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Date: Mon, 16 Mar 2015 09:55:01 +0100
From: Johan Hovold <johan@kernel.org>
To: Peter Hung <hpeter@gmail.com>
Cc: Johan Hovold <johan@kernel.org>, gregkh@linuxfoundation.org,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        tom_tsai@fintek.com.tw, peter_hong@fintek.com.tw,
        Peter Hung <hpeter+linux_kernel@gmail.com>
Subject: Re: [PATCH V8 04/10] USB: f81232: implement read IIR/MSR with
 endpoint
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On Mon, Mar 16, 2015 at 11:08:29AM +0800, Peter Hung wrote:
> Hello,
> 
> Johan Hovold 於 2015/3/14 下午 08:02 寫道:
> > On Thu, Feb 26, 2015 at 06:02:10PM +0800, Peter Hung wrote:
> >> +	if (status != sizeof(*val)) {
> >> +		dev_err(&port->dev, "%s failed status: %d\n", __func__, status);
> >> +
> >> +		if (status == 0)
> >> +			status = -EIO;
> >> +		else
> >> +			status = usb_translate_errors(status);
> >
> > Could you rewrite this as
> >
> > 	if (status < 0)
> > 		status = usb_translate_errors(status);
> > 	else
> > 		status = 0;
> 
> In my definition the return value of set/getregister(), 0 is success, 
> negative values are errors. The function usb_control_msg() return value 
> is success transmited/received byte. It's maybe return 0. I want to 
> treat 0 with error(-EIO). But if pass 0 to usb_translate_errors(), It 
> will return 0 back. So I need especially handle with status == 0.

I meant to write

	if (status < 0)
 		status = usb_translate_errors(status);
	else
		status = -EIO;

which I think is more readable.

Sorry for the confusion.

Johan