[PATCH v2 6/6] arm64: allwinner: a64: Increase the MMC max frequency
wens at csie.org
Tue Jan 10 22:44:00 PST 2017
On Wed, Jan 11, 2017 at 3:15 AM, Maxime Ripard
<maxime.ripard at free-electrons.com> wrote:
> 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 at 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 at 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
It's limited by the vqmmc regulator. Either way the host controller
supports it right?
More information about the linux-arm-kernel