[PATCH v2 00/10] Add HPD support for Rockchip Analogix DP

[PATCH v2 00/10] Add HPD support for Rockchip Analogix DP

[Damon Ding]

This series improves the HPD (Hotplug Detect) interrupt handling in
the Analogix DP driver to enable reliable native HPD pin detection on
Rockchip platforms, and introduces platform-specific HPD detection
schemes with fine-grained interrupt control.

On Rockchip platforms, the Analogix DP native HPD pin IRQ requires the
DP controller to remain powered, clocked and initialized to generate
plug/unplug interrupts. The previous driver enabled/disabled IRQ during
bridge enable/disable, which left no HPD detection when the display
pipeline was inactive. Additionally, the interrupt mute/unmute/clear
routines operated on all HPD interrupt bits unconditionally, lacking
the granularity needed for per-event control.

The series reorganizes IRQ and pm_runtime management into bind/unbind,
adds IRQF_ONESHOT to eliminate read-modify-write races on interrupt
mask registers between hardirq and threaded handlers, converts the
interrupt type detection to a bitmask-based scheme for fine-grained
mute/unmute/clear operations, and configures Rockchip platforms to use
the HOTPLUG_CHG interrupt with a 2ms HPD deglitch setting for better
stability.

Patch  1: Move enable_irq()/disable_irq() to bind/unbind and hold a
          pm_runtime reference for Rockchip native HPD pin mode.
Patch  2: Convert analogix_dp_get_irq_type() to return a u32 bitmask
          instead of an enum, accumulating all pending interrupt flags.
Patch  3: Add IRQF_ONESHOT to prevent hardirq from preempting the
          threaded handler; remove redundant mute/unmute from runtime
          IRQ path; move status clearing before event handling.
Patch  4: Extend clear_hotplug_interrupts() to accept an irq_type
          bitmask for per-event pending interrupt clearing.
Patch  5: Extend mute/unmute helpers to accept an irq_type bitmask for
          init-time platform-specific interrupt mask configuration.
Patch  6: Simplify analogix_dp_config_interrupt() by removing redundant
          local macros and leveraging the unmute helper.
Patch  7: Configure Rockchip platforms to use HOTPLUG_CHG interrupt with
          2ms HPD deglitch; other platforms keep PLUG + HPD_LOST pair.
Patch  8: Skip native HPD interrupt register operations for GPIO HPD
          mode, where hotplug is detected through an external GPIO.
Patch  9: Restrict the forced connected-status shortcut to panel
          endpoints only, so DP connector bridges rely on HPD detection.
Patch 10: Handle HPD notification from downstream bridges (e.g.,
          display-connector with hpd-gpios) to short-circuit
          analogix_dp_detect_hpd() when connection is already confirmed.

Tested on RK3576 with both native HPD pin and GPIO HPD configurations.

Native HPD pin mode:

  &edp {
      status = "okay";
      pinctrl-names = "default";
      pinctrl-0 = <&edp_txm0_pins>;
  };

GPIO HPD mode:

  &edp {
      status = "okay";
      pinctrl-names = "default";
      pinctrl-0 = <&edp0_hpd>;
      hpd-gpios = <&gpio4 RK_PC1 GPIO_ACTIVE_HIGH>;
  };

  &pinctrl {
      edp {
          edp0_hpd: edp0-hpd {
              rockchip,pins = <4 RK_PC1 0 &pcfg_pull_none>;
          };
      };
  };

Display-connector mode (DP connector without HPD GPIO):

  &edp_out_conn {
      remote-endpoint = <&dp_con_in>;
  };

  dp-con {
      compatible = "dp-connector";
      label = "DP OUT";
      type = "full-size";

      port {
          dp_con_in: endpoint {
              remote-endpoint = <&edp_out_conn>;
          };
      };
  };

Display-connector mode (DP connector with HPD GPIO):

  dp-con {
      compatible = "dp-connector";
      label = "DP OUT";
      type = "full-size";
      pinctrl-0 = <&edp0_hpd>;
      pinctrl-names = "default";
      hpd-gpios = <&gpio4 RK_PC1 GPIO_ACTIVE_HIGH>;

      port {
          dp_con_in: endpoint {
              remote-endpoint = <&edp_out_conn>;
          };
      };
  };

All four configurations detect cable plug/unplug events correctly.

Damon Ding (10):
  drm/bridge: analogix_dp: Manage pm runtime and IRQ for native HPD pin
    detection
  drm/bridge: analogix_dp: Return bitmask from
    analogix_dp_get_irq_type()
  drm/bridge: analogix_dp: Add IRQF_ONESHOT and simplify IRQ handling
  drm/bridge: analogix_dp: Extend clear_hotplug_interrupts to accept IRQ
    bitmask
  drm/bridge: analogix_dp: Extend mute/unmute HPD interrupts to accept
    irq bitmask
  drm/bridge: analogix_dp: Simplify analogix_dp_config_interrupt()
  drm/bridge: analogix_dp: Use platform-specific HPD detection scheme
  drm/bridge: analogix_dp: Skip native HPD interrupt ops for GPIO HPD
  drm/bridge: analogix_dp: Restrict forced connected status only for
    panel endpoint
  drm/bridge: analogix_dp: Handle HPD notification from downstream
    bridge

 .../drm/bridge/analogix/analogix_dp_core.c    |  87 +++++++---
 .../drm/bridge/analogix/analogix_dp_core.h    |  12 +-
 .../gpu/drm/bridge/analogix/analogix_dp_reg.c | 152 ++++++++++++------
 3 files changed, 175 insertions(+), 76 deletions(-)

