[PATCH v3 0/3] soc: qcom: pmic_glink: v6.11-rc bug fixes

[PATCH v3 0/3] soc: qcom: pmic_glink: v6.11-rc bug fixes

[Bjorn Andersson]

Amit and Johan both reported a NULL pointer dereference in the
pmic_glink client code during initialization, and Stephen Boyd pointed
out the problem (race condition).

While investigating, and writing the fix, I noticed that
ucsi_unregister() is called in atomic context but tries to sleep, and I
also noticed that the condition for when to inform the pmic_glink client
drivers when the remote has gone down is just wrong.

So, let's fix all three.

As mentioned in the commit message for the UCSI fix, I have a series in
the works that makes the GLINK callback happen in a sleepable context,
which would remove the need for the clients list to be protected by a
spinlock, and removing the work scheduling. This is however not -rc
material...

In addition to the NULL pointer dereference, there is the -ECANCELED
issue reported here:
https://lore.kernel.org/all/Zqet8iInnDhnxkT9@hovoldconsulting.com/
Johan reports that these fixes do not address that issue.

Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
---
Changes in v3:
- Renamed new_client()/register_client() to client_alloc()/client_register()
- Actually refer the correct commit in patch 2
- Parenthesis around comparison in patch 2
- IRQ context -> atomic context in commit message of patch 2
- Fixed typo in patch 3 subject
- Link to v2: https://lore.kernel.org/r/20240819-pmic-glink-v6-11-races-v2-0-88fe3ab1f0e2@quicinc.com

Changes in v2:
- Refer to the correct commit in the ucsi_unregister() patch.
- Updated wording in the same commit message about the new error message
  in the log.
- Changed the data type of the introduced state variables, opted to go
  for a bool as we only represent two states (and I would like to
  further clean this up going forward)
- Initialized the spinlock
- Link to v1: https://lore.kernel.org/r/20240818-pmic-glink-v6-11-races-v1-0-f87c577e0bc9@quicinc.com

---
Bjorn Andersson (3):
      soc: qcom: pmic_glink: Fix race during initialization
      usb: typec: ucsi: Move unregister out of atomic section
      soc: qcom: pmic_glink: Actually communicate when remote goes down

 drivers/power/supply/qcom_battmgr.c   | 16 ++++++++-----
 drivers/soc/qcom/pmic_glink.c         | 40 ++++++++++++++++++++++----------
 drivers/soc/qcom/pmic_glink_altmode.c | 17 +++++++++-----
 drivers/usb/typec/ucsi/ucsi_glink.c   | 43 ++++++++++++++++++++++++++---------
 include/linux/soc/qcom/pmic_glink.h   | 11 +++++----
 5 files changed, 87 insertions(+), 40 deletions(-)
---
base-commit: 2fd613d27928293eaa87788b10e8befb6805cd42
change-id: 20240818-pmic-glink-v6-11-races-363f5964c339

Best regards,
-- 
Bjorn Andersson <quic_bjorande@quicinc.com>

[PATCH v3 1/3] soc: qcom: pmic_glink: Fix race during initialization

[Bjorn Andersson]

As pointed out by Stephen Boyd it is possible that during initialization
of the pmic_glink child drivers, the protection-domain notifiers fires,
and the associated work is scheduled, before the client registration
returns and as a result the local "client" pointer has been initialized.

The outcome of this is a NULL pointer dereference as the "client"
pointer is blindly dereferenced.

Timeline provided by Stephen:
 CPU0                               CPU1
 ----                               ----
 ucsi->client = NULL;
 devm_pmic_glink_register_client()
  client->pdr_notify(client->priv, pg->client_state)
   pmic_glink_ucsi_pdr_notify()
    schedule_work(&ucsi->register_work)
    <schedule away>
                                    pmic_glink_ucsi_register()
                                     ucsi_register()
                                      pmic_glink_ucsi_read_version()
                                       pmic_glink_ucsi_read()
                                        pmic_glink_ucsi_read()
                                         pmic_glink_send(ucsi->client)
                                         <client is NULL BAD>
 ucsi->client = client // Too late!

