[PATCH v1 1/7] drm/bridge: analogix_dp: Manage pm runtime and IRQ for native HPD pin detection

[Damon Ding]

On Rockchip platforms, the Analogix DP native HPD pin IRQ functionality
requires the DP controller to be powered, clocked and initialized to
generate plug/unplug interrupts correctly.

To keep HPD detection active, move enable_irq()/disable_irq() from
bridge enabling/disabling handlers into analogix_dp_bind() and
analogix_dp_unbind(). Call pm_runtime_resume_and_get() before enabling
IRQ and pm_runtime_put_sync() after disabling IRQ for symmetric power
management.

Persistent power is only necessary for native HPD pin mode. It is not
required for force-HPD or GPIO HPD modes. Add helper to handle this
special case exclusively for Rockchip native HPD pin configurations.

Signed-off-by: Damon Ding <damon.ding at rock-chips.com>
---
 .../drm/bridge/analogix/analogix_dp_core.c    | 22 ++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 8d3d4a6e6ca2..d414f4ff40c8 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -40,6 +40,12 @@
 
 static const bool verify_fast_training;
 
+static bool analogix_dp_require_pm_for_hpd_irq(struct analogix_dp_device *dp)
+{
+	return analogix_dp_is_rockchip(dp->plat_data->dev_type) && !dp->hpd_gpiod &&
+	       !dp->force_hpd;
+}
+
 static void analogix_dp_init_dp(struct analogix_dp_device *dp)
 {
 	analogix_dp_reset(dp);
@@ -1014,7 +1020,6 @@ static int analogix_dp_set_bridge(struct analogix_dp_device *dp)
 		goto out_dp_init;
 	}
 
-	enable_irq(dp->irq);
 	return 0;
 
 out_dp_init:
@@ -1156,8 +1161,6 @@ static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
 	if (dp->dpms_mode != DRM_MODE_DPMS_ON)
 		return;
 
-	disable_irq(dp->irq);
-
 	analogix_dp_set_analog_power_down(dp, POWER_ALL, 1);
 
 	pm_runtime_put_sync(dp->dev);
@@ -1504,6 +1507,14 @@ int analogix_dp_bind(struct analogix_dp_device *dp, struct drm_device *drm_dev)
 		goto err_unregister_aux;
 	}
 
+	if (analogix_dp_require_pm_for_hpd_irq(dp)) {
+		ret = pm_runtime_resume_and_get(dp->dev);
+		if (ret)
+			goto err_unregister_aux;
+	}
+
+	enable_irq(dp->irq);
+
 	return 0;
 
 err_unregister_aux:
@@ -1515,6 +1526,11 @@ EXPORT_SYMBOL_GPL(analogix_dp_bind);
 
 void analogix_dp_unbind(struct analogix_dp_device *dp)
 {
+	disable_irq(dp->irq);
+
+	if (analogix_dp_require_pm_for_hpd_irq(dp))
+		pm_runtime_put_sync(dp->dev);
+
 	drm_dp_aux_unregister(&dp->aux);
 }
 EXPORT_SYMBOL_GPL(analogix_dp_unbind);
-- 
2.34.1