---

Changes in v2:
- Split IRQ enable/disable logic, handle native HPD pin and
  GPIO/force-HPD modes separately to avoid unbalanced enable_irq()
  calls.(Sashiko)
- Add separate patch for IRQF_ONESHOT to resolve interrupt mask issues
  triggered by interrupt preemption.(Sashiko)
- Update commit messages to align with newly added IRQF_ONESHOT related
  commit.
- Move ANALOGIX_DP_HPD_DEGLITCH_L/ANALOGIX_DP_HPD_DEGLITCH_H configs to
  analogix_dp_reset().
- Add new patch to restrict the forced connected-status shortcut to
  panel endpoints only, allowing DP connector bridges to rely on HPD
  detection. (Reported by Heiko Stuebner)
- Add new patch to handle HPD notification from downstream bridges
  (e.g., display-connector with hpd-gpios).

-- 
2.34.1

[PATCH v2 01/10] 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 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

[PATCH v2 02/10] drm/bridge: analogix_dp: Return bitmask from analogix_dp_get_irq_type()

[Damon Ding]

Analogix DP controllers support two sets of interrupts for hotplug
detection: HOTPLUG_CHG, and the pair PLUG / HPD_LOST. The current
driver logic relies on PLUG/HPD_LOST and does not consume HOTPLUG_CHG,
nor does it check for INT_HPD for IRQ_HPD events.

The existing analogix_dp_get_irq_type() returns on the first matched
interrupt flag. This causes the hardirq handler to unconditionally mute
all HPD interrupts, including HOTPLUG_CHG and INT_HPD, creating a
limitation for future extensions.

To prepare fine-grained interrupt handling, convert the return type
from enum dp_irq_type to a u32 bitmask. Accumulate all pending
interrupt flags instead of returning early, and add detection for
DP_IRQ_TYPE_IRQ_HPD. Remove DP_IRQ_TYPE_UNKNOWN sentinel; use zero
to indicate no pending interrupts, which simplifies code and
facilitates future extension for additional interrupt types.

This prepares subsequent changes to pass specific irq flags into
mute/unmute helpers for selective interrupt control.

Signed-off-by: Damon Ding <damon.ding@rock-chips.com>
---
 .../gpu/drm/bridge/analogix/analogix_dp_core.c |  8 ++++----
 .../gpu/drm/bridge/analogix/analogix_dp_core.h |  4 ++--
 .../gpu/drm/bridge/analogix/analogix_dp_reg.c  | 18 ++++++++++--------
 3 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 18f300b49644..7ef8ef812b55 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -704,10 +704,10 @@ static irqreturn_t analogix_dp_hardirq(int irq, void *arg)
 {
 	struct analogix_dp_device *dp = arg;
 	irqreturn_t ret = IRQ_NONE;
-	enum dp_irq_type irq_type;
+	u32 irq_type;
 
 	irq_type = analogix_dp_get_irq_type(dp);
-	if (irq_type != DP_IRQ_TYPE_UNKNOWN) {
+	if (irq_type) {
 		analogix_dp_mute_hpd_interrupt(dp);
 		ret = IRQ_WAKE_THREAD;
 	}
@@ -718,7 +718,7 @@ static irqreturn_t analogix_dp_hardirq(int irq, void *arg)
 static irqreturn_t analogix_dp_irq_thread(int irq, void *arg)
 {
 	struct analogix_dp_device *dp = arg;
-	enum dp_irq_type irq_type;
+	u32 irq_type;
 
 	irq_type = analogix_dp_get_irq_type(dp);
 	if (irq_type & DP_IRQ_TYPE_HP_CABLE_IN ||
@@ -728,7 +728,7 @@ static irqreturn_t analogix_dp_irq_thread(int irq, void *arg)
 			drm_helper_hpd_irq_event(dp->drm_dev);
 	}
 
-	if (irq_type != DP_IRQ_TYPE_UNKNOWN) {
+	if (irq_type) {
 		analogix_dp_clear_hotplug_interrupts(dp);
 		analogix_dp_unmute_hpd_interrupt(dp);
 	}
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
index c7997677a286..c2eba77f9a81 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
@@ -120,7 +120,7 @@ enum dp_irq_type {
 	DP_IRQ_TYPE_HP_CABLE_IN  = BIT(0),
 	DP_IRQ_TYPE_HP_CABLE_OUT = BIT(1),
 	DP_IRQ_TYPE_HP_CHANGE    = BIT(2),
-	DP_IRQ_TYPE_UNKNOWN      = BIT(3),
+	DP_IRQ_TYPE_IRQ_HPD      = BIT(3),
 };
 
 struct video_info {
@@ -193,7 +193,7 @@ void analogix_dp_set_analog_power_down(struct analogix_dp_device *dp,
 int analogix_dp_init_analog_func(struct analogix_dp_device *dp);
 void analogix_dp_init_hpd(struct analogix_dp_device *dp);
 void analogix_dp_force_hpd(struct analogix_dp_device *dp);
-enum dp_irq_type analogix_dp_get_irq_type(struct analogix_dp_device *dp);
+u32 analogix_dp_get_irq_type(struct analogix_dp_device *dp);
 void analogix_dp_clear_hotplug_interrupts(struct analogix_dp_device *dp);
 void analogix_dp_reset_aux(struct analogix_dp_device *dp);
 void analogix_dp_init_aux(struct analogix_dp_device *dp);
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index ea8401293a23..f4f859cb2936 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -413,8 +413,9 @@ void analogix_dp_force_hpd(struct analogix_dp_device *dp)
 	writel(reg, dp->reg_base + ANALOGIX_DP_SYS_CTL_3);
 }
 
