arm64: dts: allwinner: A64: Limit MMC2 bus frequency to 150 MHz

[ Upstream commit 948c657cc45e8ce48cb533d4e2106145fa765759 ]

In contrast to the H6 (and later) manuals, the A64 datasheet does not
specify any limitations in the maximum possible frequency for eMMC
controllers.
However experimentation has found that a 150 MHz limit similar to other
SoCs and also the MMC0 and MMC1 controllers on the A64 seems to exist
for the MMC2 controller.

Limit the frequency for the MMC2 controller to 150 MHz in the SoC .dtsi.
The Pinebook seems to be the an odd exception, since it apparently seems
to work with 200 MHz as well, so overwrite this in its board .dts file.

Tested on a Pine64-LTS: 200 MHz HS-200 fails, 150 MHz HS-200 works.

Fixes: 22be992faea7 ("arm64: allwinner: a64: Increase the MMC max frequency")
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210113152630.28810-7-andre.przywara@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64-pinebook.dts b/arch/arm64/boot/dts/allwinner/sun50i-a64-pinebook.dts
index b2f0729d92d2ce71c3b0e755d089893a674e09b2..ecb3e10c85e07448201cd2d3d7d04b97b62f644e 100644 (file)
--- a/arch/arm64/boot/dts/allwinner/sun50i-a64-pinebook.dts
+++ b/arch/arm64/boot/dts/allwinner/sun50i-a64-pinebook.dts
@@ -105,6 +105,7 @@
        pinctrl-0 = <&mmc2_pins>;
        vmmc-supply = <&reg_dcdc1>;
        vqmmc-supply = <&reg_eldo1>;
+       max-frequency = <200000000>;
        bus-width = <8>;
        non-removable;
        cap-mmc-hw-reset;

diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
index 47949f14c49f429a4443edc71a673c3084640a52..30cc2e83a288eac35833a4a4c16dfaf603718f86 100644 (file)
--- a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
+++ b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
@@ -264,7 +264,7 @@
                        resets = <&ccu RST_BUS_MMC2>;
                        reset-names = "ahb";
                        interrupts = <GIC_SPI 62 IRQ_TYPE_LEVEL_HIGH>;
-                       max-frequency = <200000000>;
+                       max-frequency = <150000000>;
                        status = "disabled";
                        #address-cells = <1>;
                        #size-cells = <0>;