[PATCH 2/2] watchdog: mtk_wdt: Add support for MT6735 WDT

[Yassine Oudjana <yassine.oudjana@gmail.com>]

From: Yassine Oudjana <y.oudjana@protonmail.com>

Add support for the watchdog timer/top reset generation unit found on MT6735.
Disable WDT_MODE_IRQ_EN in mtk_wdt_restart in order to make TOPRGU assert
the SYSRST pin instead of issuing an IRQ. This change may be needed in other
SoCs as well.

Signed-off-by: Yassine Oudjana <y.oudjana@protonmail.com>
---
 drivers/watchdog/mtk_wdt.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
index a9c437598e7e..5a7a7b2b3727 100644
--- a/drivers/watchdog/mtk_wdt.c
+++ b/drivers/watchdog/mtk_wdt.c
@@ -10,6 +10,7 @@
  */
 
 #include <dt-bindings/reset/mt2712-resets.h>
+#include <dt-bindings/reset/mediatek,mt6735-wdt.h>
 #include <dt-bindings/reset/mediatek,mt6795-resets.h>
 #include <dt-bindings/reset/mt7986-resets.h>
 #include <dt-bindings/reset/mt8183-resets.h>
@@ -82,6 +83,10 @@ static const struct mtk_wdt_data mt2712_data = {
 	.toprgu_sw_rst_num = MT2712_TOPRGU_SW_RST_NUM,
 };
 
+static const struct mtk_wdt_data mt6735_data = {
+	.toprgu_sw_rst_num = MT6735_TOPRGU_RST_NUM,
+};
+
 static const struct mtk_wdt_data mt6795_data = {
 	.toprgu_sw_rst_num = MT6795_TOPRGU_SW_RST_NUM,
 };
@@ -187,9 +192,15 @@ static int mtk_wdt_restart(struct watchdog_device *wdt_dev,
 {
 	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
 	void __iomem *wdt_base;
+	u32 reg;
 
 	wdt_base = mtk_wdt->wdt_base;
 
+	/* Enable reset in order to issue a system reset instead of an IRQ */
+	reg = readl(wdt_base + WDT_MODE);
+	reg &= ~WDT_MODE_IRQ_EN;
+	writel(reg | WDT_MODE_KEY, wdt_base + WDT_MODE);
+
 	while (1) {
 		writel(WDT_SWRST_KEY, wdt_base + WDT_SWRST);
 		mdelay(5);
@@ -443,6 +454,7 @@ static int mtk_wdt_resume(struct device *dev)
 static const struct of_device_id mtk_wdt_dt_ids[] = {
 	{ .compatible = "mediatek,mt2712-wdt", .data = &mt2712_data },
 	{ .compatible = "mediatek,mt6589-wdt" },
+	{ .compatible = "mediatek,mt6735-wdt", .data = &mt6735_data },
 	{ .compatible = "mediatek,mt6795-wdt", .data = &mt6795_data },
 	{ .compatible = "mediatek,mt7986-wdt", .data = &mt7986_data },
 	{ .compatible = "mediatek,mt8183-wdt", .data = &mt8183_data },
-- 
2.39.2