-enum dp_irq_type analogix_dp_get_irq_type(struct analogix_dp_device *dp)
+u32 analogix_dp_get_irq_type(struct analogix_dp_device *dp)
 {
+	u32 irq_type = 0;
 	u32 reg;
 
 	if (dp->hpd_gpiod) {
@@ -426,17 +427,18 @@ enum dp_irq_type analogix_dp_get_irq_type(struct analogix_dp_device *dp)
 	} else {
 		/* Parse hotplug interrupt status register */
 		reg = readl(dp->reg_base + ANALOGIX_DP_COMMON_INT_STA_4);
-
 		if (reg & PLUG)
-			return DP_IRQ_TYPE_HP_CABLE_IN;
-
+			irq_type |= DP_IRQ_TYPE_HP_CABLE_IN;
 		if (reg & HPD_LOST)
-			return DP_IRQ_TYPE_HP_CABLE_OUT;
-
+			irq_type |= DP_IRQ_TYPE_HP_CABLE_OUT;
 		if (reg & HOTPLUG_CHG)
-			return DP_IRQ_TYPE_HP_CHANGE;
+			irq_type |= DP_IRQ_TYPE_HP_CHANGE;
+
+		reg = readl(dp->reg_base + ANALOGIX_DP_INT_STA);
+		if (reg & INT_HPD)
+			irq_type |= DP_IRQ_TYPE_IRQ_HPD;
 
-		return DP_IRQ_TYPE_UNKNOWN;
+		return irq_type;
 	}
 }
 
-- 
2.34.1

[PATCH v2 03/10] drm/bridge: analogix_dp: Add IRQF_ONESHOT and simplify IRQ handling

[Damon Ding]

The threaded IRQ is requested without IRQF_ONESHOT, allowing hardirq to
preempt the threaded handler. This creates a read-modify-write race on
HPD interrupt mask registers between the hardirq mute and thread unmute
operations.

Add IRQF_ONESHOT to keep the IRQ line masked during thread execution,
which eliminates the race and makes the per-event mute/unmute calls in
hardirq and thread handlers redundant. Move interrupt status clearing
to the beginning of the threaded handler, before
drm_helper_hpd_irq_event(), to avoid losing events that arrive during
the event handling.

Signed-off-by: Damon Ding <damon.ding@rock-chips.com>
---
 .../gpu/drm/bridge/analogix/analogix_dp_core.c  | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 7ef8ef812b55..4fe248e66515 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -707,10 +707,8 @@ static irqreturn_t analogix_dp_hardirq(int irq, void *arg)
 	u32 irq_type;
 
 	irq_type = analogix_dp_get_irq_type(dp);
-	if (irq_type) {
-		analogix_dp_mute_hpd_interrupt(dp);
+	if (irq_type)
 		ret = IRQ_WAKE_THREAD;
-	}
 
 	return ret;
 }
@@ -721,6 +719,9 @@ static irqreturn_t analogix_dp_irq_thread(int irq, void *arg)
 	u32 irq_type;
 
 	irq_type = analogix_dp_get_irq_type(dp);
+	if (irq_type)
+		analogix_dp_clear_hotplug_interrupts(dp);
+
 	if (irq_type & DP_IRQ_TYPE_HP_CABLE_IN ||
 	    irq_type & DP_IRQ_TYPE_HP_CABLE_OUT) {
 		dev_dbg(dp->dev, "Detected cable status changed!\n");
@@ -728,11 +729,6 @@ static irqreturn_t analogix_dp_irq_thread(int irq, void *arg)
 			drm_helper_hpd_irq_event(dp->drm_dev);
 	}
 
-	if (irq_type) {
-		analogix_dp_clear_hotplug_interrupts(dp);
-		analogix_dp_unmute_hpd_interrupt(dp);
-	}
-
 	return IRQ_HANDLED;
 }
 
@@ -1403,10 +1399,11 @@ analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data)
 		 * that we can get the current state of the GPIO.
 		 */
 		dp->irq = gpiod_to_irq(dp->hpd_gpiod);
-		irq_flags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_NO_AUTOEN;
+		irq_flags = IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_NO_AUTOEN |
+			    IRQF_ONESHOT;
 	} else {
 		dp->irq = platform_get_irq(pdev, 0);
-		irq_flags = IRQF_NO_AUTOEN;
+		irq_flags = IRQF_NO_AUTOEN | IRQF_ONESHOT;
 	}
 
 	if (dp->irq == -ENXIO) {
-- 
2.34.1

[PATCH v2 04/10] drm/bridge: analogix_dp: Extend clear_hotplug_interrupts to accept IRQ bitmask

[Damon Ding]

Update analogix_dp_clear_hotplug_interrupts() to take an irq_type
bitmask argument. Instead of clearing all hotplug interrupt bits
unconditionally, only clear the interrupt flags corresponding to the
triggered events.

Pass the detected IRQ bitmask from the irq thread handler, and use the
full HPD_IRQ mask during HPD initialization.

This implements fine-grained pending interrupt clearing logic and
removes limitations brought by unconditional register writes,
supporting improved accuracy for HPD event handling.

