From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: [PATCH linux v1 0/4] Seven segment display support Date: Wed, 14 Dec 2016 04:56:41 -0800 Message-ID: <20161214125641.GA5379@kroah.com> References: <1481702104-8617-1-git-send-email-jaghu@google.com> <20161214134530.2bd54a4e@free-electrons.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20161214134530.2bd54a4e@free-electrons.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Thomas Petazzoni Cc: mark.rutland@arm.com, Jaghathiswari Rankappagounder Natarajan , arnd@arndb.de, devicetree@vger.kernel.org, openbmc@lists.ozlabs.org, linux@armlinux.org.uk, linux-kernel@vger.kernel.org, robh+dt@kernel.org, joel@jms.id.au, linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org On Wed, Dec 14, 2016 at 01:45:30PM +0100, Thomas Petazzoni wrote: > Hello, > > On Tue, 13 Dec 2016 23:55:00 -0800, Jaghathiswari Rankappagounder > Natarajan wrote: > > > Documentation for the binding which provides an interface for adding clock, > > data and clear signal GPIO lines to control seven segment display. > > > > The platform device driver provides an API for displaying on two 7-segment > > displays, and implements the required bit-banging. The hardware assumed is > > 74HC164 wired to two 7-segment displays. > > > > The character device driver implements the user-space API for letting a user > > write to two 7-segment displays including any conversion methods necessary > > to map the user input to two 7-segment displays. > > > > Adding clock, data and clear signal GPIO lines in the devicetree to control > > seven segment display on zaius platform. > > > > The platform driver matches on the device tree node; the platform driver also > > initializes the character device. > > > > Tested that the seven segment display works properly by writing to the > > character device file on a EVB AST2500 board which also has 74HC164 wired > > to two 7-segment displays. > > FWIW, I proposed a driver for seven segment displays back in 2013: > > http://lists.infradead.org/pipermail/linux-arm-kernel/2013-January/139986.html > > And the feedback from Greg KH was: we don't need a driver for that, do > it from userspace. See: > > http://lists.infradead.org/pipermail/linux-arm-kernel/2013-January/139992.html > > So: good luck :-) Did anyone ever write a library for this type of thing? Again, I don't want to see one-off drivers for random devices like this that should be able to all be controlled from userspace in a common manner. Much like we did for fingerprint readers a long long time ago... thanks, greg k-h