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SubjectRE: [RFC 5/5] i3c: add i3cdev module to expose i3c dev in /dev
Date
From: Greg KH <gregkh@linuxfoundation.org>
Date: Thu, Dec 12, 2019 at 16:00:45

> On Thu, Dec 12, 2019 at 02:56:56PM +0000, Vitor Soares wrote:
> > Hi Greg,
> >
> > From: Greg KH <gregkh@linuxfoundation.org>
> > Date: Thu, Dec 12, 2019 at 14:44:59
> >
> > > On Tue, Dec 10, 2019 at 04:37:33PM +0100, Vitor Soares wrote:
> > > > +static int __init i3cdev_init(void)
> > > > +{
> > > > + int res;
> > > > +
> > > > + pr_info("i3c /dev entries driver\n");
> > >
> > > Please remove debugging information, kernel code should be quiet unless
> > > something goes wrong.
> >
> > I will remove it.
> >
> > >
> > > > + /* Dynamically request unused major number */
> > > > + res = alloc_chrdev_region(&i3cdev_number, 0, N_I3C_MINORS, "i3c");
> > >
> > > Do you really need a whole major, or will a few minors work?
> > >
> > > thanks,
> > >
> > > greg k-h
> >
> > I'm reserving one per device. What do you suggest?
>
> How many devices do you have in a system?

According to MIPI I3C spec, the maximum number of devices on a bus will
depend on trace length, bus load, and clock requirements.

Frankly, I don't know what is the best compromise because it depends from
system to system and the end-use of it. In my case, I started developing
this to help me during the HC controller driver development.
Even If I choose a fixed major, I wouldn't know in which one i3c fits.

Best regards,
Vitor Soares


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