board/sunxi/board.c tries to set ldo3 to 2.8v however drivers/power/axp209.c
contains an incorrect limit on ldo3 of 2.275v

The origin of the incorrect limit seems likely due to some inconsistencies
in the axp209 datasheet. ldo3 is described with different limits in
different sections. register 0x29 uses 7 bits for voltage configuration
while the 2.275v limit would apply if only 6 bits were used.
Probably this is a cut&paste error from register 0x23

The linux kernel driver has the correct limit and operation up to the 2.8v
required by my board has been physically verified with a multimeter.

Signed-off-by: Iain Paton <ipaton0@gmail.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Some of the AXP PMICs support VBUS detection, i.e. checking whether
VBUS power input is available and usable (supplied by an external
source). A few boards use this instead of a separate GPIO to detect
VBUS on USB OTG.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

It turns out that the device_mode_data is rsb specific, rather then slave
specific, so integrate the rsb_set_device_mode() call into rsb_init().

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>

Rather than assuming that the chip offset length is 1, allow it to be
provided. This allows chips that don't use the default offset length to
be used (at present they are only supported by the command line 'i2c'
command which sets the offset length explicitly).

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Heiko Schocher <hs@denx.de>

Add a dm_ prefix to driver model I2C functions so that we can keep the old
ones around.

This is a little unfortunate, but on reflection it is too difficult to
change the API. We can undo this rename when most boards and drivers are
converted to use driver model for I2C.

Signed-off-by: Simon Glass <sjg@chromium.org>

And also add Kconfig option for selecting ELDO3 voltage. The reason
for having this option is that the Android kernel sets ELDO3 to
1.2V when powering up LCD in the case if 'lcd_if' configuration
variable is set to 6 (LCD_IF_EXT_DSI) in the FEX file. Most likely
to supply power for a SSD2828 chip.

However on the MSI Primo81 tablet, which is using this particular
'lcd_if = 6' setup for LCD, setting the ELDO3 voltage appears to
be unnecessary and it works regardless. Having no schematics of
this tablet, I can only guess that 1.2V is supplied to SSD2828
in some other way.

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

We do not use the axp209 interrupt, and at least in my mini-x (which does not
have a power button) the pwr-button pin and the irq pin are soldered together,
so if the axp209 keeps it irq asserted too long it will see a 10s pwr-button
press and hard power off the board, disabling the irqs fixes this.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>

The axp221 / axp223's N_VBUSEN pin can be configured as an output rather
then an input, add axp_drivebus_enable() and _disable() functions to set
the pin in output mode and control it.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>