[PATCH 0/15] Add support for OLPC XO 1.75 Embedded Controller

Hi.

This patchset adds support for the Embedded Controller on an OLPC XO
1.75 machine. OLPC XO 1.75 is a MMP2 based ARM laptop. It plugs into
the existing OLPC platform infrastructure, currently used by the x86
based models.

The EC operates in SPI master mode, meaning the SOC is the SPI slave. It
uses extra handshake signal to signal readiness of SOC to accept data
from EC and to initiate a transaction if SOC wishes to submit data.

The SPI slave support for MMP2 was submitted separately:
https://lore.kernel.org/lkml/20181010170936.316862-1-lkundrak at v3.sk/T/#t

THe "power: supply: olpc_battery: correct the temperature" patch was
already sent out separately, but I'm including it because the last
commit of the set depends on it.

Tested to work on an OLPC XO 1.75 and also tested not to break x86
support with an OLPC XO 1 machine. I don't have a XO 1.5, but it's
unlikely this breaks it when XO 1 works.

Thanks in advance for reviews and feedback of any kind.

Lubo