Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH v3 2/5] mfd: syscon: add a DT property to set value width | Date | Sat, 21 Nov 2015 00:13:27 +0100 |
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On Tuesday 17 November 2015 09:26:49 Guenter Roeck wrote: > > > > This syntax is confusing, as we normally associate it with an error > > condition. Instead, I'd use: > > > > if (of_property_read_u32(np, "bus-width", &bus_width) == 0) > > Or maybe better > > if (!of_property_read_u32(np, "bus-width", &bus_width))
I would also prefer the latter, but it doesn't matter much either way.
> > > > 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.
Right.
Another option would be
ret = of_property_read_u32(np, "bus-width", &bus_width); /* no bus width provided, default to 32-bit */ if (ret) bus_width = 32;
syscon_config.val_bits = bus_width; syscon_config.reg_stride = syscon_config.val_bits / 8;
which has the same effect but seems a little clearer to me.
Arnd
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