From ba784a029b61016a12518fca504b1edf74e58b83 Mon Sep 17 00:00:00 2001
From: "H. Nikolaus Schaller" <hns@goldelico.com>
Date: Thu, 7 Apr 2022 13:16:09 +0200
Subject: drm/bridge: display-connector: add ddc-en gpio support
Git-commit: 6de79dd3a920a138a292231e2da82ab8e019ec99
Patch-mainline: v5.19-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

"hdmi-connector.yaml" bindings defines an optional property
"ddc-en-gpios" for a single gpio to enable DDC operation.

Usually this controls +5V power on the HDMI connector.
This +5V may also be needed for HPD.

This was not reflected in code but is needed to make the CI20
board work.

Now, the driver activates the ddc gpio after probe and
deactivates after remove so it is "almost on".

But only if this driver is loaded (and not e.g. blacklisted
as module).

Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://patchwork.freedesktop.org/patch/msgid/3607e924b7c0cf0be956c0d49894be1442dbda41.1649330171.git.hns@goldelico.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/bridge/display-connector.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/gpu/drm/bridge/display-connector.c b/drivers/gpu/drm/bridge/display-connector.c
index d24f5b90feab..e4d52a7e31b7 100644
--- a/drivers/gpu/drm/bridge/display-connector.c
+++ b/drivers/gpu/drm/bridge/display-connector.c
@@ -24,6 +24,7 @@ struct display_connector {
 	int			hpd_irq;
 
 	struct regulator	*dp_pwr;
+	struct gpio_desc	*ddc_en;
 };
 
 static inline struct display_connector *
@@ -345,6 +346,17 @@ static int display_connector_probe(struct platform_device *pdev)
 		}
 	}
 
+	/* enable DDC */
+	if (type == DRM_MODE_CONNECTOR_HDMIA) {
+		conn->ddc_en = devm_gpiod_get_optional(&pdev->dev, "ddc-en",
+						       GPIOD_OUT_HIGH);
+
+		if (IS_ERR(conn->ddc_en)) {
+			dev_err(&pdev->dev, "Couldn't get ddc-en gpio\n");
+			return PTR_ERR(conn->ddc_en);
+		}
+	}
+
 	conn->bridge.funcs = &display_connector_bridge_funcs;
 	conn->bridge.of_node = pdev->dev.of_node;
 
@@ -373,6 +385,9 @@ static int display_connector_remove(struct platform_device *pdev)
 {
 	struct display_connector *conn = platform_get_drvdata(pdev);
 
+	if (conn->ddc_en)
+		gpiod_set_value(conn->ddc_en, 0);
+
 	if (conn->dp_pwr)
 		regulator_disable(conn->dp_pwr);
 
-- 
2.38.1