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

---

Changes in v2:
- Add separate patch for IRQF_ONESHOT to resolve interrupt mask issues
  triggered by interrupt preemption.(Sashiko)
---
 .../drm/bridge/analogix/analogix_dp_core.c    |  2 +-
 .../drm/bridge/analogix/analogix_dp_core.h    |  2 +-
 .../gpu/drm/bridge/analogix/analogix_dp_reg.c | 28 +++++++++++++------
 3 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 4fe248e66515..603abd940a7c 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -720,7 +720,7 @@ static irqreturn_t analogix_dp_irq_thread(int irq, void *arg)
 
 	irq_type = analogix_dp_get_irq_type(dp);
 	if (irq_type)
-		analogix_dp_clear_hotplug_interrupts(dp);
+		analogix_dp_clear_hotplug_interrupts(dp, irq_type);
 
 	if (irq_type & DP_IRQ_TYPE_HP_CABLE_IN ||
 	    irq_type & DP_IRQ_TYPE_HP_CABLE_OUT) {
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
index c2eba77f9a81..ecb86a6c1fc3 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
@@ -194,7 +194,7 @@ int analogix_dp_init_analog_func(struct analogix_dp_device *dp);
 void analogix_dp_init_hpd(struct analogix_dp_device *dp);
 void analogix_dp_force_hpd(struct analogix_dp_device *dp);
 u32 analogix_dp_get_irq_type(struct analogix_dp_device *dp);
-void analogix_dp_clear_hotplug_interrupts(struct analogix_dp_device *dp);
+void analogix_dp_clear_hotplug_interrupts(struct analogix_dp_device *dp, u32 irq_type);
 void analogix_dp_reset_aux(struct analogix_dp_device *dp);
 void analogix_dp_init_aux(struct analogix_dp_device *dp);
 int analogix_dp_get_plug_in_status(struct analogix_dp_device *dp);
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index f4f859cb2936..024f342da461 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -24,6 +24,11 @@
 #define COMMON_INT_MASK_4	(HOTPLUG_CHG | HPD_LOST | PLUG)
 #define INT_STA_MASK		INT_HPD
 
+#define HPD_IRQ			(DP_IRQ_TYPE_HP_CABLE_IN | DP_IRQ_TYPE_HP_CABLE_OUT | \
+				 DP_IRQ_TYPE_HP_CHANGE | DP_IRQ_TYPE_IRQ_HPD)
+#define COMMON_INT_4_HPD_IRQ	(DP_IRQ_TYPE_HP_CABLE_IN | DP_IRQ_TYPE_HP_CABLE_OUT | \
+				 DP_IRQ_TYPE_HP_CHANGE)
+
 void analogix_dp_enable_video_mute(struct analogix_dp_device *dp, bool enable)
 {
 	u32 reg;
@@ -376,18 +381,25 @@ int analogix_dp_init_analog_func(struct analogix_dp_device *dp)
 	return 0;
 }
 
-void analogix_dp_clear_hotplug_interrupts(struct analogix_dp_device *dp)
+void analogix_dp_clear_hotplug_interrupts(struct analogix_dp_device *dp, u32 irq_type)
 {
-	u32 reg;
+	u32 reg = 0;
 
-	if (dp->hpd_gpiod)
+	if (dp->hpd_gpiod || !irq_type)
 		return;
 
-	reg = HOTPLUG_CHG | HPD_LOST | PLUG;
-	writel(reg, dp->reg_base + ANALOGIX_DP_COMMON_INT_STA_4);
+	if (irq_type & COMMON_INT_4_HPD_IRQ) {
+		if (irq_type & DP_IRQ_TYPE_HP_CABLE_IN)
+			reg |= PLUG;
+		if (irq_type & DP_IRQ_TYPE_HP_CABLE_OUT)
+			reg |= HPD_LOST;
+		if (irq_type & DP_IRQ_TYPE_HP_CHANGE)
+			reg |= HOTPLUG_CHG;
+		writel(reg, dp->reg_base + ANALOGIX_DP_COMMON_INT_STA_4);
+	}
 
-	reg = INT_HPD;
-	writel(reg, dp->reg_base + ANALOGIX_DP_INT_STA);
+	if (irq_type & DP_IRQ_TYPE_IRQ_HPD)
+		writel(INT_HPD, dp->reg_base + ANALOGIX_DP_INT_STA);
 }
 
 void analogix_dp_init_hpd(struct analogix_dp_device *dp)
@@ -397,7 +409,7 @@ void analogix_dp_init_hpd(struct analogix_dp_device *dp)
 	if (dp->hpd_gpiod)
 		return;
 
-	analogix_dp_clear_hotplug_interrupts(dp);
+	analogix_dp_clear_hotplug_interrupts(dp, HPD_IRQ);
 
 	reg = readl(dp->reg_base + ANALOGIX_DP_SYS_CTL_3);
 	reg &= ~(F_HPD | HPD_CTRL);
-- 
2.34.1

[PATCH v2 05/10] drm/bridge: analogix_dp: Extend mute/unmute HPD interrupts to accept irq bitmask

[Damon Ding]

Update the HPD interrupt mute/unmute routines to accept an irq_type
bitmask parameter, allowing selective per-bit mask control instead of
operating on all HPD interrupt bits unconditionally.

With IRQF_ONESHOT handling IRQ line masking during threaded handler
execution, these helpers are no longer needed in the runtime IRQ path.
They are retained for init-time use by analogix_dp_config_interrupt()
to configure platform-specific HPD interrupt masks.

