From: Vitor Soares <Vitor.Soares@synopsys.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Joao Pinto <Joao.Pinto@synopsys.com>,
"arnd@arndb.de" <arnd@arndb.de>,
"wsa@the-dreams.de" <wsa@the-dreams.de>,
"bbrezillon@kernel.org" <bbrezillon@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"broonie@kernel.org" <broonie@kernel.org>,
"linux-i3c@lists.infradead.org" <linux-i3c@lists.infradead.org>
Subject: RE: [RFC 5/5] i3c: add i3cdev module to expose i3c dev in /dev
Date: Thu, 12 Dec 2019 17:25:28 +0000 [thread overview]
Message-ID: <CH2PR12MB4216CB1D650A543A635CC67FAE550@CH2PR12MB4216.namprd12.prod.outlook.com> (raw)
In-Reply-To: <20191212160045.GA1672362@kroah.com>
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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next prev parent reply other threads:[~2019-12-12 17:25 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-10 15:37 [RFC 0/5] Introduce i3c device userspace interface Vitor Soares
2019-12-10 15:37 ` [RFC 1/5] i3c: master: export i3c_masterdev_type Vitor Soares
2019-12-10 15:37 ` [RFC 2/5] i3c: master: export i3c_bus_type symbol Vitor Soares
2019-12-10 15:37 ` [RFC 3/5] i3c: device: expose transfer strutures to uapi Vitor Soares
2019-12-12 14:42 ` Greg KH
2019-12-12 14:48 ` Vitor Soares
2019-12-10 15:37 ` [RFC 4/5] i3c: master: add i3c_for_each_dev helper Vitor Soares
2019-12-10 15:37 ` [RFC 5/5] i3c: add i3cdev module to expose i3c dev in /dev Vitor Soares
2019-12-10 17:51 ` Arnd Bergmann
2019-12-10 19:15 ` Vitor Soares
2019-12-10 19:37 ` Arnd Bergmann
2019-12-11 15:07 ` Vitor Soares
2019-12-11 15:33 ` Arnd Bergmann
2019-12-20 12:39 ` Vitor Soares
2019-12-12 14:44 ` Greg KH
2019-12-12 14:56 ` Vitor Soares
2019-12-12 16:00 ` Greg KH
2019-12-12 17:25 ` Vitor Soares [this message]
2019-12-12 17:32 ` Greg KH
2019-12-12 14:46 ` Greg KH
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