watchdog: mtk: add disable_wdt_extrst support

In some cases, we may need watchdog just to trigger an
internal soc reset without sending any output signal.

Provide a disable_wdt_extrst parameter for configuration.
We can disable or enable it just by configuring dts.

Signed-off-by: Fengquan Chen <fengquan.chen@mediatek.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210914123454.32603-3-Fengquan.Chen@mediatek.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
index 796fbb048cbea9edfc926a18563969bcb0223ba8..ceb57ea627cd22a1a9633a71ae1b55b86321e1a6 100644 (file)
--- a/drivers/watchdog/mtk_wdt.c
+++ b/drivers/watchdog/mtk_wdt.c
@@ -65,6 +65,7 @@ struct mtk_wdt_dev {
        void __iomem *wdt_base;
        spinlock_t lock; /* protects WDT_SWSYSRST reg */
        struct reset_controller_dev rcdev;
+       bool disable_wdt_extrst;
 };
 
 struct mtk_wdt_data {
@@ -256,6 +257,8 @@ static int mtk_wdt_start(struct watchdog_device *wdt_dev)
                reg |= (WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
        else
                reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
+       if (mtk_wdt->disable_wdt_extrst)
+               reg &= ~WDT_MODE_EXRST_EN;
        reg |= (WDT_MODE_EN | WDT_MODE_KEY);
        iowrite32(reg, wdt_base + WDT_MODE);
 
@@ -381,6 +384,10 @@ static int mtk_wdt_probe(struct platform_device *pdev)
                if (err)
                        return err;
        }
+
+       mtk_wdt->disable_wdt_extrst =
+               of_property_read_bool(dev->of_node, "mediatek,disable-extrst");
+
        return 0;
 }