[PATCH v3 12/13] drm/msm/hdmi: ensure that HDMI is up if HPD is requested

[Dmitry Baryshkov]

The HDMI block needs to be enabled to properly generate HPD events. Make
sure it is not turned off in the disable paths if HPD delivery is enabled.

Reviewed-by: Jessica Zhang <quic_jesszhan at quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
---
 drivers/gpu/drm/msm/hdmi/hdmi.c        | 1 +
 drivers/gpu/drm/msm/hdmi/hdmi.h        | 2 ++
 drivers/gpu/drm/msm/hdmi/hdmi_bridge.c | 8 +++++++-
 drivers/gpu/drm/msm/hdmi/hdmi_hpd.c    | 9 ++++++++-
 4 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/hdmi/hdmi.c b/drivers/gpu/drm/msm/hdmi/hdmi.c
index 97faa7d26cc9..9f1de4c9ffdf 100644
--- a/drivers/gpu/drm/msm/hdmi/hdmi.c
+++ b/drivers/gpu/drm/msm/hdmi/hdmi.c
@@ -384,6 +384,7 @@ static int msm_hdmi_dev_probe(struct platform_device *pdev)
 	hdmi->pdev = pdev;
 	hdmi->config = config;
 	spin_lock_init(&hdmi->reg_lock);
+	mutex_init(&hdmi->state_mutex);
 
 	ret = drm_of_find_panel_or_bridge(pdev->dev.of_node, 1, 0, NULL, &hdmi->next_bridge);
 	if (ret && ret != -ENODEV)
diff --git a/drivers/gpu/drm/msm/hdmi/hdmi.h b/drivers/gpu/drm/msm/hdmi/hdmi.h
index 6faf4397ed58..9961dae9e9b3 100644
--- a/drivers/gpu/drm/msm/hdmi/hdmi.h
+++ b/drivers/gpu/drm/msm/hdmi/hdmi.h
@@ -42,6 +42,8 @@ struct hdmi {
 
 	/* video state: */
 	bool power_on;
+	bool hpd_enabled;
+	struct mutex state_mutex; /* protects two booleans */
 	unsigned long int pixclock;
 
 	void __iomem *mmio;
diff --git a/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c b/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
index c15c49c08d30..7bf1c3b379c1 100644
--- a/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
+++ b/drivers/gpu/drm/msm/hdmi/hdmi_bridge.c
@@ -308,11 +308,13 @@ static void msm_hdmi_bridge_atomic_pre_enable(struct drm_bridge *bridge,
 
 	hdmi->pixclock = conn_state->hdmi.tmds_char_rate;
 
+	mutex_lock(&hdmi->state_mutex);
 	if (!hdmi->power_on) {
 		msm_hdmi_phy_resource_enable(phy);
 		msm_hdmi_power_on(bridge);
 		hdmi->power_on = true;
 	}
+	mutex_unlock(&hdmi->state_mutex);
 
 	drm_atomic_helper_connector_hdmi_update_infoframes(connector, state);
 
@@ -337,7 +339,10 @@ static void msm_hdmi_bridge_atomic_post_disable(struct drm_bridge *bridge,
 		msm_hdmi_hdcp_off(hdmi->hdcp_ctrl);
 
 	DBG("power down");
-	msm_hdmi_set_mode(hdmi, false);
+
+	/* Keep the HDMI enabled if the HPD is enabled */
+	mutex_lock(&hdmi->state_mutex);
+	msm_hdmi_set_mode(hdmi, hdmi->hpd_enabled);
 
 	msm_hdmi_phy_powerdown(phy);
 
@@ -346,6 +351,7 @@ static void msm_hdmi_bridge_atomic_post_disable(struct drm_bridge *bridge,
 		hdmi->power_on = false;
 		msm_hdmi_phy_resource_disable(phy);
 	}
+	mutex_unlock(&hdmi->state_mutex);
 }
 
 static void msm_hdmi_bridge_atomic_set_timings(struct hdmi *hdmi,
diff --git a/drivers/gpu/drm/msm/hdmi/hdmi_hpd.c b/drivers/gpu/drm/msm/hdmi/hdmi_hpd.c
index d3353c6148ed..cb89e9e2c6ea 100644
--- a/drivers/gpu/drm/msm/hdmi/hdmi_hpd.c
+++ b/drivers/gpu/drm/msm/hdmi/hdmi_hpd.c
@@ -73,10 +73,14 @@ int msm_hdmi_hpd_enable(struct drm_bridge *bridge)
 	if (ret)
 		return ret;
 
+	mutex_lock(&hdmi->state_mutex);
 	msm_hdmi_set_mode(hdmi, false);
 	msm_hdmi_phy_reset(hdmi);
 	msm_hdmi_set_mode(hdmi, true);
 
+	hdmi->hpd_enabled = true;
+	mutex_unlock(&hdmi->state_mutex);
+
 	hdmi_write(hdmi, REG_HDMI_USEC_REFTIMER, 0x0001001b);
 
 	/* enable HPD events: */
@@ -106,7 +110,10 @@ void msm_hdmi_hpd_disable(struct hdmi *hdmi)
 	/* Disable HPD interrupt */
 	hdmi_write(hdmi, REG_HDMI_HPD_INT_CTRL, 0);
 
-	msm_hdmi_set_mode(hdmi, false);
+	mutex_lock(&hdmi->state_mutex);
+	hdmi->hpd_enabled = false;
+	msm_hdmi_set_mode(hdmi, hdmi->power_on);
+	mutex_unlock(&hdmi->state_mutex);
 
 	pm_runtime_put(dev);
 }

-- 
2.39.2