[PATCH net-next v9 3/3] w5100: detect carrier state using link status bit and optional interrupt
From: Arthur Crepin Leblond
Date: Fri Sep 18 2026 - 11:42:14 EST
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. The carrier state is also not
reported using netif_carrier_on|off().
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, only .get_link() can be
used to get the carrier state, netif_carrier_on|off() is not called. The
interrupt handler and the PHYCFGR register read are synchronized using
a mutex.
A few changes are brought to the bring-up teardown:
- 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_remove(), w5100_stop() and w5100_suspend() call
cancel_work_sync()/flush_work() to make sure there is no pending
work
- the main irq is enabled/disabled in open()/stop() and
suspend()/resume()
- enable the link irq after checking PHYCFGR
Commit dacf281771a9 ("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.
Signed-off-by: Arthur Crepin Leblond <arthur@xxxxxxxxxxxxx>
---
v9:
- Address Sashiko review
- Rework commit message
- Disable the link irq first in w5100_stop()
- Call w5100_hw_close earlier in w5100_stop()
- Flush rx/tx work and cancel restart in w5100_stop()
- Call cancel_work_sync() after unregister_netdev in w5100_remove()
- Call cancel_work_sync before netif_carrier_off in w5100_suspend()
- Enable/Disable main irq in open()/stop() and suspend()/resume()
- Check the number of irqs defined in DT
- Ignore fwnode_irq_get errors other than EPROBE_DEFER
v8:
- Add myself in the MAINTAINERS file
- Address Sashiko reviews from online bot and locally run
- Add a mutex to synchronize the link state read and interrupt
- Return last known carrier state (netif_carrier_ok()) in
w5500_get_link on SPI error or if the device is not present
- Only set ops .get_link on w5500
- Check the netif state, disable/enable the irq and re-check the
carrier state in w5100_restart
- Cancel the restart work on stop/suspend
- Only set carrier state to off in w5100_stop/suspend when a link
irq is present
- Warn on fwnode_irq_get errors for the link irq
- Free the main irq and flush queues before resetting the hardware
in w5100_remove
v7:
- Address Sashiko reviews
- Propagate spi read error to the caller
- Do not change the state of the carrier on SPI read error
- Enable the link IRQ before reading the PHYCFGR bit
- Call unregister_netdev before reset
- Update commit message
v6:
- Revert to the reviewed v4 version by Arnd Bergmann with a few
changes based on Sashiko's review
- Address Sashiko reviews
- call netif_carrier_off in open if there is no link_irq or get_link
returns false
- call register_netdev at the very end of probe
- call unregister_netdev before destroying work queue
- handle link irq probe defer error
- call netif_device_attach in resume before re enabling the link irq
- disable the link irq first in suspend
- log netif_err when PHYCFGR cannot be read
- enable link irq in open
- disable link irq in stop
- free irq and invalidate it in remove
v5:
- Address Sashiko review
- Read the link status register only on w5500 instead of checking
link_irq
- call netif_carrier_off on w5500 link status off in open
- enable/disable the link irq in open/stop
- enable/disable the link irq in resume/suspend
