On Thu, Jan 21, 2016 at 8:25 PM, Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > Hi, > > On 21-01-16 13:23, Chen-Yu Tsai wrote: >> >> On Thu, Jan 21, 2016 at 7:16 PM, Hans de Goede <hdegoede@xxxxxxxxxx> >> wrote: >>> >>> Hi, >>> >>> On 21-01-16 06:26, Chen-Yu Tsai wrote: >>>> >>>> >>>> According to Allwinner, only mmc3 supports 8 bit DDR transfers for eMMC. >>>> Switch to mmc3 for the onboard eMMC, and also assign vqmmc for signal >>>> voltage sensing/switching, and "cap-mmc-hw-reset" to denote this >>>> instance can use eMMC hardware reset. >>> >>> >>> >>> This is going to need some more explanation, does this mean >>> that the old dtsi is wrong and the emmc does not work there are all ? >> >> >> mmc2 works fine for either 4 bit SDR/DDR or 8 bit SDR only. It does >> not work for 8 bit DDR. I actually tested all the above combinations. >> >> Also see >> https://groups.google.com/d/msg/linux-sunxi/pMzwMWwLALw/6WGgCN1eAQAJ >> >> About old DTs not working: >> >> a) The old DT will not work with the mmc patches, as it will try 8 bit DDR >> and fail. Also, the old DT does not use the highest drive strength for >> the mmc pins, meaning it might not work for the other chip families. >> >> b) Old DT + old kernel works fine (8 bit high-speed), just slower. >> >> An alternative would be to drop MMC_CAP_1_8V_DDR from the driver, and >> use the "mmc-ddr-1_8v" DT capability flag at the dtsi or board level. >> There's no real way to describe "don't use 8 bit with MMC DDR" in the DT. > > > OK, so what is confusing me, is how can we choose between the emmc being > connected to mmc2 resp mmc3, are there dipswitches on the board? Or can both > mmc controllers be routed to the outside on the same port/pins ? They are on the same pins, just with a different mux value/function. I believe the previous patch explains this. ChenYu > > Regards, > > Hans > > > >> >> >> Regards >> ChenYu >> >>> >>> Regards, >>> >>> Hans >>> >>> >>> >>>> >>>> Signed-off-by: Chen-Yu Tsai <wens@xxxxxxxx> >>>> --- >>>> arch/arm/boot/dts/sun6i-a31s-sina31s-core.dtsi | 6 ++++-- >>>> 1 file changed, 4 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/arch/arm/boot/dts/sun6i-a31s-sina31s-core.dtsi >>>> b/arch/arm/boot/dts/sun6i-a31s-sina31s-core.dtsi >>>> index ea69fb8ad4d8..4ec0c8679b2e 100644 >>>> --- a/arch/arm/boot/dts/sun6i-a31s-sina31s-core.dtsi >>>> +++ b/arch/arm/boot/dts/sun6i-a31s-sina31s-core.dtsi >>>> @@ -61,12 +61,14 @@ >>>> }; >>>> >>>> /* eMMC on core board */ >>>> -&mmc2 { >>>> +&mmc3 { >>>> pinctrl-names = "default"; >>>> - pinctrl-0 = <&mmc2_8bit_emmc_pins>; >>>> + pinctrl-0 = <&mmc3_8bit_emmc_pins>; >>>> vmmc-supply = <®_dcdc1>; >>>> + vqmmc-supply = <®_dcdc1>; >>>> bus-width = <8>; >>>> non-removable; >>>> + cap-mmc-hw-reset; >>>> status = "okay"; >>>> }; >>>> >>>> >>> > -- 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
