Re: [PATCH] usb: usb251xb: Remove unnecessary comparison of unsigned integer with >= 0

[Richard Leitner]

Hi Marco, Hi Gustavo,
thanks for the fix, please feel free to add

	Reviewed-by: Richard Leitner <richard.leitner@xxxxxxxxxxx>

On 18/03/2019 16:34, Marco Felsch wrote:
> Hi Silva,
>
> On 19-03-18 09:50, Gustavo A. R. Silva wrote:
> > There is no need to compare *port* with >= 0 because such comparison
> > of an unsigned value is always true.
>
> Absolutly.. It seems that it was an copy'n'paste failure. Thanks for
> fixing that.

A small note on further improvement from my side:

According the datasheet, when you set swap-dx-lanes to 0 (-> setting 
port to 0 -> setting bit 0 of PRTSP) "   the upstream port DP/DM is 
swapped".

IMHO this is not straight-forward, so maybe we want to additionally

	a) mention it somewhere in the documentation
	b) check on port >= 1
	c) something else?

Any opinions on that from your side? ... I'd prefer "a"...

regards;Richard.L

> Regards,
> Marco
>
> > Fix this by removing such comparison.
> >
> > Addresses-Coverity-ID: 1443949 ("Unsigned compared against 0")
> > Fixes: 02a50b875046 ("usb: usb251xb: add usb data lane port swap feature")
> > Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
> > ---
> >   drivers/usb/misc/usb251xb.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/misc/usb251xb.c b/drivers/usb/misc/usb251xb.c
> > index 4d72b7d1d383..2c8e2cad7e10 100644
> > --- a/drivers/usb/misc/usb251xb.c
> > +++ b/drivers/usb/misc/usb251xb.c
> > @@ -547,7 +547,7 @@ static int usb251xb_get_ofdata(struct usb251xb *hub,
> >   	 */
> >   	hub->port_swap = USB251XB_DEF_PORT_SWAP;
> >   	of_property_for_each_u32(np, "swap-dx-lanes", prop, p, port) {
> > -		if ((port >= 0) && (port <= data->port_cnt))
> > +		if (port <= data->port_cnt)
> >   			hub->port_swap |= BIT(port);
> >   	}
> >   
> > --
> > 2.21.0