From: Badola Nikhil <nikhil.badola@freescale.com>
To: Greg KH <gregkh@linuxfoundation.org>
CC: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "stern@rowland.harvard.edu" <stern@rowland.harvard.edu>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        Joe Perches <joe@perches.com>
Subject: RE: [PATCH 3/5] drivers:usb:fsl: Replace macros with enumerated type
Thread-Topic: [PATCH 3/5] drivers:usb:fsl: Replace macros with enumerated type
Thread-Index: AQHQl6YjOcmv9iJfwkW31DPNv7r3cZ2VrOSAgAAFygCAAOgUgIAAhnsggASkdjA=
Date: Thu, 4 Jun 2015 04:05:19 +0000
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> -----Original Message-----
> From: Badola Nikhil-B46172
> Sent: Monday, June 01, 2015 11:50 AM
> To: 'Greg KH'
> Cc: linux-kernel@vger.kernel.org; stern@rowland.harvard.edu; linux-
> usb@vger.kernel.org; Joe Perches
> Subject: RE: [PATCH 3/5] drivers:usb:fsl: Replace macros with enumerated
> type
> 
> > -----Original Message-----
> > From: Greg KH [mailto:gregkh@linuxfoundation.org]
> > Sent: Monday, June 01, 2015 2:32 AM
> > To: Joe Perches
> > Cc: Badola Nikhil-B46172; linux-kernel@vger.kernel.org;
> > stern@rowland.harvard.edu; linux-usb@vger.kernel.org
> > Subject: Re: [PATCH 3/5] drivers:usb:fsl: Replace macros with
> > enumerated type
> >
> > On Sun, May 31, 2015 at 12:11:18AM -0700, Joe Perches wrote:
> > > On Sun, 2015-05-31 at 15:50 +0900, Greg KH wrote:
> > > > On Tue, May 26, 2015 at 05:15:48PM +0530, Nikhil Badola wrote:
> > > > > Replace macros with enumerated type to represent usb ip
> > > > > controller version
> > > > >
> > > > > Signed-off-by: Nikhil Badola <nikhil.badola@freescale.com>
> > > > > ---
> > > > >  include/linux/fsl_devices.h | 13 ++++++++-----
> > > > >  1 file changed, 8 insertions(+), 5 deletions(-)
> > > > >
> > > > > diff --git a/include/linux/fsl_devices.h
> > > > > b/include/linux/fsl_devices.h
> > > []
> > > > > +enum fsl_usb2_controller_ver {
> > > > > +	FSL_USB_VER_OLD = 0,
> > > > > +	FSL_USB_VER_1_6,
> > > > > +	FSL_USB_VER_2_2,
> > > > > +	FSL_USB_VER_2_4,
> > > > > +	FSL_USB_VER_2_5,
> > > > > +};
> > > >
> > > > Don't you want to change that function that uses these to return
> > > > the enumerated type and not an integer?
> > > >
> 
> I missed that. I will do this change in the next patch version.
> 
> > > > Also, I don't think the C standard forces the non-numbered values
> > > > to be sequential,
> > >
> > > Then you haven't read the standard in awhile and you likely forgot.
> > >
> > > 6.7.2.2
> > > If the first enumerator has no =, the value of its enumeration
> > > constant is 0. Each subsequent enumerator with no = defines its
> > > enumeration constant as the value of the constant expression
> > > obtained by adding 1 to the value of the previous enumeration constant.
> >
> > Ah, you are right, I did forget.
> >
> > But if you are wanting to use the "numerical" value of these, please
> > be explicit when defining it.  Otherwise someone might think it was
> > just fine to put a new entry in the middle of the list.
> >
> We are only relying on the controller version to be less (or greater) than a
> specific version and we are not using exact "numerical" value. Refer
> drivers/usb/host/ehci-fsl.c .
> In addition, the enum entries defined are specific to controller version i.e 1.6,
> 2.2, 2.4 and 2.5.
> In future if anyone needs to add an entry; supposedly 2.6; he would do so as
> per the sequence maintained.

Is it fine by above explanation to keep value for only first entry as done in this patch?

Should I move ahead with next patch version changing the return type to enum for
function which is returning usb controller version?
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