FAILED: patch "[PATCH] platform/chrome: cros_ec: Unregister notifier in" failed to apply to 5.15-stable tree

FAILED: patch "[PATCH] platform/chrome: cros_ec: Unregister notifier in" failed to apply to 5.15-stable tree

[gregkh]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x e2374953461947eee49f69b3e3204ff080ef31b1
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025082112-freight-pesticide-c276@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e2374953461947eee49f69b3e3204ff080ef31b1 Mon Sep 17 00:00:00 2001
From: Tzung-Bi Shih <tzungbi@kernel.org>
Date: Tue, 22 Jul 2025 12:05:13 +0000
Subject: [PATCH] platform/chrome: cros_ec: Unregister notifier in
 cros_ec_unregister()

The blocking notifier is registered in cros_ec_register(); however, it
isn't unregistered in cros_ec_unregister().

Fix it.

Fixes: 42cd0ab476e2 ("platform/chrome: cros_ec: Query EC protocol version if EC transitions between RO/RW")
Cc: stable@vger.kernel.org
Reviewed-by: Benson Leung <bleung@chromium.org>
Link: https://lore.kernel.org/r/20250722120513.234031-1-tzungbi@kernel.org
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>

diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
index 110771a8645e..fd58781a2fb7 100644
--- a/drivers/platform/chrome/cros_ec.c
+++ b/drivers/platform/chrome/cros_ec.c
@@ -318,6 +318,9 @@ EXPORT_SYMBOL(cros_ec_register);
  */
 void cros_ec_unregister(struct cros_ec_device *ec_dev)
 {
+	if (ec_dev->mkbp_event_supported)
+		blocking_notifier_chain_unregister(&ec_dev->event_notifier,
+						   &ec_dev->notifier_ready);
 	platform_device_unregister(ec_dev->pd);
 	platform_device_unregister(ec_dev->ec);
 	mutex_destroy(&ec_dev->lock);

[PATCH 5.15.y 1/4] platform/chrome: cros_ec: Make cros_ec_unregister() return void

[Sasha Levin]

From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

[ Upstream commit afb0a80e63d67e957b5d0eb4ade301aff6e13c8c ]

Up to now cros_ec_unregister() returns zero unconditionally. Make it
return void instead which makes it easier to see in the callers that
there is no error to handle.

Also the return value of i2c, platform and spi remove callbacks is
ignored anyway.

Reviewed-by: Guenter Roeck <groeck@chromium.org>
Link: https://lore.kernel.org/r/20211020071753.wltjslmimb6wtlp5@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220123175201.34839-5-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
Stable-dep-of: e23749534619 ("platform/chrome: cros_ec: Unregister notifier in cros_ec_unregister()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/platform/chrome/cros_ec.c     | 4 +---
 drivers/platform/chrome/cros_ec.h     | 2 +-
 drivers/platform/chrome/cros_ec_i2c.c | 4 +++-
 drivers/platform/chrome/cros_ec_lpc.c | 4 +++-
 drivers/platform/chrome/cros_ec_spi.c | 4 +++-
 5 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
index 9664e13ded59..ea2296104634 100644
--- a/drivers/platform/chrome/cros_ec.c
+++ b/drivers/platform/chrome/cros_ec.c
@@ -306,13 +306,11 @@ EXPORT_SYMBOL(cros_ec_register);
  *
  * Return: 0 on success or negative error code.
  */
-int cros_ec_unregister(struct cros_ec_device *ec_dev)
+void cros_ec_unregister(struct cros_ec_device *ec_dev)
 {
 	if (ec_dev->pd)
 		platform_device_unregister(ec_dev->pd);
 	platform_device_unregister(ec_dev->ec);
-
-	return 0;
 }
 EXPORT_SYMBOL(cros_ec_unregister);
 
diff --git a/drivers/platform/chrome/cros_ec.h b/drivers/platform/chrome/cros_ec.h
index 78363dcfdf23..bbca0096868a 100644
--- a/drivers/platform/chrome/cros_ec.h
+++ b/drivers/platform/chrome/cros_ec.h
@@ -11,7 +11,7 @@
 #include <linux/interrupt.h>
 
