From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Kroah-Hartman Subject: Re: [PATCH 3.9] Driver for 7-segment displays connected over GPIOs Date: Mon, 7 Jan 2013 10:36:42 -0800 Message-ID: <20130107183642.GA26612@kroah.com> References: <1357576928-29133-1-git-send-email-thomas.petazzoni@free-electrons.com> <20130107164845.GA2911@kroah.com> <20130107180708.2ffc1540@skate> <20130107172340.GA32401@kroah.com> <20130107185357.6da83d60@skate> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20130107185357.6da83d60@skate> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: "devicetree-discuss" To: Thomas Petazzoni Cc: Lior Amsalem , Andrew Lunn , Jason Cooper , devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org On Mon, Jan 07, 2013 at 06:53:57PM +0100, Thomas Petazzoni wrote: > Dear Greg Kroah-Hartman, > > On Mon, 7 Jan 2013 09:23:40 -0800, Greg Kroah-Hartman wrote: > > > > Not having a kernel driver means that gazillions of applications > > > re-invent the same piece of code over and over again, have to hardcode > > > the GPIO numbers for a given piece of hardware, while the kernel > > > abstract all of this very nicely. > > > > That sounds like a wonderful use of a userspace library to do this > > properly. Much like libusb does, right? > > > > I still think as this can be done in userspace, it probably should be. > > So that's why we have drivers/usb/misc/usbsevseg.c in the kernel, which > uses sysfs files to output text or numbers on a 7-segment display, > while it could all be done using libusb from userspace? Seems like back > in 2008 you Signed-off-by on the patch adding this driver :-) I don't remember what I committed a month ago, let alone 4 years ago. So trying to use that as an excuse as to why I should take your patch isn't a really good idea, sorry :) As Russell points out, if you want this in the kernel, it needs to have a good userspace api, and that needs a lot more work than just a single sysfs file. thanks, greg k-h