[RFC PATCH 2/2] usb: Example for how to use device node at usb device driver

Peter Chen hzpeterchen at gmail.com
Sat Jan 9 00:57:56 PST 2016


On Fri, Jan 08, 2016 at 09:26:10AM +0100, Arnd Bergmann wrote:
> On Friday 08 January 2016 13:44:24 Peter Chen wrote:
> > +	  u32 duration_us = 0;
> 
> > +       of_property_read_u32(hdev->dev.of_node, "delay-duration-us", &duration_us);
> > +       if (duration_us > 0) {
> > +               usleep_range(duration_us, duration_us + 10);
> > +               dev_info(&hdev->dev, "The delay is %d us\n", duration_us);
> > +       }
> > +
> 
> I think especially for an example, it would be better to use error checking and
> not initialize the variable:
> 
> 	u32 duration_us;
> 	int ret;
> ...
> 	ret = of_property_read_u32(hdev->dev.of_node, "delay-duration-us", &duration_us);
> 	if (!ret && duration_us > 0) {
> 		...
> 	}
> 
> The effect is the same as the other one.
> 

Thanks, will change.

-- 

Best Regards,
Peter Chen



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