- handle link irq probe defer error
- register the netdev last
v4:
- Use directly an interrupt line instead of gpio -> irq
- Address Sashiko reviews
- drop devm_ on request_threaded_irq to avoid use after free
- disable/enable the link_irq in the suspend/resume
- only call netif_carrier_on|off if the link interrupt is present
v3:
- Use the Link Status bit of the PHY Configuration Register
- Use the LINKLED gpio binding for change detection only
v2:
- Use devm_request_threaded_irq instead of request_any_context_irq
- Use devm_gpiod_get_optional instead of gpiod_get_optional
- Call dev_err_probe on gpiod_to_irq failure
- Remove link_irq from priv
- Use a fixed string for the IRQ name
- Remove empty new lines
---
MAINTAINERS | 1 +
drivers/net/ethernet/wiznet/w5100.c | 220 ++++++++++++++++++++++++++++++++----
2 files changed, 199 insertions(+), 22 deletions(-)
diff --git a/MAINTAINERS b/MAINTAINERS
index e6a5a4e245a0..7e6f7a95a341 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -29444,6 +29444,7 @@ M: Arthur Crepin Leblond <arthur@xxxxxxxxxxxxx>
L: netdev@xxxxxxxxxxxxxxx
S: Maintained
F: Documentation/devicetree/bindings/net/wiznet,w5100.yaml
+F: drivers/net/ethernet/wiznet/
WMI BINARY MOF DRIVER
M: Armin Wolf <W_Armin@xxxxxx>
diff --git a/drivers/net/ethernet/wiznet/w5100.c b/drivers/net/ethernet/wiznet/w5100.c
index 53d8dc642fbd..e6dc5fe7c088 100644
--- a/drivers/net/ethernet/wiznet/w5100.c
+++ b/drivers/net/ethernet/wiznet/w5100.c
@@ -18,9 +18,11 @@
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
+#include <linux/mutex.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
+#include <linux/property.h>
#include <linux/irq.h>
#include "w5100.h"
@@ -124,6 +126,8 @@ MODULE_LICENSE("GPL");
*/
#define W5500_SIMR 0x0018 /* Socket Interrupt Mask Register */
#define W5500_RTR 0x0019 /* Retry Time-value Register */
+#define W5500_PHYCFGR 0x002e /* PHY Configuration Register */
+#define PHYCFGR_LNK 0x01 /* Link status */
#define W5500_S0_REGS 0x10000
@@ -154,6 +158,9 @@ struct w5100_priv {
u16 s0_rx_buf_size;
int irq;
+ int link_irq;
+ /* Protects link state and carrier updates */
+ struct mutex link_lock;
struct napi_struct napi;
struct net_device *ndev;
@@ -345,6 +352,77 @@ static void w5500_memory_configure(struct w5100_priv *priv)
}
}
+static int w5500_get_phycfgr_lnk(struct net_device *ndev)
+{
+ struct w5100_priv *priv = netdev_priv(ndev);
+ int ret = w5100_read(priv, W5500_PHYCFGR);
+
+ if (ret < 0) {
+ netif_err(priv, link, ndev,
+ "failed to read link status: %d\n", ret);
+ return ret;
+ }
+
+ return ret & PHYCFGR_LNK;
+}
+
+static void w5500_report_carrier_state(struct net_device *ndev)
+{
+ struct w5100_priv *priv = netdev_priv(ndev);
+ int state;
+
+ mutex_lock(&priv->link_lock);
+
+ state = w5500_get_phycfgr_lnk(ndev);
+ if (state > 0) {
+ netif_info(priv, link, ndev, "link is up\n");
+ netif_carrier_on(ndev);
+ } else if (state == 0) {
+ netif_info(priv, link, ndev, "link is down\n");
+ netif_carrier_off(ndev);
+ }
+
+ mutex_unlock(&priv->link_lock);
+}
+
+static irqreturn_t w5500_detect_link_interrupt(int irq, void *ndev_instance)
+{
+ struct net_device *ndev = ndev_instance;
+
+ if (netif_running(ndev))
+ w5500_report_carrier_state(ndev);
+
+ return IRQ_HANDLED;
+}
+
