Re: [PATCH V3 02/12] misc: xilinx-sdfec: add core driver

From: Greg KH
Date: Sat May 04 2019 - 03:58:44 EST


On Fri, May 03, 2019 at 04:41:21PM +0000, Dragan Cvetic wrote:
> Hi Greg,
>
> Please find my inline comments below,
>
> Regards
> Dragan
>
> > -----Original Message-----
> > From: Greg KH [mailto:gregkh@xxxxxxxxxxxxxxxxxxx]
> > Sent: Thursday 2 May 2019 18:20
> > To: Dragan Cvetic <draganc@xxxxxxxxxx>
> > Cc: arnd@xxxxxxxx; Michal Simek <michals@xxxxxxxxxx>; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; robh+dt@xxxxxxxxxx;
> > mark.rutland@xxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Derek Kiernan <dkiernan@xxxxxxxxxx>
> > Subject: Re: [PATCH V3 02/12] misc: xilinx-sdfec: add core driver
> >
> > On Sat, Apr 27, 2019 at 11:04:56PM +0100, Dragan Cvetic wrote:
> > > +#define DRIVER_NAME "xilinx_sdfec"
> > > +#define DRIVER_VERSION "0.3"
> >
> > Version means nothing with the driver in the kernel tree, please remove
> > it.
>
> Will be removed. Thank you.
>
> >
> > > +#define DRIVER_MAX_DEV BIT(MINORBITS)
> >
> > Why this number? Why limit yourself to any number?
> >
>
> There can be max 8 devices for this driver. I'll change to 8.
>
> > > +
> > > +static struct class *xsdfec_class;
> >
> > Do you really need your own class?
>
> When writing a character device driver, my goal is to create and register an instance
> of that structure associated with a struct file_operations, exposing a set of operations
> to the user-space. One of the steps to make this goal is Create a class for a devices,
> visible in /sys/class/.

Why do you need a class? Again, why not just use the misc_device api,
that seems much more relevant here and will make the code a lot simpler.

thanks,

greg k-h