[PATCH v7 15/30] drm/bridge: dw-hdmi-qp: Provide dw_hdmi_qp_hpd_notify() helper

[Cristian Ciocaltea]

Export dw_hdmi_qp_hpd_notify() for platform drivers to report hot-plug
detection events.  Unlike drm_helper_hpd_irq_event() which polls all
connectors, this helper targets only the affected connector and ensures
.detect_ctx() is invoked on reconnection events to trigger SCDC state
recovery.

Note that this helper may sleep, so it must only be called from a
threaded HPD interrupt handler or a work function.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxxxxxx>
---
 drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c | 31 ++++++++++++++++++++++++++++
 include/drm/bridge/dw_hdmi_qp.h              |  1 +
 2 files changed, 32 insertions(+)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
index 0250ddd8f91a..999229705ffb 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
@@ -29,6 +29,7 @@
 #include <drm/drm_edid.h>
 #include <drm/drm_modes.h>
 #include <drm/drm_print.h>
+#include <drm/drm_probe_helper.h>
 
 #include <media/cec.h>
 
@@ -1433,6 +1434,36 @@ struct dw_hdmi_qp *dw_hdmi_qp_bind(struct platform_device *pdev,
 }
 EXPORT_SYMBOL_GPL(dw_hdmi_qp_bind);
 
+/**
+ * dw_hdmi_qp_hpd_notify() - Notify a hot-plug detection event
+ * @hdmi: pointer to the DW HDMI QP controller
+ *
+ * Platform drivers should call this from their threaded IRQ handler or work
+ * function to notify the bridge of a connection status change.
+ * The bridge's .read_hpd() phy_ops callback is used to read the current
+ * connection status.
+ */
+void dw_hdmi_qp_hpd_notify(struct dw_hdmi_qp *hdmi)
+{
+	enum drm_connector_status status;
+
+	status = hdmi->phy.ops->read_hpd(hdmi, hdmi->phy.data);
+	dev_dbg(hdmi->dev, "%s status=%d\n", __func__, status);
+
+	/*
+	 * When the display pipeline has been already active, switch to
+	 * drm_connector_helper_hpd_irq_event() to ensure .detect_ctx()
+	 * gets invoked, i.e. via drm_helper_probe_detect(), because
+	 * drm_bridge_hpd_notify() defers to a delayed hotplug path in
+	 * this case.
+	 */
+	if (hdmi->curr_conn && status == connector_status_connected)
+		drm_connector_helper_hpd_irq_event(hdmi->curr_conn);
+	else
+		drm_bridge_hpd_notify(&hdmi->bridge, status);
+}
+EXPORT_SYMBOL_GPL(dw_hdmi_qp_hpd_notify);
+
 void dw_hdmi_qp_suspend(struct device *dev, struct dw_hdmi_qp *hdmi)
 {
 	disable_irq(hdmi->main_irq);
diff --git a/include/drm/bridge/dw_hdmi_qp.h b/include/drm/bridge/dw_hdmi_qp.h
index b80fceffc315..b4fb1c578a5b 100644
--- a/include/drm/bridge/dw_hdmi_qp.h
+++ b/include/drm/bridge/dw_hdmi_qp.h
@@ -36,6 +36,7 @@ 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_hpd_notify(struct dw_hdmi_qp *hdmi);
 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__ */

-- 
2.54.0