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* [PATCH 0/2] prevent undesired de-assertion of phy-reset
@ 2022-03-01 20:15 Tim Harvey
  2022-03-01 20:15 ` [PATCH 1/2] net: fec: prevent undesired de-assertion of phy-reset on request Tim Harvey
  2022-03-01 20:15 ` [PATCH 2/2] net: eth-phy: " Tim Harvey
  0 siblings, 2 replies; 10+ messages in thread
From: Tim Harvey @ 2022-03-01 20:15 UTC (permalink / raw)
  To: u-boot, Joe Hershberger, Ramon Fried; +Cc: Tim Harvey

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
performed.

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
flag.

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:
 drivers/net/eth-phy-uclass.c
 drivers/net/fec_mxc.c

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
reset.

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(-)

-- 
[1]
https://lore.kernel.org/all/20210202143239.10714-1-mike.looijmans@topic.nl/
2.17.1


^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2022-04-10  5:05 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-03-01 20:15 [PATCH 0/2] prevent undesired de-assertion of phy-reset Tim Harvey
2022-03-01 20:15 ` [PATCH 1/2] net: fec: prevent undesired de-assertion of phy-reset on request Tim Harvey
2022-03-01 20:38   ` Joe Hershberger
2022-03-02  1:58     ` Adam Ford
2022-03-03  7:55       ` Ramon Fried
2022-04-10  5:05         ` Ramon Fried
2022-03-01 20:15 ` [PATCH 2/2] net: eth-phy: " Tim Harvey
2022-03-01 20:38   ` Joe Hershberger
2022-03-03  7:55     ` Ramon Fried
2022-04-10  5:05       ` Ramon Fried

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