[PATCH v2 01/10] drm/bridge: analogix_dp: Manage pm runtime and IRQ for native HPD pin detection

[Damon Ding <damon.ding@rock-chips.com>]

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 while the display is disabled, move
enable_irq()/disable_irq() out of bridge enable/disable handlers and
split IRQ management paths:
- Native HPD pin mode: enable IRQ in analogix_dp_bind() and disable
  in analogix_dp_unbind(). Hold runtime PM power to keep controller
  alive for hotplug interrupts.
- GPIO HPD and force-HPD modes: retain original logic, manage IRQ
  within bridge enable/disable callbacks.

Persistent power hold is only necessary for native HPD pin mode.
It is not required for force-HPD or GPIO HPD modes. Add helper
analogix_dp_require_pm_for_hpd_irq() to identify Rockchip native HPD
pin configurations and switch IRQ handling accordingly.

Signed-off-by: Damon Ding <damon.ding@rock-chips.com>

---

Change in v2:
- Split IRQ enable/disable logic, handle native HPD pin and
  GPIO/force-HPD modes separately to avoid unbalanced enable_irq()
  calls.(Sashiko)
---
 .../drm/bridge/analogix/analogix_dp_core.c    | 25 +++++++++++++++++--
 1 file changed, 23 insertions(+), 2 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..18f300b49644 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 +1020,8 @@ static int analogix_dp_set_bridge(struct analogix_dp_device *dp)
 		goto out_dp_init;
 	}
 
-	enable_irq(dp->irq);
+	if (!analogix_dp_require_pm_for_hpd_irq(dp))
+		enable_irq(dp->irq);
 	return 0;
 
 out_dp_init:
@@ -1156,7 +1163,8 @@ static void analogix_dp_bridge_disable(struct drm_bridge *bridge)
 	if (dp->dpms_mode != DRM_MODE_DPMS_ON)
 		return;
 
-	disable_irq(dp->irq);
+	if (!analogix_dp_require_pm_for_hpd_irq(dp))
+		disable_irq(dp->irq);
 
 	analogix_dp_set_analog_power_down(dp, POWER_ALL, 1);
 
@@ -1504,6 +1512,14 @@ 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 +1531,11 @@ EXPORT_SYMBOL_GPL(analogix_dp_bind);
 
 void analogix_dp_unbind(struct analogix_dp_device *dp)
 {
+	if (analogix_dp_require_pm_for_hpd_irq(dp)) {
+		disable_irq(dp->irq);
+		pm_runtime_put_sync(dp->dev);
+	}
+
 	drm_dp_aux_unregister(&dp->aux);
 }
 EXPORT_SYMBOL_GPL(analogix_dp_unbind);
-- 
2.34.1