sunxi: axp221: Add ELDO[1-3] support

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>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index e68e16b..f8f0239 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -63,3 +63,13 @@ config AXP221_ALDO3_VOLT
 	Set the voltage (mV) to program the axp221 aldo3 at, set to 0 to
 	disable aldo3. This is typically connected to VCC-PLL and AVCC and
 	must be set to 3V.
+
+config AXP221_ELDO3_VOLT
+	int "axp221 eldo3 voltage"
+	depends on AXP221_POWER
+	default 0
+	---help---
+	Set the voltage (mV) to program the axp221 eldo3 at, set to 0 to
+	disable eldo3. On some A31(s) tablets it might be used to supply
+	1.2V for the SSD2828 chip (converter of parallel LCD interface
+	into MIPI DSI).