A83T, A64 and H3. >From my tests, it is required to access the eMMC of the Banana Pi M3 (mmc2). > > Signed-off-by: Jean-Francois Moine <moinejf@xxxxxxx> > > --- > > I don't know if this mode works or is needed at 25MHz. > > --- > > Documentation/devicetree/bindings/mmc/sunxi-mmc.txt | 1 + > > drivers/mmc/host/sunxi-mmc.c | 21 +++++++++++++++++++-- > > 2 files changed, 20 insertions(+), 2 deletions(-) > > > > diff --git a/Documentation/devicetree/bindings/mmc/sunxi-mmc.txt b/Documentation/devicetree/bindings/mmc/sunxi-mmc.txt > > index 4bf41d8..a541bf4 100644 > > --- a/Documentation/devicetree/bindings/mmc/sunxi-mmc.txt > > +++ b/Documentation/devicetree/bindings/mmc/sunxi-mmc.txt > > @@ -19,6 +19,7 @@ Optional properties: > > - reset-names : must contain "ahb" > > - for cd, bus-width and additional generic mmc parameters > > please refer to mmc.txt within this directory > > + - allwinner,new-timings: the controller may accept the "New Timings" mode > > It's not at all clear to me what this means. This needs a better > description. > > Which devices have this? Can we determine this based on compatible > string? No, only some devices of the SoCs have this capability: the mmc2 of the A83T, the smhc0 and smhc1 of the A64, and the mmc1 and mmc2 of the H3. -- Ken ar c'hentañ | ** Breizh ha Linux atav! ** Jef | http://moinejf.free.fr/ -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
