[3/9] watchdog: Add Photonicat PMU watchdog driver

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index bae1d97cce89..4094216a1c09 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -300,6 +300,18 @@  config MENZ069_WATCHDOG
 	  This driver can also be built as a module. If so the module
 	  will be called menz069_wdt.
 
+config PHOTONICAT_PMU_WDT
+	tristate "Photonicat PMU Watchdog"
+	depends on MFD_PHOTONICAT_PMU
+	select WATCHDOG_CORE
+	help
+	  This driver provides access to Photonicat PMU watchdog functionality.
+
+	  Say Y here to include support for the Photonicat PMU Watchdog.
+
+	  This driver can also be built as a module. If so the module
+	  will be called photonicat-wdt.
+
 config WDAT_WDT
 	tristate "ACPI Watchdog Action Table (WDAT)"
 	depends on ACPI
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index b51030f035a6..14375af84039 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -234,6 +234,7 @@  obj-$(CONFIG_ZIIRAVE_WATCHDOG) += ziirave_wdt.o
 obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
 obj-$(CONFIG_MENF21BMC_WATCHDOG) += menf21bmc_wdt.o
 obj-$(CONFIG_MENZ069_WATCHDOG) += menz69_wdt.o
+obj-$(CONFIG_PHOTONICAT_PMU_WDT) += photonicat-wdt.o
 obj-$(CONFIG_RAVE_SP_WATCHDOG) += rave-sp-wdt.o
 obj-$(CONFIG_STPMIC1_WATCHDOG) += stpmic1_wdt.o
 obj-$(CONFIG_SL28CPLD_WATCHDOG) += sl28cpld_wdt.o
diff --git a/drivers/watchdog/photonicat-wdt.c b/drivers/watchdog/photonicat-wdt.c
new file mode 100644
index 000000000000..1e758fcfb49f
--- /dev/null
+++ b/drivers/watchdog/photonicat-wdt.c
@@ -0,0 +1,124 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2024 Junhao Xie <bigfoot@classfun.cn>
+ */
+
+#include <linux/mfd/photonicat-pmu.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+struct pcat_watchdog {
+	struct device *dev;
+	struct pcat_pmu *pmu;
+	struct watchdog_device wdd;
+	u8 timeout;
+	bool started;
+};
+
+static const struct watchdog_info pcat_wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+	.identity = "Photonicat PMU Watchdog",
+};
+
+static int pcat_wdt_setup(struct pcat_watchdog *data, int timeout)
+{
+	int ret;
+	u8 time = 0;
+	u8 times[3] = { 60, 60, 0 };
+
+	time = MIN(255, MAX(0, timeout));
+
+	ret = pcat_pmu_write_data(data->pmu, PCAT_CMD_WATCHDOG_TIMEOUT_SET,
+				  times, sizeof(times));
+	if (!ret)
+		data->started = timeout != 0;
+
+	return ret;
+}
+
+static int pcat_wdt_start(struct watchdog_device *wdev)
+{
+	struct pcat_watchdog *data = watchdog_get_drvdata(wdev);
+
+	return pcat_wdt_setup(data, data->timeout);
+}
+
+static int pcat_wdt_stop(struct watchdog_device *wdev)
+{
+	struct pcat_watchdog *data = watchdog_get_drvdata(wdev);
+
+	return pcat_wdt_setup(data, 0);
+}
+
+static int pcat_wdt_ping(struct watchdog_device *wdev)
+{
+	struct pcat_watchdog *data = watchdog_get_drvdata(wdev);
+
+	return pcat_pmu_send(data->pmu, PCAT_CMD_HEARTBEAT, NULL, 0);
+}
+
+static int pcat_wdt_set_timeout(struct watchdog_device *wdev, unsigned int val)
+{
+	int ret = 0;
+	struct pcat_watchdog *data = watchdog_get_drvdata(wdev);
+
+	data->timeout = val;
+	if (data->started)
+		ret = pcat_wdt_setup(data, data->timeout);
+
+	return ret;
+}
+
+static const struct watchdog_ops pcat_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = pcat_wdt_start,
+	.stop = pcat_wdt_stop,
+	.ping = pcat_wdt_ping,
+	.set_timeout = pcat_wdt_set_timeout,
+};
+
+static int pcat_watchdog_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct pcat_watchdog *watchdog;
+
+	watchdog = devm_kzalloc(dev, sizeof(*watchdog), GFP_KERNEL);
+	if (!watchdog)
+		return -ENOMEM;
+
+	watchdog->dev = dev;
+	watchdog->pmu = dev_get_drvdata(dev->parent);
+	watchdog->wdd.info = &pcat_wdt_info;
+	watchdog->wdd.ops = &pcat_wdt_ops;
+	watchdog->wdd.timeout = 60;
+	watchdog->wdd.max_timeout = U8_MAX;
+	watchdog->wdd.min_timeout = 0;
+	watchdog->wdd.parent = dev;
+
+	watchdog_stop_on_reboot(&watchdog->wdd);
+	watchdog_set_drvdata(&watchdog->wdd, watchdog);
+	platform_set_drvdata(pdev, watchdog);
+
+	return devm_watchdog_register_device(dev, &watchdog->wdd);
+}
+
+static const struct of_device_id pcat_watchdog_dt_ids[] = {
+	{ .compatible = "ariaboard,photonicat-pmu-watchdog", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, pcat_watchdog_dt_ids);
+
+static struct platform_driver pcat_watchdog_driver = {
+	.driver = {
+		.name = "photonicat-watchdog",
+		.of_match_table = pcat_watchdog_dt_ids,
+	},
+	.probe = pcat_watchdog_probe,
+};
+module_platform_driver(pcat_watchdog_driver);
+
+MODULE_AUTHOR("Junhao Xie <bigfoot@classfun.cn>");
+MODULE_DESCRIPTION("Photonicat PMU watchdog");
+MODULE_LICENSE("GPL");