linux-kernel - [PATCH 3/4] usb: ucsi: Quirk to ack a connector change ack cmd

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Date: Sun,  7 Jan 2024 01:17:00 +0100
From: "Christian A. Ehrhardt" <lk@...e.de>
To: Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
	linux-usb@...r.kernel.org
Cc: "Christian A. Ehrhardt" <lk@...e.de>,
	Dell.Client.Kernel@...l.com,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Hans de Goede <hdegoede@...hat.com>,
	Jack Pham <quic_jackp@...cinc.com>,
	Fabrice Gasnier <fabrice.gasnier@...s.st.com>,
	Samuel Čavoj <samuel@...oj.net>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 3/4] usb: ucsi: Quirk to ack a connector change ack cmd

The PPM on some Dell laptops seems to expect that the ACK_CC_CI
command to clear the connector change notification is in turn
followed by another ACK_CC_CI to acknowledge the ACK_CC_CI command
itself. This is in violation of the UCSI spec that states:

    "The only notification that is not acknowledged by the OPM is
     the command completion notification for the ACK_CC_CI or the
     PPM_RESET command."

Add a quirk to send this ack anyway.

Signed-off-by: Christian A. Ehrhardt <lk@...e.de>
---
 drivers/usb/typec/ucsi/ucsi.c | 7 ++++++-
 drivers/usb/typec/ucsi/ucsi.h | 1 +
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index 00b23292f46f..8718836b6aba 100644
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -54,11 +54,16 @@ static int ucsi_acknowledge_command(struct ucsi *ucsi)
 static int ucsi_acknowledge_connector_change(struct ucsi *ucsi)
 {
 	u64 ctrl;
+	int ret;
 
 	ctrl = UCSI_ACK_CC_CI;
 	ctrl |= UCSI_ACK_CONNECTOR_CHANGE;
 
-	return ucsi->ops->sync_write(ucsi, UCSI_CONTROL, &ctrl, sizeof(ctrl));
+	ret = ucsi->ops->sync_write(ucsi, UCSI_CONTROL, &ctrl, sizeof(ctrl));
+	if (ret == 0 && ucsi->quirks & UCSI_ACK_CONNECTOR_CHANGE_ACK_CMD)
+		ret = ucsi_acknowledge_command(ucsi);
+
+	return ret;
 }
 
 static int ucsi_exec_command(struct ucsi *ucsi, u64 command);
diff --git a/drivers/usb/typec/ucsi/ucsi.h b/drivers/usb/typec/ucsi/ucsi.h
index 5e6d2225c9c8..9ea2143776cf 100644
--- a/drivers/usb/typec/ucsi/ucsi.h
+++ b/drivers/usb/typec/ucsi/ucsi.h
@@ -321,6 +321,7 @@ struct ucsi {
 
 	/* Enabled quirks. */
 	unsigned int quirks;
+#define UCSI_ACK_CONNECTOR_CHANGE_ACK_CMD BIT(0)
 };
 
 #define UCSI_MAX_SVID		5
-- 
2.40.1