Re: [PATCH linux v1 0/4] Seven segment display support
From: Thomas Petazzoni <hidden>
Date: 2016-12-14 12:45:47
Also in:
linux-arm-kernel, lkml, openbmc
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