This code is identical across the altmode, battery manager and usci
child drivers.

Resolve this by splitting the allocation of the "client" object and the
registration thereof into two operations.

This only happens if the protection domain registry is populated at the
time of registration, which by the introduction of commit '1ebcde047c54
("soc: qcom: add pd-mapper implementation")' became much more likely.

Reported-by: Amit Pundir <amit.pundir@linaro.org>
Closes: https://lore.kernel.org/all/CAMi1Hd2_a7TjA7J9ShrAbNOd_CoZ3D87twmO5t+nZxC9sX18tA@mail.gmail.com/
Reported-by: Johan Hovold <johan@kernel.org>
Closes: https://lore.kernel.org/all/ZqiyLvP0gkBnuekL@hovoldconsulting.com/
Reported-by: Stephen Boyd <swboyd@chromium.org>
Closes: https://lore.kernel.org/all/CAE-0n52JgfCBWiFQyQWPji8cq_rCsviBpW-m72YitgNfdaEhQg@mail.gmail.com/
Fixes: 58ef4ece1e41 ("soc: qcom: pmic_glink: Introduce base PMIC GLINK driver")
Cc: stable@vger.kernel.org
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Tested-by: Amit Pundir <amit.pundir@linaro.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Tested-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
---
 drivers/power/supply/qcom_battmgr.c   | 16 ++++++++++------
 drivers/soc/qcom/pmic_glink.c         | 28 ++++++++++++++++++----------
 drivers/soc/qcom/pmic_glink_altmode.c | 17 +++++++++++------
 drivers/usb/typec/ucsi/ucsi_glink.c   | 16 ++++++++++------
 include/linux/soc/qcom/pmic_glink.h   | 11 ++++++-----
 5 files changed, 55 insertions(+), 33 deletions(-)

diff --git a/drivers/power/supply/qcom_battmgr.c b/drivers/power/supply/qcom_battmgr.c
index 49bef4a5ac3f..07758ab6ac1c 100644
--- a/drivers/power/supply/qcom_battmgr.c
+++ b/drivers/power/supply/qcom_battmgr.c
@@ -1387,12 +1387,16 @@ static int qcom_battmgr_probe(struct auxiliary_device *adev,
 					     "failed to register wireless charing power supply\n");
 	}
 
-	battmgr->client = devm_pmic_glink_register_client(dev,
-							  PMIC_GLINK_OWNER_BATTMGR,
-							  qcom_battmgr_callback,
-							  qcom_battmgr_pdr_notify,
-							  battmgr);
-	return PTR_ERR_OR_ZERO(battmgr->client);
+	battmgr->client = devm_pmic_glink_client_alloc(dev, PMIC_GLINK_OWNER_BATTMGR,
+						     qcom_battmgr_callback,
+						     qcom_battmgr_pdr_notify,
+						     battmgr);
+	if (IS_ERR(battmgr->client))
+		return PTR_ERR(battmgr->client);
+
+	pmic_glink_client_register(battmgr->client);
+
+	return 0;
 }
 
 static const struct auxiliary_device_id qcom_battmgr_id_table[] = {
diff --git a/drivers/soc/qcom/pmic_glink.c b/drivers/soc/qcom/pmic_glink.c
index 9ebc0ba35947..53b176d04fbd 100644
--- a/drivers/soc/qcom/pmic_glink.c
+++ b/drivers/soc/qcom/pmic_glink.c
@@ -66,15 +66,14 @@ static void _devm_pmic_glink_release_client(struct device *dev, void *res)
 	spin_unlock_irqrestore(&pg->client_lock, flags);
 }
 
