Add a proper module alias so the driver can be autoloaded when the
parent axp20x mfd driver registers its cells.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Carlo Caione <carlo@caione.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Currently we are reporting the button state as inverted on all boards with
an axp209 pmic, tested on a ba10-tvbox, bananapi, bananapro, cubietruck and
utoo-p66 tablet.

The axp209 datasheet clearly states that the power button must be connected
between the PWRON key and ground. Which means that on a press we will get
a falling edge (dbf) irq not a rising one, and likewise on release we will
get a rising edge (dbr) irq, not a falling one.

This commit swaps the check for the 2 irqs fixing the inverted reporting of
the power button state.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Carlo Caione <carlo@caione.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Instead of registering device attributes individually let's use attribute
groups and also devm_* infrastructure to ease cleanup.

Tested-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

This change adds support for the Power Enable Key found on MFD AXP202
and AXP209. Besides the basic support for the button, the driver adds
two entries in sysfs to configure the time delay for power on/off.

Signed-off-by: Carlo Caione <carlo@caione.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
[wens@csie.org: made axp20x_pek_remove() static; removed driver owner
 field; fixed path for sysfs entries]
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>