mfd: AXP20x: Add mfd driver for AXP20x PMIC

This patch introduces the preliminary support for PMICs X-Powers AXP202
and AXP209. The AXP209 and AXP202 are the PMUs (Power Management Unit)
used by A10, A13 and A20 SoCs and developed by X-Powers, a sister company
of Allwinner.

The core enables support for two subsystems:
- PEK (Power Enable Key)
- Regulators

Signed-off-by: Carlo Caione <carlo@caione.org>
dt-bindings: add vendor-prefix for X-Powers

Signed-off-by: Carlo Caione <carlo@caione.org>
mfd: AXP20x: Add bindings documentation

Bindings documentation for the AXP20x driver. In this file also
sub-nodes are documented.

Signed-off-by: Carlo Caione <carlo@caione.org>
input: misc: Add driver for AXP20x Power Enable Key

This patch add 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>
input: misc: Add ABI docs for AXP20x PEK

Add ABI entries for the PEK found on PMU X-Powers AXP202 and AXP209.

Signed-off-by: Carlo Caione <carlo@caione.org>
regulator: AXP20x: Add support for regulators subsystem

AXP202 and AXP209 come with two synchronous step-down DC-DCs and five
LDOs. This patch introduces basic support for those regulators.

Signed-off-by: Carlo Caione <carlo@caione.org>
ARM: sunxi: dt: Add x-powers-axp209.dtsi file

This dtsi describes the axp209 PMIC, and is to be included from inside
the i2c controller node to which the axp209 is connected.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Carlo Caione <carlo@caione.org>
ARM: sun7i/sun4i: dt: Add AXP209 support to various boards

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Carlo Caione <carlo@caione.org>
ARM: sunxi: Add AXP20x support in defconfig

Signed-off-by: Carlo Caione <carlo@caione.org>
ARM: sunxi: Add AXP20x support multi_v7_defconfig

Signed-off-by: Carlo Caione <carlo@caione.org>