Thread (20 messages) 20 messages, 4 authors, 2021-01-13
STALE1983d
Revisions (2)
  1. v1 current
  2. v2 [diff vs current]

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

From: Andre Przywara <andre.przywara@arm.com>
Date: 2021-01-06 15:06:44
Also in: linux-arm-kernel
Subsystem: arm/allwinner sunxi soc support, the rest · Maintainers: Chen-Yu Tsai, Jernej Skrabec, Samuel Holland, Linus Torvalds

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.

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@arm.com>
---
 arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi | 3 +++
 1 file changed, 3 insertions(+)
diff --git a/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi b/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi
index f593cfeaecc9..77765d4a05ec 100644
--- a/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi
+++ b/arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi
@@ -436,6 +436,7 @@
 			interrupts = <GIC_SPI 35 IRQ_TYPE_LEVEL_HIGH>;
 			pinctrl-names = "default";
 			pinctrl-0 = <&mmc0_pins>;
+			max-frequency = <150000000>;
 			status = "disabled";
 			#address-cells = <1>;
 			#size-cells = <0>;
@@ -452,6 +453,7 @@
 			interrupts = <GIC_SPI 36 IRQ_TYPE_LEVEL_HIGH>;
 			pinctrl-names = "default";
 			pinctrl-0 = <&mmc1_pins>;
+			max-frequency = <150000000>;
 			status = "disabled";
 			#address-cells = <1>;
 			#size-cells = <0>;
@@ -468,6 +470,7 @@
 			interrupts = <GIC_SPI 37 IRQ_TYPE_LEVEL_HIGH>;
 			pinctrl-names = "default";
 			pinctrl-0 = <&mmc2_pins>;
+			max-frequency = <150000000>;
 			status = "disabled";
 			#address-cells = <1>;
 			#size-cells = <0>;
-- 
2.17.5
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