+static u32 w5500_get_link(struct net_device *ndev)
+{
+ struct w5100_priv *priv = netdev_priv(ndev);
+ int state;
+ bool link;
+
+ mutex_lock(&priv->link_lock);
+
+ if (!netif_device_present(ndev)) {
+ link = netif_carrier_ok(ndev);
+ goto out;
+ }
+
+ state = w5500_get_phycfgr_lnk(ndev);
+
+ if (state < 0) {
+ link = netif_carrier_ok(ndev);
+ goto out;
+ }
+
+ link = state > 0;
+
+out:
+ mutex_unlock(&priv->link_lock);
+
+ return link;
+}
+
static int w5100_hw_reset(struct w5100_priv *priv)
{
u32 rtr;
@@ -448,12 +526,25 @@ static void w5100_restart(struct net_device *ndev)
{
struct w5100_priv *priv = netdev_priv(ndev);
+ if (!netif_running(ndev) || !netif_device_present(ndev))
+ return;
+
+ disable_irq(priv->irq);
+ if (priv->link_irq > 0)
+ disable_irq(priv->link_irq);
+
netif_stop_queue(ndev);
w5100_hw_reset(priv);
+ enable_irq(priv->irq);
w5100_hw_start(priv);
ndev->stats.tx_errors++;
netif_trans_update(ndev);
netif_wake_queue(ndev);
+
+ if (priv->link_irq > 0) {
+ w5500_report_carrier_state(ndev);
+ enable_irq(priv->link_irq);
+ }
}
static void w5100_restart_work(struct work_struct *work)
@@ -656,9 +747,16 @@ static int w5100_open(struct net_device *ndev)
struct w5100_priv *priv = netdev_priv(ndev);
netif_info(priv, ifup, ndev, "enabling\n");
- w5100_hw_start(priv);
napi_enable(&priv->napi);
+ enable_irq(priv->irq);
+ w5100_hw_start(priv);
netif_start_queue(ndev);
+
+ if (priv->link_irq > 0) {
+ w5500_report_carrier_state(ndev);
+ enable_irq(priv->link_irq);
+ }
+
return 0;
}
@@ -667,13 +765,38 @@ static int w5100_stop(struct net_device *ndev)
struct w5100_priv *priv = netdev_priv(ndev);
netif_info(priv, ifdown, ndev, "shutting down\n");
+
+ disable_irq(priv->irq);
+ if (priv->link_irq > 0)
+ disable_irq(priv->link_irq);
+
+ cancel_work_sync(&priv->restart_work);
+ cancel_work_sync(&priv->setrx_work);
+ flush_work(&priv->rx_work);
+ flush_work(&priv->tx_work);
+
w5100_hw_close(priv);
- netif_carrier_off(ndev);
+
+ if (priv->link_irq > 0) {
+ mutex_lock(&priv->link_lock);
+ netif_carrier_off(ndev);
+ mutex_unlock(&priv->link_lock);
+ }
+
netif_stop_queue(ndev);
napi_disable(&priv->napi);
return 0;
}
+static const struct ethtool_ops w5500_ethtool_ops = {
+ .get_drvinfo = w5100_get_drvinfo,
+ .get_msglevel = w5100_get_msglevel,
+ .set_msglevel = w5100_set_msglevel,
+ .get_link = w5500_get_link,
+ .get_regs_len = w5100_get_regs_len,
+ .get_regs = w5100_get_regs,
+};
+
static const struct ethtool_ops w5100_ethtool_ops = {
.get_drvinfo = w5100_get_drvinfo,
.get_msglevel = w5100_get_msglevel,
@@ -721,6 +844,8 @@ int w5100_probe(struct device *dev, const struct w5100_ops *ops,
dev_set_drvdata(dev, ndev);
priv = netdev_priv(ndev);
+ mutex_init(&priv->link_lock);
+
switch (ops->chip_id) {
case W5100:
priv->s0_regs = W5100_S0_REGS;
@@ -745,15 +870,26 @@ int w5100_probe(struct device *dev, const struct w5100_ops *ops,
break;
default:
err = -EINVAL;
- goto err_register;
+ goto err_mutex;
}
priv->ndev = ndev;
priv->ops = ops;
priv->irq = irq;
+ priv->link_irq = -EINVAL;
+ if (ops->chip_id == W5500) {
+ priv->link_irq = fwnode_irq_get(dev_fwnode(dev), 1);
+ if (priv->link_irq == -EPROBE_DEFER) {
+ err = dev_err_probe(dev, priv->link_irq,
+ "failed to get link irq\n");
+ goto err_mutex;
+ }
+ }
+
ndev->netdev_ops = &w5100_netdev_ops;
