linux-kernel - [PATCH] platform/chrome: cros_ec_typec: Set Pin Assignment E in DP PORT VDO

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Message-ID: <20250426024810.3876884-1-bleung@chromium.org>
Date: Sat, 26 Apr 2025 02:48:10 +0000
From: Benson Leung <bleung@...omium.org>
To: abhishekpandit@...omium.org,
	jthies@...gle.com,
	akuchynski@...omium.org,
	tzungbi@...nel.org,
	chrome-platform@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Cc: sukoo@...gle.com,
	bleung@...gle.com,
	Benson Leung <bleung@...omium.org>
Subject: [PATCH] platform/chrome: cros_ec_typec: Set Pin Assignment E in DP PORT VDO

Pin C and D are used on C-to-C cable applications including docks,
and for USB-C adapters that convert from DP over USB-C to other
video standards.

Pin Assignment E is intended to be used with adapter from USB-C to DP
plugs or receptacles.

All Chromebook USB-C DFPs support DisplayPort Alternate Mode as the DP
Source with support for all 3 pin assignments. Pin Assignment E is required
in order to support if the user attaches a Pin E C-to-DP cable.

Without this, the displayport.c alt mode driver will error out of
dp_altmode_probe with an -ENODEV, as it cannot find a compatible matching
pin assignment between the DFP_D and UFP_D.

Signed-off-by: Benson Leung <bleung@...omium.org>
---
 drivers/platform/chrome/cros_ec_typec.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
index d2228720991f..7678e3d05fd3 100644
--- a/drivers/platform/chrome/cros_ec_typec.c
+++ b/drivers/platform/chrome/cros_ec_typec.c
@@ -22,8 +22,10 @@

 #define DRV_NAME "cros-ec-typec"

-#define DP_PORT_VDO	(DP_CONF_SET_PIN_ASSIGN(BIT(DP_PIN_ASSIGN_C) | BIT(DP_PIN_ASSIGN_D)) | \
-				DP_CAP_DFP_D | DP_CAP_RECEPTACLE)
+#define DP_PORT_VDO	(DP_CAP_DFP_D | DP_CAP_RECEPTACLE | \
+			 DP_CONF_SET_PIN_ASSIGN(BIT(DP_PIN_ASSIGN_C) | \
+						BIT(DP_PIN_ASSIGN_D) | \
+						BIT(DP_PIN_ASSIGN_E)))

 static void cros_typec_role_switch_quirk(struct fwnode_handle *fwnode)
 {
-- 
2.49.0.850.g28803427d3-goog