button: Remove <common.h> and add needed includes

Remove <common.h> from this driver directory and when needed
add missing include files directly.

Signed-off-by: Tom Rini <trini@konsulko.com>

button: adc: set state to pressed when the voltage is closest to nominal

In the Linux implementation of adc-keys
(drivers/input/keyboard/adc-keys.c), `press-threshold-microvolt` is not
really interpreted as a threshold, but rather as the "nominal voltage"
of the button. When the voltage read from the ADC is closest to a
button's `press-threshold-microvolt`, the button is considered pressed.

This patch reconciles the behavior of button-adc with Linux's adc-keys
such that device trees can be synchronized with minimal modifications.

Signed-off-by: Peter Cai <peter@typeblog.net>

button: adc: fix treshold typo

Fix the treshold typo in code by threshold.

Fixes: c0165c85c3 ("button: add a simple Analog to Digital Converter device based button driver")
Suggested-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>

button: add a simple Analog to Digital Converter device based button driver

Add a simple Analog to Digital Converter device based button driver. This
driver binds to the 'adc-keys' device tree node.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

button: adc: set state to pressed when the voltage is closest to nominal

In the Linux implementation of adc-keys
(drivers/input/keyboard/adc-keys.c), `press-threshold-microvolt` is not
really interpreted as a threshold, but rather as the "nominal voltage"
of the button. When the voltage read from the ADC is closest to a
button's `press-threshold-microvolt`, the button is considered pressed.

This patch reconciles the behavior of button-adc with Linux's adc-keys
such that device trees can be synchronized with minimal modifications.

Signed-off-by: Peter Cai <peter@typeblog.net>

button: adc: fix treshold typo

Fix the treshold typo in code by threshold.

Fixes: c0165c85c3 ("button: add a simple Analog to Digital Converter device based button driver")
Suggested-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>

button: add a simple Analog to Digital Converter device based button driver

Add a simple Analog to Digital Converter device based button driver. This
driver binds to the 'adc-keys' device tree node.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

button: adc: fix treshold typo

Fix the treshold typo in code by threshold.

Fixes: c0165c85c3 ("button: add a simple Analog to Digital Converter device based button driver")
Suggested-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>

button: add a simple Analog to Digital Converter device based button driver

Add a simple Analog to Digital Converter device based button driver. This
driver binds to the 'adc-keys' device tree node.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

button: add a simple Analog to Digital Converter device based button driver

Add a simple Analog to Digital Converter device based button driver. This
driver binds to the 'adc-keys' device tree node.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>