soc: qcom: smp2p: Add wakeup capability to SMP2P IRQ

Remote susbsystems notify fatal crash through smp2p interrupt.
When remoteproc crashes it can cause soc to come out of low power
state and may not allow again to enter in low power state until
crash is handled.

Mark smp2p interrupt wakeup capable so that interrupt handler is
executed and remoteproc crash can be handled in system  resume path.
This patch marks interrupt wakeup capable but keeps wakeup disabled
by default. User space can enable it based on its requirement for
wakeup from suspend.
Signed-off-by: Deepak Kumar Singh <deesin@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/1632220467-27410-1-git-send-email-deesin@codeaurora.org

drivers/soc/qcom/smp2p.c

@@ -14,6 +14,7 @@
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/pm_wakeirq.h>
 #include <linux/regmap.h>
 #include <linux/soc/qcom/smem.h>
 #include <linux/soc/qcom/smem_state.h>
@@ -538,9 +539,26 @@ static int qcom_smp2p_probe(struct platform_device *pdev)
 		goto unwind_interfaces;
 	}
 
+	/*
+	 * Treat smp2p interrupt as wakeup source, but keep it disabled
+	 * by default. User space can decide enabling it depending on its
+	 * use cases. For example if remoteproc crashes and device wants
+	 * to handle it immediatedly (e.g. to not miss phone calls) it can
+	 * enable wakeup source from user space, while other devices which
+	 * do not have proper autosleep feature may want to handle it with
+	 * other wakeup events (e.g. Power button) instead waking up immediately.
+	 */
+	device_set_wakeup_capable(&pdev->dev, true);
+
+	ret = dev_pm_set_wake_irq(&pdev->dev, irq);
+	if (ret)
+		goto set_wake_irq_fail;
 
 	return 0;
 
+set_wake_irq_fail:
+	dev_pm_clear_wake_irq(&pdev->dev);
+
 unwind_interfaces:
 	list_for_each_entry(entry, &smp2p->inbound, node)
 		irq_domain_remove(entry->domain);
@@ -565,6 +583,8 @@ static int qcom_smp2p_remove(struct platform_device *pdev)
 	struct qcom_smp2p *smp2p = platform_get_drvdata(pdev);
 	struct smp2p_entry *entry;
 
+	dev_pm_clear_wake_irq(&pdev->dev);
+
 	list_for_each_entry(entry, &smp2p->inbound, node)
 		irq_domain_remove(entry->domain);