Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Dragan Cvetic <draganc@xilinx.com>
To:     Greg KH <gregkh@linuxfoundation.org>
CC:     "arnd@arndb.de" <arnd@arndb.de>, Michal Simek <michals@xilinx.com>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "robh+dt@kernel.org" <robh+dt@kernel.org>,
        "mark.rutland@arm.com" <mark.rutland@arm.com>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Derek Kiernan <dkiernan@xilinx.com>
Subject: RE: [PATCH V3 02/12] misc: xilinx-sdfec: add core driver
Thread-Topic: [PATCH V3 02/12] misc: xilinx-sdfec: add core driver
Thread-Index: AQHU/UVOyBvhwX5Hf0mi9G9IHzQgRKZYHAiAgAGBAECAAQXIAIADZtRggAAL5YCAATcywA==
Date:   Tue, 7 May 2019 08:48:41 +0000
Message-ID: <BL0PR02MB568169E26DCD12498EBDFC3ACB310@BL0PR02MB5681.namprd02.prod.outlook.com>
References: <1556402706-176271-1-git-send-email-dragan.cvetic@xilinx.com>
 <1556402706-176271-3-git-send-email-dragan.cvetic@xilinx.com>
 <20190502172007.GA1874@kroah.com>
 <BL0PR02MB5681B0F2BC0D74D8604D4289CB350@BL0PR02MB5681.namprd02.prod.outlook.com>
 <20190504075502.GA11133@kroah.com>
 <BL0PR02MB56814D6EACC16938A0575D16CB300@BL0PR02MB5681.namprd02.prod.outlook.com>
 <20190506123425.GA26360@kroah.com>
In-Reply-To: <20190506123425.GA26360@kroah.com>
Accept-Language: en-US
Content-Language: en-US
received-spf: None (protection.outlook.com: xilinx.com does not designate
 permitted sender hosts)
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: 7b1bdd10-0ce8-4b6a-226a-08d6d2c8ce24
X-MS-Exchange-CrossTenant-originalarrivaltime: 07 May 2019 08:48:41.1791
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 657af505-d5df-48d0-8300-c31994686c5c
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL0PR02MB4898
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


> -----Original Message-----
> From: Greg KH [mailto:gregkh@linuxfoundation.org]
> Sent: Monday 6 May 2019 13:34
> To: Dragan Cvetic <draganc@xilinx.com>
> Cc: arnd@arndb.de; Michal Simek <michals@xilinx.com>; linux-arm-kernel@li=
sts.infradead.org; robh+dt@kernel.org;
> mark.rutland@arm.com; devicetree@vger.kernel.org; linux-kernel@vger.kerne=
l.org; Derek Kiernan <dkiernan@xilinx.com>
> Subject: Re: [PATCH V3 02/12] misc: xilinx-sdfec: add core driver
>=20
> On Mon, May 06, 2019 at 12:23:56PM +0000, Dragan Cvetic wrote:
> >
> >
> > > -----Original Message-----
> > > From: Greg KH [mailto:gregkh@linuxfoundation.org]
> > > Sent: Saturday 4 May 2019 08:55
> > > To: Dragan Cvetic <draganc@xilinx.com>
> > > Cc: arnd@arndb.de; Michal Simek <michals@xilinx.com>; linux-arm-kerne=
l@lists.infradead.org; robh+dt@kernel.org;
> > > mark.rutland@arm.com; devicetree@vger.kernel.org; linux-kernel@vger.k=
ernel.org; Derek Kiernan <dkiernan@xilinx.com>
> > > Subject: Re: [PATCH V3 02/12] misc: xilinx-sdfec: add core driver
> > >
> > > 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@linuxfoundation.org]
> > > > > Sent: Thursday 2 May 2019 18:20
> > > > > To: Dragan Cvetic <draganc@xilinx.com>
> > > > > Cc: arnd@arndb.de; Michal Simek <michals@xilinx.com>; linux-arm-k=
ernel@lists.infradead.org; robh+dt@kernel.org;
> > > > > mark.rutland@arm.com; devicetree@vger.kernel.org; linux-kernel@vg=
er.kernel.org; Derek Kiernan <dkiernan@xilinx.com>
> > > > > 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 re=
gister an instance
> > > > of that structure associated with a struct file_operations, exposin=
g a set of operations
> > > > to the user-space. One of the steps to make this goal is Create a c=
lass 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 simpl=
er.
> > >
> >
> > The driver can have 8 devices in SoC plus more in Programming Logic.
> > It looked logical to group them under the same MAJOR, although they
> > are independent of each other.  Is this argument strong enough to use
> > class?
>=20
> Not really :)
>=20
> 8 devices is pretty small.  What tool will be trying to talk to all of
> these devices and how was it going to find out what devices were in the
> system?
>

These devices are Forward Error Correction encoder/decoder
and will be part of the RF communication chain. They will be included
in the system through DT. Also, described in DT.
  =20

> thanks,
>=20
> greg k-h