arm64: dts: imx8mm-verdin: note about disabled sd1 pull-ups

Add a note about us using discrete external on-module resistors
pulling-up to the on-module +V3.3_1.8_SD (LDO5) rail and explicitly
disabling the internal pull-ups due to ERR050080 [1]:

IO: Degradation of internal IO pullup/pulldown current capability for
IO’s continuously driven in a 3.3V operating mode

[1] https://www.nxp.com/webapp/Download?colCode=IMX8MM_0N87W

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

diff --git a/arch/arm64/boot/dts/freescale/imx8mm-verdin.dtsi b/arch/arm64/boot/dts/freescale/imx8mm-verdin.dtsi
index 6e1c762fd2e7613f58f5e1cb498b7ecad33eb863..97dd7a00d63b088cd4167613940cf686c31173d1 100644 (file)
--- a/arch/arm64/boot/dts/freescale/imx8mm-verdin.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mm-verdin.dtsi
@@ -1179,6 +1179,10 @@
                        <MX8MM_IOMUXC_NAND_CLE_GPIO3_IO5                0x6>;   /* SODIMM 76 */
        };
 
+       /*
+        * Note: Due to ERR050080 we use discrete external on-module resistors pulling-up to the
+        * on-module +V3.3_1.8_SD (LDO5) rail and explicitly disable the internal pull-ups here.
+        */
        pinctrl_usdhc2: usdhc2grp {
                fsl,pins =
                        <MX8MM_IOMUXC_GPIO1_IO04_USDHC2_VSELECT         0x10>,