linux/arch/arm/boot
Rabeeh Khoury bf8147208e 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 <rabeeh@solid-run.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
2014-08-27 13:32:26 +08:00
..
bootp
compressed ARM: 8079/1: zImage: identify kernel endianness 2014-07-18 12:29:08 +01:00
dts ARM: dts: microsom-ar8035: MDIO pad must be set open drain 2014-08-27 13:32:26 +08:00
.gitignore
install.sh
Makefile