-struct pmic_glink_client *devm_pmic_glink_register_client(struct device *dev,
-							  unsigned int id,
-							  void (*cb)(const void *, size_t, void *),
-							  void (*pdr)(void *, int),
-							  void *priv)
+struct pmic_glink_client *devm_pmic_glink_client_alloc(struct device *dev,
+						       unsigned int id,
+						       void (*cb)(const void *, size_t, void *),
+						       void (*pdr)(void *, int),
+						       void *priv)
 {
 	struct pmic_glink_client *client;
 	struct pmic_glink *pg = dev_get_drvdata(dev->parent);
-	unsigned long flags;
 
 	client = devres_alloc(_devm_pmic_glink_release_client, sizeof(*client), GFP_KERNEL);
 	if (!client)
@@ -85,6 +84,18 @@ struct pmic_glink_client *devm_pmic_glink_register_client(struct device *dev,
 	client->cb = cb;
 	client->pdr_notify = pdr;
 	client->priv = priv;
+	INIT_LIST_HEAD(&client->node);
+
+	devres_add(dev, client);
+
+	return client;
+}
+EXPORT_SYMBOL_GPL(devm_pmic_glink_client_alloc);
+
+void pmic_glink_client_register(struct pmic_glink_client *client)
+{
+	struct pmic_glink *pg = client->pg;
+	unsigned long flags;
 
 	mutex_lock(&pg->state_lock);
 	spin_lock_irqsave(&pg->client_lock, flags);
@@ -95,11 +106,8 @@ struct pmic_glink_client *devm_pmic_glink_register_client(struct device *dev,
 	spin_unlock_irqrestore(&pg->client_lock, flags);
 	mutex_unlock(&pg->state_lock);
 
-	devres_add(dev, client);
-
-	return client;
 }
-EXPORT_SYMBOL_GPL(devm_pmic_glink_register_client);
+EXPORT_SYMBOL_GPL(pmic_glink_client_register);
 
 int pmic_glink_send(struct pmic_glink_client *client, void *data, size_t len)
 {
diff --git a/drivers/soc/qcom/pmic_glink_altmode.c b/drivers/soc/qcom/pmic_glink_altmode.c
index 1e0808b3cb93..c6f3d5188fc6 100644
--- a/drivers/soc/qcom/pmic_glink_altmode.c
+++ b/drivers/soc/qcom/pmic_glink_altmode.c
@@ -520,12 +520,17 @@ static int pmic_glink_altmode_probe(struct auxiliary_device *adev,
 			return ret;
 	}
 
-	altmode->client = devm_pmic_glink_register_client(dev,
-							  altmode->owner_id,
-							  pmic_glink_altmode_callback,
-							  pmic_glink_altmode_pdr_notify,
-							  altmode);
-	return PTR_ERR_OR_ZERO(altmode->client);
+	altmode->client = devm_pmic_glink_client_alloc(dev,
+						     altmode->owner_id,
+						     pmic_glink_altmode_callback,
+						     pmic_glink_altmode_pdr_notify,
+						     altmode);
+	if (IS_ERR(altmode->client))
+		return PTR_ERR(altmode->client);
+
+	pmic_glink_client_register(altmode->client);
+
+	return 0;
 }
 
 static const struct auxiliary_device_id pmic_glink_altmode_id_table[] = {
diff --git a/drivers/usb/typec/ucsi/ucsi_glink.c b/drivers/usb/typec/ucsi/ucsi_glink.c
index 16c328497e0b..6425904f2bfc 100644
--- a/drivers/usb/typec/ucsi/ucsi_glink.c
+++ b/drivers/usb/typec/ucsi/ucsi_glink.c
@@ -367,12 +367,16 @@ static int pmic_glink_ucsi_probe(struct auxiliary_device *adev,
 		ucsi->port_orientation[port] = desc;
 	}
 
