w5100: detect carrier state using link status bit and optional interrupt

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Detect the carrier state on the w5500 Ethernet controller using the
Link Status bit from the PHY Configuration register (PHYCFGR).

On w5100/w5200, which lack this register, get_link() is not implemented
and the carrier state is not reported (netif_carrier_(on|off) is not
called).

For the w5500, add an optional interrupt, wired to the LINKLED pin of
the device, to detect link status changes with a read of the PHYCFGR
register and update of the carrier state with netif_carrier_(on|off).
If this interrupt is not set in the DT binding, get_link() is not
implemented and the carrier state is not reported
(netif_carrier_(on|off) is not called).
The interrupt handler and the PHYCFGR register readings are
synchronized using a mutex.

A few changes are also brought for the bring-up/teardown
synchronization:

 - The net device is registered last in the probe() function so no
   operation can be performed before the probing is finished
 - The net device is unregistered first in remove()
 - dev_name is now used instead of netdev_name
 - w5100_stop() calls cancel_work_sync() and flush_work() to make sure
   there is no race condition or unfinished work
 - w5100_suspend() calls w5100_stop()
 - w5100_resume() calls w5100_open()
 - The main irq is not automatically enabled in w5100_probe() but in
   w5100_open() and disabled in w5100_stop()

Commit dacf281771 ("w5100: remove unused gpio link detection")
dropped the link_gpio/link_irq handling on the grounds that no
devicetree user passed a "link" gpio at the time and that it used the
old gpio interface.
This isn't a plain revert of that removal: link detection is now done
using a second interrupt rather than a gpio with a documented DT
binding.

Set the WIZNET entry as DRIVER and add drivers/net/ethernet/wiznet in
MAINTAINERS file.

Signed-off-by: Arthur Crepin Leblond <arthur@marmottus.net>
Fixes: dacf281771 ("w5100: remove unused gpio link detection")
Link: https://patch.msgid.link/20260924-wiznet-link-gpio-v11-3-42a332517b30@marmottus.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

...

This commit is contained in:

Arthur Crepin Leblond 2026-09-24 11:48:13 +02:00 • committed by Jakub Kicinski

parent 50c4bbaa0d

commit 323767fa31

2 changed files with 206 additions and 31 deletions

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3

MAINTAINERS

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234

drivers/net/ethernet/wiznet/w5100.c

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