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

---

Changes in v2:
- Update commit messages to align with newly added IRQF_ONESHOT related
  commit.
---
 .../drm/bridge/analogix/analogix_dp_core.h    |  4 +-
 .../gpu/drm/bridge/analogix/analogix_dp_reg.c | 59 ++++++++++++++-----
 2 files changed, 46 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
index ecb86a6c1fc3..2066e575ce10 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
@@ -183,8 +183,8 @@ void analogix_dp_init_interrupt(struct analogix_dp_device *dp);
 void analogix_dp_reset(struct analogix_dp_device *dp);
 void analogix_dp_swreset(struct analogix_dp_device *dp);
 void analogix_dp_config_interrupt(struct analogix_dp_device *dp);
-void analogix_dp_mute_hpd_interrupt(struct analogix_dp_device *dp);
-void analogix_dp_unmute_hpd_interrupt(struct analogix_dp_device *dp);
+void analogix_dp_mute_hpd_interrupt(struct analogix_dp_device *dp, u32 irq_type);
+void analogix_dp_unmute_hpd_interrupt(struct analogix_dp_device *dp, u32 irq_type);
 int analogix_dp_wait_pll_locked(struct analogix_dp_device *dp);
 void analogix_dp_set_pll_power_down(struct analogix_dp_device *dp, bool enable);
 void analogix_dp_set_analog_power_down(struct analogix_dp_device *dp,
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index 024f342da461..816be79a8da6 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -197,30 +197,59 @@ void analogix_dp_config_interrupt(struct analogix_dp_device *dp)
 	writel(reg, dp->reg_base + ANALOGIX_DP_INT_STA_MASK);
 }
 
-void analogix_dp_mute_hpd_interrupt(struct analogix_dp_device *dp)
+void analogix_dp_mute_hpd_interrupt(struct analogix_dp_device *dp, u32 irq_type)
 {
-	u32 reg;
+	u32 reg, mask = 0;
 
-	/* 0: mask, 1: unmask */
-	reg = readl(dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_4);
-	reg &= ~COMMON_INT_MASK_4;
-	writel(reg, dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_4);
+	if (!irq_type)
+		return;
 
-	reg = readl(dp->reg_base + ANALOGIX_DP_INT_STA_MASK);
-	reg &= ~INT_STA_MASK;
-	writel(reg, dp->reg_base + ANALOGIX_DP_INT_STA_MASK);
+	if (irq_type & COMMON_INT_4_HPD_IRQ) {
+		/* 0: mask, 1: unmask */
+		reg = readl(dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_4);
+		if (irq_type & DP_IRQ_TYPE_HP_CABLE_IN)
+			mask |= PLUG;
+		if (irq_type & DP_IRQ_TYPE_HP_CABLE_OUT)
+			mask |= HPD_LOST;
+		if (irq_type & DP_IRQ_TYPE_HP_CHANGE)
+			mask |= HOTPLUG_CHG;
+		reg &= ~mask;
+		writel(reg, dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_4);
+	}
+
+	if (irq_type & DP_IRQ_TYPE_IRQ_HPD) {
+		/* 0: mask, 1: unmask */
+		reg = readl(dp->reg_base + ANALOGIX_DP_INT_STA_MASK);
+		reg &= ~INT_HPD;
+		writel(reg, dp->reg_base + ANALOGIX_DP_INT_STA_MASK);
+	}
 }
 
-void analogix_dp_unmute_hpd_interrupt(struct analogix_dp_device *dp)
+void analogix_dp_unmute_hpd_interrupt(struct analogix_dp_device *dp, u32 irq_type)
 {
 	u32 reg;
 
-	/* 0: mask, 1: unmask */
-	reg = COMMON_INT_MASK_4;
-	writel(reg, dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_4);
+	if (!irq_type)
+		return;
 
-	reg = INT_STA_MASK;
-	writel(reg, dp->reg_base + ANALOGIX_DP_INT_STA_MASK);
+	if (irq_type & COMMON_INT_4_HPD_IRQ) {
+		/* 0: mask, 1: unmask */
+		reg = readl(dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_4);
+		if (irq_type & DP_IRQ_TYPE_HP_CABLE_IN)
+			reg |= PLUG;
+		if (irq_type & DP_IRQ_TYPE_HP_CABLE_OUT)
+			reg |= HPD_LOST;
+		if (irq_type & DP_IRQ_TYPE_HP_CHANGE)
+			reg |= HOTPLUG_CHG;
+		writel(reg, dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_4);
+	}
+
+	if (irq_type & DP_IRQ_TYPE_IRQ_HPD) {
+		/* 0: mask, 1: unmask */
+		reg = readl(dp->reg_base + ANALOGIX_DP_INT_STA_MASK);
+		reg |= INT_HPD;
+		writel(reg, dp->reg_base + ANALOGIX_DP_INT_STA_MASK);
+	}
 }
 
 int analogix_dp_wait_pll_locked(struct analogix_dp_device *dp)
-- 
2.34.1

[PATCH v2 06/10] drm/bridge: analogix_dp: Simplify analogix_dp_config_interrupt()

[Damon Ding]

Remove local COMMON_INT_MASK and INT_STA_MASK macros. These constants
are only used once inside this function and bring no reuse benefit.

Replace open-coded register writes for COMMON_INT_MASK_1~3 with
direct writel(0) calls.

Leverage analogix_dp_unmute_hpd_interrupt() using the full HPD_IRQ
mask to initialize HPD interrupt state, removing duplicated register
handling.

