linux-kernel - [PATCH v2] usb: typec: qcom-pmic-typec: split HPD bridge alloc and registration

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Message-Id: <20240408-qc-pmic-typec-hpd-split-v2-1-1704f5321b73@linaro.org>
Date: Mon, 08 Apr 2024 04:06:40 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Bryan O'Donoghue <bryan.odonoghue@...aro.org>, 
 Heikki Krogerus <heikki.krogerus@...ux.intel.com>, 
 Bjorn Andersson <andersson@...nel.org>, 
 Konrad Dybcio <konrad.dybcio@...aro.org>, 
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: linux-arm-msm@...r.kernel.org, linux-usb@...r.kernel.org, 
 linux-kernel@...r.kernel.org, Caleb Connolly <caleb.connolly@...aro.org>
Subject: [PATCH v2] usb: typec: qcom-pmic-typec: split HPD bridge alloc and
 registration

If a probe function returns -EPROBE_DEFER after creating another device
there is a change of ending up in a probe deferral loop, (see commit
fbc35b45f9f6 ("Add documentation on meaning of -EPROBE_DEFER").

In order to prevent such probe-defer loops caused by qcom-pmic-typec
driver, use the API added by Johan Hovold and move HPD bridge
registration to the end of the probe function.

Reported-by: Caleb Connolly <caleb.connolly@...aro.org>
Acked-by: Bryan O'Donoghue <bryan.odonoghue@...aro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
---
Changes in v2:
- Fix commit message (Bryan)
- Link to v1: https://lore.kernel.org/r/20240405-qc-pmic-typec-hpd-split-v1-1-363daafb3c36@linaro.org
---
 drivers/usb/typec/tcpm/qcom/qcom_pmic_typec.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/typec/tcpm/qcom/qcom_pmic_typec.c b/drivers/usb/typec/tcpm/qcom/qcom_pmic_typec.c
index e48412cdcb0f..96b41efae318 100644
--- a/drivers/usb/typec/tcpm/qcom/qcom_pmic_typec.c
+++ b/drivers/usb/typec/tcpm/qcom/qcom_pmic_typec.c
@@ -41,7 +41,7 @@ static int qcom_pmic_typec_probe(struct platform_device *pdev)
 	struct device_node *np = dev->of_node;
 	const struct pmic_typec_resources *res;
 	struct regmap *regmap;
-	struct device *bridge_dev;
+	struct auxiliary_device *bridge_dev;
 	u32 base;
 	int ret;
 
@@ -92,7 +92,7 @@ static int qcom_pmic_typec_probe(struct platform_device *pdev)
 	if (!tcpm->tcpc.fwnode)
 		return -EINVAL;
 
-	bridge_dev = drm_dp_hpd_bridge_register(tcpm->dev, to_of_node(tcpm->tcpc.fwnode));
+	bridge_dev = devm_drm_dp_hpd_bridge_alloc(tcpm->dev, to_of_node(tcpm->tcpc.fwnode));
 	if (IS_ERR(bridge_dev))
 		return PTR_ERR(bridge_dev);
 
@@ -110,6 +110,10 @@ static int qcom_pmic_typec_probe(struct platform_device *pdev)
 	if (ret)
 		goto fwnode_remove;
 
+	ret = devm_drm_dp_hpd_bridge_add(tcpm->dev, bridge_dev);
+	if (ret)
+		goto fwnode_remove;
+
 	return 0;
 
 fwnode_remove:

---
base-commit: a6bd6c9333397f5a0e2667d4d82fef8c970108f2
change-id: 20240405-qc-pmic-typec-hpd-split-22804201902b

Best regards,
-- 
Dmitry Baryshkov <dmitry.baryshkov@...aro.org>