 int cros_ec_register(struct cros_ec_device *ec_dev);
-int cros_ec_unregister(struct cros_ec_device *ec_dev);
+void cros_ec_unregister(struct cros_ec_device *ec_dev);
 
 int cros_ec_suspend(struct cros_ec_device *ec_dev);
 int cros_ec_resume(struct cros_ec_device *ec_dev);
diff --git a/drivers/platform/chrome/cros_ec_i2c.c b/drivers/platform/chrome/cros_ec_i2c.c
index 30c8938c27d5..22feb0fd4ce7 100644
--- a/drivers/platform/chrome/cros_ec_i2c.c
+++ b/drivers/platform/chrome/cros_ec_i2c.c
@@ -313,7 +313,9 @@ static int cros_ec_i2c_remove(struct i2c_client *client)
 {
 	struct cros_ec_device *ec_dev = i2c_get_clientdata(client);
 
-	return cros_ec_unregister(ec_dev);
+	cros_ec_unregister(ec_dev);
+
+	return 0;
 }
 
 #ifdef CONFIG_PM_SLEEP
diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c
index 1f7861944044..8527a1bac765 100644
--- a/drivers/platform/chrome/cros_ec_lpc.c
+++ b/drivers/platform/chrome/cros_ec_lpc.c
@@ -439,7 +439,9 @@ static int cros_ec_lpc_remove(struct platform_device *pdev)
 		acpi_remove_notify_handler(adev->handle, ACPI_ALL_NOTIFY,
 					   cros_ec_lpc_acpi_notify);
 
-	return cros_ec_unregister(ec_dev);
+	cros_ec_unregister(ec_dev);
+
+	return 0;
 }
 
 static const struct acpi_device_id cros_ec_lpc_acpi_device_ids[] = {
diff --git a/drivers/platform/chrome/cros_ec_spi.c b/drivers/platform/chrome/cros_ec_spi.c
index 14c4046fa04d..713c58687721 100644
--- a/drivers/platform/chrome/cros_ec_spi.c
+++ b/drivers/platform/chrome/cros_ec_spi.c
@@ -790,7 +790,9 @@ static int cros_ec_spi_remove(struct spi_device *spi)
 {
 	struct cros_ec_device *ec_dev = spi_get_drvdata(spi);
 
-	return cros_ec_unregister(ec_dev);
+	cros_ec_unregister(ec_dev);
+
+	return 0;
 }
 
 #ifdef CONFIG_PM_SLEEP
-- 
2.50.1

[PATCH 5.15.y 2/4] platform/chrome: cros_ec: Use per-device lockdep key

[Sasha Levin]

From: Chen-Yu Tsai <wenst@chromium.org>

[ Upstream commit 961a325becd9a142ae5c8b258e5c2f221f8bfac8 ]

Lockdep reports a bogus possible deadlock on MT8192 Chromebooks due to
the following lock sequences:

1. lock(i2c_register_adapter) [1]; lock(&ec_dev->lock)
2. lock(&ec_dev->lock); lock(prepare_lock);

The actual dependency chains are much longer. The shortened version
looks somewhat like:

1. cros-ec-rpmsg on mtk-scp
   ec_dev->lock -> prepare_lock
2. In rt5682_i2c_probe() on native I2C bus:
   prepare_lock -> regmap->lock -> (possibly) i2c_adapter->bus_lock
3. In rt5682_i2c_probe() on native I2C bus:
   regmap->lock -> i2c_adapter->bus_lock
4. In sbs_probe() on i2c-cros-ec-tunnel I2C bus attached on cros-ec:
   i2c_adapter->bus_lock -> ec_dev->lock

While lockdep is correct that the shared lockdep classes have a circular
dependency, it is bogus because

  a) 2+3 happen on a native I2C bus
  b) 4 happens on the actual EC on ChromeOS devices
  c) 1 happens on the SCP coprocessor on MediaTek Chromebooks that just
     happens to expose a cros-ec interface, but does not have an
     i2c-cros-ec-tunnel I2C bus

In short, the "dependencies" are actually on different devices.

Setup a per-device lockdep key for cros_ec devices so lockdep can tell
the two instances apart. This helps with getting rid of the bogus
lockdep warning. For ChromeOS devices that only have one cros-ec
instance this doesn't change anything.

