[PATCH v2 02/10] usb: tcpm: continue polling after PD negotiation to handle source messages

[Peng Fan (OSS)]

From: Peng Fan <peng.fan at nxp.com>

After reaching SNK_READY or SRC_READY, the poll loop exits immediately.
However, some PD sources send follow-up messages (e.g., Get_Sink_Cap,
Get_Status) shortly after the explicit contract is established. Since
the TCPCI hardware auto-sends GoodCRC for received messages, the
source expects a timely response. If no response arrives within
SenderResponseTimer (24-30ms), the source sends a Hard Reset,
causing VBUS to drop and resetting VBUS-powered boards.

Add a 500ms settling period after reaching Ready state to process
any follow-up messages from the source before entering low power
mode and disabling PD message reception.

Signed-off-by: Peng Fan <peng.fan at nxp.com>
---
 drivers/usb/tcpm/tcpm.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/usb/tcpm/tcpm.c b/drivers/usb/tcpm/tcpm.c
index 25ff0926cdf..d6af0fae7c1 100644
--- a/drivers/usb/tcpm/tcpm.c
+++ b/drivers/usb/tcpm/tcpm.c
@@ -2252,6 +2252,16 @@ static void tcpm_poll_event(struct udevice *dev)
 		tcpm_check_and_run_delayed_work(dev);
 	}
 
+	if (port->state == SNK_READY || port->state == SRC_READY) {
+		int settle;
+
+		for (settle = 0; settle < 1000; settle++) {
+			drvops->poll_event(dev);
+			udelay(500);
+			tcpm_check_and_run_delayed_work(dev);
+		}
+	}
+
 	if (port->state != SNK_READY && port->state != SRC_READY)
 		dev_warn(dev, "TCPM: exit in state %s\n",
 			 tcpm_states[port->state]);

-- 
2.51.0