From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Subject: Re: [PATCH linux v1 0/4] Seven segment display support Date: Wed, 14 Dec 2016 13:45:30 +0100 Message-ID: <20161214134530.2bd54a4e@free-electrons.com> References: <1481702104-8617-1-git-send-email-jaghu@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1481702104-8617-1-git-send-email-jaghu-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jaghathiswari Rankappagounder Natarajan Cc: openbmc-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org, arnd-r2nGTMty4D4@public.gmane.org, gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, joel-U3u1mxZcP9KHXe+LvDLADg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org 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 :-) Best regards, Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html