Re: [PATCH v3 2/5] mfd: syscon: add a DT property to set value width

Guenter Roeck
2015-11-18T15:11:05Z

On 11/18/2015 12:21 AM, Lee Jones wrote:
[ ... ]
>>> Or, for more clarity:
>>>
>>> of_property_read_u32(np, "bus-width", &bus_width);
>>> if (bus_width)
>>>
>>> If you choose this version (which I think is my preferred method, don't
>>> forget to initialise 'bus_width' to zero.
>>>
>> Ignoring an error and depending on bus_width==0 to determine if the property
>> was provided seems odd, especially since it would "hide" if the bus-width
>> property is set to 0. In the original code, this would be detected as error.
>
> I'm not sure what you mean. If bus_width==0, then a problem has
> occurred and we will not use the value. If bus_width!=0 then we can
> assume that it's been set and (as the comment describes) the value
> will be checked for errors in regmap_init_mmio().
>

Your proposed code does not distinguish a missing property from "bus-width = <0>;".
It will silently ignore this case.

Guenter