drm/bridge: ite66121: Register HPD interrupt handler only when 'client->irq > 0'

If a specific design doesn't wire IT66121's interrupt signal output pin up
to the display controller side, then we should not register the interrupt
handler. Such a decision is valid usage, as we can fall back to polling
mode. So, don't make the assumption that a specific board always supports
HPD. Carry out a sanity check on 'client->irq' before using it, fall back
to polling mode if client->irq < 0 is true. Such a design increases the
overall flexibility.
Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20240316160536.1051513-1-sui.jingfeng@linux.devSigned-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240316160536.1051513-1-sui.jingfeng@linux.dev

drivers/gpu/drm/bridge/ite-it66121.c

@@ -1586,13 +1586,18 @@ static int it66121_probe(struct i2c_client *client)
 	ctx->bridge.funcs = &it66121_bridge_funcs;
 	ctx->bridge.of_node = dev->of_node;
 	ctx->bridge.type = DRM_MODE_CONNECTOR_HDMIA;
-	ctx->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID | DRM_BRIDGE_OP_HPD;
-
-	ret = devm_request_threaded_irq(dev, client->irq, NULL,	it66121_irq_threaded_handler,
-					IRQF_ONESHOT, dev_name(dev), ctx);
-	if (ret < 0) {
-		dev_err(dev, "Failed to request irq %d:%d\n", client->irq, ret);
-		return ret;
+	ctx->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID;
+	if (client->irq > 0) {
+		ctx->bridge.ops |= DRM_BRIDGE_OP_HPD;
+
+		ret = devm_request_threaded_irq(dev, client->irq, NULL,
+						it66121_irq_threaded_handler,
+						IRQF_ONESHOT, dev_name(dev),
+						ctx);
+		if (ret < 0) {
+			dev_err(dev, "Failed to request irq %d:%d\n", client->irq, ret);
+			return ret;
+		}
 	}
 
 	it66121_audio_codec_init(ctx, dev);