-	ucsi->client = devm_pmic_glink_register_client(dev,
-						       PMIC_GLINK_OWNER_USBC,
-						       pmic_glink_ucsi_callback,
-						       pmic_glink_ucsi_pdr_notify,
-						       ucsi);
-	return PTR_ERR_OR_ZERO(ucsi->client);
+	ucsi->client = devm_pmic_glink_client_alloc(dev, PMIC_GLINK_OWNER_USBC,
+						  pmic_glink_ucsi_callback,
+						  pmic_glink_ucsi_pdr_notify,
+						  ucsi);
+	if (IS_ERR(ucsi->client))
+		return PTR_ERR(ucsi->client);
+
+	pmic_glink_client_register(ucsi->client);
+
+	return 0;
 }
 
 static void pmic_glink_ucsi_remove(struct auxiliary_device *adev)
diff --git a/include/linux/soc/qcom/pmic_glink.h b/include/linux/soc/qcom/pmic_glink.h
index fd124aa18c81..4c68385b2765 100644
--- a/include/linux/soc/qcom/pmic_glink.h
+++ b/include/linux/soc/qcom/pmic_glink.h
@@ -23,10 +23,11 @@ struct pmic_glink_hdr {
 
 int pmic_glink_send(struct pmic_glink_client *client, void *data, size_t len);
 
-struct pmic_glink_client *devm_pmic_glink_register_client(struct device *dev,
-							  unsigned int id,
-							  void (*cb)(const void *, size_t, void *),
-							  void (*pdr)(void *, int),
-							  void *priv);
+struct pmic_glink_client *devm_pmic_glink_client_alloc(struct device *dev,
+						     unsigned int id,
+						     void (*cb)(const void *, size_t, void *),
+						     void (*pdr)(void *, int),
+						     void *priv);
+void pmic_glink_client_register(struct pmic_glink_client *client);
 
 #endif

-- 
2.34.1

[PATCH v3 2/3] usb: typec: ucsi: Move unregister out of atomic section

[Bjorn Andersson]

Commit '9329933699b3 ("soc: qcom: pmic_glink: Make client-lock
non-sleeping")' moved the pmic_glink client list under a spinlock, as it
is accessed by the rpmsg/glink callback, which in turn is invoked from
IRQ context.

This means that ucsi_unregister() is now called from atomic context,
which isn't feasible as it's expecting a sleepable context. An effort is
under way to get GLINK to invoke its callbacks in a sleepable context,
but until then lets schedule the unregistration.

A side effect of this is that ucsi_unregister() can now happen
after the remote processor, and thereby the communication link with it, is
gone. pmic_glink_send() is amended with a check to avoid the resulting NULL
pointer dereference.
This does however result in the user being informed about this error by
the following entry in the kernel log:

  ucsi_glink.pmic_glink_ucsi pmic_glink.ucsi.0: failed to send UCSI write request: -5

Fixes: 9329933699b3 ("soc: qcom: pmic_glink: Make client-lock non-sleeping")
Cc: stable@vger.kernel.org
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Tested-by: Amit Pundir <amit.pundir@linaro.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Tested-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
---
 drivers/soc/qcom/pmic_glink.c       | 10 +++++++++-
 drivers/usb/typec/ucsi/ucsi_glink.c | 27 ++++++++++++++++++++++-----
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/drivers/soc/qcom/pmic_glink.c b/drivers/soc/qcom/pmic_glink.c
index 53b176d04fbd..b218460219b7 100644
--- a/drivers/soc/qcom/pmic_glink.c
+++ b/drivers/soc/qcom/pmic_glink.c
@@ -112,8 +112,16 @@ EXPORT_SYMBOL_GPL(pmic_glink_client_register);
 int pmic_glink_send(struct pmic_glink_client *client, void *data, size_t len)
 {
 	struct pmic_glink *pg = client->pg;
+	int ret;
 
