reset: ath79: Add system restart support

Add a system restart handler that use the FULL_CHIP_RESET bit of the
reset controller.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

drivers/reset/reset-ath79.c

@@ -15,13 +15,17 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/reset-controller.h>
+#include <linux/reboot.h>
 
 struct ath79_reset {
 	struct reset_controller_dev rcdev;
+	struct notifier_block restart_nb;
 	void __iomem *base;
 	spinlock_t lock;
 };
 
+#define FULL_CHIP_RESET 24
+
 static int ath79_reset_update(struct reset_controller_dev *rcdev,
 			unsigned long id, bool assert)
 {
@@ -72,10 +76,22 @@ static struct reset_control_ops ath79_reset_ops = {
 	.status = ath79_reset_status,
 };
 
+static int ath79_reset_restart_handler(struct notifier_block *nb,
+				unsigned long action, void *data)
+{
+	struct ath79_reset *ath79_reset =
+		container_of(nb, struct ath79_reset, restart_nb);
+
+	ath79_reset_assert(&ath79_reset->rcdev, FULL_CHIP_RESET);
+
+	return NOTIFY_DONE;
+}
+
 static int ath79_reset_probe(struct platform_device *pdev)
 {
 	struct ath79_reset *ath79_reset;
 	struct resource *res;
+	int err;
 
 	ath79_reset = devm_kzalloc(&pdev->dev,
 				sizeof(*ath79_reset), GFP_KERNEL);
@@ -96,13 +112,25 @@ static int ath79_reset_probe(struct platform_device *pdev)
 	ath79_reset->rcdev.of_reset_n_cells = 1;
 	ath79_reset->rcdev.nr_resets = 32;
 
-	return reset_controller_register(&ath79_reset->rcdev);
+	err = reset_controller_register(&ath79_reset->rcdev);
+	if (err)
+		return err;
+
+	ath79_reset->restart_nb.notifier_call = ath79_reset_restart_handler;
+	ath79_reset->restart_nb.priority = 128;
+
+	err = register_restart_handler(&ath79_reset->restart_nb);
+	if (err)
+		dev_warn(&pdev->dev, "Failed to register restart handler\n");
+
+	return 0;
 }
 
 static int ath79_reset_remove(struct platform_device *pdev)
 {
 	struct ath79_reset *ath79_reset = platform_get_drvdata(pdev);
 
+	unregister_restart_handler(&ath79_reset->restart_nb);
 	reset_controller_unregister(&ath79_reset->rcdev);
 
 	return 0;