mfd: ntxec: Add version number for EC in Tolino Vision

The EC firmware has a different version number than anything
defined until now.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230127165828.3256170-1-andreas@kemnade.info

mfd: ntxec: Change return type of ntxec_reg8 from __be16 to u16

Register values in NTXEC are big-endian on the I2C bus, but the regmap
subsystem handles the conversion between CPU-endian and big-endian data
internally. ntxec_reg8 should thus return u16, not __be16.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20211218152553.744615-1-j.neuschaefer@gmx.net

mfd: ntxec: Support for EC in Tolino Shine 2 HD

Add the version of the EC in the Tolino Shine 2 HD
to the supported versions. It seems not to have an RTC
and does not ack data written to it.
The vendor kernel happily ignores write errors, using
I2C via userspace i2c-set also shows the error.
So add a quirk to ignore that error.

PWM can be successfully configured despite of that error.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

mfd: Add base driver for Netronix embedded controller

The Netronix embedded controller is a microcontroller found in some
e-book readers designed by the original design manufacturer Netronix,
Inc. It contains RTC, battery monitoring, system power management, and
PWM functionality.

This driver implements register access and version detection.

Third-party hardware documentation is available at:

https://github.com/neuschaefer/linux/wiki/Netronix-MSP430-embedded-controller

The EC supports interrupts, but the driver doesn't make use of them so
far.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>