linux-kernel - Re: [PATCH V1 1/1] watchdog: f71808e

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Date:   Fri, 22 Mar 2019 06:06:18 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     "Ji-Ze Hong (Peter Hong)" <hpeter@...il.com>,
        wim@...ux-watchdog.orgw
Cc:     linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org,
        "Ji-Ze Hong (Peter Hong)" <hpeter+linux_kernel@...il.com>
Subject: Re: [PATCH V1 1/1] watchdog: f71808e_wdt: fix F81866 bit operation

On 3/21/19 8:36 PM, Ji-Ze Hong (Peter Hong) wrote:
> Fix error bit operation in watchdog_start()
> 

Hmm ... does that mean it never worked ? Did you test it this time ?

A secondary concern is that the watchdog doesn't _have_ to trigger WDTRST,
but may also trigger PWOK. But that may be a separate issue.

Please add:

Fixes: 14b24a88a3660 ("watchdog: f71808e_wdt: Add F81866 support")

> Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@...il.com>
> ---
>   drivers/watchdog/f71808e_wdt.c | 11 +++++------
>   1 file changed, 5 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/watchdog/f71808e_wdt.c b/drivers/watchdog/f71808e_wdt.c
> index 9a1c761258ce..9129485732c7 100644
> --- a/drivers/watchdog/f71808e_wdt.c
> +++ b/drivers/watchdog/f71808e_wdt.c
> @@ -387,18 +387,17 @@ static int watchdog_start(void)
>   
>   	case f81866:
>   		/* Set pin 70 to WDTRST# */
> -		superio_clear_bit(watchdog.sioaddr, SIO_F81866_REG_PORT_SEL,
> -				  BIT(3) | BIT(0));
> -		superio_set_bit(watchdog.sioaddr, SIO_F81866_REG_PORT_SEL,
> -				BIT(2));
> +		superio_clear_bit(watchdog.sioaddr, SIO_F81866_REG_PORT_SEL, 3);
> +		superio_clear_bit(watchdog.sioaddr, SIO_F81866_REG_PORT_SEL, 0);
> +		superio_set_bit(watchdog.sioaddr, SIO_F81866_REG_PORT_SEL, 2);

Better use superio_inb()/superio_outb(). The above is (much) more expensive,
and  we have no real idea what the impact of changing one bit at a time may be.

Thanks,
Guenter

> +
>   		/*
>   		 * GPIO1 Control Register when 27h BIT3:2 = 01 & BIT0 = 0.
>   		 * The PIN 70(GPIO15/WDTRST) is controlled by 2Ch:
>   		 *     BIT5: 0 -> WDTRST#
>   		 *           1 -> GPIO15
>   		 */
> -		superio_clear_bit(watchdog.sioaddr, SIO_F81866_REG_GPIO1,
> -				  BIT(5));
> +		superio_clear_bit(watchdog.sioaddr, SIO_F81866_REG_GPIO1, 5);
>   		break;
>   
>   	default:
>