lkml.org 
[lkml]   [2011]   [May]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2] arch/tile: add hypervisor-based character driver for SPI flash ROM
On 5/29/2011 7:45 AM, Greg KH wrote:
> On Sat, May 28, 2011 at 08:32:07PM -0400, Chris Metcalf wrote:
>>> As you are only using 1 minor device, why not just use a misc device
>>> instead? It's simpler, and you get the sysfs code for free, which you
>>> forgot to do, so your device node will never show up in userspace :(
>> Interesting; this appears to be a bug. We use 4 minors (see "srom_devs =
>> 4" higher up). I'll fix this. We may have some other devices that would
>> benefit from being recast as misc devices, so I'll look at our set of
>> internal devices.
> This kind of implies that you didn't test this code, right? You might
> want to do that next time :)

No, this bug has been in the code since day one (I just double-checked our
SCM), and it has always worked fine. I'm looking into how this is possible
now, but trust me, we've tested this aspect of the driver the whole time. :-)

>> Is there a good example of a character device that has multiple minors and
>> also is registered with sysfs?
> Lots of them, look all over the kernel, and in LDD3 there's even an
> outdated example of one I think.

I didn't actually find many drivers that have both cdev_add with count>1,
and mention sysfs or kobj, but char/raw.c is one that looks pretty clean.
(I found only four others total: uio/uio.c, s390/char/vmlogrdr.c,
staging/comedi/comedi_fops.c, and staging/vme/devices/vme_user.c.)

--
Chris Metcalf, Tilera Corp.
http://www.tilera.com




\
 
 \ /
  Last update: 2011-05-29 14:21    [W:0.071 / U:0.156 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site