[PATCH v1 2/7] 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 at 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 d414f4ff40c8..c04af9fd4092 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