Also add a missing mutex_destroy, just to make the teardown complete.

[1] This is likely the per I2C bus lock with shared lockdep class

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20230111074146.2624496-1-wenst@chromium.org
Stable-dep-of: e23749534619 ("platform/chrome: cros_ec: Unregister notifier in cros_ec_unregister()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/platform/chrome/cros_ec.c           | 14 +++++++++++---
 include/linux/platform_data/cros_ec_proto.h |  4 ++++
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
index ea2296104634..c5c0b273a8d7 100644
--- a/drivers/platform/chrome/cros_ec.c
+++ b/drivers/platform/chrome/cros_ec.c
@@ -200,12 +200,14 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 	if (!ec_dev->dout)
 		return -ENOMEM;
 
+	lockdep_register_key(&ec_dev->lockdep_key);
 	mutex_init(&ec_dev->lock);
+	lockdep_set_class(&ec_dev->lock, &ec_dev->lockdep_key);
 
 	err = cros_ec_query_all(ec_dev);
 	if (err) {
 		dev_err(dev, "Cannot identify the EC: error %d\n", err);
-		return err;
+		goto destroy_mutex;
 	}
 
 	if (ec_dev->irq > 0) {
@@ -217,7 +219,7 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 		if (err) {
 			dev_err(dev, "Failed to request IRQ %d: %d",
 				ec_dev->irq, err);
-			return err;
+			goto destroy_mutex;
 		}
 	}
 
@@ -228,7 +230,8 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 	if (IS_ERR(ec_dev->ec)) {
 		dev_err(ec_dev->dev,
 			"Failed to create CrOS EC platform device\n");
-		return PTR_ERR(ec_dev->ec);
+		err = PTR_ERR(ec_dev->ec);
+		goto destroy_mutex;
 	}
 
 	if (ec_dev->max_passthru) {
@@ -294,6 +297,9 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 exit:
 	platform_device_unregister(ec_dev->ec);
 	platform_device_unregister(ec_dev->pd);
+destroy_mutex:
+	mutex_destroy(&ec_dev->lock);
+	lockdep_unregister_key(&ec_dev->lockdep_key);
 	return err;
 }
 EXPORT_SYMBOL(cros_ec_register);
@@ -311,6 +317,8 @@ void cros_ec_unregister(struct cros_ec_device *ec_dev)
 	if (ec_dev->pd)
 		platform_device_unregister(ec_dev->pd);
 	platform_device_unregister(ec_dev->ec);
+	mutex_destroy(&ec_dev->lock);
+	lockdep_unregister_key(&ec_dev->lockdep_key);
 }
 EXPORT_SYMBOL(cros_ec_unregister);
 
diff --git a/include/linux/platform_data/cros_ec_proto.h b/include/linux/platform_data/cros_ec_proto.h
index 7f03e02c48cd..4e78365bad83 100644
--- a/include/linux/platform_data/cros_ec_proto.h
+++ b/include/linux/platform_data/cros_ec_proto.h
@@ -9,6 +9,7 @@
 #define __LINUX_CROS_EC_PROTO_H
 
 #include <linux/device.h>
+#include <linux/lockdep_types.h>
 #include <linux/mutex.h>
 #include <linux/notifier.h>
 
@@ -114,6 +115,8 @@ struct cros_ec_command {
  *            command. The caller should check msg.result for the EC's result
  *            code.
  * @pkt_xfer: Send packet to EC and get response.
+ * @lockdep_key: Lockdep class for each instance. Unused if CONFIG_LOCKDEP is
+ *		 not enabled.
  * @lock: One transaction at a time.
  * @mkbp_event_supported: 0 if MKBP not supported. Otherwise its value is
  *                        the maximum supported version of the MKBP host event
@@ -159,6 +162,7 @@ struct cros_ec_device {
 			struct cros_ec_command *msg);
 	int (*pkt_xfer)(struct cros_ec_device *ec,
 			struct cros_ec_command *msg);
+	struct lock_class_key lockdep_key;
 	struct mutex lock;
 	u8 mkbp_event_supported;
 	bool host_sleep_v1;
-- 
2.50.1

[PATCH 5.15.y 3/4] platform/chrome: cros_ec: remove unneeded label and if-condition

[Sasha Levin]

From: Tzung-Bi Shih <tzungbi@kernel.org>

[ Upstream commit 554ec02c97254962bbb0a8776c3160d294fc7e51 ]

Both `ec_dev->ec` and `ec_dev->pd` are initialized to NULL at the
beginning of cros_ec_register().  Also, platform_device_unregister()
takes care if the given platform_device is NULL.

