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>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>

diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64-pinebook.dts b/arch/arm64/boot/dts/allwinner/sun50i-a64-pinebook.dts
index d07cf05549c3260eab435b51b4cd1a483dc38bc1..7ae16541d14f5f738901d86c57997c3b72f5f659 100644 (file)
--- a/arch/arm64/boot/dts/allwinner/sun50i-a64-pinebook.dts
+++ b/arch/arm64/boot/dts/allwinner/sun50i-a64-pinebook.dts
@@ -167,6 +167,7 @@
        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 19e9b8ca8432fb7260c8a4aa1fa2c8ae97f60b6a..57786fc120c30b884c4509648c7ded86f2cc030c 100644 (file)
--- a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
+++ b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
@@ -514,7 +514,7 @@
                        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>;