watchdog: loongson1: Add Loongson-2k0300 watchdog support

According to the manual, the Loongson-2K0300 watchdog is similar to the
Loongson-1, except for some register offsets and inconsistent register
bit definitions. Separate definitions via driver_data suffice.

Co-developed-by: Xiaochuang Mao <maoxiaochuan@loongson.cn>
Signed-off-by: Xiaochuang Mao <maoxiaochuan@loongson.cn>
Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

Author: AaronDot

drivers/watchdog/Kconfig

@@ -1984,10 +1984,10 @@ config LANTIQ_WDT
 
 config LOONGSON1_WDT
 	tristate "Loongson1 SoC hardware watchdog"
-	depends on MACH_LOONGSON32 || COMPILE_TEST
+	depends on MACH_LOONGSON32 || MACH_LOONGSON64 || COMPILE_TEST
 	select WATCHDOG_CORE
 	help
-	  Hardware driver for the Loongson1 SoC Watchdog Timer.
+	  Hardware driver for the Loongson family Watchdog Timer.
 
 config RALINK_WDT
 	tristate "Ralink SoC watchdog"

drivers/watchdog/loongson1_wdt.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (c) 2016 Yang Ling <gnaygnil@gmail.com>
+ * Copyright (C) 2025 Binbin Zhou <zhoubinbin@loongson.cn>
  */
 
 #include <linux/clk.h>
@@ -10,10 +11,8 @@
 #include <linux/platform_device.h>
 #include <linux/watchdog.h>
 
-/* Loongson 1 Watchdog Register Definitions */
+/* Loongson Watchdog Register Definitions */
 #define WDT_EN			0x0
-#define WDT_TIMER		0x4
-#define WDT_SET			0x8
 
 #define DEFAULT_HEARTBEAT	30
 
@@ -27,18 +26,37 @@ module_param(heartbeat, uint, 0);
 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (default="
 		 __MODULE_STRING(DEFAULT_HEARTBEAT) ")");
 
+struct ls1x_wdt_pdata {
+	u32 timer_offset;
+	u32 set_offset;
+	u32 wdt_en_bit;
+};
+
+static const struct ls1x_wdt_pdata ls1b_wdt_pdata = {
+	.timer_offset = 0x4,
+	.set_offset = 0x8,
+	.wdt_en_bit = BIT(0),
+};
+
+static const struct ls1x_wdt_pdata ls2k0300_wdt_pdata = {
+	.timer_offset = 0x8,
+	.set_offset = 0x4,
+	.wdt_en_bit = BIT(1),
+};
+
 struct ls1x_wdt_drvdata {
 	void __iomem *base;
 	struct clk *clk;
 	unsigned long clk_rate;
 	struct watchdog_device wdt;
+	const struct ls1x_wdt_pdata *pdata;
 };
 
 static int ls1x_wdt_ping(struct watchdog_device *wdt_dev)
 {
 	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 
-	writel(0x1, drvdata->base + WDT_SET);
+	writel(0x1, drvdata->base + drvdata->pdata->set_offset);
 
 	return 0;
 }
@@ -53,7 +71,7 @@ static int ls1x_wdt_set_timeout(struct watchdog_device *wdt_dev,
 	wdt_dev->timeout = timeout;
 
 	counts = drvdata->clk_rate * min(timeout, max_hw_heartbeat);
-	writel(counts, drvdata->base + WDT_TIMER);
+	writel(counts, drvdata->base + drvdata->pdata->timer_offset);
 
 	return 0;
 }
@@ -62,16 +80,18 @@ static int ls1x_wdt_start(struct watchdog_device *wdt_dev)
 {
 	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 
-	writel(0x1, drvdata->base + WDT_EN);
+	writel(drvdata->pdata->wdt_en_bit, drvdata->base + WDT_EN);
 
 	return 0;
 }
 
 static int ls1x_wdt_stop(struct watchdog_device *wdt_dev)
 {
 	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
+	u32 val = readl(drvdata->base + WDT_EN);
 
-	writel(0x0, drvdata->base + WDT_EN);
+	val &= ~(drvdata->pdata->wdt_en_bit);
+	writel(val, drvdata->base + WDT_EN);
 
 	return 0;
 }
@@ -81,9 +101,9 @@ static int ls1x_wdt_restart(struct watchdog_device *wdt_dev,
 {
 	struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 
-	writel(0x1, drvdata->base + WDT_EN);
-	writel(0x1, drvdata->base + WDT_TIMER);
-	writel(0x1, drvdata->base + WDT_SET);
+	writel(drvdata->pdata->wdt_en_bit, drvdata->base + WDT_EN);
+	writel(0x1, drvdata->base + drvdata->pdata->timer_offset);
+	writel(0x1, drvdata->base + drvdata->pdata->set_offset);
 
 	return 0;
 }
@@ -114,6 +134,8 @@ static int ls1x_wdt_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	platform_set_drvdata(pdev, drvdata);
 
+	drvdata->pdata = of_device_get_match_data(dev);
+
 	drvdata->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(drvdata->base))
 		return PTR_ERR(drvdata->base);
@@ -142,9 +164,32 @@ static int ls1x_wdt_probe(struct platform_device *pdev)
 	return devm_watchdog_register_device(dev, &drvdata->wdt);
 }
 
+static int ls1x_wdt_resume(struct device *dev)
+{
+	struct ls1x_wdt_drvdata *data = dev_get_drvdata(dev);
+
+	if (watchdog_active(&data->wdt))
+		ls1x_wdt_start(&data->wdt);
+
+	return 0;
+}
+
+static int ls1x_wdt_suspend(struct device *dev)
+{
+	struct ls1x_wdt_drvdata *data = dev_get_drvdata(dev);
+
+	if (watchdog_active(&data->wdt))
+		ls1x_wdt_stop(&data->wdt);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(ls1x_wdt_pm_ops, ls1x_wdt_suspend, ls1x_wdt_resume);
+
 static const struct of_device_id ls1x_wdt_dt_ids[] = {
-	{ .compatible = "loongson,ls1b-wdt", },
-	{ .compatible = "loongson,ls1c-wdt", },
+	{ .compatible = "loongson,ls1b-wdt", .data = &ls1b_wdt_pdata },
+	{ .compatible = "loongson,ls1c-wdt", .data = &ls1b_wdt_pdata },
+	{ .compatible = "loongson,ls2k0300-wdt", .data = &ls2k0300_wdt_pdata },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, ls1x_wdt_dt_ids);
@@ -154,11 +199,13 @@ static struct platform_driver ls1x_wdt_driver = {
 	.driver = {
 		.name = "ls1x-wdt",
 		.of_match_table = ls1x_wdt_dt_ids,
+		.pm = pm_ptr(&ls1x_wdt_pm_ops),
 	},
 };
 
 module_platform_driver(ls1x_wdt_driver);
 
 MODULE_AUTHOR("Yang Ling <gnaygnil@gmail.com>");
-MODULE_DESCRIPTION("Loongson1 Watchdog Driver");
+MODULE_AUTHOR("Binbin Zhou <zhoubinbin@loongson.cn>");
+MODULE_DESCRIPTION("Loongson Watchdog Driver");
 MODULE_LICENSE("GPL");