remoteproc: stm32: wakeup the system by wdg irq

If the device node defines the 'wakeup-source' property, use the WDG
exti IRQ as a wakeup source of the system.

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Link: https://lore.kernel.org/r/1566833923-16718-3-git-send-email-fabien.dessenne@st.com
[bjorn: Replace ifdef with __maybe_unused for suspend/resume functions]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/remoteproc/stm32_rproc.c

@@ -15,6 +15,7 @@
 #include <linux/of_address.h>
 #include <linux/of_device.h>
 #include <linux/of_reserved_mem.h>
+#include <linux/pm_wakeirq.h>
 #include <linux/regmap.h>
 #include <linux/remoteproc.h>
 #include <linux/reset.h>
@@ -69,6 +70,7 @@ struct stm32_rproc {
 	struct reset_control *rst;
 	struct stm32_syscon hold_boot;
 	struct stm32_syscon pdds;
+	int wdg_irq;
 	u32 nb_rmems;
 	struct stm32_rproc_mem *rmems;
 	struct stm32_mbox mb[MBOX_NB_MBX];
@@ -546,6 +548,13 @@ static int stm32_rproc_parse_dt(struct platform_device *pdev)
 			return err;
 		}
 
+		ddata->wdg_irq = irq;
+
+		if (of_property_read_bool(np, "wakeup-source")) {
+			device_init_wakeup(dev, true);
+			dev_pm_set_wake_irq(dev, irq);
+		}
+
 		dev_info(dev, "wdg irq registered\n");
 	}
 
@@ -633,6 +642,10 @@ static int stm32_rproc_probe(struct platform_device *pdev)
 free_wkq:
 	destroy_workqueue(ddata->workqueue);
 free_rproc:
+	if (device_may_wakeup(dev)) {
+		dev_pm_clear_wake_irq(dev);
+		device_init_wakeup(dev, false);
+	}
 	rproc_free(rproc);
 	return ret;
 }
@@ -641,23 +654,55 @@ static int stm32_rproc_remove(struct platform_device *pdev)
 {
 	struct rproc *rproc = platform_get_drvdata(pdev);
 	struct stm32_rproc *ddata = rproc->priv;
+	struct device *dev = &pdev->dev;
 
 	if (atomic_read(&rproc->power) > 0)
 		rproc_shutdown(rproc);
 
 	rproc_del(rproc);
 	stm32_rproc_free_mbox(rproc);
 	destroy_workqueue(ddata->workqueue);
+
+	if (device_may_wakeup(dev)) {
+		dev_pm_clear_wake_irq(dev);
+		device_init_wakeup(dev, false);
+	}
 	rproc_free(rproc);
 
 	return 0;
 }
 
+static int __maybe_unused stm32_rproc_suspend(struct device *dev)
+{
+	struct rproc *rproc = dev_get_drvdata(dev);
+	struct stm32_rproc *ddata = rproc->priv;
+
+	if (device_may_wakeup(dev))
+		return enable_irq_wake(ddata->wdg_irq);
+
+	return 0;
+}
+
+static int __maybe_unused stm32_rproc_resume(struct device *dev)
+{
+	struct rproc *rproc = dev_get_drvdata(dev);
+	struct stm32_rproc *ddata = rproc->priv;
+
+	if (device_may_wakeup(dev))
+		return disable_irq_wake(ddata->wdg_irq);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(stm32_rproc_pm_ops,
+			 stm32_rproc_suspend, stm32_rproc_resume);
+
 static struct platform_driver stm32_rproc_driver = {
 	.probe = stm32_rproc_probe,
 	.remove = stm32_rproc_remove,
 	.driver = {
 		.name = "stm32-rproc",
+		.pm = &stm32_rproc_pm_ops,
 		.of_match_table = of_match_ptr(stm32_rproc_match),
 	},
 };