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From: Guenter Roeck <linux@roeck-us.net>
To: Wolfram Sang <wsa+renesas@sang-engineering.com>,
	linux-watchdog@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH 01/16] watchdog: refactor watchdog_init_timeout
Date: Sun, 14 Apr 2019 06:25:36 -0700
Message-ID: <64e8adf0-cf87-3d54-4513-fd531ab7b7f2@roeck-us.net> (raw)
In-Reply-To: <20190414102627.5564-2-wsa+renesas@sang-engineering.com>

On 4/14/19 3:26 AM, Wolfram Sang wrote:
> The function is not easy to read and has two problems: a) -EINVAL is
> returned when the module parameter is invalid but the DT parameter is
> OK, and b) for the module parameter, zero is a valid value but for DT it
> is invalid.
> 

That was on purpose: A module parameter of 0 reflects that no module parameter
was provided, which is not an error. An explicit DT property with value 0 _is_
an error and does not make sense. "use the default", in the DT case, can and
should be expressed by providing no property, not by providing a property with
value 0.

Guenter

> Refactor the code to have a the same pattern of checks for the module
> parameter and DT. Further ones can be easily added in the future if the
> need arises. The above mentioned problems are fixed, too.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>   drivers/watchdog/watchdog_core.c | 33 ++++++++++++++++++---------------
>   1 file changed, 18 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
> index eb8fa25f8eb2..85c136acc0e9 100644
> --- a/drivers/watchdog/watchdog_core.c
> +++ b/drivers/watchdog/watchdog_core.c
> @@ -104,10 +104,11 @@ static void watchdog_check_min_max_timeout(struct watchdog_device *wdd)
>    * Initialize the timeout field of the watchdog_device struct with either the
>    * timeout module parameter (if it is valid value) or the timeout-sec property
>    * (only if it is a valid value and the timeout_parm is out of bounds).
> - * If none of them are valid then we keep the old value (which should normally
> - * be the default timeout value).
> + * If none of them are valid or all of them are zero ("don't care") then we keep
> + * the old value (which should normally be the default timeout value).
>    *
> - * A zero is returned on success and -EINVAL for failure.
> + * A zero is returned on success or -EINVAL if all provided values are out of
> + * bounds.
>    */
>   int watchdog_init_timeout(struct watchdog_device *wdd,
>   				unsigned int timeout_parm, struct device *dev)
> @@ -117,22 +118,24 @@ int watchdog_init_timeout(struct watchdog_device *wdd,
>   
>   	watchdog_check_min_max_timeout(wdd);
>   
> -	/* try to get the timeout module parameter first */
> -	if (!watchdog_timeout_invalid(wdd, timeout_parm) && timeout_parm) {
> -		wdd->timeout = timeout_parm;
> -		return ret;
> -	}
> -	if (timeout_parm)
> +	/* check the driver supplied value (likely a module parameter) first */
> +	if (timeout_parm) {
> +		if (!watchdog_timeout_invalid(wdd, timeout_parm)) {
> +			wdd->timeout = timeout_parm;
> +			return 0;
> +		}
>   		ret = -EINVAL;
> +	}
>   
>   	/* try to get the timeout_sec property */
> -	if (dev == NULL || dev->of_node == NULL)
> -		return ret;
> -	of_property_read_u32(dev->of_node, "timeout-sec", &t);
> -	if (!watchdog_timeout_invalid(wdd, t) && t)
> -		wdd->timeout = t;
> -	else
> +	if (dev && dev->of_node &&
> +	    of_property_read_u32(dev->of_node, "timeout-sec", &t) == 0 && t) {
> +		if (!watchdog_timeout_invalid(wdd, t)) {
> +			wdd->timeout = t;
> +			return 0;
> +		}
>   		ret = -EINVAL;
> +	}
>   
>   	return ret;
>   }
> 


  reply index

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-14 10:26 [PATCH 00/16] watchdog: refactor init_timeout and update users Wolfram Sang
2019-04-14 10:26 ` [PATCH 01/16] watchdog: refactor watchdog_init_timeout Wolfram Sang
2019-04-14 13:25   ` Guenter Roeck [this message]
2019-04-14 13:42     ` Wolfram Sang
2019-04-14 14:03       ` Guenter Roeck
2019-04-15  8:21   ` Sergei Shtylyov
2019-04-14 10:26 ` [PATCH 02/16] watchdog: add error messages when initializing timeout fails Wolfram Sang
2019-04-14 10:26 ` [PATCH 03/16] watchdog: cadence_wdt: drop warning after calling watchdog_init_timeout Wolfram Sang
2019-04-14 10:26 ` [PATCH 04/16] watchdog: cadence_wdt: still probe if user supplied timeout is invalid Wolfram Sang
2019-04-14 10:26 ` [PATCH 05/16] watchdog: ebc-c384_wdt: drop warning after calling watchdog_init_timeout Wolfram Sang
2019-04-14 10:26 ` [PATCH 06/16] watchdog: hpwdt: " Wolfram Sang
2019-04-14 10:26 ` [PATCH 07/16] watchdog: i6300esb: " Wolfram Sang
2019-04-14 10:26 ` [PATCH 08/16] watchdog: imx_sc_wdt: " Wolfram Sang
2019-04-14 10:26 ` [PATCH 09/16] watchdog: ni903x_wdt: " Wolfram Sang
2019-04-14 10:26 ` [PATCH 10/16] watchdog: nic7018_wdt: " Wolfram Sang
2019-04-14 10:26 ` [PATCH 11/16] watchdog: renesas_wdt: " Wolfram Sang
2019-04-14 10:26 ` [PATCH 12/16] watchdog: sp5100_tco: " Wolfram Sang
2019-04-14 10:26 ` [PATCH 13/16] watchdog: st_lpc_wdt: " Wolfram Sang
2019-04-14 10:26 ` [PATCH 14/16] watchdog: stm32_iwdg: " Wolfram Sang
2019-04-14 10:26 ` [PATCH 15/16] watchdog: xen_wdt: " Wolfram Sang
2019-04-14 10:26 ` [PATCH 16/16] watchdog: ziirave_wdt: " Wolfram Sang
2019-04-14 10:30 ` [PATCH 00/16] watchdog: refactor init_timeout and update users Wolfram Sang
2019-04-14 15:41 ` Guenter Roeck

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