[PATCH v2 1/2] usb: typec: ucsi: fix UCSI on buggy Qualcomm devices

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

On sevral Qualcomm platforms (SC8180X, SM8350, SC8280XP) a call to
UCSI_GET_PDOS for non-PD partners will cause a firmware crash with no
easy way to recover from it. Since we have no easy way to determine
whether the partner really has PD support, shortcut UCSI_GET_PDOS on
such platforms. This allows us to enable UCSI support on such devices.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 drivers/usb/typec/ucsi/ucsi.c       |  3 +++
 drivers/usb/typec/ucsi/ucsi.h       |  3 +++
 drivers/usb/typec/ucsi/ucsi_glink.c | 13 +++++++++++++
 3 files changed, 19 insertions(+)

diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index 61b64558f96c..5392ec698959 100644
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -578,6 +578,9 @@ static int ucsi_read_pdos(struct ucsi_connector *con,
 	u64 command;
 	int ret;
 
+	if (ucsi->quirks & UCSI_NO_PARTNER_PDOS)
+		return 0;
+
 	command = UCSI_COMMAND(UCSI_GET_PDOS) | UCSI_CONNECTOR_NUMBER(con->num);
 	command |= UCSI_GET_PDOS_PARTNER_PDO(is_partner);
 	command |= UCSI_GET_PDOS_PDO_OFFSET(offset);
diff --git a/drivers/usb/typec/ucsi/ucsi.h b/drivers/usb/typec/ucsi/ucsi.h
index 474315a72c77..6478016d5cb8 100644
--- a/drivers/usb/typec/ucsi/ucsi.h
+++ b/drivers/usb/typec/ucsi/ucsi.h
@@ -317,6 +317,9 @@ struct ucsi {
 #define EVENT_PENDING	0
 #define COMMAND_PENDING	1
 #define ACK_PENDING	2
+
+	unsigned long quirks;
+#define UCSI_NO_PARTNER_PDOS	BIT(0)	/* Don't read partner's PDOs */
 };
 
 #define UCSI_MAX_SVID		5
diff --git a/drivers/usb/typec/ucsi/ucsi_glink.c b/drivers/usb/typec/ucsi/ucsi_glink.c
index db6e248f8208..a94e2df6fd45 100644
--- a/drivers/usb/typec/ucsi/ucsi_glink.c
+++ b/drivers/usb/typec/ucsi/ucsi_glink.c
@@ -6,6 +6,7 @@
 #include <linux/auxiliary_bus.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/of_device.h>
 #include <linux/property.h>
 #include <linux/soc/qcom/pdr.h>
 #include <linux/usb/typec_mux.h>
@@ -296,11 +297,19 @@ static void pmic_glink_ucsi_destroy(void *data)
 	mutex_unlock(&ucsi->lock);
 }
 
+static const struct of_device_id pmic_glink_ucsi_of_quirks[] = {
+	{ .compatible = "qcom,sc8180x-pmic-glink", .data = (void *)UCSI_NO_PARTNER_PDOS, },
+	{ .compatible = "qcom,sc8280xp-pmic-glink", .data = (void *)UCSI_NO_PARTNER_PDOS, },
+	{ .compatible = "qcom,sm8350-pmic-glink", .data = (void *)UCSI_NO_PARTNER_PDOS, },
+	{}
+};
+
 static int pmic_glink_ucsi_probe(struct auxiliary_device *adev,
 				 const struct auxiliary_device_id *id)
 {
 	struct pmic_glink_ucsi *ucsi;
 	struct device *dev = &adev->dev;
+	const struct of_device_id *match;
 	struct fwnode_handle *fwnode;
 	int ret;
 
@@ -327,6 +336,10 @@ static int pmic_glink_ucsi_probe(struct auxiliary_device *adev,
 	if (ret)
 		return ret;
 
+	match = of_match_device(pmic_glink_ucsi_of_quirks, dev->parent);
+	if (match)
+		ucsi->ucsi->quirks = (unsigned long)match->data;
+
 	ucsi_set_drvdata(ucsi->ucsi, ucsi);
 
 	device_for_each_child_node(dev, fwnode) {
-- 
2.42.0