Signed-off-by: Damon Ding <damon.ding@rock-chips.com>
---
 .../gpu/drm/bridge/analogix/analogix_dp_reg.c | 25 +++----------------
 1 file changed, 4 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index 816be79a8da6..42463e18f392 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -18,12 +18,6 @@
 #include "analogix_dp_core.h"
 #include "analogix_dp_reg.h"
 
-#define COMMON_INT_MASK_1	0
-#define COMMON_INT_MASK_2	0
-#define COMMON_INT_MASK_3	0
-#define COMMON_INT_MASK_4	(HOTPLUG_CHG | HPD_LOST | PLUG)
-#define INT_STA_MASK		INT_HPD
-
 #define HPD_IRQ			(DP_IRQ_TYPE_HP_CABLE_IN | DP_IRQ_TYPE_HP_CABLE_OUT | \
 				 DP_IRQ_TYPE_HP_CHANGE | DP_IRQ_TYPE_IRQ_HPD)
 #define COMMON_INT_4_HPD_IRQ	(DP_IRQ_TYPE_HP_CABLE_IN | DP_IRQ_TYPE_HP_CABLE_OUT | \
@@ -178,23 +172,12 @@ void analogix_dp_swreset(struct analogix_dp_device *dp)
 
 void analogix_dp_config_interrupt(struct analogix_dp_device *dp)
 {
-	u32 reg;
-
 	/* 0: mask, 1: unmask */
-	reg = COMMON_INT_MASK_1;
-	writel(reg, dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_1);
-
-	reg = COMMON_INT_MASK_2;
-	writel(reg, dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_2);
-
-	reg = COMMON_INT_MASK_3;
-	writel(reg, dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_3);
-
-	reg = COMMON_INT_MASK_4;
-	writel(reg, dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_4);
+	writel(0, dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_1);
+	writel(0, dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_2);
+	writel(0, dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_3);
 
-	reg = INT_STA_MASK;
-	writel(reg, dp->reg_base + ANALOGIX_DP_INT_STA_MASK);
+	analogix_dp_unmute_hpd_interrupt(dp, HPD_IRQ);
 }
 
 void analogix_dp_mute_hpd_interrupt(struct analogix_dp_device *dp, u32 irq_type)
-- 
2.34.1

[PATCH v2 07/10] drm/bridge: analogix_dp: Use platform-specific HPD detection scheme

[Damon Ding]

Hotplug detection can be implemented either via HOTPLUG_CHG interrupt,
or the combination of PLUG and HPD_LOST interrupts.

For Rockchip platforms, configure HPD deglitch to 2ms and rely on
HOTPLUG_CHG interrupt for hotplug events, which is verified as the
optimal solution through engineering tests. Other platforms continue
using PLUG + HPD_LOST pair.

Adjust analogix_dp_config_interrupt() to apply platform-specific
interrupt masking and deglitch settings. Update threaded irq handler
to check corresponding interrupt flags according to platform type.

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

---

Changes in v2:
- Move ANALOGIX_DP_HPD_DEGLITCH_L/ANALOGIX_DP_HPD_DEGLITCH_H configs to
  analogix_dp_reset().
---
 .../drm/bridge/analogix/analogix_dp_core.c    |  9 ++++++--
 .../gpu/drm/bridge/analogix/analogix_dp_reg.c | 22 ++++++++++++++++---
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 603abd940a7c..d207cc864bdc 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -717,13 +717,18 @@ static irqreturn_t analogix_dp_irq_thread(int irq, void *arg)
 {
 	struct analogix_dp_device *dp = arg;
 	u32 irq_type;
+	bool hpd_detected;
 
 	irq_type = analogix_dp_get_irq_type(dp);
 	if (irq_type)
 		analogix_dp_clear_hotplug_interrupts(dp, irq_type);
 
-	if (irq_type & DP_IRQ_TYPE_HP_CABLE_IN ||
-	    irq_type & DP_IRQ_TYPE_HP_CABLE_OUT) {
+	if (!dp->hpd_gpiod && analogix_dp_is_rockchip(dp->plat_data->dev_type))
+		hpd_detected = irq_type & DP_IRQ_TYPE_HP_CHANGE;
+	else
+		hpd_detected = (irq_type & DP_IRQ_TYPE_HP_CABLE_IN) ||
+			       (irq_type & DP_IRQ_TYPE_HP_CABLE_OUT);
+	if (hpd_detected) {
 		dev_dbg(dp->dev, "Detected cable status changed!\n");
 		if (dp->drm_dev)
 			drm_helper_hpd_irq_event(dp->drm_dev);
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index 42463e18f392..fa8e2f104d6c 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -149,8 +149,13 @@ void analogix_dp_reset(struct analogix_dp_device *dp)
 	writel(0x0, dp->reg_base + ANALOGIX_DP_PKT_SEND_CTL);
 	writel(0x0, dp->reg_base + ANALOGIX_DP_HDCP_CTL);
 
-	writel(0x5e, dp->reg_base + ANALOGIX_DP_HPD_DEGLITCH_L);
-	writel(0x1a, dp->reg_base + ANALOGIX_DP_HPD_DEGLITCH_H);
+	if (analogix_dp_is_rockchip(dp->plat_data->dev_type)) {
+		writel(0x80, dp->reg_base + ANALOGIX_DP_HPD_DEGLITCH_L);
+		writel(0xbb, dp->reg_base + ANALOGIX_DP_HPD_DEGLITCH_H);
+	} else {
+		writel(0x5e, dp->reg_base + ANALOGIX_DP_HPD_DEGLITCH_L);
+		writel(0x1a, dp->reg_base + ANALOGIX_DP_HPD_DEGLITCH_H);
+	}
 
 	writel(0x10, dp->reg_base + ANALOGIX_DP_LINK_DEBUG_CTL);
 
@@ -177,7 +182,18 @@ void analogix_dp_config_interrupt(struct analogix_dp_device *dp)
 	writel(0, dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_2);
 	writel(0, dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_3);
 