-	return rpmsg_send(pg->ept, data, len);
+	mutex_lock(&pg->state_lock);
+	if (!pg->ept)
+		ret = -ECONNRESET;
+	else
+		ret = rpmsg_send(pg->ept, data, len);
+	mutex_unlock(&pg->state_lock);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(pmic_glink_send);
 
diff --git a/drivers/usb/typec/ucsi/ucsi_glink.c b/drivers/usb/typec/ucsi/ucsi_glink.c
index 6425904f2bfc..ca89f9037f08 100644
--- a/drivers/usb/typec/ucsi/ucsi_glink.c
+++ b/drivers/usb/typec/ucsi/ucsi_glink.c
@@ -68,6 +68,9 @@ struct pmic_glink_ucsi {
 
 	struct work_struct notify_work;
 	struct work_struct register_work;
+	spinlock_t state_lock;
+	bool ucsi_registered;
+	bool pd_running;
 
 	u8 read_buf[UCSI_BUF_SIZE];
 };
@@ -244,8 +247,20 @@ static void pmic_glink_ucsi_notify(struct work_struct *work)
 static void pmic_glink_ucsi_register(struct work_struct *work)
 {
 	struct pmic_glink_ucsi *ucsi = container_of(work, struct pmic_glink_ucsi, register_work);
+	unsigned long flags;
+	bool pd_running;
 
-	ucsi_register(ucsi->ucsi);
+	spin_lock_irqsave(&ucsi->state_lock, flags);
+	pd_running = ucsi->pd_running;
+	spin_unlock_irqrestore(&ucsi->state_lock, flags);
+
+	if (!ucsi->ucsi_registered && pd_running) {
+		ucsi_register(ucsi->ucsi);
+		ucsi->ucsi_registered = true;
+	} else if (ucsi->ucsi_registered && !pd_running) {
+		ucsi_unregister(ucsi->ucsi);
+		ucsi->ucsi_registered = false;
+	}
 }
 
 static void pmic_glink_ucsi_callback(const void *data, size_t len, void *priv)
@@ -269,11 +284,12 @@ static void pmic_glink_ucsi_callback(const void *data, size_t len, void *priv)
 static void pmic_glink_ucsi_pdr_notify(void *priv, int state)
 {
 	struct pmic_glink_ucsi *ucsi = priv;
+	unsigned long flags;
 
-	if (state == SERVREG_SERVICE_STATE_UP)
-		schedule_work(&ucsi->register_work);
-	else if (state == SERVREG_SERVICE_STATE_DOWN)
-		ucsi_unregister(ucsi->ucsi);
+	spin_lock_irqsave(&ucsi->state_lock, flags);
+	ucsi->pd_running = (state == SERVREG_SERVICE_STATE_UP);
+	spin_unlock_irqrestore(&ucsi->state_lock, flags);
+	schedule_work(&ucsi->register_work);
 }
 
 static void pmic_glink_ucsi_destroy(void *data)
@@ -320,6 +336,7 @@ static int pmic_glink_ucsi_probe(struct auxiliary_device *adev,
 	INIT_WORK(&ucsi->register_work, pmic_glink_ucsi_register);
 	init_completion(&ucsi->read_ack);
 	init_completion(&ucsi->write_ack);
+	spin_lock_init(&ucsi->state_lock);
 	mutex_init(&ucsi->lock);
 
 	ucsi->ucsi = ucsi_create(dev, &pmic_glink_ucsi_ops);

-- 
2.34.1

[PATCH v3 3/3] soc: qcom: pmic_glink: Actually communicate when remote goes down

[Bjorn Andersson]

When the pmic_glink state is UP and we either receive a protection-
domain (PD) notification indicating that the PD is going down, or that
the whole remoteproc is going down, it's expected that the pmic_glink
client instances are notified that their function has gone DOWN.

This is not what the code does, which results in the client state either
not updating, or being wrong in many cases. So let's fix the conditions.

