drm/bridge: dw-hdmi-qp: Fix spurious IRQ on resume

After resume from suspend to RAM, the following splash is generated if
the HDMI driver is probed (independent of a connected cable):

[ 1194.484052] irq 80: nobody cared (try booting with the "irqpoll" option)
[ 1194.484074] CPU: 0 UID: 0 PID: 627 Comm: rtcwake Not tainted 6.17.0-rc7-g96f1a11414b3 #1 PREEMPT
[ 1194.484082] Hardware name: Rockchip RK3576 EVB V10 Board (DT)
[ 1194.484085] Call trace:
[ 1194.484087]  ... (stripped)
[ 1194.484283] handlers:
[ 1194.484285] [<00000000bc363dcb>] dw_hdmi_qp_main_hardirq [dw_hdmi_qp]
[ 1194.484302] Disabling IRQ #80

Apparently the HDMI IP is losing part of its state while the system
is suspended and generates spurious interrupts during resume. The
bug has not yet been noticed, as system suspend does not yet work
properly on upstream kernel with either the Rockchip RK3588 or RK3576
platform.

Fixes: 128a9bf ("drm/rockchip: Add basic RK3588 HDMI output support")
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patch.msgid.link/20251014-rockchip-hdmi-suspend-fix-v1-1-983fcbf44839@collabora.com

Author: sre

drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c

@@ -163,6 +163,7 @@ struct dw_hdmi_qp {
 
 	unsigned long ref_clk_rate;
 	struct regmap *regm;
+	int main_irq;
 
 	unsigned long tmds_char_rate;
 };
@@ -1271,6 +1272,7 @@ struct dw_hdmi_qp *dw_hdmi_qp_bind(struct platform_device *pdev,
 
 	dw_hdmi_qp_init_hw(hdmi);
 
+	hdmi->main_irq = plat_data->main_irq;
 	ret = devm_request_threaded_irq(dev, plat_data->main_irq,
 					dw_hdmi_qp_main_hardirq, NULL,
 					IRQF_SHARED, dev_name(dev), hdmi);
@@ -1331,9 +1333,16 @@ struct dw_hdmi_qp *dw_hdmi_qp_bind(struct platform_device *pdev,
 }
 EXPORT_SYMBOL_GPL(dw_hdmi_qp_bind);
 
+void dw_hdmi_qp_suspend(struct device *dev, struct dw_hdmi_qp *hdmi)
+{
+	disable_irq(hdmi->main_irq);
+}
+EXPORT_SYMBOL_GPL(dw_hdmi_qp_suspend);
+
 void dw_hdmi_qp_resume(struct device *dev, struct dw_hdmi_qp *hdmi)
 {
 	dw_hdmi_qp_init_hw(hdmi);
+	enable_irq(hdmi->main_irq);
 }
 EXPORT_SYMBOL_GPL(dw_hdmi_qp_resume);
 

drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c

@@ -640,6 +640,15 @@ static void dw_hdmi_qp_rockchip_remove(struct platform_device *pdev)
 	component_del(&pdev->dev, &dw_hdmi_qp_rockchip_ops);
 }
 
+static int __maybe_unused dw_hdmi_qp_rockchip_suspend(struct device *dev)
+{
+	struct rockchip_hdmi_qp *hdmi = dev_get_drvdata(dev);
+
+	dw_hdmi_qp_suspend(dev, hdmi->hdmi);
+
+	return 0;
+}
+
 static int __maybe_unused dw_hdmi_qp_rockchip_resume(struct device *dev)
 {
 	struct rockchip_hdmi_qp *hdmi = dev_get_drvdata(dev);
@@ -655,7 +664,8 @@ static int __maybe_unused dw_hdmi_qp_rockchip_resume(struct device *dev)
 }
 
 static const struct dev_pm_ops dw_hdmi_qp_rockchip_pm = {
-	SET_SYSTEM_SLEEP_PM_OPS(NULL, dw_hdmi_qp_rockchip_resume)
+	SET_SYSTEM_SLEEP_PM_OPS(dw_hdmi_qp_rockchip_suspend,
+				dw_hdmi_qp_rockchip_resume)
 };
 
 struct platform_driver dw_hdmi_qp_rockchip_pltfm_driver = {

include/drm/bridge/dw_hdmi_qp.h

@@ -34,5 +34,6 @@ struct dw_hdmi_qp_plat_data {
 struct dw_hdmi_qp *dw_hdmi_qp_bind(struct platform_device *pdev,
 				   struct drm_encoder *encoder,
 				   const struct dw_hdmi_qp_plat_data *plat_data);
+void dw_hdmi_qp_suspend(struct device *dev, struct dw_hdmi_qp *hdmi);
 void dw_hdmi_qp_resume(struct device *dev, struct dw_hdmi_qp *hdmi);
 #endif /* __DW_HDMI_QP__ */