Remove the unneeded goto-label and if-condition.

Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Link: https://lore.kernel.org/r/20230308031247.2866401-1-tzungbi@kernel.org
Stable-dep-of: e23749534619 ("platform/chrome: cros_ec: Unregister notifier in cros_ec_unregister()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/platform/chrome/cros_ec.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
index c5c0b273a8d7..f75b735b36ef 100644
--- a/drivers/platform/chrome/cros_ec.c
+++ b/drivers/platform/chrome/cros_ec.c
@@ -207,7 +207,7 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 	err = cros_ec_query_all(ec_dev);
 	if (err) {
 		dev_err(dev, "Cannot identify the EC: error %d\n", err);
-		goto destroy_mutex;
+		goto exit;
 	}
 
 	if (ec_dev->irq > 0) {
@@ -219,7 +219,7 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 		if (err) {
 			dev_err(dev, "Failed to request IRQ %d: %d",
 				ec_dev->irq, err);
-			goto destroy_mutex;
+			goto exit;
 		}
 	}
 
@@ -231,7 +231,7 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 		dev_err(ec_dev->dev,
 			"Failed to create CrOS EC platform device\n");
 		err = PTR_ERR(ec_dev->ec);
-		goto destroy_mutex;
+		goto exit;
 	}
 
 	if (ec_dev->max_passthru) {
@@ -297,7 +297,6 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 exit:
 	platform_device_unregister(ec_dev->ec);
 	platform_device_unregister(ec_dev->pd);
-destroy_mutex:
 	mutex_destroy(&ec_dev->lock);
 	lockdep_unregister_key(&ec_dev->lockdep_key);
 	return err;
@@ -314,8 +313,7 @@ EXPORT_SYMBOL(cros_ec_register);
  */
 void cros_ec_unregister(struct cros_ec_device *ec_dev)
 {
-	if (ec_dev->pd)
-		platform_device_unregister(ec_dev->pd);
+	platform_device_unregister(ec_dev->pd);
 	platform_device_unregister(ec_dev->ec);
 	mutex_destroy(&ec_dev->lock);
 	lockdep_unregister_key(&ec_dev->lockdep_key);
-- 
2.50.1

[PATCH 5.15.y 4/4] platform/chrome: cros_ec: Unregister notifier in cros_ec_unregister()

[Sasha Levin]

From: Tzung-Bi Shih <tzungbi@kernel.org>

[ Upstream commit e2374953461947eee49f69b3e3204ff080ef31b1 ]

The blocking notifier is registered in cros_ec_register(); however, it
isn't unregistered in cros_ec_unregister().

Fix it.

Fixes: 42cd0ab476e2 ("platform/chrome: cros_ec: Query EC protocol version if EC transitions between RO/RW")
Cc: stable@vger.kernel.org
Reviewed-by: Benson Leung <bleung@chromium.org>
Link: https://lore.kernel.org/r/20250722120513.234031-1-tzungbi@kernel.org
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/platform/chrome/cros_ec.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
index f75b735b36ef..2a92adfa1958 100644
--- a/drivers/platform/chrome/cros_ec.c
+++ b/drivers/platform/chrome/cros_ec.c
@@ -313,6 +313,9 @@ EXPORT_SYMBOL(cros_ec_register);
  */
 void cros_ec_unregister(struct cros_ec_device *ec_dev)
 {
+	if (ec_dev->mkbp_event_supported)
+		blocking_notifier_chain_unregister(&ec_dev->event_notifier,
+						   &ec_dev->notifier_ready);
 	platform_device_unregister(ec_dev->pd);
 	platform_device_unregister(ec_dev->ec);
 	mutex_destroy(&ec_dev->lock);
-- 
2.50.1