[PATCH 2/3] usb: typec: ps883x: fix missing accessibility check

From: Johan Hovold
Date: Tue Feb 18 2025 - 10:30:05 EST


Make sure that the retimer is accessible before registering to avoid
having later consumer calls fail to configure it, something which, for
example, can lead to a hotplugged display not being recognised:

[drm:msm_dp_panel_read_sink_caps [msm]] *ERROR* read dpcd failed -110

Fixes: 257a087c8b52 ("usb: typec: Add support for Parade PS8830 Type-C Retimer")
Cc: Abel Vesa <abel.vesa@xxxxxxxxxx>
Signed-off-by: Johan Hovold <johan+linaro@xxxxxxxxxx>
---
drivers/usb/typec/mux/ps883x.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/drivers/usb/typec/mux/ps883x.c b/drivers/usb/typec/mux/ps883x.c
index 274de7abe585..f8b47187f4cf 100644
--- a/drivers/usb/typec/mux/ps883x.c
+++ b/drivers/usb/typec/mux/ps883x.c
@@ -291,6 +291,7 @@ static int ps883x_retimer_probe(struct i2c_client *client)
struct typec_switch_desc sw_desc = { };
struct typec_retimer_desc rtmr_desc = { };
struct ps883x_retimer *retimer;
+ unsigned int val;
int ret;

retimer = devm_kzalloc(dev, sizeof(*retimer), GFP_KERNEL);
@@ -360,6 +361,16 @@ static int ps883x_retimer_probe(struct i2c_client *client)

/* firmware initialization delay */
msleep(60);
+
+ /* make sure device is accessible */
+ ret = regmap_read(retimer->regmap, REG_USB_PORT_CONN_STATUS_0,
+ &val);
+ if (ret) {
+ dev_err(dev, "failed to read conn_status_0: %d\n", ret);
+ if (ret == -ENXIO)
+ ret = -EIO;
+ goto err_clk_disable;
+ }
}

sw_desc.drvdata = retimer;
--
2.45.3