-	analogix_dp_unmute_hpd_interrupt(dp, HPD_IRQ);
+	/*
+	 * Either HOTPLUG_CHG interrupt or PLUG + HPD_LOST interrupt
+	 * pair can be used to implement hotplug detection.
+	 *
+	 * On Rockchip platforms, configuring HPD deglitch to 2ms and
+	 * using HOTPLUG_CHG interrupt for hotplug detection is proven
+	 * as a better solution via engineering verification.
+	 */
+	if (analogix_dp_is_rockchip(dp->plat_data->dev_type))
+		analogix_dp_unmute_hpd_interrupt(dp, DP_IRQ_TYPE_HP_CHANGE);
+	else
+		analogix_dp_unmute_hpd_interrupt(dp, HPD_IRQ);
 }
 
 void analogix_dp_mute_hpd_interrupt(struct analogix_dp_device *dp, u32 irq_type)
-- 
2.34.1

[PATCH v2 08/10] drm/bridge: analogix_dp: Skip native HPD interrupt ops for GPIO HPD

[Damon Ding]

GPIO HPD does not rely on DP controller internal native HPD interrupts.
Skip native HPD register manipulations to avoid irrelevant operations.

In analogix_dp_config_interrupt(), mute all native HPD interrupts when
dp->hpd_gpiod is set. Move the dp->hpd_gpiod guard from inside
analogix_dp_clear_hotplug_interrupts() to its caller in the threaded
IRQ handler, so that the function operates purely on the given irq_type
bitmask without implicit mode-dependent behavior. This makes it
reusable for future callers that may need to clear specific interrupt
status bits regardless of the HPD detection mode.

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

---

Changes in v2:
- Adapt to the newly added IRQF_ONESHOT related commit and expand the
  commit msg.
---
 .../drm/bridge/analogix/analogix_dp_core.c    |  2 +-
 .../gpu/drm/bridge/analogix/analogix_dp_reg.c | 30 +++++++++++--------
 2 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index d207cc864bdc..f05db455b430 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -720,7 +720,7 @@ static irqreturn_t analogix_dp_irq_thread(int irq, void *arg)
 	bool hpd_detected;
 
 	irq_type = analogix_dp_get_irq_type(dp);
-	if (irq_type)
+	if (!dp->hpd_gpiod && irq_type)
 		analogix_dp_clear_hotplug_interrupts(dp, irq_type);
 
 	if (!dp->hpd_gpiod && analogix_dp_is_rockchip(dp->plat_data->dev_type))
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index fa8e2f104d6c..4b210e685747 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -182,18 +182,22 @@ void analogix_dp_config_interrupt(struct analogix_dp_device *dp)
 	writel(0, dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_2);
 	writel(0, dp->reg_base + ANALOGIX_DP_COMMON_INT_MASK_3);
 
-	/*
-	 * Either HOTPLUG_CHG interrupt or PLUG + HPD_LOST interrupt
-	 * pair can be used to implement hotplug detection.
-	 *
-	 * On Rockchip platforms, configuring HPD deglitch to 2ms and
-	 * using HOTPLUG_CHG interrupt for hotplug detection is proven
-	 * as a better solution via engineering verification.
-	 */
-	if (analogix_dp_is_rockchip(dp->plat_data->dev_type))
-		analogix_dp_unmute_hpd_interrupt(dp, DP_IRQ_TYPE_HP_CHANGE);
-	else
-		analogix_dp_unmute_hpd_interrupt(dp, HPD_IRQ);
+	if (dp->hpd_gpiod) {
+		analogix_dp_mute_hpd_interrupt(dp, HPD_IRQ);
+	} else {
+		/*
+		 * Either HOTPLUG_CHG interrupt or PLUG + HPD_LOST interrupt
+		 * pair can be used to implement hotplug detection.
+		 *
+		 * On Rockchip platforms, configuring HPD deglitch to 2ms and
+		 * using HOTPLUG_CHG interrupt for hotplug detection is proven
+		 * as a better solution via engineering verification.
+		 */
+		if (analogix_dp_is_rockchip(dp->plat_data->dev_type))
+			analogix_dp_unmute_hpd_interrupt(dp, DP_IRQ_TYPE_HP_CHANGE);
+		else
+			analogix_dp_unmute_hpd_interrupt(dp, HPD_IRQ);
+	}
 }
 
 void analogix_dp_mute_hpd_interrupt(struct analogix_dp_device *dp, u32 irq_type)
@@ -413,7 +417,7 @@ void analogix_dp_clear_hotplug_interrupts(struct analogix_dp_device *dp, u32 irq
 {
 	u32 reg = 0;
 
-	if (dp->hpd_gpiod || !irq_type)
+	if (!irq_type)
 		return;
 
 	if (irq_type & COMMON_INT_4_HPD_IRQ) {
-- 
2.34.1

[PATCH v2 09/10] drm/bridge: analogix_dp: Restrict forced connected status only for panel endpoint

[Damon Ding]

Limit the shortcut which unconditionally returns connected status when
a next bridge exists. Only apply this logic if the last bridge in the
chain is a panel. For all other cases, rely on analogix_dp_detect_hpd()
to report accurate hotplug state.

Background for the special handling:
- If the chain ends with a DP connector bridge, the connector relies
on analogix_dp to perform detection. We must avoid hardcoding connected
status here.
- For intermediate bridges such as PS8625 / PTN3460 without detect
support [1], historically the bridge connector defaults to connected
via drm_helper_probe_detect() when no per-bridge detect callback
exists. Maintain compatibility by keeping the shortcut exclusively for
panel endpoints.

