dm: Simple Watchdog uclass

This is a simple uclass for Watchdog Timers. It has four operations:
start, restart, reset, stop. Drivers must implement start, restart and
stop operations, while implementing reset is optional: It's default
implementation expires watchdog timer in one clock tick.

Signed-off-by: Maxim Sloyko <maxims@google.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 72 insertions, 0 deletions

diff --git a/drivers/watchdog/wdt-uclass.c b/drivers/watchdog/wdt-uclass.c
new file mode 100644
index 0000000000..ab8a64c354
--- /dev/null
+++ b/drivers/watchdog/wdt-uclass.c
@@ -0,0 +1,72 @@
+/*
+ * Copyright 2017 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <wdt.h>
+#include <dm/device-internal.h>
+#include <dm/lists.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+int wdt_start(struct udevice *dev, u64 timeout, ulong flags)
+{
+	const struct wdt_ops *ops = device_get_ops(dev);
+
+	if (!ops->start)
+		return -ENOSYS;
+
+	return ops->start(dev, timeout, flags);
+}
+
+int wdt_stop(struct udevice *dev)
+{
+	const struct wdt_ops *ops = device_get_ops(dev);
+
+	if (!ops->stop)
+		return -ENOSYS;
+
+	return ops->stop(dev);
+}
+
+int wdt_reset(struct udevice *dev)
+{
+	const struct wdt_ops *ops = device_get_ops(dev);
+
+	if (!ops->reset)
+		return -ENOSYS;
+
+	return ops->reset(dev);
+}
+
+int wdt_expire_now(struct udevice *dev, ulong flags)
+{
+	int ret = 0;
+	const struct wdt_ops *ops;
+
+	debug("WDT Resettting: %lu\n", flags);
+	ops = device_get_ops(dev);
+	if (ops->expire_now) {
+		return ops->expire_now(dev, flags);
+	} else {
+		if (!ops->start)
+			return -ENOSYS;
+
+		ret = ops->start(dev, 1, flags);
+		if (ret < 0)
+			return ret;
+
+		hang();
+	}
+
+	return ret;
+}
+
+UCLASS_DRIVER(wdt) = {
+	.id		= UCLASS_WDT,
+	.name		= "wdt",
+};