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    SubjectRe: [PATCH v2 6/6] arm64: allwinner: a64: Increase the MMC max frequency
    On Wed, Jan 11, 2017 at 3:15 AM, Maxime Ripard
    <maxime.ripard@free-electrons.com> wrote:
    > Hi,
    >
    > On Tue, Jan 10, 2017 at 01:01:20AM +0800, Chen-Yu Tsai wrote:
    >> On Tue, Jan 10, 2017 at 12:46 AM, Maxime Ripard
    >> <maxime.ripard@free-electrons.com> wrote:
    >> > All the controllers can have a maximum frequency of 200MHz.
    >> >
    >> > Since older SoCs cannot go that high, we cannot change the default maximum
    >> > frequency, but fortunately for us we have a property for that in the DT.
    >> >
    >> > This also has the side effect of allowing to use the MMC HS200 mode for the
    >> > boards that support it (with either 1.2v or 1.8v IOs).
    >> >
    >> > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
    >> > ---
    >> > arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi | 3 +++
    >> > 1 file changed, 3 insertions(+), 0 deletions(-)
    >> >
    >> > diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
    >> > index 8e149498e096..f46ae965cf5b 100644
    >> > --- a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
    >> > +++ b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
    >> > @@ -332,6 +332,7 @@
    >> > resets = <&ccu RST_BUS_MMC0>;
    >> > reset-names = "ahb";
    >> > interrupts = <GIC_SPI 60 IRQ_TYPE_LEVEL_HIGH>;
    >> > + max-frequency = <200000000>;
    >>
    >> You also have to set one of MMC_CAP2_HS200* in the driver,
    >> or mmc-hs200-1_8v or mmc-hs200-1_2v in the device tree to
    >> actually use HS200, right?
    >
    > Yes, but that requires a board with 1.8V IOs to work properly, which
    > not all board use, so it's probably best to enable it in the board
    > DTS.

    It's limited by the vqmmc regulator. Either way the host controller
    supports it right?

    ChenYu

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