[PATCH v3 2/5] ARM: dts: aspeed: ast2600evb: Add comment for gpio regulator of sdhci
steven_lee at aspeedtech.com
Thu May 6 20:03:09 AEST 2021
Add the description for describing the AST2600-A2 EVB reference design of
Signed-off-by: Steven Lee <steven_lee at aspeedtech.com>
arch/arm/boot/dts/aspeed-ast2600-evb.dts | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/arch/arm/boot/dts/aspeed-ast2600-evb.dts b/arch/arm/boot/dts/aspeed-ast2600-evb.dts
index 2772796e215e..1ae0facc3d5f 100644
@@ -104,6 +104,21 @@
status = "okay";
+ * The signal voltage of sdhci0 and sdhci1 on AST2600-A2 EVB is able to be
+ * toggled by GPIO pins.
+ * In the reference design, GPIOV0 of AST2600-A2 EVB is connected to the
+ * power load switch that providing 3.3v to sdhci0 vdd, GPIOV1 is connected to
+ * a 1.8v and a 3.3v power load switch that providing signal voltage to
+ * sdhci0 bus.
+ * If GPIOV0 is active high, sdhci0 is enabled, otherwise, sdhci0 is disabled.
+ * If GPIOV1 is active high, 3.3v power load switch is enabled, sdhci0 signal
+ * voltage is 3.3v, otherwise, 1.8v power load switch will be enabled,
+ * sdhci0 signal voltage becomes 1.8v.
+ * AST2600-A2 EVB also support toggling signal voltage for sdhci1.
+ * The design is the same as sdhci0, it uses GPIOV2 as power-gpio and GPIOV3
+ * as power-switch-gpio.
bus-width = <4>;
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