watchdog: mtk_wdt: Add reset_by_toprgu support

In some cases, the MediaTek watchdog requires the TOPRGU to reset
timer after system resets.

Provide a reset_by_toprgu parameter for configuration.

Signed-off-by: Allen-KH Cheng <allen-kh.cheng@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230117014023.2993-3-allen-kh.cheng@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 3e62125..a9c4375 100644 (file)
--- a/drivers/watchdog/mtk_wdt.c
+++ b/drivers/watchdog/mtk_wdt.c
@@ -50,6 +50,7 @@
 #define WDT_MODE_IRQ_EN                (1 << 3)
 #define WDT_MODE_AUTO_START    (1 << 4)
 #define WDT_MODE_DUAL_EN       (1 << 6)
+#define WDT_MODE_CNT_SEL       (1 << 8)
 #define WDT_MODE_KEY           0x22000000
 
 #define WDT_SWRST              0x14
@@ -70,6 +71,7 @@ struct mtk_wdt_dev {
        spinlock_t lock; /* protects WDT_SWSYSRST reg */
        struct reset_controller_dev rcdev;
        bool disable_wdt_extrst;
+       bool reset_by_toprgu;
 };
 
 struct mtk_wdt_data {
@@ -279,6 +281,8 @@ static int mtk_wdt_start(struct watchdog_device *wdt_dev)
                reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
        if (mtk_wdt->disable_wdt_extrst)
                reg &= ~WDT_MODE_EXRST_EN;
+       if (mtk_wdt->reset_by_toprgu)
+               reg |= WDT_MODE_CNT_SEL;
        reg |= (WDT_MODE_EN | WDT_MODE_KEY);
        iowrite32(reg, wdt_base + WDT_MODE);
 
@@ -408,6 +412,9 @@ static int mtk_wdt_probe(struct platform_device *pdev)
        mtk_wdt->disable_wdt_extrst =
                of_property_read_bool(dev->of_node, "mediatek,disable-extrst");
 
+       mtk_wdt->reset_by_toprgu =
+               of_property_read_bool(dev->of_node, "mediatek,reset-by-toprgu");
+
        return 0;
 }