Fixes: 58ef4ece1e41 ("soc: qcom: pmic_glink: Introduce base PMIC GLINK driver")
Cc: stable@vger.kernel.org
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Tested-by: Amit Pundir <amit.pundir@linaro.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Tested-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
---
 drivers/soc/qcom/pmic_glink.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/soc/qcom/pmic_glink.c b/drivers/soc/qcom/pmic_glink.c
index b218460219b7..9606222993fd 100644
--- a/drivers/soc/qcom/pmic_glink.c
+++ b/drivers/soc/qcom/pmic_glink.c
@@ -191,7 +191,7 @@ static void pmic_glink_state_notify_clients(struct pmic_glink *pg)
 		if (pg->pdr_state == SERVREG_SERVICE_STATE_UP && pg->ept)
 			new_state = SERVREG_SERVICE_STATE_UP;
 	} else {
-		if (pg->pdr_state == SERVREG_SERVICE_STATE_UP && pg->ept)
+		if (pg->pdr_state == SERVREG_SERVICE_STATE_DOWN || !pg->ept)
 			new_state = SERVREG_SERVICE_STATE_DOWN;
 	}
 

-- 
2.34.1

Re: [PATCH v3 0/3] soc: qcom: pmic_glink: v6.11-rc bug fixes

[Bjorn Andersson]

On Tue, 20 Aug 2024 13:29:29 -0700, Bjorn Andersson wrote:
> Amit and Johan both reported a NULL pointer dereference in the
> pmic_glink client code during initialization, and Stephen Boyd pointed
> out the problem (race condition).
> 
> While investigating, and writing the fix, I noticed that
> ucsi_unregister() is called in atomic context but tries to sleep, and I
> also noticed that the condition for when to inform the pmic_glink client
> drivers when the remote has gone down is just wrong.
> 
> [...]

Applied, thanks!

[1/3] soc: qcom: pmic_glink: Fix race during initialization
      commit: e4bff3088afc459687ed90c6584c443bcb5fba90
[2/3] usb: typec: ucsi: Move unregister out of atomic section
      commit: 15f19bc3de2ab0a5ece2e6aa34f626b38e9317cc
[3/3] soc: qcom: pmic_glink: Actually communicate when remote goes down
      commit: 8d856ad26551f9a9f428a73bf422e81c98e774ae

Best regards,
-- 
Bjorn Andersson <andersson@kernel.org>

Re: [PATCH v3 1/3] soc: qcom: pmic_glink: Fix race during initialization

[Johan Hovold]

On Tue, Aug 20, 2024 at 01:29:30PM -0700, Bjorn Andersson wrote:
> As pointed out by Stephen Boyd it is possible that during initialization
> of the pmic_glink child drivers, the protection-domain notifiers fires,
> and the associated work is scheduled, before the client registration
> returns and as a result the local "client" pointer has been initialized.
> 
> The outcome of this is a NULL pointer dereference as the "client"
> pointer is blindly dereferenced.

> Resolve this by splitting the allocation of the "client" object and the
> registration thereof into two operations.

It seems something went wrong when you posted v3 (using b4 automagic?)
so the cover letter and changelog is now missing and no one is on CC any
more.

Patches look good, though, with the exception of one nit below.

> diff --git a/drivers/power/supply/qcom_battmgr.c b/drivers/power/supply/qcom_battmgr.c
> index 49bef4a5ac3f..07758ab6ac1c 100644
> --- a/drivers/power/supply/qcom_battmgr.c
> +++ b/drivers/power/supply/qcom_battmgr.c
> @@ -1387,12 +1387,16 @@ static int qcom_battmgr_probe(struct auxiliary_device *adev,
>  					     "failed to register wireless charing power supply\n");
>  	}
>  
> -	battmgr->client = devm_pmic_glink_register_client(dev,
> -							  PMIC_GLINK_OWNER_BATTMGR,
> -							  qcom_battmgr_callback,
> -							  qcom_battmgr_pdr_notify,
> -							  battmgr);
> -	return PTR_ERR_OR_ZERO(battmgr->client);
> +	battmgr->client = devm_pmic_glink_client_alloc(dev, PMIC_GLINK_OWNER_BATTMGR,
> +						     qcom_battmgr_callback,
> +						     qcom_battmgr_pdr_notify,
> +						     battmgr);

I'm not a fan of open-parenthesis alignment of arguments, but since this
driver uses it you need to adjust the alignment to the new symbol name
in v3.

