[linux-sunxi] [PATCH 4/7] arm64: dts: allwinner: H6: Allow up to 150 MHz MMC bus frequency

[Chen-Yu Tsai]

On Wed, Jan 6, 2021 at 11:06 PM Andre Przywara <andre.przywara at arm.com> wrote:
>
> The H6 manual explicitly lists a frequency limit of 150 MHz for the bus
> frequency of the MMC controllers. So far we had no explicit limits in the
> DT, which limited eMMC to a rather conservative 52 MHz.

I'd say this is implementation specific. FreeBSD might have other defaults?

> Put those maximum frequencies in the SoC .dtsi, to allow higher speed
> modes (which still would need to be explicitly enabled, per board).
>
> Tested with an eMMC using HS-200 on a Pine H64. Running at the spec'ed
> 200 MHz indeed fails with I/O errors, but 150 MHz seems to work stably.
>
> Signed-off-by: Andre Przywara <andre.przywara at arm.com>

Fixes tag?


Thanks
ChenYu