diff mbox series

[4/4] watchdog: it87_wdt: Keep WDTCTRL bit 3 unmodified for IT8784/IT8786

Message ID 20231213094525.11849-4-devlists@wefi.net (mailing list archive)
State New
Headers show
Series [1/4] watchdog: it87_wdt: add blank line after variable declaration | expand

Commit Message

Werner Fischer Dec. 13, 2023, 9:45 a.m. UTC
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.net/

Signed-off-by: Werner Fischer <devlists@wefi.net>
---
 drivers/watchdog/it87_wdt.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

Comments

Guenter Roeck Dec. 13, 2023, 2:54 p.m. UTC | #1
On Wed, Dec 13, 2023 at 10:45:25AM +0100, Werner Fischer wrote:
> 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.net/
> 
> Signed-off-by: Werner Fischer <devlists@wefi.net>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  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 f6a344c002af..9297a5891912 100644
> --- a/drivers/watchdog/it87_wdt.c
> +++ b/drivers/watchdog/it87_wdt.c
> @@ -258,6 +258,7 @@ static struct watchdog_device wdt_dev = {
>  static int __init it87_wdt_init(void)
>  {
>  	u8  chip_rev;
> +	u8 ctrl;
>  	int rc;
>  
>  	rc = superio_enter();
> @@ -316,7 +317,18 @@ 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) {
> -- 
> 2.39.2
>
diff mbox series

Patch

diff --git a/drivers/watchdog/it87_wdt.c b/drivers/watchdog/it87_wdt.c
index f6a344c002af..9297a5891912 100644
--- a/drivers/watchdog/it87_wdt.c
+++ b/drivers/watchdog/it87_wdt.c
@@ -258,6 +258,7 @@  static struct watchdog_device wdt_dev = {
 static int __init it87_wdt_init(void)
 {
 	u8  chip_rev;
+	u8 ctrl;
 	int rc;
 
 	rc = superio_enter();
@@ -316,7 +317,18 @@  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) {