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 b0f81802d334b12e187d7e9dadaec85ebb938524..bb1de8217b86d3af5e10d05467cd32b864d9064f 100644 (file)
--- a/arch/arm64/boot/dts/allwinner/sun50i-a64-pinebook.dts
+++ b/arch/arm64/boot/dts/allwinner/sun50i-a64-pinebook.dts
@@ -140,6 +140,7 @@
        pinctrl-0 = <&mmc2_pins>, <&mmc2_ds_pin>;
        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 4c85dfc811c80a3b128eb83102a93b088622124c..cf9e3234afaf829673b1a433fc438bdaae225d96 100644 (file)
--- a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
+++ b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
@@ -476,7 +476,7 @@
                        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>;