[PATCH v1 04/12] input: matrix-keypad: push/pull, separate polarity
Stephen Warren
swarren at wwwdotorg.org
Sat Jun 22 07:34:01 EST 2013
On 06/21/2013 12:09 PM, Gerhard Sittig wrote:
> extend the device tree adjustable hardware configuration:
> - allow for differing polarity of the row and column GPIO pins
> - optionally fully drive column output pins instead of the former
> unconditional open collector emulation approach
> diff --git a/Documentation/devicetree/bindings/input/gpio-matrix-keypad.txt b/Documentation/devicetree/bindings/input/gpio-matrix-keypad.txt
> +- row-gpios-activelow: row GPIO pins are active low
> +- col-gpios-activelow: column GPIO pins are active low
> - gpio-activelow: row pins as well as column pins are active low
> + (provided for backward compatibility, and useful
> + for matrix layouts of identical polarity for
> + rows and columns)
Those should all come from the existing GPIO flags, and may even differ
for each GPIO.
> +- col-gpios-pushpull: fully drive the column selection pins in either
> + direction (high and low signals), the default
> + behaviour is to actively drive low signals and
> + be passive otherwise (emulates an open collector
> + output driver)
We don't actually have GPIO flags defined for pushpull-vs-open-collector
etc. Perhaps we should do so. Then, we wouldn't need to invent custom
properties to represent that in this binding.
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