[PATCH 1/2] ARM: dts: stm32: Enable internal pull-ups for SDMMC1 on DHCOM SoM

Marek Vasut marex at denx.de
Tue Dec 1 06:14:40 EST 2020


The default state of SD bus and clock line is logical HI. SD card IO is
open-drain and pulls the bus lines LO. Always enable the SD bus pull ups
to guarantee this behavior on DHCOM SoM. Note that on SoMs with SD bus
voltage level shifter, the pull ups are built into the level shifter,
however that has no negative impact.

Signed-off-by: Marek Vasut <marex at denx.de>
Cc: Alexandre Torgue <alexandre.torgue at st.com>
Cc: Maxime Coquelin <mcoquelin.stm32 at gmail.com>
Cc: Patrice Chotard <patrice.chotard at st.com>
Cc: Patrick Delaunay <patrick.delaunay at st.com>
Cc: linux-stm32 at st-md-mailman.stormreply.com
To: linux-arm-kernel at lists.infradead.org
---
 arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi b/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi
index daff5318f301..97c6e0cd582c 100644
--- a/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi
+++ b/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi
@@ -400,6 +400,20 @@ &sdmmc1 {
 	status = "okay";
 };
 
+&sdmmc1_b4_pins_a {
+	/*
+	 * SD bus pull-up resistors:
+	 * - optional on SoMs with SD voltage translator
+	 * - mandatory on SoMs without SD voltage translator
+	 */
+	pins1 {
+		bias-pull-up;
+	};
+	pins2 {
+		bias-pull-up;
+	};
+};
+
 &sdmmc2 {
 	pinctrl-names = "default", "opendrain", "sleep";
 	pinctrl-0 = <&sdmmc2_b4_pins_a &sdmmc2_d47_pins_a>;
-- 
2.29.2




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