- ndev->ethtool_ops = &w5100_ethtool_ops;
+ ndev->ethtool_ops = ops->chip_id == W5500 ? &w5500_ethtool_ops :
+ &w5100_ethtool_ops;
netif_napi_add_weight(ndev, &priv->napi, w5100_napi_poll, 16);
/* This chip doesn't support VLAN packets with normal MTU,
@@ -761,15 +897,11 @@ int w5100_probe(struct device *dev, const struct w5100_ops *ops,
*/
ndev->features |= NETIF_F_VLAN_CHALLENGED;
- err = register_netdev(ndev);
- if (err < 0)
- goto err_register;
-
priv->xfer_wq = alloc_workqueue("%s", WQ_MEM_RECLAIM | WQ_PERCPU, 0,
- netdev_name(ndev));
+ dev_name(dev));
if (!priv->xfer_wq) {
err = -ENOMEM;
- goto err_wq;
+ goto err_mutex;
}
INIT_WORK(&priv->rx_work, w5100_rx_work);
@@ -794,22 +926,44 @@ int w5100_probe(struct device *dev, const struct w5100_ops *ops,
if (ops->may_sleep) {
err = request_threaded_irq(priv->irq, NULL, w5100_interrupt,
- IRQF_TRIGGER_LOW | IRQF_ONESHOT,
- netdev_name(ndev), ndev);
+ IRQF_TRIGGER_LOW | IRQF_ONESHOT |
+ IRQF_NO_AUTOEN,
+ dev_name(dev), ndev);
} else {
err = request_irq(priv->irq, w5100_interrupt,
- IRQF_TRIGGER_LOW, netdev_name(ndev), ndev);
+ IRQF_TRIGGER_LOW | IRQF_NO_AUTOEN, dev_name(dev), ndev);
}
if (err)
goto err_hw;
+ if (priv->link_irq > 0) {
+ err = request_threaded_irq(priv->link_irq, NULL,
+ w5500_detect_link_interrupt,
+ IRQF_TRIGGER_RISING |
+ IRQF_TRIGGER_FALLING |
+ IRQF_ONESHOT | IRQF_NO_AUTOEN,
+ "w5100-link", ndev);
+ if (err < 0)
+ goto err_irq;
+
+ netif_carrier_off(ndev);
+ }
+
+ err = register_netdev(ndev);
+ if (err < 0)
+ goto err_link_irq;
+
return 0;
+err_link_irq:
+ if (priv->link_irq > 0)
+ free_irq(priv->link_irq, ndev);
+err_irq:
+ free_irq(priv->irq, ndev);
err_hw:
destroy_workqueue(priv->xfer_wq);
-err_wq:
- unregister_netdev(ndev);
-err_register:
+err_mutex:
+ mutex_destroy(&priv->link_lock);
free_netdev(ndev);
return err;
}
@@ -820,14 +974,19 @@ void w5100_remove(struct device *dev)
struct net_device *ndev = dev_get_drvdata(dev);
struct w5100_priv *priv = netdev_priv(ndev);
- w5100_hw_reset(priv);
+ unregister_netdev(ndev);
+
+ if (priv->link_irq > 0)
+ free_irq(priv->link_irq, ndev);
free_irq(priv->irq, ndev);
- flush_work(&priv->setrx_work);
- flush_work(&priv->restart_work);
- destroy_workqueue(priv->xfer_wq);
+ w5100_hw_reset(priv);
- unregister_netdev(ndev);
+ cancel_work_sync(&priv->setrx_work);
+ cancel_work_sync(&priv->restart_work);
+
+ destroy_workqueue(priv->xfer_wq);
+ mutex_destroy(&priv->link_lock);
free_netdev(ndev);
}
EXPORT_SYMBOL_GPL(w5100_remove);
@@ -839,7 +998,18 @@ static int w5100_suspend(struct device *dev)
struct w5100_priv *priv = netdev_priv(ndev);
if (netif_running(ndev)) {
- netif_carrier_off(ndev);
+ disable_irq(priv->irq);
+ if (priv->link_irq > 0)
+ disable_irq(priv->link_irq);
+
+ cancel_work_sync(&priv->restart_work);
+
+ if (priv->link_irq > 0) {
+ mutex_lock(&priv->link_lock);
+ netif_carrier_off(ndev);
+ mutex_unlock(&priv->link_lock);
+ }
+
netif_device_detach(ndev);
w5100_hw_close(priv);
@@ -854,9 +1024,15 @@ static int w5100_resume(struct device *dev)
if (netif_running(ndev)) {
w5100_hw_reset(priv);
+ enable_irq(priv->irq);
w5100_hw_start(priv);
netif_device_attach(ndev);
+
+ if (priv->link_irq > 0) {
+ w5500_report_carrier_state(ndev);
+ enable_irq(priv->link_irq);
+ }
}
return 0;
}
--
2.55.0