[PATCH 0/2] prevent undesired de-assertion of phy-reset

Tim Harvey tharvey at gateworks.com
Tue Mar 1 21:15:00 CET 2022

Some PHY's have strict requirements on reset timings which can be
violated if the PHY is taken out of reset before a proper reset pulse is

When gpio_request_by_name is used for reset gpios without
GPIOD_IS_OUT_ACTIVE the GPIO will be de-asserted when requested taking
the PHY out of reset. Resolve this by adding the GPIOD_IS_OUT_ACTIVE

There are 42 occurances of gpio_request_by_name in U-Boot for gpio's
with 'reset' in their name yet the only one that uses
GPIOD_IS_OUT_ACTIVE is drivers/net/dwc_eth_qos.c. While I think setting
GPIOD_IS_OUT_ACTIVE is the right thing to do, I'm only changing the ones
that I have run into issues with:

Both of these have functions that are called that assert, delay,
de-assert, delay such that I know they will properly be taken out of

The Linux kernel had a similar issue [1]

Tim Harvey (2):
  net: fec: prevent undesired de-assertion of phy-reset on request
  net: eth-phy: prevent undesired de-assertion of phy-reset on request

 drivers/net/eth-phy-uclass.c | 2 +-
 drivers/net/fec_mxc.c        | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)


More information about the U-Boot mailing list