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From:   Vitor Soares <Vitor.Soares@synopsys.com>
To:     Greg KH <gregkh@linuxfoundation.org>
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Subject: RE: [RFC 5/5] i3c: add i3cdev module to expose i3c dev in /dev
Thread-Topic: [RFC 5/5] i3c: add i3cdev module to expose i3c dev in /dev
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Date:   Thu, 12 Dec 2019 17:25:28 +0000
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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,
> >=20
> > From: Greg KH <gregkh@linuxfoundation.org>
> > Date: Thu, Dec 12, 2019 at 14:44:59
> >=20
> > > 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");
> > >=20
> > > Please remove debugging information, kernel code should be quiet unle=
ss
> > > something goes wrong.
> >=20
> > I will remove it.
> >=20
> > >=20
> > > > +	/* Dynamically request unused major number */
> > > > +	res =3D alloc_chrdev_region(&i3cdev_number, 0, N_I3C_MINORS, "i3c=
");
> > >=20
> > > Do you really need a whole major, or will a few minors work?
> > >=20
> > > thanks,
> > >=20
> > > greg k-h
> >=20
> > I'm reserving one per device. What do you suggest?
>=20
> How many devices do you have in a system?

According to MIPI I3C spec, the maximum number of devices on a bus will=20
depend on trace length, bus load, and clock requirements.

Frankly, I don't know what is the best compromise because it depends from=20
system to system and the end-use of it. In my case, I started developing=20
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