linux-kernel - [PATCH] usb: typec: fusb302: Revert incorrect threaded irq fix

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Message-Id: <20250818-fusb302-unthreaded-irq-v1-1-3a9a11a9f56f@kernel.org>
Date: Mon, 18 Aug 2025 18:50:19 +0200
From: Sebastian Reichel <sebastian.reichel@...labora.com>
To: Heikki Krogerus <heikki.krogerus@...ux.intel.com>, 
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
 Yongbo Zhang <giraffesnn123@...il.com>, Hans de Goede <hansg@...nel.org>
Cc: linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org, 
 kernel@...labora.com, Sebastian Reichel <sebastian.reichel@...labora.com>
Subject: [PATCH] usb: typec: fusb302: Revert incorrect threaded irq fix

The fusb302 irq handler has been carefully optimized by Hans de Goede in
commit 207338ec5a27 ("usb: typec: fusb302: Improve suspend/resume
handling"). A recent 'fix' undid most of that work to avoid a virtio-gpio
driver bug.

This reverts the incorrect fix, since it is of very low quality. It
reverts the quirks from Hans change (and thus reintroduces the problems
fixed by Hans) while keeping the overhead from the original change.

The proper fix to support using fusb302 with an interrupt line provided
by virtio-gpio must be implemented in the virtio driver instead, which
should support disabling the IRQ from the fusb302 interrupt routine.

Cc: Hans de Goede <hansg@...nel.org>
Cc: Yongbo Zhang <giraffesnn123@...il.com>
Fixes: 1c2d81bded19 ("usb: typec: fusb302: fix scheduling while atomic when using virtio-gpio")
Signed-off-by: Sebastian Reichel <sebastian.reichel@...labora.com>
---
Note, that the referenced patch is in 6.17-rc, but not yet in any
released kernel. It breaks boot for Radxa ROCK 5B when fusb302 is
enabled in its device tree (strictly speaking that's not a regression,
since upstream DT does not yet describe fusb302).
---
 drivers/usb/typec/tcpm/fusb302.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
index a4ff2403ddd66fb7aaa27fd890533c7aff1dc163..870a71f953f6cd8dfc618caea56f72782e40ee1c 100644
--- a/drivers/usb/typec/tcpm/fusb302.c
+++ b/drivers/usb/typec/tcpm/fusb302.c
@@ -1485,6 +1485,9 @@ static irqreturn_t fusb302_irq_intn(int irq, void *dev_id)
 	struct fusb302_chip *chip = dev_id;
 	unsigned long flags;
 
+	/* Disable our level triggered IRQ until our irq_work has cleared it */
+	disable_irq_nosync(chip->gpio_int_n_irq);
+
 	spin_lock_irqsave(&chip->irq_lock, flags);
 	if (chip->irq_suspended)
 		chip->irq_while_suspended = true;
@@ -1627,6 +1630,7 @@ static void fusb302_irq_work(struct work_struct *work)
 	}
 done:
 	mutex_unlock(&chip->lock);
+	enable_irq(chip->gpio_int_n_irq);
 }
 
 static int init_gpio(struct fusb302_chip *chip)
@@ -1751,10 +1755,9 @@ static int fusb302_probe(struct i2c_client *client)
 		goto destroy_workqueue;
 	}
 
-	ret = devm_request_threaded_irq(dev, chip->gpio_int_n_irq,
-					NULL, fusb302_irq_intn,
-					IRQF_ONESHOT | IRQF_TRIGGER_LOW,
-					"fsc_interrupt_int_n", chip);
+	ret = request_irq(chip->gpio_int_n_irq, fusb302_irq_intn,
+			  IRQF_ONESHOT | IRQF_TRIGGER_LOW,
+			  "fsc_interrupt_int_n", chip);
 	if (ret < 0) {
 		dev_err(dev, "cannot request IRQ for GPIO Int_N, ret=%d", ret);
 		goto tcpm_unregister_port;
@@ -1779,6 +1782,7 @@ static void fusb302_remove(struct i2c_client *client)
 	struct fusb302_chip *chip = i2c_get_clientdata(client);
 
 	disable_irq_wake(chip->gpio_int_n_irq);
+	free_irq(chip->gpio_int_n_irq, chip);
 	cancel_work_sync(&chip->irq_work);
 	cancel_delayed_work_sync(&chip->bc_lvl_handler);
 	tcpm_unregister_port(chip->tcpm_port);

---
base-commit: c17b750b3ad9f45f2b6f7e6f7f4679844244f0b9
change-id: 20250818-fusb302-unthreaded-irq-36e5b0c48be1

Best regards,
-- 
Sebastian Reichel <sre@...nel.org>