> +	if (IS_ERR(battmgr->client))
> +		return PTR_ERR(battmgr->client);
> +
> +	pmic_glink_client_register(battmgr->client);
> +
> +	return 0;
>  }

> diff --git a/drivers/soc/qcom/pmic_glink_altmode.c b/drivers/soc/qcom/pmic_glink_altmode.c
> index 1e0808b3cb93..c6f3d5188fc6 100644
> --- a/drivers/soc/qcom/pmic_glink_altmode.c
> +++ b/drivers/soc/qcom/pmic_glink_altmode.c
> @@ -520,12 +520,17 @@ static int pmic_glink_altmode_probe(struct auxiliary_device *adev,
>  			return ret;
>  	}
>  
> -	altmode->client = devm_pmic_glink_register_client(dev,
> -							  altmode->owner_id,
> -							  pmic_glink_altmode_callback,
> -							  pmic_glink_altmode_pdr_notify,
> -							  altmode);
> -	return PTR_ERR_OR_ZERO(altmode->client);
> +	altmode->client = devm_pmic_glink_client_alloc(dev,
> +						     altmode->owner_id,
> +						     pmic_glink_altmode_callback,
> +						     pmic_glink_altmode_pdr_notify,
> +						     altmode);

Same here.

> diff --git a/drivers/usb/typec/ucsi/ucsi_glink.c b/drivers/usb/typec/ucsi/ucsi_glink.c
> index 16c328497e0b..6425904f2bfc 100644
> --- a/drivers/usb/typec/ucsi/ucsi_glink.c
> +++ b/drivers/usb/typec/ucsi/ucsi_glink.c
> @@ -367,12 +367,16 @@ static int pmic_glink_ucsi_probe(struct auxiliary_device *adev,
>  		ucsi->port_orientation[port] = desc;
>  	}
>  
> -	ucsi->client = devm_pmic_glink_register_client(dev,
> -						       PMIC_GLINK_OWNER_USBC,
> -						       pmic_glink_ucsi_callback,
> -						       pmic_glink_ucsi_pdr_notify,
> -						       ucsi);
> -	return PTR_ERR_OR_ZERO(ucsi->client);
> +	ucsi->client = devm_pmic_glink_client_alloc(dev, PMIC_GLINK_OWNER_USBC,
> +						  pmic_glink_ucsi_callback,
> +						  pmic_glink_ucsi_pdr_notify,
> +						  ucsi);

And here.

> +	if (IS_ERR(ucsi->client))
> +		return PTR_ERR(ucsi->client);
> +
> +	pmic_glink_client_register(ucsi->client);
> +
> +	return 0;
>  }
>  
>  static void pmic_glink_ucsi_remove(struct auxiliary_device *adev)
> diff --git a/include/linux/soc/qcom/pmic_glink.h b/include/linux/soc/qcom/pmic_glink.h
> index fd124aa18c81..4c68385b2765 100644
> --- a/include/linux/soc/qcom/pmic_glink.h
> +++ b/include/linux/soc/qcom/pmic_glink.h
> @@ -23,10 +23,11 @@ struct pmic_glink_hdr {
>  
>  int pmic_glink_send(struct pmic_glink_client *client, void *data, size_t len);
>  
> -struct pmic_glink_client *devm_pmic_glink_register_client(struct device *dev,
> -							  unsigned int id,
> -							  void (*cb)(const void *, size_t, void *),
> -							  void (*pdr)(void *, int),
> -							  void *priv);
> +struct pmic_glink_client *devm_pmic_glink_client_alloc(struct device *dev,
> +						     unsigned int id,
> +						     void (*cb)(const void *, size_t, void *),
> +						     void (*pdr)(void *, int),
> +						     void *priv);

And here.

Johan