Re: [PATCH v3 07/11] watchdog: xilinx: Use of_property_read_u32

[Alejandro Cabrera <acabrera@udio.cujae.edu.cu>]

On 22/2/2014 10:46 AM, Wim Van Sebroeck wrote:
> Hi All,
>
>> Hi Michal,
>>
>> On Wed, Feb 12, 2014 at 02:41:21PM +0100, Michal Simek wrote:
>>> Use of_property_read_u32 functions to clean probe function.
>>>
>>> Signed-off-by: Michal Simek<michal.simek@xilinx.com>
>>> Reviewed-by: Guenter Roeck<linux@roeck-us.net>
>>> ---
>>>
>>> Changes in v3:
>>> - Remove one if checking and use variable directly
>>>
>> Looks good.
>>
>> Another comment/remark.
>>
>>> -	pfreq = (u32 *)of_get_property(pdev->dev.of_node,
>>> -					"clock-frequency", NULL);
>>> -
>>> -	if (pfreq == NULL) {
>>> +	rc = of_property_read_u32(pdev->dev.of_node, "clock-frequency",&pfreq);
>>> +	if (rc) {
>>>   		dev_warn(&pdev->dev,
>>>   			 "The watchdog clock frequency cannot be obtained\n");
>>>   		no_timeout = true;
>>>   	}
>>>
>>> -	tmptr = (u32 *)of_get_property(pdev->dev.of_node,
>>> -					"xlnx,wdt-interval", NULL);
>>> -	if (tmptr == NULL) {
>>> +	rc = of_property_read_u32(pdev->dev.of_node, "xlnx,wdt-interval",
>>> +				&xdev->wdt_interval);
>>> +	if (rc) {
>>>   		dev_warn(&pdev->dev,
>>>   			 "Parameter \"xlnx,wdt-interval\" not found\n");
>>>   		no_timeout = true;
>>> -	} else {
>>> -		xdev->wdt_interval = *tmptr;
>>>   	}
>>>
>>> -	tmptr = (u32 *)of_get_property(pdev->dev.of_node,
>>> -					"xlnx,wdt-enable-once", NULL);
>>> -	if (tmptr == NULL) {
>>> +	rc = of_property_read_u32(pdev->dev.of_node, "xlnx,wdt-enable-once",
>>> +				&enable_once);
>>> +	if (rc)
>>>   		dev_warn(&pdev->dev,
>>>   			 "Parameter \"xlnx,wdt-enable-once\" not found\n");
>>> -		watchdog_set_nowayout(xilinx_wdt_wdd, true);
>>> -	}
>> All the above properties are optional. Is a warning really
>> warranted in this case ? I usually associate a warning with
>> something that is wrong, which is not the case here.
>>
>> I would encourage you to drop those warnings, but that should be
>> a separate patch.
> I agree with Guenter: these are not really warnings. Seperate patch is thus welcome.
Hi

I support Michal intention, I think it is a warning because device tree 
blob must have the "xlnx,wdt-enable-once" property specified in order to 
allow the system to be sure of the real value of this property. In 
addition to, this warning can be helpful to detect a wrong device tree 
specification.

Best regards
Alejandro



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