1 files changed, 59 insertions, 0 deletions
diff --git a/drivers/watchdog/siemens_pmic_wdt.c b/drivers/watchdog/siemens_pmic_wdt.c
new file mode 100644
index 00000000000..87e817bb5b2
--- /dev/null
+++ b/drivers/watchdog/siemens_pmic_wdt.c
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for a PMIC watchdog timer controlled via Siemens SCU firmware
+ * extensions. Only useful on some Siemens i.MX8-based platforms as
+ * special NXP SCFW is needed which provides the needed SCU API.
+ *
+ * Copyright (C) 2024 Siemens AG
+ */
+
+#include <dm.h>
+#include <wdt.h>
+#include <firmware/imx/sci/sci.h>
+
+/* watchdog commands */
+#define CMD_START_WDT 0x55
+#define CMD_STOP_WDT  0x45
+#define CMD_PING_WDT  0x35
+
+static int scu_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
+{
+	/* start external watchdog via Timer API */
+	return sc_timer_control_siemens_pmic_wdog(-1, CMD_START_WDT);
+}
+
+static int scu_wdt_stop(struct udevice *dev)
+{
+	/* stop external watchdog via Timer API */
+	return sc_timer_control_siemens_pmic_wdog(-1, CMD_STOP_WDT);
+}
+
+static int scu_wdt_reset(struct udevice *dev)
+{
+	return sc_timer_control_siemens_pmic_wdog(-1, CMD_PING_WDT);
+}
+
+static int scu_wdt_probe(struct udevice *dev)
+{
+	debug("%s(dev=%p)\n", __func__, dev);
+	return 0;
+}
+
+static const struct wdt_ops scu_wdt_ops = {
+	.reset		= scu_wdt_reset,
+	.start		= scu_wdt_start,
+	.stop		= scu_wdt_stop,
+};
+
+static const struct udevice_id scu_wdt_ids[] = {
+	{ .compatible = "siemens,scu-wdt" },
+	{ }
+};
+
+U_BOOT_DRIVER(scu_wdt) = {
+	.name		= "scu_wdt",
+	.id		= UCLASS_WDT,
+	.of_match	= scu_wdt_ids,
+	.probe		= scu_wdt_probe,
+	.ops		= &scu_wdt_ops,
+};