From bf8147208eab4a026558dcd686f76410de6c1643 Mon Sep 17 00:00:00 2001 From: Rabeeh Khoury Date: Sat, 23 Aug 2014 10:11:21 +0100 Subject: ARM: dts: microsom-ar8035: MDIO pad must be set open drain This patch is important for the MicroSOM implementation due to the following details - 1. VIH of the Atheros phy is 1.7V. 2. NVCC_ENET which is the power domain of the MDIO pad is driven by the PHY's LDO (i.e. either 1.8v or 2.5v). 3. The MicroSOM implements an onbouard 1.6kohm pull up to 3.3v (R3000). In the case the PHY's LDO was 1.8v then there would be only a 100mV margin for the signal to be acknowledged as high (1.8v-1.7v). Due to that setting the pad as an open drain will let the 1.6kohm pull that signal high to 3.3 that assures enough margins to the PHY to be acked as '1' logic. Signed-off-by: Rabeeh Khoury Signed-off-by: Russell King Signed-off-by: Shawn Guo --- arch/arm/boot/dts/imx6qdl-microsom-ar8035.dtsi | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/boot/dts/imx6qdl-microsom-ar8035.dtsi b/arch/arm/boot/dts/imx6qdl-microsom-ar8035.dtsi index d16066608e21..db9f45b2c573 100644 --- a/arch/arm/boot/dts/imx6qdl-microsom-ar8035.dtsi +++ b/arch/arm/boot/dts/imx6qdl-microsom-ar8035.dtsi @@ -17,7 +17,7 @@ enet { pinctrl_microsom_enet_ar8035: microsom-enet-ar8035 { fsl,pins = < - MX6QDL_PAD_ENET_MDIO__ENET_MDIO 0x1b0b0 + MX6QDL_PAD_ENET_MDIO__ENET_MDIO 0x1b8b0 MX6QDL_PAD_ENET_MDC__ENET_MDC 0x1b0b0 /* AR8035 reset */ MX6QDL_PAD_KEY_ROW4__GPIO4_IO15 0x130b0 -- cgit v1.2.3