[PATCH 4/4] watchdog: Automatically register device with sysreset

[Samuel Holland]

Add an option to automatically register the first watchdog device with
the wdt_reboot driver for use with sysreset. This allows sysreset to be
a drop-in replacement for platform-specific watchdog reset code, without
needing any device tree changes.

Signed-off-by: Samuel Holland <samuel at sholland.org>
---

 drivers/sysreset/Kconfig             |  7 +++++++
 drivers/sysreset/sysreset_watchdog.c | 24 ++++++++++++++++++++++++
 drivers/watchdog/wdt-uclass.c        |  5 +++++
 include/sysreset.h                   | 14 ++++++++++++++
 4 files changed, 50 insertions(+)

diff --git a/drivers/sysreset/Kconfig b/drivers/sysreset/Kconfig
index fdc858ccbac..49354b1b27a 100644
--- a/drivers/sysreset/Kconfig
+++ b/drivers/sysreset/Kconfig
@@ -119,6 +119,13 @@ config SYSRESET_WATCHDOG
 	help
 	  Reboot support for generic watchdog reset.
 
+config SYSRESET_WATCHDOG_AUTO
+	bool "Automatically register first watchdog with sysreset"
+	depends on SYSRESET_WATCHDOG
+	help
+	  If enabled, the first watchdog (as selected by the watchdog uclass)
+	  will automatically be registered with the watchdog reboot driver.
+
 config SYSRESET_RESETCTL
 	bool "Enable support for reset controller reboot driver"
 	select DM_RESET
diff --git a/drivers/sysreset/sysreset_watchdog.c b/drivers/sysreset/sysreset_watchdog.c
index b723f5647cd..35efcac59dd 100644
--- a/drivers/sysreset/sysreset_watchdog.c
+++ b/drivers/sysreset/sysreset_watchdog.c
@@ -5,7 +5,9 @@
 
 #include <common.h>
 #include <dm.h>
+#include <dm/device-internal.h>
 #include <errno.h>
+#include <malloc.h>
 #include <sysreset.h>
 #include <wdt.h>
 
@@ -57,3 +59,25 @@ U_BOOT_DRIVER(wdt_reboot) = {
 	.plat_auto	= sizeof(struct wdt_reboot_plat),
 	.ops = &wdt_reboot_ops,
 };
+
+#if IS_ENABLED(CONFIG_SYSRESET_WATCHDOG_AUTO)
+int sysreset_register_wdt(struct udevice *dev)
+{
+	struct wdt_reboot_plat *plat = malloc(sizeof(*plat));
+	int ret;
+
+	if (!plat)
+		return -ENOMEM;
+
+	plat->wdt = dev;
+
+	ret = device_bind(dev, DM_DRIVER_GET(wdt_reboot),
+			  dev->name, plat, ofnode_null(), NULL);
+	if (ret) {
+		free(plat);
+		return ret;
+	}
+
+	return 0;
+}
+#endif
diff --git a/drivers/watchdog/wdt-uclass.c b/drivers/watchdog/wdt-uclass.c
index 17334dbda6c..3170ef9d945 100644
--- a/drivers/watchdog/wdt-uclass.c
+++ b/drivers/watchdog/wdt-uclass.c
@@ -10,6 +10,7 @@
 #include <errno.h>
 #include <hang.h>
 #include <log.h>
+#include <sysreset.h>
 #include <time.h>
 #include <wdt.h>
 #include <asm/global_data.h>
@@ -53,6 +54,10 @@ int initr_watchdog(void)
 						    4 * reset_period) / 4;
 	}
 
+	ret = sysreset_register_wdt(gd->watchdog_dev);
+	if (ret)
+		printf("WDT:   Failed to register sysreset\n");
+
 	if (!IS_ENABLED(CONFIG_WATCHDOG_AUTOSTART)) {
 		printf("WDT:   Not starting\n");
 		return 0;
diff --git a/include/sysreset.h b/include/sysreset.h
index 701e4f5c86e..ad45fe0db28 100644
--- a/include/sysreset.h
+++ b/include/sysreset.h
@@ -118,4 +118,18 @@ void sysreset_walk_halt(enum sysreset_t type);
  */
 void reset_cpu(void);
 
+/**
+ * sysreset_register_wdt() - register a watchdog for use with sysreset
+ *
+ * This registers the given watchdog timer to be used to reset the system.
+ *
+ * @dev:	WDT device
+ * @return:	0 if OK, -errno if error
+ */
+#if IS_ENABLED(CONFIG_SYSRESET_WATCHDOG_AUTO)
+int sysreset_register_wdt(struct udevice *dev);
+#else
+static inline int sysreset_register_wdt(struct udevice *dev) { return 0; }
+#endif
+
 #endif
-- 
2.31.1