[1] https://lore.kernel.org/all/4939d55e-b560-4235-8295-adf8e48d9b74@samsung.com/

Reported-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/all/5209243.oAaWjsssbx@diego/
Signed-off-by: Damon Ding <damon.ding@rock-chips.com>
---
 .../gpu/drm/bridge/analogix/analogix_dp_core.c   | 16 ++++++++++++++--
 .../gpu/drm/bridge/analogix/analogix_dp_core.h   |  1 +
 2 files changed, 15 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 f05db455b430..a5a50b9ab8a7 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -906,8 +906,15 @@ analogix_dp_bridge_detect(struct drm_bridge *bridge, struct drm_connector *conne
 	struct analogix_dp_device *dp = to_dp(bridge);
 	enum drm_connector_status status = connector_status_disconnected;
 
-	if (dp->plat_data->next_bridge)
-		return connector_status_connected;
+	/*
+	 * Only assume connected when the bridge chain ends with a panel.
+	 * Panel bridges lack a detect callback and historically rely on
+	 * this shortcut. For other next bridge types (e.g., DP connector
+	 * bridges), fall through to analogix_dp_detect_hpd() to report
+	 * accurate hotplug state.
+	 */
+	if (dp->plat_data->next_bridge && dp->last_bridge_is_panel)
+		status = connector_status_connected;
 
 	if (!analogix_dp_detect_hpd(dp))
 		status = connector_status_connected;
@@ -920,6 +927,7 @@ static int analogix_dp_bridge_attach(struct drm_bridge *bridge,
 				     enum drm_bridge_attach_flags flags)
 {
 	struct analogix_dp_device *dp = to_dp(bridge);
+	struct drm_bridge *last_bridge;
 	int ret = 0;
 
 	if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)) {
@@ -934,6 +942,10 @@ static int analogix_dp_bridge_attach(struct drm_bridge *bridge,
 			dev_err(dp->dev, "failed to attach following panel or bridge (%d)\n", ret);
 			return ret;
 		}
+
+		last_bridge = drm_bridge_chain_get_last_bridge(dp->encoder);
+		if (drm_bridge_is_panel(last_bridge))
+			dp->last_bridge_is_panel = true;
 	}
 
 	return 0;
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
index 2066e575ce10..bcb5674801a2 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
@@ -168,6 +168,7 @@ struct analogix_dp_device {
 	bool			force_hpd;
 	bool			fast_train_enable;
 	bool			psr_supported;
+	bool			last_bridge_is_panel;
 
 	u8 dpcd[DP_RECEIVER_CAP_SIZE];
 
-- 
2.34.1

[PATCH v2 10/10] drm/bridge: analogix_dp: Handle HPD notification from downstream bridge

[Damon Ding]

When the display pipeline includes a display-connector bridge with
hpd-gpios configured, the connector's hotplug status is managed by the
display-connector bridge through its GPIO, not by the Analogix DP
controller's native HPD. In this configuration, the DP controller's
internal HPD polling in analogix_dp_detect_hpd() does not reflect the
actual connection state.

Implement the .hpd_notify bridge callback to receive connection status
updates from downstream bridges. Cache the connection status in a
connection_notified flag, and use it to short-circuit
analogix_dp_detect_hpd() when a downstream bridge has already confirmed
the connection.

Signed-off-by: Damon Ding <damon.ding@rock-chips.com>
---
 .../gpu/drm/bridge/analogix/analogix_dp_core.c   | 16 ++++++++++++++++
 .../gpu/drm/bridge/analogix/analogix_dp_core.h   |  1 +
 2 files changed, 17 insertions(+)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index a5a50b9ab8a7..f0476a60ece3 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -68,6 +68,13 @@ static int analogix_dp_detect_hpd(struct analogix_dp_device *dp)
 {
 	int timeout_loop = 0;
 
+	/*
+	 * Trust connection status from downstream bridge (e.g.,
+	 * display-connector with hpd-gpios).
+	 */
+	if (dp->plat_data->next_bridge && dp->connection_notified)
+		return 0;
+
 	while (timeout_loop < DP_TIMEOUT_LOOP_COUNT) {
 		if (analogix_dp_get_plug_in_status(dp) == 0)
 			return 0;
@@ -1247,6 +1254,14 @@ static void analogix_dp_bridge_atomic_post_disable(struct drm_bridge *bridge,
 		DRM_ERROR("Failed to enable psr (%d)\n", ret);
 }
 
+static void analogix_dp_bridge_notify(struct drm_bridge *bridge, struct drm_connector *connector,
+				      enum drm_connector_status status)
+{
+	struct analogix_dp_device *dp = to_dp(bridge);
+
+	dp->connection_notified = (status == connector_status_connected);
+}
+
 static const struct drm_bridge_funcs analogix_dp_bridge_funcs = {
 	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
@@ -1259,6 +1274,7 @@ static const struct drm_bridge_funcs analogix_dp_bridge_funcs = {
 	.attach = analogix_dp_bridge_attach,
 	.edid_read = analogix_dp_bridge_edid_read,
 	.detect = analogix_dp_bridge_detect,
+	.hpd_notify = analogix_dp_bridge_notify,
 };
 
 static int analogix_dp_dt_parse_pdata(struct analogix_dp_device *dp)
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
index bcb5674801a2..cd8a5d52f973 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
@@ -169,6 +169,7 @@ struct analogix_dp_device {
 	bool			fast_train_enable;
 	bool			psr_supported;
 	bool			last_bridge_is_panel;
+	bool			connection_notified;
 
 	u8 dpcd[DP_RECEIVER_CAP_SIZE];
 
-- 
2.34.1