[tip: timers/clocksource] clocksource/drivers/timer-tegra186: Fix support for multiple watchdog instances

["tip-bot2 for Kartik Rajput" <tip-bot2@linutronix.de>]

The following commit has been merged into the timers/clocksource branch of tip:

Commit-ID:     ca57bf46e7a94f8c53d05c376df9fcfdcb482100
Gitweb:        https://git.kernel.org/tip/ca57bf46e7a94f8c53d05c376df9fcfdcb482100
Author:        Kartik Rajput <kkartik@nvidia.com>
AuthorDate:    Thu, 07 May 2026 21:15:54 +05:30
Committer:     Daniel Lezcano <daniel.lezcano@kernel.org>
CommitterDate: Wed, 10 Jun 2026 07:25:08 +02:00

clocksource/drivers/timer-tegra186: Fix support for multiple watchdog instances

Tegra SoCs support multiple watchdogs; currently only one (WDT0) is
used. When multiple watchdogs are registered, tegra186_wdt_enable()
overwrites the TKEIE(x) register, discarding any existing watchdog
interrupt enable bits. As a result, enabling one watchdog inadvertently
disables interrupts for the others.

Fix this by preserving the existing TKEIE(x) value and updating it
using a read-modify-write sequence.

Fixes: 42cee19a9f83 ("clocksource: Add Tegra186 timers support")
Cc: stable@vger.kernel.org
Signed-off-by: Kartik Rajput <kkartik@nvidia.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@kernel.org>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Link: https://patch.msgid.link/20260507154557.2082697-2-kkartik@nvidia.com
---
 drivers/clocksource/timer-tegra186.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/clocksource/timer-tegra186.c b/drivers/clocksource/timer-tegra186.c
index 3555588..bfe16d2 100644
--- a/drivers/clocksource/timer-tegra186.c
+++ b/drivers/clocksource/timer-tegra186.c
@@ -149,7 +149,8 @@ static void tegra186_wdt_enable(struct tegra186_wdt *wdt)
 	u32 value;
 
 	/* unmask hardware IRQ, this may have been lost across powergate */
-	value = TKEIE_WDT_MASK(wdt->index, 1);
+	value = readl(tegra->regs + TKEIE(wdt->tmr->hwirq));
+	value |= TKEIE_WDT_MASK(wdt->index, 1);
 	writel(value, tegra->regs + TKEIE(wdt->tmr->hwirq));
 
 	/* clear interrupt */