[PATCH v5 1/2] PM: sleep: wakeirq: Add support for custom IRQ flags in dedicated wake IRQ setup

[Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>]

Some devices require more flexibility when configuring their dedicated
wake-up interrupts, such as support for IRQF_SHARED or other IRQ flags.
This is particularly useful in PCIe systems where multiple endpoints
(e.g., Wi-Fi and Bluetooth controllers) share a common WAKE# signal
line which requests platform to re-establish power and reference clocks
to the components. In such cases, drivers can use this API with IRQF_SHARED
to register a shared wake IRQ handler.

Update the internal helper __dev_pm_set_dedicated_wake_irq() to accept an
irq_flags argument. Modify the existing dev_pm_set_dedicated_wake_irq()
and dev_pm_set_dedicated_wake_irq_reverse() to preserve current behavior
by passing default flags (IRQF_ONESHOT | IRQF_NO_AUTOEN).

Introduce a new API, dev_pm_set_dedicated_wake_irq_flags(), to allow
callers to specify custom IRQ flags. If IRQF_SHARED is used, remove
IRQF_NO_AUTOEN and disable the IRQ after setup to prevent spurious wakeups.

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
---
 drivers/base/power/wakeirq.c | 43 ++++++++++++++++++++++++++++++++++++++-----
 include/linux/pm_wakeirq.h   |  6 ++++++
 2 files changed, 44 insertions(+), 5 deletions(-)

diff --git a/drivers/base/power/wakeirq.c b/drivers/base/power/wakeirq.c
index 8aa28c08b2891f3af490175362cc1a759069bd50..655c28d5fc6850f50fc2ed74c5fbc066a21ae7b3 100644
--- a/drivers/base/power/wakeirq.c
+++ b/drivers/base/power/wakeirq.c
@@ -168,7 +168,8 @@ static irqreturn_t handle_threaded_wake_irq(int irq, void *_wirq)
 	return IRQ_HANDLED;
 }
 
-static int __dev_pm_set_dedicated_wake_irq(struct device *dev, int irq, unsigned int flag)
+static int __dev_pm_set_dedicated_wake_irq(struct device *dev, int irq, unsigned int flag,
+					   unsigned int irq_flags)
 {
 	struct wake_irq *wirq;
 	int err;
@@ -197,8 +198,7 @@ static int __dev_pm_set_dedicated_wake_irq(struct device *dev, int irq, unsigned
 	 * so we use a threaded irq.
 	 */
 	err = request_threaded_irq(irq, NULL, handle_threaded_wake_irq,
-				   IRQF_ONESHOT | IRQF_NO_AUTOEN,
-				   wirq->name, wirq);
+				   irq_flags, wirq->name, wirq);
 	if (err)
 		goto err_free_name;
 
@@ -234,7 +234,7 @@ static int __dev_pm_set_dedicated_wake_irq(struct device *dev, int irq, unsigned
  */
 int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq)
 {
-	return __dev_pm_set_dedicated_wake_irq(dev, irq, 0);
+	return __dev_pm_set_dedicated_wake_irq(dev, irq, 0, IRQF_ONESHOT | IRQF_NO_AUTOEN);
 }
 EXPORT_SYMBOL_GPL(dev_pm_set_dedicated_wake_irq);
 
@@ -255,10 +255,43 @@ EXPORT_SYMBOL_GPL(dev_pm_set_dedicated_wake_irq);
  */
 int dev_pm_set_dedicated_wake_irq_reverse(struct device *dev, int irq)
 {
-	return __dev_pm_set_dedicated_wake_irq(dev, irq, WAKE_IRQ_DEDICATED_REVERSE);
+	return __dev_pm_set_dedicated_wake_irq(dev, irq, WAKE_IRQ_DEDICATED_REVERSE,
+					       IRQF_ONESHOT | IRQF_NO_AUTOEN);
 }
 EXPORT_SYMBOL_GPL(dev_pm_set_dedicated_wake_irq_reverse);
 
+/**
+ * dev_pm_set_dedicated_wake_irq_flags - Request a dedicated wake-up interrupt
+ *                                       with custom flags
+ * @dev: Device entry
+ * @irq: Device wake-up interrupt
+ * @flags: IRQ flags (e.g., IRQF_SHARED)
+ *
+ * This API sets up a threaded interrupt handler for a device that has
+ * a dedicated wake-up interrupt in addition to the device IO interrupt,
+ * allowing the caller to specify custom IRQ flags such as IRQF_SHARED.
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+int dev_pm_set_dedicated_wake_irq_flags(struct device *dev, int irq, unsigned long flags)
+{
+	struct wake_irq *wirq;
+	int ret;
+
+	flags |= IRQF_ONESHOT;
+	if (!(flags & IRQF_SHARED))
+		flags |= IRQF_NO_AUTOEN;
+
+	ret =  __dev_pm_set_dedicated_wake_irq(dev, irq, 0, flags);
+	if (!ret && (flags & IRQF_SHARED)) {
+		wirq = dev->power.wakeirq;
+		disable_irq_nosync(wirq->irq);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_set_dedicated_wake_irq_flags);
+
 /**
  * dev_pm_enable_wake_irq_check - Checks and enables wake-up interrupt
  * @dev: Device
diff --git a/include/linux/pm_wakeirq.h b/include/linux/pm_wakeirq.h
index 25b63ed51b765c2c6919f259668a12675330835e..14950616efe34f4fa5408ca54cd8eeb1f7f0ff13 100644
--- a/include/linux/pm_wakeirq.h
+++ b/include/linux/pm_wakeirq.h
@@ -11,6 +11,7 @@ extern int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq);
 extern int dev_pm_set_dedicated_wake_irq_reverse(struct device *dev, int irq);
 extern void dev_pm_clear_wake_irq(struct device *dev);
 extern int devm_pm_set_wake_irq(struct device *dev, int irq);
+extern int dev_pm_set_dedicated_wake_irq_flags(struct device *dev, int irq, unsigned long flags);
 
 #else	/* !CONFIG_PM */
 
@@ -38,5 +39,10 @@ static inline int devm_pm_set_wake_irq(struct device *dev, int irq)
 	return 0;
 }
 
+static inline int dev_pm_set_dedicated_wake_irq_flags(struct device *dev,
+						      int irq, unsigned long flags)
+{
+	return 0;
+}
 #endif	/* CONFIG_PM */
 #endif	/* _LINUX_PM_WAKEIRQ_H */

-- 
2.34.1