Re: [PATCH linux v1 0/4] Seven segment display support

From: Thomas Petazzoni
Date: Wed Dec 14 2016 - 07:45:52 EST


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:

And the feedback from Greg KH was: we don't need a driver for that, do
it from userspace. See:

So: good luck :-)

Best regards,

Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering