[PATCH 3.9] Driver for 7-segment displays connected over GPIOs

Linus Walleij linus.walleij at linaro.org
Mon Jan 7 18:05:15 EST 2013

On Mon, Jan 7, 2013 at 5:42 PM, Thomas Petazzoni
<thomas.petazzoni at free-electrons.com> wrote:

> This patch series implements a simple driver for 7-segment displays
> connected over GPIOs through a BCD encoder. The userspace interface of
> the driver is very simple: just a "value" file in the sysfs directory
> of the device, which can be written to (changes the value shown on the
> 7-segment display) and read (gives the current value).

The ARM Integrator AP and CP base boards I have here have
7-segment displays as well. But it's not on GPIO but dedicated
registers, so I could implement these as, e.g. LEDs.

But with this framework I'd just make a driver that pokes directly
into the registers.

However as Russell points out, this needs to be thought through.
I have a period on my display between the two characters, so
how do we model that period?

Linus Walleij

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