Hi, On Sat, Jan 23, 2016 at 07:04:54PM +0800, Chen-Yu Tsai wrote: > Hi, > > On Sat, Jan 23, 2016 at 4:31 AM, Maxime Ripard > <maxime.rip...@free-electrons.com> wrote: > > Hi, > > > > On Thu, Jan 21, 2016 at 01:26:35PM +0800, Chen-Yu Tsai wrote: > >> mmc2 and mmc3 are available on the same pins, with different mux values. > >> However, only mmc3 supports 8 bit DDR transfer modes. > >> > >> Since preference for mmc3 over mmc2 is due to DDR transfer modes, just > >> set the drive strength to 40mA, which is needed for DDR. > >> > >> This pinmux setting also includes the hardware reset pin for emmc. > >> > >> Signed-off-by: Chen-Yu Tsai <w...@csie.org> > >> --- > >> arch/arm/boot/dts/sun6i-a31.dtsi | 10 ++++++++++ > >> 1 file changed, 10 insertions(+) > >> > >> diff --git a/arch/arm/boot/dts/sun6i-a31.dtsi > >> b/arch/arm/boot/dts/sun6i-a31.dtsi > >> index b6ad7850fac6..1867af24ff52 100644 > >> --- a/arch/arm/boot/dts/sun6i-a31.dtsi > >> +++ b/arch/arm/boot/dts/sun6i-a31.dtsi > >> @@ -709,6 +709,16 @@ > >> allwinner,pull = <SUN4I_PINCTRL_NO_PULL>; > >> }; > >> > >> + mmc3_8bit_emmc_pins: mmc3@1 { > >> + allwinner,pins = "PC6", "PC7", "PC8", "PC9", > >> + "PC10", "PC11", "PC12", > >> + "PC13", "PC14", "PC15", > >> + "PC24"; > >> + allwinner,function = "mmc3"; > >> + allwinner,drive = <SUN4I_PINCTRL_40_MA>; > >> + allwinner,pull = <SUN4I_PINCTRL_NO_PULL>; > >> + }; > >> + > > > > Is that reset pin optional? > > > > If so, I'd prefer it to be a separate node, like we're doing for the > > SPI chip selects for example. > > > > It allows more reusability between different devices without declaring > > new nodes. > > All eMMC devices have a reset pin. The MMC standard specifies this as > one way to reset the card, others being a special reset command, or > powering the card off. It also notes a state when the card will not > accept commands, and will require a power cycle or asserting the reset > pin. > > I assume all designs would route this pin. The FEX files also have this > pin included by default.
I was more concerned about the case were you'd have a 8bits bus without an emmc. But I guess that can't happen, since all SD cards are using a 4 bits width anyway. I'll apply this patch. Thanks! Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to linux-sunxi+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
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