linux-kernel - Re: [PATCH 4/5] watchdog: ziirave_wdt: Don't bail out on unexpected timeout value

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Date:   Wed, 31 Jul 2019 11:09:38 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Andrey Smirnov <andrew.smirnov@...il.com>
Cc:     linux-watchdog@...r.kernel.org, Chris Healy <cphealy@...il.com>,
        Rick Ramstetter <rick@...eaterllc.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/5] watchdog: ziirave_wdt: Don't bail out on unexpected
 timeout value

On Wed, Jul 31, 2019 at 10:42:51AM -0700, Andrey Smirnov wrote:
> Reprogramming bootloader on watchdog MCU will result in reported
> default timeout value of "0". That in turn will be unnecesarily

unnecessarily

> rejected by the driver as invalid device (-ENODEV). Simplify probe to
> just read stored timeout value, clamp it to an acceptable range and
> program the value unconditionally to fix the above.
> 
> Signed-off-by: Andrey Smirnov <andrew.smirnov@...il.com>
> Cc: Chris Healy <cphealy@...il.com>
> Cc: Guenter Roeck <linux@...ck-us.net>
> Cc: Rick Ramstetter <rick@...eaterllc.com>
> Cc: linux-watchdog@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org
> ---
>  drivers/watchdog/ziirave_wdt.c | 22 +++++++++-------------
>  1 file changed, 9 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/watchdog/ziirave_wdt.c b/drivers/watchdog/ziirave_wdt.c
> index 89ce6982ba53..33c8d2eadada 100644
> --- a/drivers/watchdog/ziirave_wdt.c
> +++ b/drivers/watchdog/ziirave_wdt.c
> @@ -667,22 +667,18 @@ static int ziirave_wdt_probe(struct i2c_client *client,
>  			return val;
>  		}
>  
> -		if (val < ZIIRAVE_TIMEOUT_MIN)
> -			return -ENODEV;
> -
> -		w_priv->wdd.timeout = val;
> -	} else {
> -		ret = ziirave_wdt_set_timeout(&w_priv->wdd,
> -					      w_priv->wdd.timeout);
> -		if (ret) {
> -			dev_err(&client->dev, "Failed to set timeout\n");
> -			return ret;
> -		}
> +		w_priv->wdd.timeout = clamp(val, ZIIRAVE_TIMEOUT_MIN,
> +					    ZIIRAVE_TIMEOUT_MAX);

Are you sure ? Effectively that will set the timeout to the minimum,
ie three seconds. It might be better to define and set some default.
Your call, of course.

Thanks,
Guenter

> +	}
>  
> -		dev_info(&client->dev, "Timeout set to %ds\n",
> -			 w_priv->wdd.timeout);
> +	ret = ziirave_wdt_set_timeout(&w_priv->wdd, w_priv->wdd.timeout);
> +	if (ret) {
> +		dev_err(&client->dev, "Failed to set timeout\n");
> +		return ret;
>  	}
>  
> +	dev_info(&client->dev, "Timeout set to %ds\n", w_priv->wdd.timeout);
> +
>  	watchdog_set_nowayout(&w_priv->wdd, nowayout);
>  
>  	i2c_set_clientdata(client, w_priv);
> -- 
> 2.21.0
>