From: Werner Fischer devlists@wefi.net
[ Upstream commit d12971849d71781c1e4ffd1117d4878ce233d319 ]
WDTCTRL bit 3 sets the mode choice for the clock input of IT8784/IT8786. Some motherboards require this bit to be set to 1 (= PCICLK mode), otherwise the watchdog functionality gets broken. The BIOS of those motherboards sets WDTCTRL bit 3 already to 1.
Instead of setting all bits of WDTCTRL to 0 by writing 0x00 to it, keep bit 3 of it unchanged for IT8784/IT8786 chips. In this way, bit 3 keeps the status as set by the BIOS of the motherboard.
Watchdog tests have been successful with this patch with the following systems: IT8784: Thomas-Krenn LES plus v2 (YANLING YL-KBRL2 V2) IT8786: Thomas-Krenn LES plus v3 (YANLING YL-CLU L2) IT8786: Thomas-Krenn LES network 6L v2 (YANLING YL-CLU6L)
Link: https://lore.kernel.org/all/140b264d-341f-465b-8715-dacfe84b3f71@roeck-us.ne...
Signed-off-by: Werner Fischer devlists@wefi.net Reviewed-by: Guenter Roeck linux@roeck-us.net Link: https://lore.kernel.org/r/20231213094525.11849-4-devlists@wefi.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/it87_wdt.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/watchdog/it87_wdt.c b/drivers/watchdog/it87_wdt.c index a4b71ebc8cab..0a2c44a3aac0 100644 --- a/drivers/watchdog/it87_wdt.c +++ b/drivers/watchdog/it87_wdt.c @@ -260,6 +260,7 @@ static struct watchdog_device wdt_dev = { static int __init it87_wdt_init(void) { u8 chip_rev; + u8 ctrl; int rc;
rc = superio_enter(); @@ -315,7 +316,18 @@ static int __init it87_wdt_init(void)
superio_select(GPIO); superio_outb(WDT_TOV1, WDTCFG); - superio_outb(0x00, WDTCTRL); + + switch (chip_type) { + case IT8784_ID: + case IT8786_ID: + ctrl = superio_inb(WDTCTRL); + ctrl &= 0x08; + superio_outb(ctrl, WDTCTRL); + break; + default: + superio_outb(0x00, WDTCTRL); + } + superio_exit();
if (timeout < 1 || timeout > max_units * 60) {