watchdog: bcm2835_wdt: Fix WDIOC_SETTIMEOUT handling

[ Upstream commit f33f5b1fd1be5f5106d16f831309648cb0f1c31d ]

Users report about the unexpected behavior for setting timeouts above
15 sec on Raspberry Pi. According to watchdog-api.rst the ioctl
WDIOC_SETTIMEOUT shouldn't fail because of hardware limitations.
But looking at the code shows that max_timeout based on the
register value PM_WDOG_TIME_SET, which is the maximum.

Since 664a39236e ("watchdog: Introduce hardware maximum heartbeat
in watchdog core") the watchdog core is able to handle this problem.

This fix has been tested with watchdog-test from selftests.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=217374
Fixes: 664a39236e ("watchdog: Introduce hardware maximum heartbeat in watchdog core")
Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20231112173251.4827-1-wahrenst@gmx.net
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/watchdog/bcm2835_wdt.c

@@ -42,6 +42,7 @@
 
 #define SECS_TO_WDOG_TICKS(x) ((x) << 16)
 #define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
+#define WDOG_TICKS_TO_MSECS(x) ((x) * 1000 >> 16)
 
 struct bcm2835_wdt {
 	void __iomem		*base;
@@ -140,7 +141,7 @@ static struct watchdog_device bcm2835_wdt_wdd = {
 	.info =		&bcm2835_wdt_info,
 	.ops =		&bcm2835_wdt_ops,
 	.min_timeout =	1,
-	.max_timeout =	WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
+	.max_hw_heartbeat_ms =	WDOG_TICKS_TO_MSECS(PM_WDOG_TIME_SET),
 	.timeout =	WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
 };