drm: bridge: adv7511: Fix ADV7535 HPD enablement

Existing HPD enablement logic is not compatible with ADV7535
bridge, thus any runtime plug-in of HDMI cable is not working
on these bridge designs.

Unlike other ADV7511 family of bridges, the ADV7535 require
HPD_OVERRIDE bit to set and reset for proper handling of HPD
functionality.

Fix it.

Fixes: 8501fe4b ("drm: bridge: adv7511: Add support for ADV7535")
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220109172949.168167-1-jagan@amarulasolutions.comReviewed-by: Robert Foss <robert.foss@linaro.org>

drivers/gpu/drm/bridge/adv7511/adv7511.h

@@ -169,6 +169,7 @@
 #define ADV7511_PACKET_ENABLE_SPARE2		BIT(1)
 #define ADV7511_PACKET_ENABLE_SPARE1		BIT(0)
 
+#define ADV7535_REG_POWER2_HPD_OVERRIDE		BIT(6)
 #define ADV7511_REG_POWER2_HPD_SRC_MASK		0xc0
 #define ADV7511_REG_POWER2_HPD_SRC_BOTH		0x00
 #define ADV7511_REG_POWER2_HPD_SRC_HPD		0x40

drivers/gpu/drm/bridge/adv7511/adv7511_drv.c

@@ -351,8 +351,14 @@ static void __adv7511_power_on(struct adv7511 *adv7511)
 	 * from standby or are enabled. When the HPD goes low the adv7511 is
 	 * reset and the outputs are disabled which might cause the monitor to
 	 * go to standby again. To avoid this we ignore the HPD pin for the
-	 * first few seconds after enabling the output.
+	 * first few seconds after enabling the output. On the other hand
+	 * adv7535 require to enable HPD Override bit for proper HPD.
 	 */
+	if (adv7511->type == ADV7535)
+		regmap_update_bits(adv7511->regmap, ADV7511_REG_POWER2,
+				   ADV7535_REG_POWER2_HPD_OVERRIDE,
+				   ADV7535_REG_POWER2_HPD_OVERRIDE);
+	else
 		regmap_update_bits(adv7511->regmap, ADV7511_REG_POWER2,
 				   ADV7511_REG_POWER2_HPD_SRC_MASK,
 				   ADV7511_REG_POWER2_HPD_SRC_NONE);
@@ -375,6 +381,10 @@ static void adv7511_power_on(struct adv7511 *adv7511)
 static void __adv7511_power_off(struct adv7511 *adv7511)
 {
 	/* TODO: setup additional power down modes */
+	if (adv7511->type == ADV7535)
+		regmap_update_bits(adv7511->regmap, ADV7511_REG_POWER2,
+				   ADV7535_REG_POWER2_HPD_OVERRIDE, 0);
+
 	regmap_update_bits(adv7511->regmap, ADV7511_REG_POWER,
 			   ADV7511_POWER_POWER_DOWN,
 			   ADV7511_POWER_POWER_DOWN);
@@ -672,6 +682,11 @@ adv7511_detect(struct adv7511 *adv7511, struct drm_connector *connector)
 			status = connector_status_disconnected;
 	} else {
 		/* Renable HPD sensing */
+		if (adv7511->type == ADV7535)
+			regmap_update_bits(adv7511->regmap, ADV7511_REG_POWER2,
+					   ADV7535_REG_POWER2_HPD_OVERRIDE,
+					   ADV7535_REG_POWER2_HPD_OVERRIDE);
+		else
 			regmap_update_bits(adv7511->regmap, ADV7511_REG_POWER2,
 					   ADV7511_REG_POWER2_HPD_SRC_MASK,
 					   ADV7511_REG_POWER2_HPD_SRC_BOTH);