[PATCH v1] drm/bridge: ti-sn65dsi86: Enable HPD polling if IRQ is not used

[Franz Schnyder <fra.schnyder@gmail.com>]

From: Franz Schnyder <franz.schnyder@toradex.com>

Fallback to polling to detect hotplug events on systems without
interrupts.

On systems where the interrupt line of the bridge is not connected,
the bridge cannot notify hotplug events. Only add the
DRM_BRIDGE_OP_HPD flag if an interrupt has been registered
otherwise remain in polling mode.

Fixes: 9133bc3f0564 ("drm/bridge: ti-sn65dsi86: Add support for DisplayPort mode with HPD")
Fixes: 55e8ff842051 ("drm/bridge: ti-sn65dsi86: Add HPD for DisplayPort connector type")
Cc: stable@vger.kernel.org
Signed-off-by: Franz Schnyder <franz.schnyder@toradex.com>
---
 drivers/gpu/drm/bridge/ti-sn65dsi86.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index 276d05d25ad8..98d64ad791d0 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -1415,6 +1415,7 @@ static int ti_sn_bridge_probe(struct auxiliary_device *adev,
 {
 	struct ti_sn65dsi86 *pdata = dev_get_drvdata(adev->dev.parent);
 	struct device_node *np = pdata->dev->of_node;
+	const struct i2c_client *client = to_i2c_client(pdata->dev);
 	int ret;
 
 	pdata->next_bridge = devm_drm_of_get_bridge(&adev->dev, np, 1, 0);
@@ -1433,8 +1434,9 @@ static int ti_sn_bridge_probe(struct auxiliary_device *adev,
 			   ? DRM_MODE_CONNECTOR_DisplayPort : DRM_MODE_CONNECTOR_eDP;
 
 	if (pdata->bridge.type == DRM_MODE_CONNECTOR_DisplayPort) {
-		pdata->bridge.ops = DRM_BRIDGE_OP_EDID | DRM_BRIDGE_OP_DETECT |
-				    DRM_BRIDGE_OP_HPD;
+		pdata->bridge.ops = DRM_BRIDGE_OP_EDID | DRM_BRIDGE_OP_DETECT;
+		if (client->irq)
+			pdata->bridge.ops |= DRM_BRIDGE_OP_HPD;
 		/*
 		 * If comms were already enabled they would have been enabled
 		 * with the wrong value of HPD_DISABLE. Update it now. Comms
-- 
2.43.0